#!/usr/bin/env node
/* eslint-disable no-console */
const fs = require('fs');
const path = require('path');
const crypto = require('crypto');
require('dotenv').config();

const sharp = require('sharp');
const { openDatabase, closeDatabase, all, run } = require('../lib/sqlite');
const { ensurePlantSchema } = require('../lib/plants');

const OUTPUT_DIR = path.join(__dirname, '..', 'public', 'plants');
const MANIFEST_PATH = path.join(OUTPUT_DIR, 'manifest.json');
const ROOT_DIR = path.join(__dirname, '..', '..');
const PLANTS_DUMP_PATH = path.join(ROOT_DIR, 'plants_dump_utf8.json');
const SEARCH_CACHE_PATH = path.join(OUTPUT_DIR, 'wikimedia-search-cache.json');
const MAX_CONCURRENCY = Number(process.env.PLANT_IMAGE_CONCURRENCY || 1);
const REQUEST_TIMEOUT_MS = 20000;
const MAX_FETCH_RETRIES = 5;
const WIKIMEDIA_SEARCH_PREFIX = 'wikimedia-search:';

const sleep = (ms) => new Promise((resolve) => setTimeout(resolve, ms));

const slugify = (value) => {
  const normalized = String(value || '')
    .normalize('NFD')
    .replace(/[\u0300-\u036f]/g, '')
    .toLowerCase()
    .replace(/[^a-z0-9]+/g, '-')
    .replace(/^-+|-+$/g, '');
  return normalized || 'plant';
};

const buildFileBaseName = (plant) => {
  const botanicalSlug = slugify(plant.botanicalName);
  const nameSlug = slugify(plant.name);
  const suffix = crypto
    .createHash('sha1')
    .update(`${plant.id}|${plant.botanicalName}|${plant.name}`)
    .digest('hex')
    .slice(0, 8);

  if (nameSlug && nameSlug !== botanicalSlug) {
    return `${botanicalSlug}--${nameSlug}--${suffix}`;
  }

  return `${botanicalSlug}--${suffix}`;
};

const ensureOutputDir = () => {
  fs.mkdirSync(OUTPUT_DIR, { recursive: true });
};

const loadRefreshMatchers = () => new Set(
  String(process.env.PLANT_IMAGE_REFRESH || '')
    .split(',')
    .map((value) => value.trim().toLowerCase())
    .filter(Boolean),
);

const loadManifest = () => {
  try {
    const raw = fs.readFileSync(MANIFEST_PATH, 'utf8');
    return JSON.parse(raw);
  } catch {
    return { generatedAt: null, items: [] };
  }
};

const saveManifest = (manifest) => {
  fs.writeFileSync(MANIFEST_PATH, JSON.stringify(manifest, null, 2));
};

const loadSearchCache = () => {
  try {
    return JSON.parse(fs.readFileSync(SEARCH_CACHE_PATH, 'utf8'));
  } catch {
    return {};
  }
};

const saveSearchCache = (cache) => {
  fs.writeFileSync(SEARCH_CACHE_PATH, JSON.stringify(cache, null, 2));
};

const shouldRefreshPlantImage = (plant, refreshMatchers) => {
  if (!refreshMatchers || refreshMatchers.size === 0) return false;

  return [
    plant.id,
    plant.name,
    plant.botanicalName,
  ].some((value) => refreshMatchers.has(String(value || '').trim().toLowerCase()));
};

const loadDumpFallbackMap = () => {
  try {
    const raw = fs.readFileSync(PLANTS_DUMP_PATH, 'utf8');
    const entries = JSON.parse(raw);
    if (!Array.isArray(entries)) return new Map();

    const map = new Map();
    for (const entry of entries) {
      if (!entry || typeof entry.botanicalName !== 'string' || typeof entry.imageUri !== 'string') continue;
      const key = entry.botanicalName.trim().toLowerCase();
      if (!key || !/^https?:\/\//i.test(entry.imageUri)) continue;
      if (!map.has(key)) map.set(key, entry.imageUri.trim());
    }
    return map;
  } catch {
    return new Map();
  }
};

const getRetryDelayMs = (attempt, retryAfterHeader) => {
  const retryAfterSeconds = Number(retryAfterHeader);
  if (Number.isFinite(retryAfterSeconds) && retryAfterSeconds > 0) {
    return retryAfterSeconds * 1000;
  }
  return Math.min(30000, 3000 * 2 ** attempt);
};

const tryDecode = (value) => {
  try {
    return decodeURIComponent(value);
  } catch {
    return value;
  }
};

const decodeRepeatedly = (value, rounds = 3) => {
  let current = value;
  for (let index = 0; index < rounds; index += 1) {
    const decoded = tryDecode(current);
    if (decoded === current) break;
    current = decoded;
  }
  return current;
};

const toWikimediaFilePathUrl = (rawUrl) => {
  if (typeof rawUrl !== 'string' || !rawUrl.includes('upload.wikimedia.org/wikipedia/commons/')) {
    return null;
  }

  const cleanUrl = rawUrl.split(/[?#]/)[0];
  const parts = cleanUrl.split('/').filter(Boolean);
  if (parts.length < 2) return null;

  let fileName = null;
  const thumbIndex = parts.indexOf('thumb');

  if (thumbIndex >= 0 && parts.length >= thumbIndex + 5) {
    fileName = parts[parts.length - 2];
  } else {
    fileName = parts[parts.length - 1];
  }

  if (!fileName) return null;
  const decoded = tryDecode(fileName).trim();
  if (!decoded) return null;

  return `https://commons.wikimedia.org/wiki/Special:FilePath/${encodeURIComponent(decoded)}`;
};

const parseWikimediaSearchQuery = (value) => {
  if (typeof value !== 'string') return null;

  const trimmed = value.trim();
  if (!trimmed.toLowerCase().startsWith(WIKIMEDIA_SEARCH_PREFIX)) return null;

  const rawQuery = trimmed.slice(WIKIMEDIA_SEARCH_PREFIX.length).trim();
  if (!rawQuery) return null;

  return decodeRepeatedly(rawQuery);
};

const fetchImageBuffer = async (url, attempt = 0, redirectCount = 0) => {
  if (redirectCount > 5) {
    throw new Error('Too many redirects');
  }

  const controller = new AbortController();
  const timeout = setTimeout(() => controller.abort(), REQUEST_TIMEOUT_MS);

  try {
    const response = await fetch(url, {
      headers: {
        'User-Agent': 'GreenLens-PlantImageImporter/1.0',
        'Accept': 'image/avif,image/webp,image/apng,image/*,*/*;q=0.8',
        'Referer': 'https://commons.wikimedia.org/',
      },
      redirect: 'manual',
      signal: controller.signal,
    });

    if ([301, 302, 303, 307, 308].includes(response.status)) {
      const location = response.headers.get('location');
      if (!location) throw new Error(`Redirect without location for ${url}`);
      const nextUrl = new URL(location, url).toString();
      return fetchImageBuffer(nextUrl, attempt, redirectCount + 1);
    }

    if ((response.status === 429 || response.status >= 500) && attempt < MAX_FETCH_RETRIES) {
      const delayMs = getRetryDelayMs(attempt, response.headers.get('retry-after'));
      await sleep(delayMs);
      return fetchImageBuffer(url, attempt + 1, redirectCount);
    }

    if (!response.ok) {
      throw new Error(`HTTP ${response.status}`);
    }

    const arrayBuffer = await response.arrayBuffer();
    return Buffer.from(arrayBuffer);
  } finally {
    clearTimeout(timeout);
  }
};

const searchWikimediaImage = async (query, searchCache) => {
  const normalizedQuery = String(query || '').trim();
  if (!normalizedQuery) return null;

  if (Object.prototype.hasOwnProperty.call(searchCache, normalizedQuery)) {
    return searchCache[normalizedQuery] || null;
  }

  const apiUrl = `https://commons.wikimedia.org/w/api.php?action=query&generator=search&gsrnamespace=6&gsrsearch=${encodeURIComponent(normalizedQuery)}&gsrlimit=5&prop=imageinfo&iiprop=url&iiurlwidth=1200&format=json`;

  try {
    const controller = new AbortController();
    const timeout = setTimeout(() => controller.abort(), REQUEST_TIMEOUT_MS);
    const response = await fetch(apiUrl, {
      headers: {
        'User-Agent': 'GreenLens-PlantImageImporter/1.0',
        'Accept': 'application/json',
      },
      signal: controller.signal,
    });
    clearTimeout(timeout);

    if (!response.ok) {
      searchCache[normalizedQuery] = null;
      saveSearchCache(searchCache);
      return null;
    }

    const data = await response.json();
    const pages = data?.query?.pages ? Object.values(data.query.pages) : [];

    for (const page of pages) {
      const imageInfo = page?.imageinfo?.[0];
      const candidate = imageInfo?.thumburl || imageInfo?.url || null;
      if (candidate && /^https?:\/\//i.test(candidate)) {
        searchCache[normalizedQuery] = candidate;
        saveSearchCache(searchCache);
        return candidate;
      }
    }
  } catch {
    // Ignore and cache as null below.
  }

  searchCache[normalizedQuery] = null;
  saveSearchCache(searchCache);
  return null;
};

const convertToWebp = async (inputBuffer, outputPath) => {
  const tempPath = `${outputPath}.tmp-${process.pid}-${Date.now()}.webp`;
  await sharp(inputBuffer)
    .rotate()
    .resize({
      width: 1200,
      height: 1200,
      fit: 'inside',
      withoutEnlargement: true,
    })
    .webp({ quality: 82 })
    .toFile(tempPath);

  fs.copyFileSync(tempPath, outputPath);
  fs.unlinkSync(tempPath);
};

const updatePlantImageUri = async (db, plantId, localImageUri) => {
  await run(
    db,
    'UPDATE plants SET imageUri = ?, imageStatus = ?, updatedAt = datetime(\'now\') WHERE id = ?',
    [localImageUri, 'ok', plantId],
  );
};

const processPlant = async (db, plant, manifestItems, dumpFallbackMap, searchCache, refreshMatchers) => {
  const currentUri = String(plant.imageUri || '').trim();
  const placeholderQuery = parseWikimediaSearchQuery(currentUri);
  const fileBaseName = buildFileBaseName(plant);
  const fileName = `${fileBaseName}.webp`;
  const localImageUri = `/plants/${fileName}`;
  const outputPath = path.join(OUTPUT_DIR, fileName);
  const dumpFallbackUri = dumpFallbackMap.get(String(plant.botanicalName || '').trim().toLowerCase()) || null;
  const shouldRefresh = shouldRefreshPlantImage(plant, refreshMatchers);

  if (fs.existsSync(outputPath) && !shouldRefresh) {
    await updatePlantImageUri(db, plant.id, localImageUri);
    manifestItems.push({
      id: plant.id,
      botanicalName: plant.botanicalName,
      name: plant.name,
      sourceUri: currentUri,
      localImageUri,
      status: 'existing',
    });
    return { status: 'existing', plantId: plant.id, localImageUri };
  }

  if (!/^https?:\/\//i.test(currentUri) && !placeholderQuery) {
    manifestItems.push({
      id: plant.id,
      botanicalName: plant.botanicalName,
      name: plant.name,
      sourceUri: currentUri,
      localImageUri,
      status: 'skipped',
      reason: 'Current imageUri is not a remote URL and no local file exists yet.',
    });
    return { status: 'skipped', plantId: plant.id, localImageUri };
  }

  let lastError = null;
  let sourceUsed = currentUri;
  let buffer = null;

  const searchedUri = await searchWikimediaImage(placeholderQuery, searchCache)
    || await searchWikimediaImage(plant.botanicalName, searchCache)
    || await searchWikimediaImage(plant.name, searchCache);

  const candidateUris = [
    /^https?:\/\//i.test(currentUri) ? currentUri : null,
    /^https?:\/\//i.test(currentUri) ? toWikimediaFilePathUrl(currentUri) : null,
    dumpFallbackUri,
    toWikimediaFilePathUrl(dumpFallbackUri),
    searchedUri,
    toWikimediaFilePathUrl(searchedUri),
  ].filter(Boolean);

  for (const candidateUri of [...new Set(candidateUris)]) {
    try {
      buffer = await fetchImageBuffer(candidateUri);
      sourceUsed = candidateUri;
      break;
    } catch (error) {
      lastError = error;
    }
  }

  if (!buffer) {
    throw lastError || new Error('Image download failed');
  }

  await convertToWebp(buffer, outputPath);
  await updatePlantImageUri(db, plant.id, localImageUri);

  manifestItems.push({
    id: plant.id,
      botanicalName: plant.botanicalName,
      name: plant.name,
      sourceUri: sourceUsed,
      localImageUri,
      status: 'downloaded',
    });

  await sleep(900);
  return { status: 'downloaded', plantId: plant.id, localImageUri };
};

const runWithConcurrency = async (items, worker, concurrency) => {
  const queue = [...items];
  const results = [];

  const runners = Array.from({ length: Math.min(concurrency, queue.length) }, async () => {
    while (queue.length > 0) {
      const item = queue.shift();
      if (!item) return;
      results.push(await worker(item));
    }
  });

  await Promise.all(runners);
  return results;
};

const main = async () => {
  ensureOutputDir();
  const manifest = loadManifest();
  const manifestItems = [];
  const dumpFallbackMap = loadDumpFallbackMap();
  const searchCache = loadSearchCache();
  const refreshMatchers = loadRefreshMatchers();
  const db = await openDatabase();

  try {
    await ensurePlantSchema(db);
    const plants = await all(
      db,
      `SELECT id, name, botanicalName, imageUri
       FROM plants
       ORDER BY name COLLATE NOCASE ASC`,
    );

    console.log(`Preparing ${plants.length} plant images...`);

    const failures = [];
    let completed = 0;

    await runWithConcurrency(
      plants,
      async (plant) => {
        try {
          const result = await processPlant(db, plant, manifestItems, dumpFallbackMap, searchCache, refreshMatchers);
          completed += 1;
          console.log(`[${completed}/${plants.length}] ${plant.botanicalName} -> ${result.status}`);
          return result;
        } catch (error) {
          completed += 1;
          const message = error instanceof Error ? error.message : String(error);
          console.error(`[${completed}/${plants.length}] ${plant.botanicalName} -> failed: ${message}`);
          failures.push({
            id: plant.id,
            name: plant.name,
            botanicalName: plant.botanicalName,
            sourceUri: plant.imageUri,
            error: message,
          });
          manifestItems.push({
            id: plant.id,
            botanicalName: plant.botanicalName,
            name: plant.name,
            sourceUri: plant.imageUri,
            status: 'failed',
            error: message,
          });
          return { status: 'failed', plantId: plant.id };
        }
      },
      MAX_CONCURRENCY,
    );

    const downloadedCount = manifestItems.filter((item) => item.status === 'downloaded').length;
    const existingCount = manifestItems.filter((item) => item.status === 'existing').length;
    const skippedCount = manifestItems.filter((item) => item.status === 'skipped').length;

    saveManifest({
      generatedAt: new Date().toISOString(),
      summary: {
        totalPlants: plants.length,
        downloadedCount,
        existingCount,
        skippedCount,
        failureCount: failures.length,
      },
      failures,
      items: manifestItems,
    });

    console.log('');
    console.log(`Downloaded: ${downloadedCount}`);
    console.log(`Already present: ${existingCount}`);
    console.log(`Skipped: ${skippedCount}`);
    console.log(`Failed: ${failures.length}`);
    console.log(`Manifest: ${MANIFEST_PATH}`);

    if (failures.length > 0) {
      process.exitCode = 1;
    }
  } finally {
    await closeDatabase(db);
  }
};

main().catch((error) => {
  console.error('Plant image import failed.');
  console.error(error instanceof Error ? error.stack || error.message : String(error));
  process.exit(1);
});