/**
 * Bidirectional image harmonize (dev <-> prod) by file mtime,
 * then merge artists/paintings catalog rows (checkup flags + image paths),
 * then regenerate painting + portrait thumbnails on both image roots.
 *
 * Usage:
 *   npm run harmonize:images
 *   npm run harmonize:images -- --dry-run
 *   npm run harmonize:images -- --skip-thumbnails
 *   npm run harmonize:images -- --skip-db
 */
const fs = require('fs');
const path = require('path');
const { spawnSync } = require('child_process');
const { rootDir, confirmProdAction, PROD_DB_NAME } = require('./db-env');
const { loadHarmonizeConfig, prodImagesPath } = require('./lib/harmonize-config');
const { printCliResult } = require('./lib/cli-result');

const IMAGE_SUBDIRS = ['portraits', 'paintings'];
const MTIME_TOLERANCE_MS = 1000;

/** Tables that carry checkup flags and image/portrait path links. */
const IMAGE_CATALOG_TABLES = ['artists', 'paintings'];

const THUMB_SCRIPTS = [
  'regenerate-thumbnails.js',
  'regenerate-portrait-thumbs.js',
];

function parseArgs(argv) {
  const configArg = argv.find((a) => a.startsWith('--config='));
  const preferArg = argv.find((a) => a.startsWith('--prefer='));
  return {
    dryRun: argv.includes('--dry-run'),
    verbose: argv.includes('--verbose'),
    skipThumbnails: argv.includes('--skip-thumbnails'),
    skipDb: argv.includes('--skip-db'),
    prefer: preferArg ? preferArg.slice('--prefer='.length).trim().toLowerCase() : null,
    configPath: configArg ? configArg.slice('--config='.length) : null,
  };
}

function resolveDevImageDir() {
  require('dotenv').config({ path: path.join(rootDir, '.env') });
  return path.resolve(process.env.IMAGE_DIR || path.join(rootDir, 'data', 'images'));
}

function walkImageFiles(rootDir, baseRel = '') {
  const files = [];
  const abs = path.join(rootDir, baseRel);
  if (!fs.existsSync(abs)) return files;

  for (const entry of fs.readdirSync(abs, { withFileTypes: true })) {
    const rel = baseRel ? path.join(baseRel, entry.name).replace(/\\/g, '/') : entry.name;
    if (entry.isDirectory()) {
      files.push(...walkImageFiles(rootDir, rel));
    } else if (entry.isFile()) {
      files.push(rel);
    }
  }
  return files;
}

function collectRelativePaths(imageRoot) {
  const relPaths = new Set();
  for (const sub of IMAGE_SUBDIRS) {
    const subRoot = path.join(imageRoot, sub);
    if (!fs.existsSync(subRoot)) continue;
    for (const rel of walkImageFiles(subRoot, sub)) {
      relPaths.add(rel.replace(/\\/g, '/'));
    }
  }
  return relPaths;
}

function statFile(imageRoot, relPath) {
  const abs = path.join(imageRoot, relPath);
  try {
    if (!fs.existsSync(abs)) return null;
    const st = fs.statSync(abs);
    if (!st.isFile()) return null;
    return { size: st.size, mtimeMs: st.mtimeMs };
  } catch {
    return null;
  }
}

function ensureDirForFile(filePath) {
  fs.mkdirSync(path.dirname(filePath), { recursive: true });
}

function copyFile(src, dest, dryRun) {
  if (dryRun) return;
  ensureDirForFile(dest);
  fs.copyFileSync(src, dest);
}

/**
 * Rebuild thumbs from full images for one environment.
 * Child scripts honour existing env (dotenv will not override DB_NAME / IMAGE_DIR).
 */
function regenerateThumbnails({ label, imageDir, database }) {
  console.log(`\n--- Thumbnails (${label}) ---`);
  console.log(`  IMAGE_DIR=${imageDir}`);
  console.log(`  DB_NAME=${database}`);

  const env = {
    ...process.env,
    IMAGE_DIR: imageDir,
    DB_NAME: database,
  };

  for (const file of THUMB_SCRIPTS) {
    const scriptPath = path.join(__dirname, file);
    console.log(`  Running ${file}…`);
    const result = spawnSync(process.execPath, [scriptPath], {
      cwd: rootDir,
      stdio: 'inherit',
      env,
    });
    const code = result.status ?? 1;
    if (code !== 0) {
      throw new Error(`Thumbnail regeneration failed (${label}): ${file} exited ${code}`);
    }
  }
}

/**
 * Merge artists + paintings so checkup flags and image/portrait path links
 * travel with the file sync (harmonize:images alone used to leave DB stale).
 */
function syncImageCatalogRows({ dryRun, prefer, verbose }) {
  console.log('\n--- Catalog (artists + paintings checkup / image paths) ---');
  const args = [
    path.join(__dirname, 'harmonize-db.js'),
    `--tables=${IMAGE_CATALOG_TABLES.join(',')}`,
  ];
  if (dryRun) args.push('--dry-run');
  if (verbose) args.push('--verbose');
  if (prefer === 'dev' || prefer === 'prod') args.push(`--prefer=${prefer}`);

  const result = spawnSync(process.execPath, args, {
    cwd: rootDir,
    stdio: 'inherit',
    env: {
      ...process.env,
      // Parent already confirmed prod writes for this harmonize:images run.
      CONFIRM_PROD: '1',
    },
  });
  const code = result.status ?? 1;
  if (code !== 0) {
    throw new Error(`Image catalog sync failed: harmonize-db.js exited ${code}`);
  }
}

function timestampSlug(date = new Date()) {
  const pad = (n) => String(n).padStart(2, '0');
  return [
    date.getFullYear(),
    pad(date.getMonth() + 1),
    pad(date.getDate()),
    '_',
    pad(date.getHours()),
    pad(date.getMinutes()),
    pad(date.getSeconds()),
  ].join('');
}

async function main() {
  const options = parseArgs(process.argv.slice(2));
  const config = loadHarmonizeConfig(options.configPath);
  const dryRun = options.dryRun || config.dryRun;

  const devDir = resolveDevImageDir();
  const prodDir = prodImagesPath(config);

  if (!fs.existsSync(prodDir)) {
    throw new Error(
      `Prod image path not reachable: ${prodDir}. Map SMB share or set paths.prodImages in harmonize config.`,
    );
  }

  if (!dryRun && process.env.CONFIRM_PROD !== '1') {
    await confirmProdAction(
      'Harmonize will copy image files between dev and prod, merge artists/paintings checkup flags and image paths, then regenerate thumbnails on both sides (prod files and gallery_prod may be updated).',
    );
  }

  const devPaths = collectRelativePaths(devDir);
  const prodPaths = collectRelativePaths(prodDir);
  const allPaths = new Set([...devPaths, ...prodPaths]);

  const stats = {
    devToProd: 0,
    prodToDev: 0,
    skipped: 0,
    actions: [],
  };

  for (const rel of allPaths) {
    const devStat = statFile(devDir, rel);
    const prodStat = statFile(prodDir, rel);

    if (devStat && !prodStat) {
      stats.devToProd += 1;
      stats.actions.push({ path: rel, action: 'dev→prod copy' });
      copyFile(path.join(devDir, rel), path.join(prodDir, rel), dryRun);
      continue;
    }

    if (prodStat && !devStat) {
      stats.prodToDev += 1;
      stats.actions.push({ path: rel, action: 'prod→dev copy' });
      copyFile(path.join(prodDir, rel), path.join(devDir, rel), dryRun);
      continue;
    }

    if (!devStat || !prodStat) continue;

    const sameSize = devStat.size === prodStat.size;
    const mtimeClose = Math.abs(devStat.mtimeMs - prodStat.mtimeMs) <= MTIME_TOLERANCE_MS;
    if (sameSize && mtimeClose) {
      stats.skipped += 1;
      continue;
    }

    if (devStat.mtimeMs > prodStat.mtimeMs) {
      stats.devToProd += 1;
      stats.actions.push({ path: rel, action: 'dev→prod update' });
      copyFile(path.join(devDir, rel), path.join(prodDir, rel), dryRun);
    } else if (prodStat.mtimeMs > devStat.mtimeMs) {
      stats.prodToDev += 1;
      stats.actions.push({ path: rel, action: 'prod→dev update' });
      copyFile(path.join(prodDir, rel), path.join(devDir, rel), dryRun);
    } else {
      stats.skipped += 1;
    }
  }

  const reportDir = path.join(rootDir, 'db', 'SyncReports');
  fs.mkdirSync(reportDir, { recursive: true });
  const reportPath = path.join(reportDir, `harmonize_images_${timestampSlug()}.json`);

  const extraDetails = [];

  if (!options.skipDb) {
    syncImageCatalogRows({
      dryRun,
      prefer: options.prefer,
      verbose: options.verbose,
    });
    extraDetails.push(
      dryRun
        ? 'Catalog checkup/path sync previewed (artists, paintings; dry-run)'
        : 'Catalog checkup flags + image paths merged (artists, paintings)',
    );
  } else {
    extraDetails.push('Catalog checkup/path sync skipped (--skip-db)');
  }

  if (!dryRun && !options.skipThumbnails) {
    require('dotenv').config({ path: path.join(rootDir, '.env') });
    const devDb = process.env.DB_NAME || 'gallery_dev';

    regenerateThumbnails({
      label: 'dev',
      imageDir: devDir,
      database: devDb,
    });
    extraDetails.push(`Dev thumbs regenerated (${devDb} @ ${devDir})`);

    regenerateThumbnails({
      label: 'prod',
      imageDir: prodDir,
      database: PROD_DB_NAME,
    });
    extraDetails.push(`Prod thumbs regenerated (${PROD_DB_NAME} @ ${prodDir})`);
  } else if (options.skipThumbnails) {
    extraDetails.push('Thumbnails skipped (--skip-thumbnails)');
  } else {
    extraDetails.push('Thumbnails skipped (dry-run)');
  }

  fs.writeFileSync(reportPath, JSON.stringify({
    generatedAt: new Date().toISOString(),
    dryRun,
    skipThumbnails: options.skipThumbnails,
    skipDb: options.skipDb,
    prefer: options.prefer,
    devDir,
    prodDir,
    stats: {
      devToProd: stats.devToProd,
      prodToDev: stats.prodToDev,
      skipped: stats.skipped,
    },
    steps: extraDetails,
    actions: options.verbose ? stats.actions : stats.actions.slice(0, 500),
  }, null, 2));

  const mode = dryRun ? ' (dry-run)' : '';
  printCliResult({
    script: 'harmonize-images',
    ok: true,
    summary: `Image harmonize complete${mode}: dev→prod ${stats.devToProd}, prod→dev ${stats.prodToDev}, skipped ${stats.skipped}.`,
    details: [
      `Dev: ${devDir}`,
      `Prod: ${prodDir}`,
      `Report: ${reportPath}`,
      ...extraDetails,
    ],
  });
}

main().catch((err) => {
  printCliResult({
    script: 'harmonize-images',
    ok: false,
    summary: err.message,
  });
});