import React, { useState, useEffect, useRef, useCallback } from 'react';
import { View, StatusBar, Alert, ActivityIndicator, Text, AppState, Platform, Keyboard } from 'react-native';
import { useCameraPermission, usePhotoOutput } from 'react-native-vision-camera';
import * as ImagePicker from 'expo-image-picker';
import * as FileSystem from 'expo-file-system/legacy';
import * as MediaLibrary from 'expo-media-library';
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 { Recipe, ColorAdjustments, CustomWatermark, GpsWatermark, FrameId, GPSInfo, AspectRatio, MeterMode, PhotoEntry, ShutterSound, StartupMode } from './src/types';
import { getAllRecipes, saveCustomRecipe, deleteCustomRecipe } from './src/utils/storageUtils';
import { DEFAULT_ADJUSTMENTS, FILM_SIMS, filmSimToRecipe } from './src/utils/defaultRecipes';
import { getCurrentGPS, requestLocationPermissions } from './src/utils/locationUtils';
import { resolvePhotoGPS } from './src/utils/photoGps';
import { processAndExportPhoto } from './src/utils/exportEngine';
import { processAndExportPhotoNative } from './src/utils/nativeExport';
import { PARAM_DEFS } from './src/utils/paramDefs';

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

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';

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: flushes the EV to
  // the hardware AE bias right before each capture (live slider drags never
  // touch the hardware — that flashed 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);
  // Library photo rotation (FRAME tab), 0 or 90deg clockwise; feeds the
  // preview source and the export alike.
  const [photoRotation, setPhotoRotation] = useState<0 | 90>(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[]>([]);
  const [selectedRecipe, setSelectedRecipe] = useState<Recipe | null>(null);
  
  // Custom temporary overrides for the sliders
  const [adjustments, setAdjustments] = useState<ColorAdjustments>({ ...DEFAULT_ADJUSTMENTS });

  const [selectedFrame, setSelectedFrame] = useState<FrameId>('none');
  const [useGeotag, setUseGeotag] = 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 };
  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) => {
    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 = () => {
    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 = () => {
    setCustomWm({ ...customWmApplied });
    closeWatermarkEditor();
  };
  // Composition aspect-ratio (FULL / 4:3 / 3:2 upright) + RAW DNG sidecar.
  const [aspectRatio, setAspectRatio] = useState<AspectRatio>('full');
  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';
  const meteringAdj: Partial<ColorAdjustments> | undefined = meteringActive
    ? {
        highlight: clampAdj((adjustments.highlight ?? 0) + METER_HL_HIGHLIGHT),
        shadow: clampAdj((adjustments.shadow ?? 0) + METER_HL_SHADOW),
        contrast: clampAdj((adjustments.contrast ?? 0) + METER_HL_CONTRAST),
        clarity: clampAdj((adjustments.clarity ?? 0) + METER_HL_CLARITY),
      }
    : undefined;
  // Same tonal overlay for the camera EXPORT (the EV dip is not inside — the
  // hardware AE bias at capture already carries it, evFromCamera skips software
  // EV, so folding the dip here would darken twice).
  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);
  
  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);
  // 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');
  // Startup behavior: 'default' = PROVIA 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);
  // 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();
  // 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: 'quality',
  });
  // 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}`);

  useEffect(() => {
    // B5: run a single sequenced init — restore the session first, then fall
    // back to the first recipe only when no recipe was restored.
    initSession();
    // Do NOT auto-load device GPS here — it would override photo GPS on library mode
  }, []);

  // P0 spike: native decode/encode benchmark (EXPO_PUBLIC_BENCH=1 builds only).
  useEffect(() => {
    if (process.env.EXPO_PUBLIC_BENCH === '1') {
      import('./src/dev/nativeBenchProbe')
        .then((m) => m.nativeBenchProbe())
        .catch(() => {});
    }
  }, []);

  // P6 parity probe: same source through legacy Skia and native engines
  // (EXPO_PUBLIC_PARITY=1 builds only).
  useEffect(() => {
    if (process.env.EXPO_PUBLIC_PARITY === '1') {
      import('./src/dev/parityProbe')
        .then((m) => m.parityProbe())
        .catch((e) => console.error('[PARITY] effect failed', e));
    }
  }, []);

  // 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,
          meterMode,
          shutterSound,
          selectedRecipeId: selectedRecipe?.id || null,
          gpsInfo,
          customWm,
        };
        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, aspectRatio, 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);

    // 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.meterMode === 'evaluative' || s.meterMode === 'highlight') setMeterMode(s.meterMode);
        if (typeof s.rawEnabled === 'boolean') setRawEnabled(s.rawEnabled);
      }
    } catch (e) {
      console.warn('Failed to read camera settings:', e);
    }
    settingsHydratedRef.current = true;

    // Startup mode: 'default' opens camera + PROVIA 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;
        }
      }
      if (imageUri) {
        setLibraryImageUri(imageUri);
        setMode('library');
      } else {
        setMode(session.mode || 'camera');
      }
      if (session.adjustments)
        setAdjustments({ ...DEFAULT_ADJUSTMENTS, ...session.adjustments });
      if (session.selectedFrame) setSelectedFrame(session.selectedFrame);
      if (session.useGeotag !== undefined) setUseGeotag(session.useGeotag);
      if (session.aspectRatio === 'full' || session.aspectRatio === '4:3' || session.aspectRatio === '3:2') setAspectRatio(session.aspectRatio);
      // 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: typeof raw.font === 'string' ? raw.font : null,
        });
      }
      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) => {
    setSelectedRecipe(recipe);
    setAdjustments(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 film sim swaps the look only: everything the user dialled in on
  // the LIGHT/WB/FX tabs and the frame they picked stay exactly as they are.
  // A saved recipe still loads its own stored values (that is what saving it
  // was for). Same trick as the session restore below: set the recipe without
  // applyRecipe, which would snap the sliders back to the sim's canonical set.
  const handleSelectRecipe = (recipe: Recipe) => {
    if (!FILM_SIMS.some((s) => s.id === recipe.id)) {
      applyRecipe(recipe);
      return;
    }
    setSelectedRecipe({ ...recipe, adjustments, frameId: selectedFrame });
  };

  // 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 });
  };

  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 };
    setAdjustments(next);
    if (selectedRecipe) {
      setSelectedRecipe({
        ...selectedRecipe,
        adjustments: next,
      });
    }
  };

  const handleUpdateFrame = (frameId: FrameId) => {
    setSelectedFrame(frameId);
    if (selectedRecipe) {
      setSelectedRecipe({
        ...selectedRecipe,
        frameId,
      });
    }
  };

  const handleToggleGeotag = async (enabled: boolean) => {
    setUseGeotag(enabled);
    if (selectedRecipe) {
      setSelectedRecipe({
        ...selectedRecipe,
        useGeotag: enabled,
      });
    }
    if (enabled && !gpsInfo) {
      const locationGranted = await requestLocationPermissions();
      if (locationGranted) {
        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, meterMode, rawEnabled })
    ).catch(() => {});
  }, [shutterSound, meterMode, rawEnabled]);

  // 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 (!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.`);
  };

  // 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'>) => {
    const newRecipe = await saveCustomRecipe(recipe);
    const list = await getAllRecipes();
    setRecipes(list);
    applyRecipe(newRecipe);
    Haptics.notificationAsync(Haptics.NotificationFeedbackType.Success);
  };

  const handleDeleteRecipe = async (id: string) => {
    await deleteCustomRecipe(id);
    const list = await getAllRecipes();
    setRecipes(list);
    if (selectedRecipe?.id === id && list.length > 0) {
      applyRecipe(list[0]);
    }
  };

  const handlePickImage = async () => {
    if (isProcessing) return;

    // On Android 10+, picking without ACCESS_MEDIA_LOCATION makes the OS hand us
    // a redacted copy (EXIF GPS stripped). That silently kills Tier-1 EXIF GPS
    // and the photo's own coordinates (often a different place than where the
    // user stands now) get replaced by a device-GPS fallback. Request media
    // read + photo-location BEFORE the pick so the copy keeps its true EXIF GPS.
    let mediaOk = true;
    if (useGeotag && Platform.OS === 'android') {
      try {
        const perm = await MediaLibrary.requestPermissionsAsync(false, ['photo']);
        mediaOk = perm.granted;
      } catch (e) {
        mediaOk = false;
        console.warn('Pre-pick media+photo-location permission error:', e);
      }
    }

    const result = await ImagePicker.launchImageLibraryAsync({
      mediaTypes: ImagePicker.MediaTypeOptions.Images,
      allowsEditing: false,
      quality: 1,
      exif: true,
      // Android 13+ photo picker always returns a redacted cache copy with
      // assetId=null — EXIF GPS stripped, MediaStore id lost → photo GPS is
      // unreachable and we'd stamp the device's location instead. The legacy
      // picker (ACTION_GET_CONTENT → DocumentsUI) hands back a
      // com.android.providers.media.documents uri, so the MediaStore asset id
      // survives AND (with ACCESS_MEDIA_LOCATION granted) the file is not
      // redacted → tier-1 EXIF / tier-2 MediaStore both work.
      legacy: Platform.OS === 'android' && useGeotag,
    });

    if (!result.canceled && result.assets && result.assets.length > 0) {
      const asset = result.assets[0];
      setLibraryImageUri(asset.uri);
      setPhotoRotation(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 → device fallback.
      // Device fallback only when media read was granted (else we cannot know
      // whether the photo carries its own GPS — stamping the device's current
      // spot over a photo from somewhere else would be wrong).
      const { gps, permissionDenied } = await resolvePhotoGPS(asset, {
        useGeotag,
        allowDeviceFallback: useGeotag && mediaOk,
      });
      setGpsInfo(gps);
      if (permissionDenied) {
        console.warn('Media library read permission denied — photo GPS unavailable.');
      }

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

  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;

  // 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 =>
    customWmApplied.enabled && customWmApplied.text.trim().length > 0
      ? {
          text: customWmApplied.text.trim(),
          x: customWmApplied.x,
          y: customWmApplied.y,
          color: customWmApplied.color,
          size: customWmApplied.size,
          font: customWmApplied.font,
        }
      : null;

  const handleCapture = async () => {
    if (isProcessing) 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 (!photoOutput) {
        Alert.alert('Camera Not Ready', 'Please wait for the camera to start, then try again.');
        return;
      }
      captureBusyRef.current = true;
      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;
        if (useGeotag && !captureGps) {
          const deviceGps = await getCurrentGPS();
          if (deviceGps) {
            captureGps = { ...deviceGps, source: 'device' as const };
            setGpsInfo(captureGps);
          }
        }

        // Hardware AE bias for this shot (best-effort, bounded retries inside).
        // Applied here — right before the capture — instead of live during EV
        // slider drags, which re-locked AE on the Xiaomi and flashed preview.
        try {
          await viewfinderRef.current?.flushExposureBias();
        } catch (e) {
          console.warn('EV flush at capture failed:', e);
        }
        const { filePath } = await photoOutput.capturePhotoToFile({ enableShutterSound: shutterSound === 'on' }, {});
        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) {
          try {
            const rawFile = await rawPhotoOutput.capturePhotoToFile({ enableShutterSound: shutterSound === 'on' }, {});
            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.
        const recipeName = activeRecipe.name;
        const render = () => {
          const recipeArgs = {
            ...activeRecipe,
            adjustments: renderAdj,
            frameId: selectedFrame,
            useGeotag,
          };
          const options = {
            // 300dpi header + full-res screen sharpen. evFromCamera: the AE bias
            // already applied exposure compensation at capture — don't add 2^EV.
            // aspect: crop to the on-screen composition ratio (full = keep 4:3 native).
            dpi: 300,
            sharpen: true,
            evFromCamera: true,
            aspect: aspectRatio === 'full' ? undefined : aspectRatio,
            watermark: wmForExport(),
            watermarkRotation: wmRotation,
            gpsWatermark: gpsWm,
            wallframeLandscape: wallLandscape,
          };
          return NATIVE_EXPORT
            ? processAndExportPhotoNative(sourceUri, recipeArgs, selectedFrame, useGeotag, captureGps, options)
            : processAndExportPhoto(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;

    const result = NATIVE_EXPORT
      ? await processAndExportPhotoNative(
          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,
            watermark: wmForExport(),
            watermarkRotation: wmRotation,
            gpsWatermark: gpsWm,
            wallframeLandscape: wallLandscape,
          }
        )
      : await processAndExportPhoto(
          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,
            watermark: wmForExport(),
            watermarkRotation: wmRotation,
            gpsWatermark: gpsWm,
            wallframeLandscape: wallLandscape,
            // 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,
          }
        );

    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.');
    }
  };

  // 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={
            selectedRecipe || {
              id: 'temp',
              name: 'Custom',
              baseFilter: 'none',
              adjustments,
              frameId: selectedFrame,
              useGeotag,
            }
          }
          selectedFrame={selectedFrame}
          useGeotag={useGeotag}
          gpsInfo={gpsInfo}
          libraryImageUri={libraryImageUri}
          availableHeight={deckTop}
          photoRotation={photoRotation}
          cameraPermissionGranted={cameraPermissionGranted}
          onRequestCameraPermission={requestCameraPermission}
          photoOutput={photoOutput}
          rawOutput={rawPhotoOutput}
          rawEnabled={rawEnabled}
          aspectRatio={aspectRatio}
          onSessionError={handleCameraSessionError}
          onExposureChange={(ev) => handleUpdateAdjustments({ exposureCompensation: ev })}
          meteringEvOffset={meteringActive ? METER_HL_EV : 0}
          meteringAdjustments={meteringAdj}
          imageAdjustTarget={imageAdjustTarget}
          customWm={customWm}
          wmRotation={wmRotation}
          gpsWm={gpsWm}
          onGpsWmChange={(x, y, size) => setGpsWm({ x, y, size })}
          onWmSizeChange={(size) => setCustomWm((p) => ({ ...p, size }))}
          wallLandscape={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 === 'watermark'}
          onWmPositionChange={(x, y) => 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('watermark');
            setOpenParamKey(null);
            setWmEditNonce((n) => n + 1);
          }}
        />
      </View>

      {/* Top overlay: mode label + recipe name (left), Save current (right) */}
      <TopBar mode={mode} recipeName={activeRecipe.name} onSaveRecipe={handleSaveRecipe} />

      {/* 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={adjustments}
              selectedFrame={selectedFrame}
              photoRotation={photoRotation}
              onToggleRotation={() => setPhotoRotation((r) => (r === 0 ? 90 : 0))}
              wallLandscape={wallLandscape}
              onToggleWallLandscape={() => setWallLandscape((v) => !v)}
              useGeotag={useGeotag}
              openParam={openParamKey}
              onOpenParamChange={setOpenParamKey}
              currentBaseFilter={selectedRecipe?.baseFilter}
              onCreateRecipe={handleCreateRecipe}
              onSelectRecipe={handleSelectRecipe}
              onUpdateAdjustments={handleUpdateAdjustments}
              onUpdateFrame={handleUpdateFrame}
              onToggleGeotag={handleToggleGeotag}
              onSaveRecipe={handleSaveRecipe}
              onDeleteRecipe={handleDeleteRecipe}
              customWm={customWm}
              onUpdateCustomWm={handleUpdateCustomWm}
              onAcceptCustomWm={handleAcceptCustomWm}
              onCancelCustomWm={handleCancelCustomWm}
              wmEditNonce={wmEditNonce}
              wmRotation={wmRotation}
              onRotateWm={() => setWmRotation((r) => (r + 90) % 360)}
            />
          </View>
        )}

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

        <CameraControls
          lastPhotoUri={lastPhotoUri}
          onCapture={handleCapture}
          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}
        startupMode={startupMode}
        onStartupMode={handleStartupMode}
      />

      {/* 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>
  );
}