import React, { useState, useEffect, useRef, useCallback } from 'react';
import { View, StatusBar, Alert, ActivityIndicator, Text, AppState, Platform, Keyboard } from 'react-native';
import { useCameraDevice, useCameraPermission, usePhotoOutput } from 'react-native-vision-camera';
import * as DocumentPicker from 'expo-document-picker';
import * as Sharing from 'expo-sharing';
import * as FileSystem from 'expo-file-system/legacy';
import * as MediaLibraryLegacy from 'expo-media-library/legacy';
import * as Haptics from 'expo-haptics';
import AsyncStorage from '@react-native-async-storage/async-storage';

import TopBar from './src/components/TopBar';
import Viewfinder, { type ViewfinderHandle } from './src/components/Viewfinder';
import AdjustmentPanel from './src/components/AdjustmentPanel';
import CameraControls from './src/components/CameraControls';
import ToolRail, { TabId } from './src/components/ToolRail';
import SettingsModal from './src/components/SettingsModal';
import PhotoViewerModal from './src/components/PhotoViewerModal';
import LibraryPickerModal from './src/components/LibraryPickerModal';
import ProModal from './src/components/ProModal';

import { Recipe, ColorAdjustments, CustomWatermark, GpsWatermark, FrameId, GPSInfo, AspectRatio, MeterMode, PhotoEntry, ShutterSound, FlashMode, StartupMode, CropRatio, CropRect, CROP_W_H, DEFAULT_CROP_RECT } from './src/types';
import { getAllRecipes, saveCustomRecipe, updateCustomRecipe, deleteCustomRecipe, getFavoriteIds, setFavoriteId } from './src/utils/storageUtils';
import { DEFAULT_ADJUSTMENTS, FILM_SIMS, filmSimToRecipe } from './src/utils/defaultRecipes';
import { getCurrentGPS, requestLocationPermissions, reverseGeocode, withDeadline } from './src/utils/locationUtils';
// Types are erased at build time, so this one is free.
import type { PickedPhotoAsset } from './src/utils/photoGps';
import { PARAM_DEFS } from './src/utils/paramDefs';
import { LITE_FAVORITE_LIMIT, LITE_MARK, LITE_RECIPE_LIMIT, proLookInUse } from './src/utils/entitlement';
import { initProUnlock, useProUnlock } from './src/utils/proUnlock';
import UltraWide from './modules/recipescam-ultrawide';
import RecipescamExport from './modules/recipescam-export';
import VolumeShutter from './modules/recipescam-volume';

// @ts-ignore
import './global.css';

// Shallow value diff over the union of both objects' keys: undefined and a
// missing key both read as "no value", so an old session without the newer
// optional knobs is not reported as an edit.
const differs = <T extends object>(a: T, b: T) => {
  const keys = new Set([...Object.keys(a), ...Object.keys(b)]) as Set<keyof T>;
  return [...keys].some((k) => (a[k] ?? null) !== (b[k] ?? null));
};

const SESSION_KEY = 'saved_session';
const STARTUP_MODE_KEY = 'startup_mode';
// Camera/device settings that survive restarts regardless of startup mode
// (the session file only restores the full look under 'last session').
const CAMERA_SETTINGS_KEY = 'camera_settings';

// P5: native Kotlin export path. EXPO_PUBLIC_NATIVE_EXPORT=1 swaps the Skia
// render engine for the RecipesCamExport native pipeline (same look contract,
// rendering off the JS thread). Default stays legacy until P6 parity/perf gate
// decides which engine ships.
const NATIVE_EXPORT = process.env.EXPO_PUBLIC_NATIVE_EXPORT === '1';

// B1: the shutter's CameraX capture mode. 'balanced' ships as the default —
// measured on the 12S Ultra at the same 3000x4000, a frame takes ~340 ms
// against ~540 ms for 'quality', with no resolution loss, because this device
// has ZSL (supportsSpeedQualityPrioritization) and 'balanced'/speed ride it.
// EXPO_PUBLIC_CAPTURE_MODE still overrides, but ONLY in dev bundles: Metro
// inlines EXPO_PUBLIC_*, the release HBC build does not (B0 finding) — never
// gate shipped behaviour on it.
// How long a shutter may wait for a GPS fix before exporting without it. The
// photo is never held hostage by the receiver: indoors a Balanced fix takes
// 20s+ (measured 25s on the V2430), which is the whole reason a capture used to
// take half a minute to reach the gallery. The next shot picks the fix up.
const GPS_WAIT_MS = 2000;

// The photo pipeline (Skia, the frame pack, the filter maths) and the recipe
// XML codec run behind a shutter press or a share sheet, never on the first
// frame, so they are loaded on demand instead of sitting in the cold-start
// module graph. Same two functions the eager imports used to bind; wait: only
// the *renderers* moved — nothing about an export changed.
const loadRenderer = (native: boolean) =>
  native
    ? import('./src/utils/nativeExport').then((m) => m.processAndExportPhotoNative)
    : import('./src/utils/exportEngine').then((m) => m.processAndExportPhoto);
const CAPTURE_MODE =
  process.env.EXPO_PUBLIC_CAPTURE_MODE === 'speed' || process.env.EXPO_PUBLIC_CAPTURE_MODE === 'quality'
    ? process.env.EXPO_PUBLIC_CAPTURE_MODE
    : 'balanced';

export default function App() {
  const [mode, setMode] = useState<'camera' | 'library'>('camera');
  // Back/front lens the live viewfinder uses; flipping is transient UI state
  // (not persisted in sessions — startup always opens on the back camera).
  const [cameraFacing, setCameraFacing] = useState<'back' | 'front'>('back');
  // Imperative handle into the Viewfinder camera controller: reads the live
  // viewfinder state at capture/export time (framed-window zoom, crop rect,
  // horizon). There is no EV flush to do: the hardware AE bias is never
  // touched — setExposureBias re-locks AE and flashes the Xiaomi preview.
  const viewfinderRef = useRef<ViewfinderHandle>(null);
  // Edge-to-edge (app.json/gradle edgeToEdgeEnabled) makes Android ignore the
  // manifest's adjustResize, so the OS never shrinks the window for the IME and
  // the bottom deck stays under the keyboard. Track the IME height ourselves and
  // lift the deck by it (covers the custom-watermark text input).
  const [keyboardHeight, setKeyboardHeight] = useState(0);
  // Top edge of the bottom deck (its own onLayout) -> the height left for the
  // photo. Library mode letterboxes the image above it so no watermark
  // position hides under an open panel. Null until the first layout pass.
  const [deckTop, setDeckTop] = useState<number | null>(null);
  // Bottom edge of the floating top strip -> the library photo starts there; a
  // ratio band peeking under the header is a band the user cannot see.
  const [topInset, setTopInset] = useState(0);
  // Library photo rotation (FRAME tab): the quarter turn in degrees clockwise
  // plus the fine STRAIGHTEN offset. Both feed the preview source and the
  // export alike, the straighten angle applied on top of the turn.
  const [photoRotation, setPhotoRotation] = useState<0 | 90 | 180 | 270>(0);
  const [photoStraighten, setPhotoStraighten] = useState(0);
  useEffect(() => {
    const show = Keyboard.addListener('keyboardDidShow', (e) => setKeyboardHeight(e.endCoordinates.height));
    const hide = Keyboard.addListener('keyboardDidHide', () => setKeyboardHeight(0));
    return () => {
      show.remove();
      hide.remove();
    };
  }, []);
  const [recipes, setRecipes] = useState<Recipe[]>([]);
  // LITE (free) vs PRO: the PRO apk is born owned, the free one buys the tier
  // through Google Play. Runtime state, read here and passed down.
  const pro = useProUnlock().owned;
  // The paywall sheet: opened by the SETTINGS plan row and by every alert that
  // names a PRO feature, so the refusal always comes with a way to pay.
  const [showPro, setShowPro] = useState(false);
  // Ask the store what this account owns, once, at startup. Until it answers,
  // the cached answer stands (see src/utils/proUnlock.ts).
  useEffect(() => {
    initProUnlock();
  }, []);
  // Lite stores up to LITE_RECIPE_LIMIT recipes of its own; past that the save
  // paths ask for PRO. Deleting one is PRO as well, so a Lite list only grows.
  const customRecipeCount = recipes.filter((r) => r.isCustom).length;
  const liteSaveBlocked = !pro && customRecipeCount >= LITE_RECIPE_LIMIT;
  const promptRecipeLimit = () => promptProFeature(`Saving more than ${LITE_RECIPE_LIMIT} recipes`);
  // FAVORITED: ids of the starred recipes. Metadata only — never saved into the
  // session look, so RESET and applying a recipe leave it untouched.
  const [favoriteIds, setFavoriteIds] = useState<string[]>([]);
  const [selectedRecipe, setSelectedRecipe] = useState<Recipe | null>(null);
  // Custom recipe open in the parameter editor (the CREATE form in edit mode).
  const [editingRecipe, setEditingRecipe] = useState<Recipe | null>(null);
  
  // Custom temporary overrides for the sliders
  const [adjustments, setAdjustments] = useState<ColorAdjustments>({ ...DEFAULT_ADJUSTMENTS });

  const [selectedFrame, setSelectedFrame] = useState<FrameId>('none');
  // PRO only: the GPS stamp is a paid look, so a LITE session starts without
  // it and `handleToggleGeotag` refuses to turn it on.
  const [useGeotag, setUseGeotag] = useState(pro);
  // GPS master switch (SETTINGS -> GPS): may the app read the device's
  // location at all? ON resolves a fix at capture and reverse-geocodes it;
  // OFF reads nothing. The GPS WATERMARK chip is separate — it only decides
  // whether a resolved location is printed on the photo.
  const [gpsEnabled, setGpsEnabled] = useState(true);
  const [gpsInfo, setGpsInfo] = useState<GPSInfo | null>(null);
  // Custom text watermark (WATERMARK tab -> CUSTOM WATERMARK chip): enabled +
  // text + drag position as 0..1 fractions of the photo area. Lives here so the
  // live Viewfinder overlay, the panel input and every export share one state.
  const DEFAULT_CUSTOM_WM: CustomWatermark = { enabled: false, text: '', x: 0.5, y: 0.5 };
  const [customWm, setCustomWm] = useState<CustomWatermark>({ ...DEFAULT_CUSTOM_WM });
  // WATERMARK tab ROTATE chip: clockwise degrees, applied to the GPS lines and
  // the custom text in both the preview and the exported file.
  const [wmRotation, setWmRotation] = useState(0);
  // GPS mark placement (WATERMARK tab drag + pinch): fractions of the frame /
  // photo area plus a size multiplier, same space as the custom mark. There is
  // nothing to accept — the panel being open IS the edit session.
  const DEFAULT_GPS_WM: GpsWatermark = {
    x: 0.05,
    y: 0.1,
    size: 1,
    color: '#f59e0b',
    showName: true,
    showTime: true,
  };
  const [gpsWm, setGpsWm] = useState<GpsWatermark>({ ...DEFAULT_GPS_WM });
  // FRAME tab ORIENTATION chip (WALL FRAME only): hang the artwork landscape
  // (the PNG's own 4000x3117) instead of the default portrait rotation.
  const [wallLandscape, setWallLandscape] = useState(false);
  // The mark the EXPORT burns in. The chip above is the live draft (typing +
  // dragging update it); only ACCEPT in the WATERMARK tab copies the draft in
  // here — until then the file keeps the previous stamp (or none).
  const [customWmApplied, setCustomWmApplied] = useState<CustomWatermark>({
    ...DEFAULT_CUSTOM_WM,
  });
  // Bumped by a double-tap on the mark: the panel re-focuses the text input.
  const [wmEditNonce, setWmEditNonce] = useState(0);
  // Draft edit: toggling the chip OFF also drops any accepted stamp, so a
  // switched-off watermark can never come back in an export.
  const handleUpdateCustomWm = (wm: CustomWatermark) => {
    // Typing coalesces into one step per pause; a chip (colour, size, ON/OFF)
    // is a step of its own even when two of them land back to back.
    commit(wm.text !== customWm.text, () => {
      setCustomWm(wm);
      if (!wm.enabled) setCustomWmApplied({ ...DEFAULT_CUSTOM_WM });
    });
  };
  // Leaving the watermark editor = closing its panel. The mark keeps capturing
  // image touches ONLY while that panel is open (Viewfinder's wmArmed), so this
  // is what hands the photo back to tap-to-focus / pinch / double-tap zoom.
  const closeWatermarkEditor = () => {
    setOpenTab(null);
    setOpenParamKey(null);
  };
  // ACCEPT: the draft becomes the mark the export burns in, then the editor
  // closes so the image stops being a placement surface.
  const handleAcceptCustomWm = () => {
    commit(false, () => setCustomWmApplied({ ...customWm }));
    closeWatermarkEditor();
  };
  // CANCEL: drop every un-accepted edit and fall back to the last ACCEPTED mark
  // (none at all when nothing was ever accepted), then close exactly like
  // ACCEPT — the escape hatch a running session previously lacked.
  const handleCancelCustomWm = () => {
    commit(false, () => setCustomWm({ ...customWmApplied }));
    closeWatermarkEditor();
  };
  // Composition aspect-ratio (FULL / 4:3 / 3:2 upright) + RAW DNG sidecar.
  const [aspectRatio, setAspectRatio] = useState<AspectRatio>('full');
  // FRAME-tab CROP (library plain frames). 'free' keeps an explicit rectangle
  // the Viewfinder lets the user drag; fixed ratios center-crop. Both are
  // handed to the export so the file matches the preview.
  const [cropRatio, setCropRatio] = useState<CropRatio>('none');
  // CROP is a two-step tool: the ratio strip only FRAMES the band (amber
  // outline + dim surround) until APPLY commits it, after which the viewer
  // shows the crop alone. Holds the committed ratio, so picking another ratio
  // (or RESET) drops straight back to the framing state.
  const [cropApplied, setCropApplied] = useState<CropRatio | null>(null);
  const [cropRect, setCropRect] = useState<CropRect>(DEFAULT_CROP_RECT);
  const [rawEnabled, setRawEnabled] = useState(false);
  // Full-frame metering mode (FOCUS → METERING MODE): highlight-weighted meters
  // the BRIGHTEST area to protect its detail (never blow whites) and pushes the
  // shadows very deep — extreme contrast (GR/Sony). Realised as: a small EV dip
  // (capture headroom; NOT a full-frame dim), a highlight roll (keep bright
  // detail), deep shadow crush and raised contrast/clarity. All constants are a
  // starting approximation — tune after device testing.
  const [meterMode, setMeterMode] = useState<MeterMode>('evaluative');
  const METER_HL_EV = -0.5;
  const METER_HL_HIGHLIGHT = -3;
  const METER_HL_SHADOW = -4;
  const METER_HL_CONTRAST = 3;
  const METER_HL_CLARITY = 3;
  const clampAdj = (v: number) => Math.max(-10, Math.min(10, v));
  const meteringActive = mode === 'camera' && meterMode === 'highlight';
  // The overlay is built FROM the adjustments it is laid on, so the preview can
  // ask for the pre-edit one while the finger holds the compare. Built from the
  // live values it always was, it kept painting the EDITED look back over the
  // recipe the peek had swapped in, and neither HIGHLIGHT nor SHADOW (nor EV,
  // CONTRAST, CLARITY) ever came back.
  const meteringOverlay = (a: ColorAdjustments): Partial<ColorAdjustments> => ({
    exposureCompensation: clampAdj((a.exposureCompensation ?? 0) + METER_HL_EV),
    highlight: clampAdj((a.highlight ?? 0) + METER_HL_HIGHLIGHT),
    shadow: clampAdj((a.shadow ?? 0) + METER_HL_SHADOW),
    contrast: clampAdj((a.contrast ?? 0) + METER_HL_CONTRAST),
    clarity: clampAdj((a.clarity ?? 0) + METER_HL_CLARITY),
  });
  const meteringAdj: Partial<ColorAdjustments> | undefined = meteringActive
    ? meteringOverlay(adjustments)
    : undefined;
  // Same overlay for the camera EXPORT — the EV dip included: EV is software
  // only (no hardware AE bias anywhere), so preview and file must both apply it.
  const renderAdj: ColorAdjustments = meteringAdj ? { ...adjustments, ...meteringAdj } : adjustments;
  const rawFailRef = useRef(false);
  // Progressive disclosure: a tool chip opens its panel; null = photo hero only.
  const [openTab, setOpenTab] = useState<TabId | null>(null);
  // The parameter whose slider row is open inside the panel — lifted here (not
  // local to AdjustmentPanel) because an open row arms drag-anywhere-on-the-
  // image adjustment in the Viewfinder. Cleared when the panel/tab closes.
  const [openParamKey, setOpenParamKey] = useState<string | null>(null);
  // FRAME → WATERMARK sub-panel is open (the rail's WATERMARK tab is gone).
  const [wmPanelOpen, setWmPanelOpen] = useState(false);
  const [libraryImageUri, setLibraryImageUri] = useState<string | null>(null);
  // Session photo history (camera captures + library exports). The camera
  // thumbnail/preview button shows the newest entry; the swipe viewer walks the
  // whole list. Not persisted across restarts — entries are app-cache files.
  const [photoHistory, setPhotoHistory] = useState<PhotoEntry[]>([]);
  // Index into photoHistory of the photo shown in the swipe viewer; null = closed.
  const [viewerIndex, setViewerIndex] = useState<number | null>(null);
  // In-app library picker (grid -> full-screen preview -> USE/CANCEL).
  const [libraryPickerVisible, setLibraryPickerVisible] = useState(false);
  // Gear sheet (sound / ratio / metering mode). Camera captures never auto-open
  // the viewer anymore — the thumbnail button does.
  const [settingsVisible, setSettingsVisible] = useState(false);
  // Shutter click: only OFF/ON (no volume API on Android). Applied at capture.
  const [shutterSound, setShutterSound] = useState<ShutterSound>('on');
  // LED flash mode. Capture-time only (no live torch): 'off' keeps today's
  // behaviour, 'auto' lets the pipeline decide, 'on' always fires. Applied to
  // the still, so the preview itself never changes brightness.
  const [flashMode, setFlashMode] = useState<FlashMode>('off');
  // Touch-to-shutter (gear sheet): a plain tap on the live viewfinder locks
  // AE/AF/AWB on the tapped point and, once focus has settled, fires a capture.
  // OFF = a tap only focuses (the historical behaviour).
  const [touchToShutter, setTouchToShutter] = useState(false);
  // Startup behavior: 'default' = PROVIPES neutral at 4:3 camera; 'last' = restore
  // previous session from AsyncStorage. Default is 'default'.
  const [startupMode, setStartupMode] = useState<StartupMode>('default');
  const photoSeq = useRef(0);
  const [isProcessing, setIsProcessing] = useState(false);
  // Short shutter-burst lock: guards the capturePhotoToFile calls from
  // overlapping. Released as soon as the frames are written — NOT after the
  // render, so a new shot can start while the previous photo is still being
  // processed in the background.
  const captureBusyRef = useRef(false);
  // Cold-start shutter gate: the Viewfinder reports when the CameraX session
  // is actually bound (onStarted/onStopped). A shutter press landing before
  // that is QUEUED, not dropped — the built-in camera answers the first tap
  // too, and a press into a dead session produced no file at all.
  const cameraReadyRef = useRef(false);
  const pendingShotRef = useRef(false);
  // FIFO background render queue: processAndExportPhoto (Skia render + gallery
  // save, ~1s) runs OFF the shutter path, one at a time, so the next photo can
  // be taken immediately. FIFO keeps history order == shutter order. Renders
  // are heavy on the JS thread but yield between awaits — UI keeps responding.
  const exportQueueRef = useRef<Promise<void>>(Promise.resolve());
  const enqueueExport = (task: () => Promise<void>) => {
    exportQueueRef.current = exportQueueRef.current
      .catch(() => {}) // a failed render must not stall the queue
      .then(task)
      .catch((e) => console.error('Background export failed:', e));
  };

  // Hardware Permissions (vision-camera)
  const { hasPermission: cameraPermissionGranted, requestPermission: requestCameraPermission } = useCameraPermission();
  // The lens the flash control belongs to. CameraX throws when asked for
  // 'on'/'auto' on a device with no flash unit (the front lens, most tablets),
  // so the control is only offered while this reads true.
  const flashAvailable = useCameraDevice(cameraFacing)?.hasFlash ?? false;
  // Full-resolution photo output — attached to the live <Camera> in Viewfinder.
  // Photo capture is resolution-independent from the Skia preview output.
  const photoOutput = usePhotoOutput({
    qualityPrioritization: CAPTURE_MODE,
  });
  // Second photo output for RAW DNG sidecars (RATIO panel → RAW on). Kept as
  // a live output only while rawEnabled — CameraX cannot bind two ImageCapture
  // use cases, so attaching both at once would break the session. Attaching a
  // DNG output while RAW is on gives ~one exposure per capture: the JPEG below
  // and this DNG are separate shots taken a few tens of ms apart.
  const rawPhotoOutput = usePhotoOutput({
    containerFormat: 'dng',
    qualityPrioritization: 'quality',
  });

  // vision-camera may return a raw absolute path on Android; surface a file:// URI.
  const toUri = (path: string) => (/^(file|content|ph):\/\//.test(path) ? path : `file://${path}`);

  // Resolved by the mount effect just below, awaited by the share intake further
  // down: a share that cold-starts the app must land AFTER the session restore,
  // or the restored libraryImageUri/mode would replace the shared photo — and by
  // then the intent is consumed, so the photo is unreachable for good.
  const sessionInitRef = useRef<Promise<void> | null>(null);

  useEffect(() => {
    // B5: run a single sequenced init — restore the session first, then fall
    // back to the first recipe only when no recipe was restored.
    // The restored look is step zero: BACK can never walk behind the load.
    sessionInitRef.current = initSession().then(clearHistory);
    // Do NOT auto-load device GPS here — it would override photo GPS on library mode
  }, []);

  // A photo picked while the GPS chip was OFF kept its coordinates but no place
  // name (the geocode only ran when the chip was already on), and toggleGeotag
  // skips GPS loading entirely when coordinates exist — so turning the chip on
  // showed "STREET VIEW". Resolve the name whenever the mark needs one.
  useEffect(() => {
    if (!gpsEnabled || !gpsInfo || gpsInfo.locality) return;
    let stale = false;
    reverseGeocode(gpsInfo.latitude, gpsInfo.longitude).then((name) => {
      if (!stale && name) setGpsInfo((g) => (g && !g.locality ? { ...g, locality: name } : g));
    });
    return () => {
      stale = true;
    };
  }, [gpsEnabled, gpsInfo]);

  // Warm the fix up at launch instead of at the shutter. A fix taken here is
  // what the first photo stamps, so the capture path normally has nothing to
  // wait for — the same head start the built-in camera gets from its own
  // always-on location client. GPS_WAIT_MS below is the backstop when it is not
  // ready yet.
  useEffect(() => {
    if (!gpsEnabled) return;
    let stale = false;
    getCurrentGPS().then((info) => {
      if (!stale && info) setGpsInfo((g) => g ?? { ...info, source: 'device' as const });
    });
    return () => {
      stale = true;
    };
  }, [gpsEnabled]);

  // Save/restore session on app lifecycle changes
  useEffect(() => {
    const subscription = AppState.addEventListener('change', async (nextAppState) => {
      if (nextAppState === 'background' || nextAppState === 'inactive') {
        const session = {
          mode,
          libraryImageUri,
          adjustments,
          selectedFrame,
          useGeotag,
          aspectRatio,
          cropRatio,
          cropRect,
          cropApplied,
          meterMode,
          shutterSound,
          selectedRecipeId: selectedRecipe?.id || null,
          gpsInfo,
          customWm,
          gpsWm,
        };
        try {
          await AsyncStorage.setItem(SESSION_KEY, JSON.stringify(session));
        } catch (e) {
          console.warn('Failed to save session:', e);
        }
      }
    });
    return () => subscription.remove();
  }, [mode, libraryImageUri, adjustments, selectedFrame, useGeotag, selectedRecipe, gpsInfo, customWm, gpsWm, aspectRatio, cropRatio, cropRect, cropApplied, meterMode, shutterSound]);

  // Guards the camera-settings persist effect below: until initSession has
  // read the stored values, changes are just the initial defaults — writing
  // them would overwrite the saved settings (async restore loses the race
  // against the mount effect).
  const settingsHydratedRef = useRef(false);

  const initSession = async () => {
    const list = await getAllRecipes();
    setRecipes(list);
    setFavoriteIds(await getFavoriteIds());

    // Device/camera settings restore first: they apply under BOTH startup
    // modes ('default' resets only the look, not these hardware choices).
    try {
      const raw = await AsyncStorage.getItem(CAMERA_SETTINGS_KEY);
      if (raw) {
        const s = JSON.parse(raw);
        if (s.shutterSound === 'on' || s.shutterSound === 'off') setShutterSound(s.shutterSound);
        if (s.flashMode === 'off' || s.flashMode === 'auto' || s.flashMode === 'on') setFlashMode(s.flashMode);
        if (s.meterMode === 'evaluative' || s.meterMode === 'highlight') setMeterMode(s.meterMode);
        if (typeof s.rawEnabled === 'boolean') setRawEnabled(s.rawEnabled);
        if (typeof s.gpsEnabled === 'boolean') setGpsEnabled(s.gpsEnabled);
        if (typeof s.touchToShutter === 'boolean') setTouchToShutter(s.touchToShutter);
      }
    } catch (e) {
      console.warn('Failed to read camera settings:', e);
    }
    settingsHydratedRef.current = true;

    // Startup mode: 'default' opens camera + PROVIPES film sim (neutral
    // adjustments, DEFAULT_ADJUSTMENTS) at 4:3. 'last' restores the previous
    // session from AsyncStorage; with no saved session it falls back to the
    // same clean default state.
    let startup: StartupMode = 'default';
    try {
      const raw = await AsyncStorage.getItem(STARTUP_MODE_KEY);
      if (raw === 'last') startup = 'last';
    } catch (e) {
      console.warn('Failed to read startup mode:', e);
    }
    setStartupMode(startup);

    const applyDefaultStartup = () => {
      setMode('camera');
      setLibraryImageUri(null);
      setAspectRatio('4:3');
      const provia = FILM_SIMS.find((f) => f.id === 'sim-provia');
      if (provia) applyRecipe(filmSimToRecipe(provia));
      // Clean camera start: GPS watermark stays OFF until the user opts in.
      setUseGeotag(false);
    };

    if (startup === 'default') {
      applyDefaultStartup();
      return;
    }

    let session: any = null;
    try {
      const raw = await AsyncStorage.getItem(SESSION_KEY);
      if (raw) session = JSON.parse(raw);
    } catch (e) {
      console.warn('Failed to read session:', e);
    }

    let restoredRecipe: Recipe | null = null;
    if (session) {
      // B12: the restored library image may no longer exist on disk
      let imageUri: string | null = session.libraryImageUri || null;
      if (imageUri) {
        try {
          const info = await FileSystem.getInfoAsync(imageUri);
          if (!info.exists) imageUri = null;
        } catch {
          imageUri = null;
        }
      }
      // A saved 'camera' mode is a deliberate choice and outranks a lingering
      // library image: switching modes never clears libraryImageUri, so without
      // this a session closed on the live camera came back up in the viewer.
      if (imageUri && session.mode !== 'camera') {
        setLibraryImageUri(imageUri);
        setMode('library');
      } else {
        // No usable photo (or the user had chosen the camera): open the camera.
        setMode('camera');
      }
      if (session.adjustments)
        setAdjustments({ ...DEFAULT_ADJUSTMENTS, ...session.adjustments });
      if (session.selectedFrame) setSelectedFrame(session.selectedFrame);
      if (session.useGeotag !== undefined) setUseGeotag(pro && session.useGeotag);
      if (session.aspectRatio === 'full' || session.aspectRatio === '4:3' || session.aspectRatio === '3:2') setAspectRatio(session.aspectRatio);
      if (session.cropRatio) setCropRatio(session.cropRatio);
      if (session.cropRect && typeof session.cropRect === 'object') setCropRect({ ...DEFAULT_CROP_RECT, ...session.cropRect });
      // Committed crop: only trust a value that still matches the restored
      // ratio, so a stale snapshot can never show a crop it never framed.
      if (session.cropApplied && session.cropApplied === session.cropRatio) setCropApplied(session.cropApplied);
      // NOTE: meterMode/shutterSound/rawEnabled are NOT restored from the
      // session snapshot here — the session file is only written on background,
      // so it can be stale after a force-kill. CAMERA_SETTINGS_KEY above
      // persists them on every change and is authoritative for these three.
      if (session.gpsInfo) setGpsInfo(session.gpsInfo);
      if (session.customWm && typeof session.customWm === 'object') {
        // Restore defensively: a session saved by an older build may miss the
        // field entirely or hold a malformed shape.
        const raw = session.customWm as Partial<CustomWatermark>;
        const clamp01 = (v: unknown, fb: number) =>
          typeof v === 'number' && Number.isFinite(v) ? Math.max(0, Math.min(1, v)) : fb;
        setCustomWm({
          enabled: raw.enabled === true,
          text: typeof raw.text === 'string' ? raw.text : '',
          x: clamp01(raw.x, 0.5),
          y: clamp01(raw.y, 0.5),
          color: typeof raw.color === 'string' ? raw.color : undefined,
          size: typeof raw.size === 'number' && Number.isFinite(raw.size) ? raw.size : undefined,
          font: pro && typeof raw.font === 'string' ? raw.font : null,
        });
      }
      if (session.gpsWm && typeof session.gpsWm === 'object') {
        // Style chips only — the placement fractions are left alone (restoring
        // a stale x/y would silently move the stamp the user just dragged).
        const raw = session.gpsWm as Partial<GpsWatermark>;
        const keep = (v: unknown, fb: boolean) => (typeof v === 'boolean' ? v : fb);
        setGpsWm((g) => ({
          ...g,
          color: typeof raw.color === 'string' ? raw.color : g.color,
          showName: keep(raw.showName, true),
          showTime: keep(raw.showTime, true),
        }));
      }
      if (session.selectedRecipeId) {
        // Film sims are never persisted in the recipe list (sims applied on the
        // fly) — resolve sim ids via FILM_SIMS, real recipes via the list.
        const sim = FILM_SIMS.find((f) => f.id === session.selectedRecipeId);
        restoredRecipe = sim
          ? filmSimToRecipe(sim)
          : list.find((r: Recipe) => r.id === session.selectedRecipeId) || null;
      }
    }

    if (restoredRecipe) {
      // Recipe identity restored; the look (adjustments/frame/geotag/ratio)
      // stays exactly as saved in the session above — applyRecipe would reset
      // them to the recipe's canonical values and drop the user's tweaks.
      setSelectedRecipe(restoredRecipe);
    } else {
      applyDefaultStartup();
    }
  };

  const loadGPS = async () => {
    const info = await getCurrentGPS();
    if (info) {
      setGpsInfo({ ...info, source: 'device' });
    }
  };

  const applyRecipe = (recipe: Recipe) => {
    commit(false, () => {
      setSelectedRecipe(recipe);
      // EVERY knob the recipe carries lands in the panel, backfilled over the
      // defaults so a recipe saved before a knob existed cannot leave that knob
      // on whatever the previous look happened to have.
      setAdjustments({ ...DEFAULT_ADJUSTMENTS, ...recipe.adjustments });
      setSelectedFrame(recipe.frameId || 'none');
    });
    // GPS watermark is the user's own setting (FRAME tab), not part of a
    // preset look: recipes carry a useGeotag field but selecting one must
    // never flip the watermark on/off.
  };

  // Picking a look — sim or saved recipe — loads the whole thing: identity,
  // every parameter and the frame it was saved with. The panel then shows the
  // values that are actually on screen (and stays editable from there). This
  // used to keep the sliders for sims, which left the panel naming numbers the
  // look no longer had: the sim carried its own adjustments and they were
  // silently dropped. The session restore below is a different case — there the
  // stored adjustments ARE the user's, so it still sets the recipe alone.
  const handleSelectRecipe = (recipe: Recipe) => {
    applyRecipe(recipe);
  };

  // The recipe exactly as the user picked it. `selectedRecipe` is NOT a safe
  // copy of it: every slider move rewrites its `adjustments` in place
  // (handleUpdateAdjustments), so the canonical values only survive in the
  // film-sim table and in the saved list.
  const pristineRecipe = (recipe: Recipe): Recipe | null => {
    const sim = FILM_SIMS.find((f) => f.id === recipe.id);
    if (sim) return filmSimToRecipe(sim);
    return recipes.find((r) => r.id === recipe.id) || null;
  };

  // Every edit belongs to the mode and the photo it was made on, so it never
  // crosses into the next session: the sliders go back to the recipe's own
  // values, a frame picked for that still is dropped, and the custom mark —
  // placed against that very photo — is switched back off.
  const resetEditsToRecipe = () => {
    const base = selectedRecipe ? pristineRecipe(selectedRecipe) : null;
    if (base) {
      applyRecipe(base);
    } else {
      setAdjustments({ ...DEFAULT_ADJUSTMENTS });
      setSelectedFrame('none');
    }
    setCustomWm({ ...DEFAULT_CUSTOM_WM });
    setCustomWmApplied({ ...DEFAULT_CUSTOM_WM });
    setGpsWm({ ...DEFAULT_GPS_WM });
    // A look belongs to the photo and the mode it was edited on: the next load
    // starts a fresh history, even when the values come back the same.
    clearHistory();
  };

  // RESET (panel chip, any tab): the state a default start would leave — the
  // startup look, every parameter back to neutral, frame off and both
  // watermarks back to their defaults. Same pieces as resetEditsToRecipe, but
  // the look goes back to the app's own default rather than the recipe's.
  // A RESET on an already-clean look is not a step: BACK would have nothing
  // to put back and would burn a press on a no-op.
  const handleResetAll = () => {
    if (resetDirty) commit(false, resetLookInPlace);
  };
  const resetLookInPlace = () => {
    const provia = FILM_SIMS.find((f) => f.id === 'sim-provia');
    if (provia) {
      applyRecipe(filmSimToRecipe(provia));
    } else {
      setSelectedRecipe(null);
      setAdjustments({ ...DEFAULT_ADJUSTMENTS });
      setSelectedFrame('none');
    }
    setCustomWm({ ...DEFAULT_CUSTOM_WM });
    setCustomWmApplied({ ...DEFAULT_CUSTOM_WM });
    setGpsWm({ ...DEFAULT_GPS_WM });
    // The rest of the look's state, each back to the value a clean start ships
    // with: the GPS stamp off, both watermark rotations upright, the library
    // photo and its wall frame back to portrait. ponytail: mode + aspect stay
    // put — they frame the shot you are working on, not the look.
    setUseGeotag(false);
    setWmRotation(0);
    setPhotoRotation(0);
    setPhotoStraighten(0);
    setWallLandscape(false);
    setCropRatio('none');
    setCropApplied(null);
    setCropRect(DEFAULT_CROP_RECT);
  };

  // RESET lights up while the look differs from what handleResetAll puts back —
  // every clause here has a matching setter there, or the star never goes out.
  // The clean-start values: the startup sim, neutral knobs, no frame, no crop,
  // both marks at their defaults, GPS stamp off, nothing rotated.
  const resetDirty =
    (selectedRecipe?.id ?? 'sim-provia') !== 'sim-provia' ||
    differs(adjustments, DEFAULT_ADJUSTMENTS) ||
    selectedFrame !== 'none' ||
    differs(customWm, DEFAULT_CUSTOM_WM) ||
    differs(customWmApplied, DEFAULT_CUSTOM_WM) ||
    differs(gpsWm, DEFAULT_GPS_WM) ||
    useGeotag ||
    wmRotation !== 0 ||
    photoRotation !== 0 ||
    photoStraighten !== 0 ||
    wallLandscape ||
    cropRatio !== 'none' ||
    differs(cropRect, DEFAULT_CROP_RECT);

  // ---- Look history: BACK (undo) + PEEK (hold to compare) ------------------
  // Every edit the panel can make is a step: PRESETS/RECIPES, LIGHT, WB, FX and
  // FRAME (frame, crop, turn, straighten, both watermarks, the GPS stamp). BACK
  // pops one step; PEEK — a hold on the picture — shows the
  // look one step back, with every tab's values travelling with it. Neither
  // touches the stored values, the RECIPE or the export: undo writes them, peek
  // only shows them. The history is seeded at every load, so BACK stops there.
  type Look = {
    recipe: Recipe | null;
    adjustments: ColorAdjustments;
    frame: FrameId;
    cropRatio: CropRatio;
    cropApplied: CropRatio | null;
    cropRect: CropRect;
    photoRotation: 0 | 90 | 180 | 270;
    photoStraighten: number;
    wallLandscape: boolean;
    useGeotag: boolean;
    wmRotation: number;
    customWm: CustomWatermark;
    customWmApplied: CustomWatermark;
    gpsWm: GpsWatermark;
  };
  const lookNow = (): Look => ({
    recipe: selectedRecipe,
    adjustments,
    frame: selectedFrame,
    cropRatio,
    cropApplied,
    cropRect,
    photoRotation,
    photoStraighten,
    wallLandscape,
    useGeotag,
    wmRotation,
    customWm,
    customWmApplied,
    gpsWm,
  });
  const lookRef = useRef<Look | null>(null);
  const pastRef = useRef<Look[]>([]);
  const [undoDepth, setUndoDepth] = useState(0);
  const [peekLook, setPeekLook] = useState<Look | null>(null);
  // A gesture is one step: a slider drag (or a run of keystrokes) inside this
  // gap stays the step it started as, so BACK undoes the whole gesture rather
  // than one event of it.
  const PEEK_GAP_MS = 700;
  const lastStepRef = useRef(0);
  // A step is pushed BEFORE the change lands. Nested commits (a handler whose
  // work calls another committing one, e.g. RESET -> applyRecipe) belong to the
  // outer step, or BACK would need one press per layer of one press.
  const commitDepthRef = useRef(0);
  const commit = (coalesce: boolean, mutate: () => void) => {
    if (commitDepthRef.current > 0) {
      mutate();
      return;
    }
    const now = Date.now();
    if (!coalesce || now - lastStepRef.current > PEEK_GAP_MS) {
      if (lookRef.current) pastRef.current.push(lookRef.current);
      setUndoDepth(pastRef.current.length);
    }
    lastStepRef.current = coalesce ? now : 0;
    commitDepthRef.current++;
    try {
      mutate();
    } finally {
      commitDepthRef.current--;
    }
  };
  // The loaded look is step zero — nothing before it can be undone.
  const clearHistory = () => {
    pastRef.current = [];
    lastStepRef.current = 0;
    setUndoDepth(0);
  };
  const applyLook = (l: Look) => {
    setSelectedRecipe(l.recipe);
    setAdjustments(l.adjustments);
    setSelectedFrame(l.frame);
    setCropRatio(l.cropRatio);
    setCropApplied(l.cropApplied);
    setCropRect(l.cropRect);
    setPhotoRotation(l.photoRotation);
    setPhotoStraighten(l.photoStraighten);
    setWallLandscape(l.wallLandscape);
    setUseGeotag(l.useGeotag);
    setWmRotation(l.wmRotation);
    setCustomWm(l.customWm);
    setCustomWmApplied(l.customWmApplied);
    setGpsWm(l.gpsWm);
  };
  const handleUndo = () => {
    if (!pro) {
      promptProFeature('Undo');
      return;
    }
    const prev = pastRef.current.pop();
    if (!prev) return;
    setPeekLook(null);
    lastStepRef.current = 0;
    setUndoDepth(pastRef.current.length);
    applyLook(prev);
  };
  const handlePeek = (on: boolean) => {
    if (!on) {
      setPeekLook(null);
      return;
    }
    const before = pastRef.current[pastRef.current.length - 1];
    setPeekLook(before ?? null);
  };
  // PEEK follows the finger on the picture (the chip is gone). Armed only when
  // there is a step to compare against, so a long press to focus cannot turn
  // into a paywall in a LITE build.
  const peekArmed = pro && undoDepth > 0;
  // The live look, mirrored every render so a handler can snapshot what was on
  // screen just before it changes it.
  const liveLook = lookNow();
  lookRef.current = liveLook;
  // The look the panel and the picture SHOW. While the finger is down on PEEK
  // (or on the picture) every number and every tab travels back a step, so the
  // before/after is readable, not just visible. The real values stay untouched:
  // writes, RECIPE and the on-image drag baseline all read the live ones.
  const shown = peekLook ?? liveLook;
  const shownAdjustments = shown.adjustments;
  const peeking = peekLook !== null;
  // What the preview draws: the shown recipe's own chrome (base filter, name)
  // rebuilt over the shown values, so a peek that steps over a PRESETS/RECIPES
  // change brings that look's filter back with it. A camera start carries no
  // recipe, so that stays the synthetic one.
  const previewRecipe: Recipe = {
    id: 'temp',
    name: 'Custom',
    baseFilter: 'none',
    ...(shown.recipe ?? {}),
    adjustments: shown.adjustments,
    frameId: shown.frame,
    useGeotag: shown.useGeotag,
  };

  const handleUpdateAdjustments = (updates: Partial<ColorAdjustments>) => {
    // Storm guard, generic across every param: same-value writes (slider
    // micro-jitter / repeated pointer-move events) still build a fresh
    // adjustments object and re-render the whole tree — skip them. Supersedes
    // the old EV-only dedupe; EV flush at capture reads its own ref, so a
    // skipped identical EV needs no re-send.
    const keys = Object.keys(updates) as (keyof ColorAdjustments)[];
    if (keys.every((k) => updates[k] === adjustments[k])) return;
    // B8: never call a setState inside another setState's updater.
    const next = { ...adjustments, ...updates };
    // One drag = one step (see commit's coalescing): the step holds the values
    // the drag started from, so BACK and PEEK land on the drag's own start.
    // ponytail: a >700ms stall in the middle of one drag splits it in two.
    commit(true, () => {
      setAdjustments(next);
      if (selectedRecipe) {
        setSelectedRecipe({
          ...selectedRecipe,
          adjustments: next,
        });
      }
    });
  };

  const handleUpdateFrame = (frameId: FrameId) => commit(false, () => applyFrame(frameId));
  const applyFrame = (frameId: FrameId) => {
    setSelectedFrame(frameId);
    // CROP is a plain-frame tool (polaroid/wall crop through their own window).
    // Keep the crop out of a frame that ignores it, or the ratio survives in the
    // strip and lights the CROP chip on a frame the export never crops.
    if (frameId !== 'none' && frameId !== 'classic-white' && frameId !== 'cinematic') {
      setCropRatio('none');
      setCropApplied(null);
      setCropRect(DEFAULT_CROP_RECT);
    }
    if (selectedRecipe) {
      setSelectedRecipe({
        ...selectedRecipe,
        frameId,
      });
    }
  };

  // SETTINGS -> GPS. ON asks for the permission once and resolves a fix
  // now, so the coordinates are already there when the shutter fires.
  const handleToggleGps = async (enabled: boolean) => {
    if (!enabled) {
      setGpsEnabled(false);
      // Only the device fix goes: a picked photo keeps its own EXIF location.
      setGpsInfo((g) => (g && g.source === 'device' ? null : g));
      return;
    }
    if (!(await requestLocationPermissions())) {
      Alert.alert('Permission Denied', 'Enable location services to use GPS.');
      return;
    }
    setGpsEnabled(true);
    loadGPS();
  };

  const handleToggleGeotag = async (enabled: boolean) => {
    if (enabled && !pro) {
      promptProFeature('The GPS watermark');
      return;
    }
    commit(false, () => {
      setUseGeotag(enabled);
      if (selectedRecipe) {
        setSelectedRecipe({
          ...selectedRecipe,
          useGeotag: enabled,
        });
      }
    });
    if (enabled && !gpsInfo) {
      const locationGranted = await requestLocationPermissions();
      if (locationGranted) {
        setGpsEnabled(true);
        loadGPS();
      } else {
        Alert.alert('Permission Denied', 'Enable location services to use GPS Watermark.');
        setUseGeotag(false);
      }
    }
  };

  const handleAspectRatio = (ratio: AspectRatio) => {
    setAspectRatio(ratio);
  };

  const handleRawEnabled = (enabled: boolean) => {
    rawFailRef.current = false; // allow one recovery alert per enable
    setRawEnabled(enabled);
    if (enabled) {
      Haptics.impactAsync(Haptics.ImpactFeedbackStyle.Medium);
    }
  };

  const handleStartupMode = (mode: StartupMode) => {
    setStartupMode(mode);
    AsyncStorage.setItem(STARTUP_MODE_KEY, mode).catch(() => {});
  };

  // Persist device/camera settings on every change — not just on background —
  // so they survive a kill/relaunch even under 'default' startup, which only
  // resets the look (mode/ratio/recipe/geotag), not these.
  useEffect(() => {
    if (!settingsHydratedRef.current) return;
    AsyncStorage.setItem(
      CAMERA_SETTINGS_KEY,
      JSON.stringify({ shutterSound, flashMode, meterMode, rawEnabled, gpsEnabled, touchToShutter })
    ).catch(() => {});
  }, [shutterSound, flashMode, meterMode, rawEnabled, gpsEnabled, touchToShutter]);

  // Latest-rawEnabled ref so the stable session-error callback below can read
  // the live toggle without re-subscribing the Camera session on every render.
  const rawEnabledRef = useRef(rawEnabled);
  rawEnabledRef.current = rawEnabled;
  // Attaching the DNG output while RAW is on adds a second ImageCapture use
  // case — CameraX historically refuses two per camera. If the session errors
  // in that state, drop RAW (removing the output reconfigures back to the
  // single working JPEG session) instead of leaving a dead camera.
  const handleCameraSessionError = useCallback((error: Error) => {
    console.error('Camera session error:', error);
    if (rawEnabledRef.current && !rawFailRef.current) {
      rawFailRef.current = true;
      setRawEnabled(false);
      Alert.alert(
        'RAW Unavailable',
        'DNG capture could not start on this device, so RAW was turned off. JPEG capture keeps working.'
      );
    }
  }, []);

  // Save the freshly captured DNG into an album literally named "RAW" (create
  // the album on first use). Failure never blocks the JPEG pipeline.
  const saveRawToAlbum = async (uri: string): Promise<boolean> => {
    try {
      const perm = await MediaLibraryLegacy.requestPermissionsAsync();
      if (!perm.granted) {
        console.warn('RAW save: media library permission denied');
        return false;
      }
      const asset = await MediaLibraryLegacy.createAssetAsync(uri);
      const albumName = 'RAW';
      let album = await MediaLibraryLegacy.getAlbumAsync(albumName);
      if (album) {
        await MediaLibraryLegacy.addAssetsToAlbumAsync(asset, album);
      } else {
        await MediaLibraryLegacy.createAlbumAsync(albumName, asset);
      }
      return true;
    } catch (e) {
      console.error('RAW album save failed:', e);
      return false;
    }
  };

  const handleSaveRecipe = async (name: string) => {
    if (liteSaveBlocked) {
      promptRecipeLimit();
      return;
    }
    if (!selectedRecipe) return;
    const newRecipe = await saveCustomRecipe({
      name,
      baseFilter: selectedRecipe.baseFilter,
      adjustments,
      frameId: selectedFrame,
      useGeotag,
    });
    const list = await getAllRecipes();
    setRecipes(list);
    applyRecipe(newRecipe);
    Alert.alert('Recipe Saved', `"${name}" has been created.`);
  };

  // TopBar SAVE & SHARE -> EXPORT & SHARE: the look on screen as an encrypted
  // recipe file, handed to the share sheet (and to the phone's storage when
  // the recipient sheet is used to save it).
  const handleExportShare = async (name: string) => {
    try {
      const { exportRecipeXml } = await import('./src/utils/recipeShare');
      const xml = exportRecipeXml({
        id: 'share',
        name,
        baseFilter: activeRecipe.baseFilter,
        adjustments,
        frameId: selectedFrame,
        useGeotag,
      });
      const file = `${FileSystem.cacheDirectory}${name.replace(/[^\w.-]+/g, '_') || 'recipe'}.rcx.xml`;
      await FileSystem.writeAsStringAsync(file, xml);
      if (!(await Sharing.isAvailableAsync())) {
        Alert.alert('Recipe Exported', `Saved as ${file}`);
        return;
      }
      await Sharing.shareAsync(file, { mimeType: 'application/xml', dialogTitle: `Share recipe "${name}"` });
    } catch (e) {
      Alert.alert('Export failed', e instanceof Error ? e.message : String(e));
    }
  };

  // PRESETS -> IMPORT: a recipe file shared from another phone, picked from
  // storage, decoded and stored as a normal custom recipe.
  const handleImportRecipe = async () => {
    if (liteSaveBlocked) {
      promptRecipeLimit();
      return;
    }
    try {
      const picked = await DocumentPicker.getDocumentAsync({ type: '*/*', copyToCacheDirectory: true });
      if (picked.canceled) return;
      const xml = await FileSystem.readAsStringAsync(picked.assets[0].uri);
      const { importRecipeXml } = await import('./src/utils/recipeShare');
      const created = await saveCustomRecipe(importRecipeXml(xml));
      setRecipes(await getAllRecipes());
      applyRecipe(created);
      Haptics.notificationAsync(Haptics.NotificationFeedbackType.Success);
      Alert.alert('Recipe Imported', `"${created.name}" has been added.`);
    } catch (e) {
      Alert.alert('Import failed', e instanceof Error ? e.message : String(e));
    }
  };

  // TopBar "SAVE" on a user-created recipe: overwrite it in place, same id.
  const handleOverwriteRecipe = async (name: string) => {
    if (!selectedRecipe) return;
    await updateCustomRecipe(selectedRecipe.id, {
      name,
      baseFilter: selectedRecipe.baseFilter,
      adjustments,
      frameId: selectedFrame,
      useGeotag,
    });
    const list = await getAllRecipes();
    setRecipes(list);
    const updated = list.find((r) => r.id === selectedRecipe.id);
    if (updated) applyRecipe(updated);
    Alert.alert('Recipe Updated', `"${name}" has been saved.`);
  };

  // The recipe editor (the CREATE form in edit mode) SAVE. The typed name is
  // the switch: unchanged = overwrite that recipe in place (same id, new
  // parameters), new = keep the original and store the edit as its own recipe.
  // The editor only closes first, the confirm dialog comes right after.
  const handleUpdateRecipe = async (recipe: Omit<Recipe, 'id' | 'isCustom'>) => {
    const target = editingRecipe;
    setEditingRecipe(null);
    if (!target) return;
    const name = recipe.name.trim();
    const unchanged = name === target.name.trim();
    if (!unchanged && liteSaveBlocked) {
      promptRecipeLimit();
      return;
    }
    const commit = async () => {
      if (unchanged) {
        await updateCustomRecipe(target.id, { ...recipe, name });
        const list = await getAllRecipes();
        setRecipes(list);
        const updated = list.find((r) => r.id === target.id);
        if (updated) applyRecipe(updated);
      } else {
        const created = await saveCustomRecipe({ ...recipe, name });
        setRecipes(await getAllRecipes());
        applyRecipe(created);
      }
      Haptics.notificationAsync(Haptics.NotificationFeedbackType.Success);
      Alert.alert(
        unchanged ? 'Recipe Updated' : 'Recipe Saved',
        `"${name}" has been saved.`
      );
    };
    Alert.alert(
      unchanged ? 'Overwrite recipe?' : 'Save as new recipe?',
      unchanged
        ? `Replace "${target.name}" with the edited parameters?`
        : `Keep "${target.name}" and save the edit as "${name}"?`,
      [
        { text: 'CANCEL', style: 'cancel' },
        { text: unchanged ? 'OVERWRITE' : 'SAVE', onPress: () => { commit(); } },
      ],
    );
  };

  // PRESETS → CREATE quick-input: build a brand-new recipe from the modal's
  // typed fields, persist it, and apply it (the user sees the look immediately).
  const handleCreateRecipe = async (recipe: Omit<Recipe, 'id' | 'isCustom'>) => {
    // Lite composes the recipe and applies it as a throwaway draft so the look
    // can be tried; storing it is what the LITE_RECIPE_LIMIT caps. 'draft' is no
    // free id, so the shutter gate already treats the look as the PRO preset.
    if (liteSaveBlocked) {
      applyRecipe({ ...recipe, id: 'draft', isCustom: false });
      promptRecipeLimit();
      return;
    }
    const newRecipe = await saveCustomRecipe(recipe);
    const list = await getAllRecipes();
    setRecipes(list);
    applyRecipe(newRecipe);
    Haptics.notificationAsync(Haptics.NotificationFeedbackType.Success);
  };

  // Deleting is PRO: Lite may create and edit its recipes, it may not drop them.
  const handleDeleteRecipe = async (id: string) => {
    if (!pro) {
      promptProFeature('Deleting recipes');
      return;
    }
    await deleteCustomRecipe(id);
    const list = await getAllRecipes();
    setRecipes(list);
    if (selectedRecipe?.id === id && list.length > 0) {
      applyRecipe(list[0]);
    }
  };

  // Star/un-star a recipe: optimistic (the chip repaints on tap), persisted in
  // the background. The write is the only failure worth logging — the look is
  // untouched either way.
  const handleToggleFavorite = (id: string) => {
    const on = !favoriteIds.includes(id);
    // LITE gets one favorite; PRO is what buys a list. Un-starring is never
    // gated, so the way back under the limit is always open.
    if (on && !pro && favoriteIds.length >= LITE_FAVORITE_LIMIT) {
      promptProFeature(`Favoriting more than ${LITE_FAVORITE_LIMIT} recipe`);
      return;
    }
    setFavoriteIds((ids) => (on ? [...ids, id] : ids.filter((x) => x !== id)));
    setFavoriteId(id, on).catch((e) => console.warn('Failed to save favorite:', e));
  };

  // FRAME-tab AUTO: the photo is levelled from its OWN pixels, not from the
  // phone. A library still carries no record of how the camera was held when
  // it was shot (EXIF Orientation only knows 0/90/180/270), so the sensor had
  // nothing to offer; the dominant line in the picture is the only horizon
  // there is. A one-shot: it replaces whatever the slider or a previous AUTO
  // left, and does nothing at all when the picture has no line worth trusting.
  const handleAutoStraighten = useCallback(() => {
    const tilt = viewfinderRef.current?.detectHorizon?.() ?? null;
    if (tilt == null) return;
    commit(false, () => setPhotoStraighten(-tilt));
    // commit only reads refs, so the empty dep list stays honest.
  }, []);

  // OPEN IMAGE: the in-app picker (LibraryPickerModal) does the choosing — a
  // grid, then the photo full screen to pinch/double-tap zoom and swipe through,
  // then USE or CANCEL. The system picker it replaced returned the still on the
  // first tap (no preview) and, on Android 13+, as a redacted cache copy with
  // assetId=null — the grid uri keeps the MediaStore asset id, so with
  // ACCESS_MEDIA_LOCATION granted the file is not redacted and tier-1 EXIF /
  // tier-2 MediaStore both still work.
  const handlePickImage = () => {
    if (isProcessing) return;
    setLibraryPickerVisible(true);
  };

  const handleLibraryPicked = async (asset: PickedPhotoAsset) => {
    setLibraryPickerVisible(false);
    if (!asset.uri) return;
    setLibraryImageUri(asset.uri);
    // A new photo starts level: the previous photo's turn and fine
    // straighten must not carry over.
    setPhotoRotation(0);
    setPhotoStraighten(0);
    setMode('library');
    // Picking from the camera is the other half of that switch (the camera
    // button is the way back), so the camera's edits must not land on the
    // photo: the picked still starts at the recipe's own values too.
    if (mode !== 'library') resetEditsToRecipe();
    // Clear old GPS — will be replaced if the photo (or device) has location data
    setGpsInfo(null);

    // Multi-tier GPS resolution: EXIF → MediaLibrary. Never the device's own
    // location — that is where the phone is now, not where the photo was
    // taken, and stamping it just printed the wrong place name on the mark.
    const { resolvePhotoGPS } = await import('./src/utils/photoGps');
    const { gps, permissionDenied } = await resolvePhotoGPS(asset, { useGeotag: gpsEnabled });
    setGpsInfo(gps);
    if (permissionDenied) {
      console.warn('Media library read permission denied — photo GPS unavailable.');
    }

    Haptics.notificationAsync(Haptics.NotificationFeedbackType.Success);
  };

  // System share intake. A shared photo arrives as the launch intent's
  // EXTRA_STREAM, which only the Kotlin module can read (takeSharedImage): it
  // copies the stream into the cache and this feeds it to the library pipeline
  // as an ordinary photo — same path as a pick, GPS and all.
  const sharedPickedRef = useRef(handleLibraryPicked);
  sharedPickedRef.current = handleLibraryPicked;
  useEffect(() => {
    let stale = false;
    let busy = false;
    const importShared = async () => {
      if (stale || busy) return;
      busy = true;
      try {
        await sessionInitRef.current;
        if (stale) return;
        const shared = await RecipescamExport.takeSharedImage();
        if (stale || !shared?.path) return;
        sharedPickedRef.current({ uri: `file://${shared.path}`, assetId: shared.assetId || null });
      } finally {
        busy = false;
      }
    };
    importShared();
    // The other half is a share landing on an app that is already alive: no
    // mount pass sees that intent, only this background -> active transition.
    // The native read clears the extra, so later resumes import nothing.
    const sub = AppState.addEventListener('change', (nextAppState) => {
      if (nextAppState === 'active') importShared();
    });
    return () => {
      stale = true;
      sub.remove();
    };
  }, []);

  const activeRecipe: Recipe =
    selectedRecipe || {
      id: 'temp',
      name: 'Custom',
      baseFilter: 'none',
      adjustments,
      frameId: selectedFrame,
      useGeotag,
    };

  // Thumbnail/preview target for the camera-mode right button: newest photo.
  const lastPhotoUri = photoHistory.length > 0 ? photoHistory[photoHistory.length - 1].uri : null;

  // The PRO feature the current look is using, or null while it is Lite-clean.
  // Only the EXPORT consults it: the preview shows every look for free, so the
  // answer is computed where the file is about to be written, not on the chips.
  // PRO unlocks every look, so a paying user has nothing left in use: only a
  // Lite session can trip them: a printed frame it previewed, or a GPS stamp
  // that arrived with a restored session.
  const proLook = pro ? null : proLookInUse({ frame: selectedFrame, gpsWm: useGeotag, hdf: adjustments.hdf ?? 0 });
  // The native Kotlin exporter has no text-watermark draw, so a Lite export
  // (which always carries the mark) must take the Skia engine.
  const nativeExport = NATIVE_EXPORT && pro;
  // Shutter/export with a PRO look: nothing is rendered — name the feature so
  // the user knows which PRO build would render it.
  const promptPro = (feature: string) => {
    Haptics.notificationAsync(Haptics.NotificationFeedbackType.Warning);
    Alert.alert(
      'PRO LOOK',
      `${feature} can be previewed and edited, but exporting it needs PRO.`,
      [
        { text: 'NOT NOW', style: 'cancel' },
        { text: 'UNLOCK PRO', onPress: () => setShowPro(true) },
      ]
    );
  };
  // Saving, starring, spawning: the action IS the feature, so there is no look
  // to preview first — a LITE tap names it and nothing else happens.
  const promptProFeature = (feature: string) => {
    Haptics.notificationAsync(Haptics.NotificationFeedbackType.Warning);
    Alert.alert('PRO FEATURE', `${feature} needs PRO.`, [
      { text: 'NOT NOW', style: 'cancel' },
      { text: 'UNLOCK PRO', onPress: () => setShowPro(true) },
    ]);
  };

  // Watermark handed to the export engines (Skia + native): the ACCEPTED mark
  // (not the live draft), null while disabled or empty, else trimmed text +
  // position. Trimming here keeps the stamped text identical to what the
  // preview drew.
  const wmForExport = (): {
    text: string;
    x: number;
    y: number;
    color?: string;
    size?: number;
    font?: string | null;
  } | null =>
    // The user's own mark is free in both tiers. LITE only narrows the FACE it
    // may use (one basic font), not the mark itself.
    customWmApplied.enabled && customWmApplied.text.trim().length > 0
      ? {
          text: customWmApplied.text.trim(),
          x: customWmApplied.x,
          y: customWmApplied.y,
          color: customWmApplied.color,
          size: customWmApplied.size,
          font: pro ? customWmApplied.font : null,
        }
      : null;

  // The free build's own mark, burned in on top of the custom one.
  const liteMark = pro ? null : LITE_MARK;

  // `burst` marks one frame of a held-shutter burst: the loop already gave the
  // single haptic and the click would machine-gun, so both are muted, and RAW
  // is skipped (a DNG per frame doubles the exposures the burst has to fit).
  const handleCapture = async (opts?: { burst?: boolean }) => {
    if (isProcessing) return;

    // A PRO look can be composed but not rendered: stop before the shutter, so
    // no capture, no queue entry and no cache file is produced.
    if (proLook) {
      promptPro(proLook);
      return;
    }

    // Camera mode (Phase 4, option A): real capture through vision-camera.
    if (mode === 'camera') {
      if (!cameraPermissionGranted) {
        Alert.alert('Permission Needed', 'Grant camera permission to take photos.');
        return;
      }
      if (!cameraReadyRef.current) {
        pendingShotRef.current = true;
        Haptics.impactAsync(Haptics.ImpactFeedbackStyle.Light);
        return;
      }
      pendingShotRef.current = false;
      if (!photoOutput) {
        Alert.alert('Camera Not Ready', 'Please wait for the camera to start, then try again.');
        return;
      }
      // One capture in flight at a time — the shutter button, a viewfinder tap
      // and a burst frame all land here.
      if (captureBusyRef.current) return;
      captureBusyRef.current = true;
      if (!opts?.burst) Haptics.impactAsync(Haptics.ImpactFeedbackStyle.Medium);
      try {
        // A photo taken now is at the device's current spot — resolve device GPS
        // fresh instead of reusing GPS left over from a previously loaded photo.
        let captureGps = gpsInfo && gpsInfo.source === 'device' ? gpsInfo : null;
        // Kick the fix off here but do NOT await it before the shutter: this is
        // a real GPS read plus a network reverse-geocode, and the sensor sat
        // idle for as long as it took. Resolved below, before the export queue.
        // Only the GPS MARK needs a fresh fix on the capture path: without it
        // the shutter must not wait for the receiver (two seconds of a
        // stamp-less photo is worse than none). EXIF still gets whatever fix
        // the launch prewarm already resolved.
        const gpsPending = gpsEnabled && useGeotag && !captureGps ? getCurrentGPS() : null;

        const capturedAt = Date.now(); // EXIF DateTimeOriginal / file name
        // 0.5x is a native Camera2 session on the hidden ultra-wide lens, not a
        // CameraX zoom ratio: no CameraX session is bound while it is live, so
        // the still has to come from the native module — and Camera2 fires no
        // shutter sound of its own. The LED is a CameraX capture setting, so the
        // native module re-applies the viewfinder's flashMode on its own still
        // request, and drops it back to 'off' on a lens with no flash unit.
        const ultraWideShot = viewfinderRef.current?.isUltraWide?.() === true;
        let filePath: string;
        if (ultraWideShot) {
          filePath = await UltraWide.captureAsync(flashMode);
        } else {
          filePath = (
            await photoOutput.capturePhotoToFile(
              {
                enableShutterSound: shutterSound === 'on' && !opts?.burst,
                // Capture-time LED flash. Forced back to 'off' on a lens with no
                // flash unit: the spec throws for anything else.
                flashMode: flashAvailable ? flashMode : 'off',
              },
              // The Nitro spec takes the callback bag as a required second
              // argument (every field in it optional) — one argument throws.
              {},
            )
          ).filePath;
        }
        const sourceUri = toUri(filePath);

        // RAW DNG sidecar: fire the second exposure immediately after the JPEG
        // so the two shots stay a few tens of ms apart, then file it into the
        // "RAW" album without blocking the JPEG export below.
        if (rawEnabled && rawPhotoOutput && !opts?.burst && !ultraWideShot) {
          try {
            const rawFile = await rawPhotoOutput.capturePhotoToFile(
              {
                enableShutterSound: shutterSound === 'on',
                // Same light as the JPEG it follows: the flash unit may still be
                // recharging tens of ms later, in which case the DNG just lands
                // darker than its JPEG — a silent raw, never a broken capture.
                flashMode: flashAvailable ? flashMode : 'off',
              },
              {},
            );
            const rawUri = toUri(rawFile.filePath);
            saveRawToAlbum(rawUri).then((ok) => {
              if (!ok) {
                Alert.alert('RAW Not Saved', 'The DNG was captured but could not be added to the RAW album.');
              }
            });
          } catch (rawError) {
            console.error('RAW capture failed:', rawError);
          }
        }

        // Snapshot the look at shutter time, then render OFF the shutter path:
        // processAndExportPhoto (~1s Skia render + gallery save) is enqueued on
        // the FIFO background queue — the shutter returns in tens of ms and the
        // next shot can be taken immediately; no full-screen RENDERING overlay.
        // Finished photos land in history (and the gallery) when their turn
        // completes; the thumbnail button shows each as it arrives.
        // P5: the native path (NATIVE_EXPORT) renders through RecipesCamExport —
        // same queue/pushPhoto/Haptics/Alert behavior, different renderer.
        if (gpsPending) {
          const deviceGps = await withDeadline(gpsPending, GPS_WAIT_MS);
          if (deviceGps) {
            captureGps = { ...deviceGps, source: 'device' as const };
            setGpsInfo(captureGps);
          }
        }

        const recipeName = activeRecipe.name;
        // Read at shutter time, not render time — the queued render runs after
        // the next shot and the gesture may have moved on.
        const frameZoom = viewfinderRef.current?.getFrameWindowZoom?.() ?? null;
        const render = async () => {
          const recipeArgs = {
            ...activeRecipe,
            adjustments: renderAdj,
            frameId: selectedFrame,
            useGeotag,
          };
          const options = {
            // Live capture: gallery name RC_<yyyymmdd_hhmmss>.jpg and the
            // shutter instant as the EXIF capture date.
            exported: false,
            capturedAt,
            // 300dpi header + full-res screen sharpen. No evFromCamera: the camera
            // AE bias is never written, so the export applies the same software EV
            // gain the preview shows.
            // aspect: crop to the on-screen composition ratio (full = keep 4:3 native).
            dpi: 300,
            sharpen: true,
            aspect: aspectRatio === 'full' ? undefined : aspectRatio,
            watermark: wmForExport(),
            liteMark,
            watermarkRotation: wmRotation,
            gpsWatermark: gpsWm,
            wallframeLandscape: wallLandscape,
            // FRAME-tab pinch/drag inside a polaroid card window or wall-frame
            // opening: save the same crop the preview showed (null = 1x).
            frameWindowZoom: frameZoom,
          };
          const paint = await loadRenderer(nativeExport);
          return paint(sourceUri, recipeArgs, selectedFrame, useGeotag, captureGps, options);
        };
        enqueueExport(async () => {
          try {
            const result = await render();
            if (result) {
              // No auto preview after a capture — the thumbnail button opens
              // the swipe viewer. Saved to session history either way.
              pushPhoto({
                uri: result.uri,
                recipeName,
                savedToLibrary: result.savedToLibrary,
                assetId: result.assetId,
              });
              Haptics.notificationAsync(Haptics.NotificationFeedbackType.Success);
            } else {
              Alert.alert('Failed', 'Error occurred while processing the captured photo.');
            }
          } catch (error) {
            console.error('Camera export failed:', error);
            Alert.alert('Failed', 'Error occurred while processing the captured photo.');
          }
        });
      } catch (error) {
        console.error('Camera capture failed:', error);
        Alert.alert('Capture Failed', 'Could not take the photo. See logs for details.');
      } finally {
        captureBusyRef.current = false;
      }
      return;
    }

    // Library mode capture/export: processes selected image with recipe, overlays, text
    if (!libraryImageUri || !selectedRecipe) {
      Alert.alert('Error', 'Please select an image from the library first.');
      return;
    }

    setIsProcessing(true);
    Haptics.impactAsync(Haptics.ImpactFeedbackStyle.Medium);

    // Plain library frames export the photo at its own aspect (the ratio band is
    // a camera-composition tool); polaroid/wall keep their framed ratio crop.
    const libraryPlainFrame =
      selectedFrame === 'none' || selectedFrame === 'classic-white' || selectedFrame === 'cinematic';
    const libraryAspect = aspectRatio === 'full' || libraryPlainFrame ? undefined : aspectRatio;
    // FRAME-tab CROP: only the plain frames (polaroid/wall crop through their
    // own window). The native exporter knows nothing about it, so a cropped
    // export always takes the Skia path.
    // The fixed ratios take their rectangle from the viewfinder: the band plus
    // whatever pinch/drag the user applied inside it. cropWH stays as the
    // fallback for the (impossible in practice) case of an unloaded photo.
    const ratioCrop =
      cropRatio !== 'none' && cropRatio !== 'free'
        ? viewfinderRef.current?.getCropRatioRect?.() ?? null
        : null;
    const cropOptions: { cropWH?: number; cropRect?: CropRect } =
      !libraryPlainFrame || cropRatio === 'none'
        ? {}
        : cropRatio === 'free'
          ? { cropRect }
          : ratioCrop
            ? { cropRect: ratioCrop }
            : { cropWH: CROP_W_H[cropRatio] };

    const paint = await loadRenderer(nativeExport && !cropOptions.cropRect);
    const result = nativeExport && !cropOptions.cropRect
      ? await paint(
          libraryImageUri,
          {
            ...selectedRecipe,
            adjustments,
            frameId: selectedFrame,
            useGeotag,
          },
          selectedFrame,
          useGeotag,
          gpsInfo,
          // Library export keeps the on-screen composition: plain frames export
          // the photo as seen (own aspect), polaroid/wall keep their ratio crop.
          {
            aspect: libraryAspect,
            // Library export: RC_<ts>_exported.jpg, and the loaded photo's
            // EXIF (camera, dates, GPS) is carried into the file.
            exported: true,
            watermark: wmForExport(),
            liteMark,
            watermarkRotation: wmRotation,
            gpsWatermark: gpsWm,
            wallframeLandscape: wallLandscape,
          }
        )
      : await paint(
          libraryImageUri,
          {
            ...selectedRecipe,
            adjustments,
            frameId: selectedFrame,
            useGeotag,
          },
          selectedFrame,
          useGeotag,
          gpsInfo,
          // Library export keeps the on-screen composition: plain frames export
          // the photo as seen (own aspect), polaroid/wall keep their ratio crop.
          {
            aspect: libraryAspect,
            // Library export: RC_<ts>_exported.jpg, and the loaded photo's
            // EXIF (camera, dates, GPS) is carried into the file.
            exported: true,
            watermark: wmForExport(),
            liteMark,
            watermarkRotation: wmRotation,
            gpsWatermark: gpsWm,
            wallframeLandscape: wallLandscape,
            // FRAME-tab CROP: the exact keep-rectangle the preview showed.
            ...cropOptions,
            // Pinch/drag inside a polaroid card window or wall-frame opening:
            // save the same crop the preview showed (null = centered 1x).
            frameWindowZoom: viewfinderRef.current?.getFrameWindowZoom?.() ?? null,
            photoRotation,
            photoStraighten,
          }
        );

    setIsProcessing(false);

    if (result) {
      pushPhoto({
        uri: result.uri,
        recipeName: activeRecipe.name,
        savedToLibrary: result.savedToLibrary,
        assetId: result.assetId,
      });
      // Library has no thumbnail button (right button switches back to camera),
      // so the export result auto-opens the viewer on the newest photo.
      setViewerIndex(photoHistory.length);
      Haptics.notificationAsync(Haptics.NotificationFeedbackType.Success);
    } else {
      Alert.alert('Failed', 'Error occurred while processing image.');
    }
  };

  // Volume keys as a shutter release. `handleCapture` is rebuilt every render,
  // so the listener is bound once and reaches the current one through a ref.
  const captureFromKeyRef = useRef(handleCapture);
  captureFromKeyRef.current = handleCapture;
  // Session up -> replay a queued press. Stable identity: the Viewfinder's
  // onStarted/onStopped callbacks are memoised around it.
  const handleCameraReady = useCallback((ready: boolean) => {
    cameraReadyRef.current = ready;
    if (ready && pendingShotRef.current) {
      pendingShotRef.current = false;
      setTimeout(() => void captureFromKeyRef.current(), 0);
    }
  }, []);
  useEffect(() => {
    const sub = VolumeShutter.addListener('onShutter', () => {
      void captureFromKeyRef.current();
    });
    return () => sub.remove();
  }, []);
  // Only the camera screen claims the keys; everywhere else (the library)
  // they stay volume keys. The modals need no flag of their own: an RN
  // Modal is a window of its own and holds the focus, so the activity never
  // sees a key while one is up.
  useEffect(() => {
    VolumeShutter.setEnabled(mode === 'camera');
  }, [mode]);

  // Held-shutter burst: press and hold the shutter, frames keep coming until
  // the finger lifts. Every frame is a normal capture (GPS resolve, RAW rules,
  // background render enqueue), so a burst photo is indistinguishable from a
  // tapped one apart from the muted haptic/sound. The `await` IS the pacing: a
  // frame cannot start before the previous one is on disk, which is why no
  // timer is needed (and why 'speed' buys nothing extra here).
  // ponytail: BURST_MAX is a runaway guard for a lost press-out (responder
  // terminated mid-hold); raise it if bursts longer than 30 frames are wanted.
  const BURST_MAX = 30;
  const burstRef = useRef(false);
  const handleBurstStart = () => {
    if (mode !== 'camera' || burstRef.current) return;
    if (proLook) {
      promptPro(proLook);
      return;
    }
    burstRef.current = true;
    Haptics.impactAsync(Haptics.ImpactFeedbackStyle.Medium);
    void (async () => {
      for (let i = 0; i < BURST_MAX && burstRef.current; i++) {
        await handleCapture({ burst: true });
      }
      burstRef.current = false;
    })();
  };
  const handleBurstStop = () => {
    burstRef.current = false;
  };

  // Switching back to camera: drop GPS that belongs to a library photo, so the
  // live view (and any capture) never stamps a stale location.
  const handleSetMode = (next: 'camera' | 'library') => {
    if (next === mode) return;
    if (next === 'camera' && gpsInfo && gpsInfo.source !== 'device') {
      setGpsInfo(null);
    }
    // The deck panels belong to one mode only (FRAME exists in library alone,
    // and the WATERMARK panel is the watermark's edit session), so every switch
    // closes them: no frame chip row over the live preview, and no watermark
    // placement layer left eating the camera's tap-to-focus.
    setOpenTab(null);
    setOpenParamKey(null);
    resetEditsToRecipe();
    // Camera mode has no FRAME picker to undo a frame, so even a recipe that
    // carries one must not follow the user onto the live camera (and into the
    // capture, which burns the frame in).
    if (next === 'camera') setSelectedFrame('none');
    setMode(next);
  };

  // Append a finished export (camera capture or library export) to the session
  // photo history. Returned entry id lets callers delete by id.
  const pushPhoto = (p: Omit<PhotoEntry, 'id'>): string => {
    const id = `photo-${Date.now()}-${photoSeq.current++}`;
    setPhotoHistory((h) => [...h, { id, ...p }]);
    return id;
  };

  // Thumbnail (camera mode) opens the viewer on the newest photo.
  const openLatestViewer = () => {
    if (photoHistory.length > 0) setViewerIndex(photoHistory.length - 1);
  };

  // Viewer trash: delete the photo from the app AND its gallery copy (when it
  // was saved). Deleting a saved photo goes through Android's per-item system
  // confirmation (scoped storage — every single delete asks again by design);
  // if the user cancels THAT dialog the photo is kept in both places.
  const handleDeletePhoto = async (id: string) => {
    const idx = photoHistory.findIndex((p) => p.id === id);
    if (idx < 0) return;
    const entry = photoHistory[idx];
    const remove = () => {
      const next = photoHistory.filter((p) => p.id !== id);
      setPhotoHistory(next);
      setViewerIndex((prev) => {
        if (prev === null) return null;
        if (next.length === 0) return null;
        if (prev > idx) return prev - 1;
        if (prev >= next.length) return next.length - 1;
        return prev;
      });
    };
    const deleteCache = async () => {
      try {
        await FileSystem.deleteAsync(entry.uri, { idempotent: true });
      } catch (e) {
        console.warn('Photo cache delete failed:', e);
      }
    };

    if (!entry.savedToLibrary || !entry.assetId) {
      // Never reached the gallery — nothing for the OS to confirm.
      remove();
      deleteCache();
      return;
    }
    try {
      // deleteAssetsAsync shows the OS delete confirmation when the photo is
      // in the gallery. false = user cancelled it → keep everything.
      const ok = await MediaLibraryLegacy.deleteAssetsAsync([entry.assetId]);
      if (!ok) {
        Alert.alert('Photo Kept', 'Android did not confirm the deletion, so the photo stays here and in your gallery.');
        return;
      }
      remove();
      deleteCache();
    } catch (e) {
      console.warn('Gallery delete failed:', e);
      Alert.alert('Delete Failed', 'Could not remove the photo from your gallery. It stays here too.');
    }
  };

  // Viewer SAVE & DONE: photo was exported to cache only — copy it into the
  // gallery now and remember its assetId so a later trash can remove it.
  const handleSavePhoto = async (id: string) => {
    const entry = photoHistory.find((p) => p.id === id);
    if (!entry || entry.savedToLibrary) return;
    const perm = await MediaLibraryLegacy.requestPermissionsAsync();
    if (!perm.granted) {
      Alert.alert('Not Saved', 'Media library access was denied, so this photo was not saved to your gallery.');
      return;
    }
    try {
      const asset = await MediaLibraryLegacy.createAssetAsync(entry.uri);
      setPhotoHistory((h) => h.map((p) => (p.id === id ? { ...p, savedToLibrary: true, assetId: asset.id } : p)));
      Haptics.notificationAsync(Haptics.NotificationFeedbackType.Success);
    } catch (e) {
      console.error('Save to gallery failed:', e);
      Alert.alert('Save Failed', 'Could not save this photo to your gallery.');
    }
  };

  // Tool-rail toggle: closing the panel (or switching tabs) also drops the open
  // parameter row — otherwise a stale slider row (and its image-drag target)
  // would survive into the next panel.
  const handleToggleTab = (tab: TabId) => {
    setOpenTab((prev) => (prev === tab ? null : tab));
    setOpenParamKey(null);
  };

  // While a panel parameter row is open, a vertical drag anywhere on the live
  // camera image adjusts that same parameter (the open slider follows). Open
  // row wins over the locked-AE EV drag; a plain tap still locks focus.
  const imageAdjustTarget = (() => {
    if (mode !== 'camera' || openTab !== 'iq' && openTab !== 'wb' && openTab !== 'filters') return null;
    if (!openParamKey) return null;
    const list = openTab === 'iq' ? PARAM_DEFS.iq : openTab === 'wb' ? PARAM_DEFS.wb : PARAM_DEFS.filters;
    const def = list.find((d) => d.key === openParamKey);
    if (!def) return null;
    return {
      key: def.key,
      min: def.min,
      max: def.max,
      step: def.step,
      value: def.get(adjustments),
      onChange: (v: number) => handleUpdateAdjustments(def.set(v)),
    };
  })();

  return (
    <View className="flex-1 bg-black">
      <StatusBar barStyle="light-content" translucent backgroundColor="transparent" />

      {/* Fullscreen hero: photo or live preview fills the whole screen */}
      <View className="absolute inset-0 bg-black">
        <Viewfinder
          ref={viewfinderRef}
          mode={mode}
          facing={cameraFacing}
          recipe={previewRecipe}
          selectedFrame={shown.frame}
          useGeotag={shown.useGeotag}
          gpsInfo={gpsInfo}
          libraryImageUri={libraryImageUri}
          availableHeight={deckTop}
          topInset={topInset}
          photoRotation={shown.photoRotation}
          photoStraighten={shown.photoStraighten}
          cameraPermissionGranted={cameraPermissionGranted}
          onRequestCameraPermission={requestCameraPermission}
          photoOutput={photoOutput}
          rawOutput={rawPhotoOutput}
          rawEnabled={rawEnabled}
          aspectRatio={aspectRatio}
          cropRatio={shown.cropRatio}
          cropApplied={shown.cropApplied}
          cropRect={shown.cropRect}
          onCropRectChange={(r) => commit(true, () => setCropRect(r))}
          onSessionError={handleCameraSessionError}
          onCameraReady={handleCameraReady}
          onExposureChange={(ev) => handleUpdateAdjustments({ exposureCompensation: ev })}
          meteringAdjustments={meteringActive ? meteringOverlay(shownAdjustments) : undefined}
          imageAdjustTarget={imageAdjustTarget}
          onComparePeek={peekArmed ? handlePeek : undefined}
          // Touch-to-shutter: tap the live image -> focus locks -> capture.
          onTouchShutter={touchToShutter ? handleCapture : undefined}
          customWm={shown.customWm}
          wmRotation={shown.wmRotation}
          gpsWm={shown.gpsWm}
          onGpsWmChange={(x, y, size) => commit(true, () => setGpsWm((g) => ({ ...g, x, y, size })))}
          onWmSizeChange={(size) => commit(true, () => setCustomWm((p) => ({ ...p, size })))}
          wallLandscape={shown.wallLandscape}
          // The mark only captures image touches while its panel is open, so a
          // watermark left ON cannot block tap-to-focus or pinch/zoom.
          wmEditing={openTab === 'frame' && wmPanelOpen}
          frameTabActive={openTab === 'frame'}
          onWmPositionChange={(x, y) => commit(true, () => setCustomWm((p) => ({ ...p, x, y })))}
          onWmEdit={() => {
            // Double-tap on the mark re-opens its editor (and with it the
            // placement layer), then focuses the input.
            setOpenTab('frame');
            setOpenParamKey(null);
            setWmEditNonce((n) => n + 1);
          }}
        />
      </View>

      {/* Top overlay: mode label + recipe name (left), Save current (right) */}
      <TopBar
        mode={mode}
        recipeName={peeking ? previewRecipe.name : activeRecipe.name}
        onSaveRecipe={handleSaveRecipe}
        onOverwriteRecipe={selectedRecipe?.isCustom ? handleOverwriteRecipe : undefined}
        onEditRecipe={
          selectedRecipe?.isCustom ? () => setEditingRecipe(selectedRecipe) : undefined
        }
        onExportShare={handleExportShare}
        onUndo={handleUndo}
        undoDepth={undoDepth}
        // Capture-time LED flash: offered only on a lens that carries a flash
        // unit, and only in camera mode (the library save never fires the
        // camera). Tap cycles OFF -> AUTO -> ON -> OFF.
        flashMode={mode === 'camera' && flashAvailable ? flashMode : undefined}
        onCycleFlash={
          mode === 'camera' && flashAvailable
            ? () => setFlashMode((m) => (m === 'off' ? 'auto' : m === 'auto' ? 'on' : 'off'))
            : undefined
        }
        onHeight={setTopInset}
      />

      {/* Bottom deck: chip panel (progressive disclosure) -> tool rail -> shutter */}
      <View
        className="absolute left-0 right-0 bottom-0 z-10"
        style={{ paddingBottom: keyboardHeight }}
        onLayout={(e) => setDeckTop(e.nativeEvent.layout.y)}
      >
        {openTab !== null && (
          <View
            style={{
              backgroundColor: 'rgba(8,8,10,0.96)',
              borderTopWidth: 1,
              borderTopColor: 'rgba(63,63,70,0.7)',
            }}
            className="rounded-t-2xl overflow-hidden border-l border-r border-zinc-800/60"
          >
            <AdjustmentPanel
              activeTab={openTab}
              recipes={recipes}
              currentRecipeId={selectedRecipe?.id || ''}
              adjustments={shownAdjustments}
              onResetAll={handleResetAll}
              resetDirty={resetDirty}
              selectedFrame={shown.frame}
              cropRatio={shown.cropRatio}
              onUpdateCropRatio={(r) => commit(false, () => setCropRatio(r))}
              cropApplied={shown.cropApplied}
              onApplyCrop={() => commit(false, () => setCropApplied(cropRatio))}
              cropEnabled={
                mode === 'library' &&
                (selectedFrame === 'none' ||
                  selectedFrame === 'classic-white' ||
                  selectedFrame === 'cinematic')
              }
              photoRotation={shown.photoRotation}
              photoStraighten={shown.photoStraighten}
              onPickRotation={(d) => commit(false, () => setPhotoRotation(d))}
              onStraighten={(d) => commit(true, () => setPhotoStraighten(d))}
              onAutoStraighten={handleAutoStraighten}
              wallLandscape={shown.wallLandscape}
              onToggleWallLandscape={() => commit(false, () => setWallLandscape((v) => !v))}
              useGeotag={shown.useGeotag}
              pro={pro}
              openParam={openParamKey}
              onOpenParamChange={setOpenParamKey}
              currentBaseFilter={selectedRecipe?.baseFilter}
              onCreateRecipe={handleCreateRecipe}
              editingRecipe={editingRecipe}
              onCloseEdit={() => setEditingRecipe(null)}
              onUpdateRecipe={handleUpdateRecipe}
              onSelectRecipe={handleSelectRecipe}
              favoriteIds={favoriteIds}
              onToggleFavorite={handleToggleFavorite}
              onUpdateAdjustments={handleUpdateAdjustments}
              onUpdateFrame={handleUpdateFrame}
              onToggleGeotag={handleToggleGeotag}
              onSaveRecipe={handleSaveRecipe}
              onImportRecipe={handleImportRecipe}
              recipeLimitReached={liteSaveBlocked}
              onRecipeLimit={promptRecipeLimit}
              onDeleteRecipe={handleDeleteRecipe}
              customWm={shown.customWm}
              onUpdateCustomWm={handleUpdateCustomWm}
              gpsWm={shown.gpsWm}
              onUpdateGpsWm={(wm) => commit(true, () => setGpsWm(wm))}
              onAcceptCustomWm={handleAcceptCustomWm}
              onCancelCustomWm={handleCancelCustomWm}
              wmEditNonce={wmEditNonce}
              wmRotation={shown.wmRotation}
              onRotateWm={() => commit(false, () => setWmRotation((r) => (r + 90) % 360))}
              onWmPanelChange={setWmPanelOpen}
            />
          </View>
        )}

        <ToolRail activeTab={openTab} onToggle={handleToggleTab} />

        {/* Library picker (grid -> zoomable preview -> USE / CANCEL) */}
        <LibraryPickerModal
          visible={libraryPickerVisible}
          onCancel={() => setLibraryPickerVisible(false)}
          onSelect={handleLibraryPicked}
        />

        <CameraControls
          lastPhotoUri={lastPhotoUri}
          onCapture={handleCapture}
          onBurstStart={mode === 'camera' ? handleBurstStart : undefined}
          onBurstStop={handleBurstStop}
          onPickImage={handlePickImage}
          onOpenPreview={openLatestViewer}
          onOpenSettings={() => setSettingsVisible(true)}
          onFlipCamera={() => setCameraFacing((f) => (f === 'back' ? 'front' : 'back'))}
          isLibraryMode={mode === 'library'}
          onSwitchToCamera={() => handleSetMode('camera')}
        />
      </View>

      {/* Gear sheet: shutter sound / ratio+RAW / metering mode */}
      <SettingsModal
        visible={settingsVisible}
        onClose={() => setSettingsVisible(false)}
        aspectRatio={aspectRatio}
        onAspectRatio={handleAspectRatio}
        rawEnabled={rawEnabled}
        onRawEnabled={handleRawEnabled}
        cameraMode={mode === 'camera'}
        meterMode={meterMode}
        onMeterModeChange={setMeterMode}
        shutterSound={shutterSound}
        onShutterSound={setShutterSound}
        touchToShutter={touchToShutter}
        onTouchToShutter={setTouchToShutter}
        gpsEnabled={gpsEnabled}
        onGpsEnabled={handleToggleGps}
        startupMode={startupMode}
        onStartupMode={handleStartupMode}
        pro={pro}
        onUpgrade={() => setShowPro(true)}
      />

      {/* The paywall: the only place the tier is sold. */}
      <ProModal visible={showPro} onClose={() => setShowPro(false)} />

      {/* Session photo viewer (swipe across captured/exported photos) */}
      <PhotoViewerModal
        visible={viewerIndex !== null && photoHistory.length > 0}
        photos={photoHistory}
        initialIndex={viewerIndex ?? 0}
        onClose={() => setViewerIndex(null)}
        onDelete={handleDeletePhoto}
        onSave={handleSavePhoto}
      />

      {/* Global Processing Loader Overlay */}
      {isProcessing && (
        <View className="absolute inset-0 bg-black/75 flex items-center justify-center space-y-4">
          <ActivityIndicator size="large" color="#f59e0b" />
          <Text className="text-amber-500 font-mono text-sm tracking-widest font-bold">
            RENDERING PHOTO...
          </Text>
        </View>
      )}
    </View>
  );
}