RecipesCam/src/utils/nativeExport.ts

// P5 native export path: mirrors exportEngine.processAndExportPhoto's pipeline
// contract (same recipe math, same output file/gallery behavior) but renders
// inside the RecipesCamExport Kotlin module — decode/crop/tone/cinema/matrix/
// denoise/clarity/grain/frame/GPS/sharpen run off the JS thread and the JPEG is
// encoded straight to disk (DPI header patched natively). JS only computes the
// parameter set with the same helpers exportEngine uses, then saves to gallery.
// Deliberately does NOT import exportEngine or Skia: when the native path is
// active the Skia engine must not even load.
import RecipescamExport, { PhotoAdjust } from '../../modules/recipescam-export';
import * as FileSystem from 'expo-file-system/legacy';
import * as MediaLibrary from 'expo-media-library/legacy';
import { Recipe, GPSInfo, FrameId, AspectRatio, ColorAdjustments } from '../types';
import { getSkiaColorMatrix, applyExposureGain } from './colorUtils';
import { getToneUniforms } from './toneShader';
import { getCinemaUniforms } from './cinemaShader';

export interface NativeExportResult {
  uri: string;
  savedToLibrary: boolean;
  assetId?: string | null;
}

export interface NativeExportOptions {
  // DPI to stamp into the JPEG header (metadata only — pixel size never changes).
  dpi?: number;
  // Apply the subtle "Screen" output sharpen (exportEngine #9) to the final
  // pixels before encoding (legacy camera captures pass sharpen: true → 0.5).
  sharpen?: boolean;
  // True for photos captured through the live camera: the AE bias already
  // applied exposure compensation at capture, so no 2^EV matrix gain is added.
  evFromCamera?: boolean;
  // Composition aspect-ratio crop ('full'/undefined = none). Native computes the
  // center-largest rect after decode because the pixel size is only known there.
  aspect?: AspectRatio;
  // Custom text watermark overlay — position fractions of the photo area, same
  // contract as ExportOptions.watermark. SHIPPED but NOT drawn yet: the Kotlin
  // module renders geo captions but has no text-watermark draw (ponytail: add
  // it when native parity with the Skia engine is completed).
  watermark?: { text: string; x: number; y: number } | null;
}

// The Kotlin module reads plain absolute paths, not file:// URIs.
const stripScheme = (uri: string) => uri.replace(/^file:\/\//, '');

// Unique filename per export (same cache-bust rationale as exportEngine: a fixed
// path would serve stale <Image> cache entries).
const nextExportFile = () => `${FileSystem.cacheDirectory}camrecipe_pro_export_${Date.now()}.jpg`;

export async function processAndExportPhotoNative(
  sourceUri: string,
  recipe: Recipe,
  frameId: FrameId,
  useGeotag: boolean,
  gpsInfo: GPSInfo | null,
  options?: NativeExportOptions
): Promise<NativeExportResult | null> {
  try {
    const adjustments: ColorAdjustments = recipe.adjustments;
    // Same matrix rule as exportEngine #3: camera captures skip 2^EV (hardware
    // AE bias already applied it), library stills get the matrix gain.
    const matrix = options?.evFromCamera
      ? getSkiaColorMatrix(recipe.baseFilter, adjustments)
      : applyExposureGain(
          getSkiaColorMatrix(recipe.baseFilter, adjustments),
          adjustments.exposureCompensation ?? 0
        );
    // Base filter is passed so a stock's own tone pass is picked up, but the
    // Kotlin side only reads toneDr/Hl/Sh — the split-tone RGB (Classic Neg) is
    // preview/engine only. Nothing in the app calls nativeExport (dev probe).
    const tone = getToneUniforms(adjustments, recipe.baseFilter);
    const cinema = getCinemaUniforms(recipe.cinema);
    // Final screen sharpen (engine #9): the sharpening knob (0..10) overrides
    // the legacy boolean sharpen flag (camera captures keep it true → 0.5).
    const sharpKnob = adjustments.sharpening ?? 0;
    const sharpenAmount = sharpKnob > 0 ? (sharpKnob / 10) * 0.8 : options?.sharpen ? 0.5 : 0;
    const aspect: '4:3' | '3:2' | undefined =
      options?.aspect && options.aspect !== 'full' && frameId !== 'wallframe'
        ? options.aspect
        : undefined;

    const adjust: PhotoAdjust = {
      toneDr: tone.dr,
      toneHl: tone.hl,
      toneSh: tone.sh,
      cinema: cinema ? cinema.flat : null,
      denoise: adjustments.denoise,
      clarity: adjustments.clarity,
      grain: adjustments.grain,
      quality: 95, // engine encodes at fixed JPEG 95
      frameId,
      // Fonts/artwork are bundled in the APK (res/raw assets_*, drawable
      // wallframe) — native reads them directly; no base64 bridge needed.
      geo:
        useGeotag && gpsInfo
          ? { locality: gpsInfo.locality || 'STREET VIEW', timestamp: gpsInfo.timestamp }
          : null,
      sharpen: sharpenAmount > 0 ? sharpenAmount : undefined,
      dpi: options?.dpi && options.dpi > 0 ? options.dpi : undefined,
      aspect,
    };

    const exportFile = nextExportFile(); // file:// URI (cacheDirectory)
    const dstPath = stripScheme(exportFile);
    await RecipescamExport.processPhotoAsync(stripScheme(sourceUri), dstPath, matrix, null, adjust);

    const mediaPermission = await MediaLibrary.requestPermissionsAsync();
    if (mediaPermission.granted) {
      try {
        const asset = await MediaLibrary.createAssetAsync(exportFile);
        return { uri: exportFile, savedToLibrary: true, assetId: asset.id };
      } catch (e) {
        console.warn('Save to gallery failed:', e);
      }
    } else {
      console.warn('Media Library permission denied. Image saved to temporary cache only.');
    }
    return { uri: exportFile, savedToLibrary: false };
  } catch (error) {
    console.error('Error during native photo processing and export:', error);
    return null;
  }
}