/**
 * Discover painting influence candidates from art-history web sources.
 * Returns normalized source refs for painting_influence_sources (artist / movement / painting).
 */
const { fetchHtml, searchWikipediaTitle, sleep } = require('./image-fetcher');
const { normalizeArtist } = require('./influence-resolver');

const SEARCH_SITES = [
  'theartstory.org',
  'metmuseum.org',
  'artsandculture.google.com',
  'nga.gov',
  'artic.edu',
  'moma.org',
  'britannica.com',
  'jstor.org',
  'oxfordartonline.com',
  'wikiart.org',
  'wikipedia.org',
];

const MOVEMENT_HINTS = [
  'Impressionism',
  'Post-Impressionism',
  'Cubism',
  'Expressionism',
  'Surrealism',
  'Baroque',
  'Renaissance',
  'Romanticism',
  'Realism',
  'Symbolism',
  'Fauvism',
  'Abstract Expressionism',
  'Pop Art',
  'Neoclassicism',
  'Rococo',
  'Mannerism',
  'Gothic',
  'Byzantine',
  'Art Nouveau',
  'Futurism',
  'Dada',
  'Minimalism',
];

function uniqueByKey(items, keyFn) {
  const seen = new Set();
  return items.filter((item) => {
    const key = keyFn(item);
    if (seen.has(key)) return false;
    seen.add(key);
    return true;
  });
}

function stripHtml(text) {
  return (text || '')
    .replace(/<[^>]+>/g, ' ')
    .replace(/&nbsp;/g, ' ')
    .replace(/&amp;/g, '&')
    .replace(/&quot;/g, '"')
    .replace(/\s+/g, ' ')
    .trim();
}

function extractInfluenceNames(text) {
  if (!text) return [];
  const names = [];
  const patterns = [
    /influenced by ([^.;\n]{4,120})/gi,
    /draw(?:s|n)? on ([^.;\n]{4,120})/gi,
    /indebted to ([^.;\n]{4,120})/gi,
    /following the example of ([^.;\n]{4,120})/gi,
  ];
  for (const pattern of patterns) {
    let match;
    while ((match = pattern.exec(text)) !== null) {
      const chunk = stripHtml(match[1]);
      chunk
        .split(/,| and |;|\//)
        .map((s) => s.trim())
        .filter((s) => s.length > 3 && s.length < 80)
        .forEach((s) => names.push(s));
    }
  }
  return names;
}

function detectMovements(text) {
  const lower = (text || '').toLowerCase();
  return MOVEMENT_HINTS.filter((m) => lower.includes(m.toLowerCase()));
}

async function fetchJson(url) {
  const res = await fetch(url, {
    headers: { 'User-Agent': 'GalleryInfluenceBot/1.0 (personal art history project)' },
  });
  if (!res.ok) throw new Error(`HTTP ${res.status}`);
  return res.json();
}

async function discoverFromWikipedia(artistName, paintingTitle) {
  const results = [];
  const wikiTitle = await searchWikipediaTitle(paintingTitle, artistName);
  if (!wikiTitle) return results;

  try {
    const parseUrl =
      `https://en.wikipedia.org/w/api.php?action=parse&page=${encodeURIComponent(wikiTitle)}` +
      '&prop=wikitext&format=json&origin=*';
    const data = await fetchJson(parseUrl);
    const wikitext = data?.parse?.wikitext?.['*'] || '';
    const plain = wikitext
      .replace(/\{\{[^{}]*\}\}/g, ' ')
      .replace(/\[\[Category:[^\]]+\]\]/gi, ' ')
      .replace(/\[\[([^\]|]+)\|([^\]]+)\]\]/g, '$2')
      .replace(/\[\[([^\]]+)\]\]/g, '$1')
      .replace(/''+/g, '');

    for (const name of extractInfluenceNames(plain)) {
      results.push({
        type: 'artist',
        artist: name,
        period: { duringCreation: true },
        notes: `Mentioned on Wikipedia article for "${wikiTitle}".`,
        source: 'Wikipedia',
        source_url: `https://en.wikipedia.org/wiki/${encodeURIComponent(wikiTitle.replace(/ /g, '_'))}`,
        discovered_via: 'wikipedia',
        confidence: 'discovered',
      });
    }

    for (const movement of detectMovements(plain)) {
      results.push({
        type: 'movement',
        movement,
        period: { duringCreation: true },
        notes: `Movement referenced on Wikipedia article for "${wikiTitle}".`,
        source: 'Wikipedia',
        source_url: `https://en.wikipedia.org/wiki/${encodeURIComponent(wikiTitle.replace(/ /g, '_'))}`,
        discovered_via: 'wikipedia',
        confidence: 'discovered',
      });
    }
  } catch {
    // skip
  }

  return results;
}

async function discoverFromWikidata(artistName) {
  const results = [];
  try {
    const searchUrl =
      'https://www.wikidata.org/w/api.php?action=wbsearchentities&format=json&language=en&type=item&limit=1' +
      `&search=${encodeURIComponent(artistName)}`;
    const search = await fetchJson(searchUrl);
    const entityId = search?.search?.[0]?.id;
    if (!entityId) return results;

    const entityUrl = `https://www.wikidata.org/wiki/Special:EntityData/${entityId}.json`;
    const entityData = await fetchJson(entityUrl);
    const entity = entityData?.entities?.[entityId];
    const claims = entity?.claims?.P737 || [];

    for (const claim of claims.slice(0, 8)) {
      const influencedId = claim?.mainsnak?.datavalue?.value?.id;
      if (!influencedId) continue;
      const labelUrl =
        `https://www.wikidata.org/w/api.php?action=wbgetentities&ids=${influencedId}` +
        '&props=labels&languages=en&format=json';
      const labelData = await fetchJson(labelUrl);
      const label = labelData?.entities?.[influencedId]?.labels?.en?.value;
      if (!label) continue;
      results.push({
        type: 'artist',
        artist: label,
        period: { duringCreation: true },
        notes: `Wikidata P737 (influenced by) on ${artistName}.`,
        source: 'Wikidata',
        source_url: `https://www.wikidata.org/wiki/${entityId}`,
        discovered_via: 'wikidata',
        confidence: 'discovered',
      });
    }
  } catch {
    // skip
  }
  return results;
}

async function discoverFromWebSearch(artistName, paintingTitle) {
  const results = [];
  const query = `"${artistName}" "${paintingTitle}" influenced by ${SEARCH_SITES.map((s) => `site:${s}`).join(' OR ')}`;

  try {
    const html = await fetchHtml('https://html.duckduckgo.com/html/', {
      method: 'POST',
      body: `q=${encodeURIComponent(query)}`,
      headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
    });

    const links = [...html.matchAll(/uddg=([^&"]+)/g)]
      .map((m) => decodeURIComponent(m[1]))
      .filter((url) => SEARCH_SITES.some((site) => url.includes(site)))
      .slice(0, 5);

    for (const url of links) {
      try {
        const page = await fetchHtml(url, {
          headers: { Referer: 'https://html.duckduckgo.com/' },
        });
        const text = stripHtml(page);
        const site = SEARCH_SITES.find((s) => url.includes(s)) || 'web';

        for (const name of extractInfluenceNames(text).slice(0, 4)) {
          results.push({
            type: 'artist',
            artist: name,
            period: { duringCreation: true },
            notes: `Found via art-history web search (${site}).`,
            source: site,
            source_url: url,
            discovered_via: `web:${site}`,
            confidence: 'discovered',
          });
        }

        for (const movement of detectMovements(text).slice(0, 3)) {
          results.push({
            type: 'movement',
            movement,
            period: { duringCreation: true },
            notes: `Movement cited on ${site}.`,
            source: site,
            source_url: url,
            discovered_via: `web:${site}`,
            confidence: 'discovered',
          });
        }

        await sleep(1200);
      } catch {
        // next result
      }
    }
  } catch {
    // skip
  }

  return results;
}

async function discoverFromMet(artistName, paintingTitle) {
  const results = [];
  try {
    const searchUrl =
      `https://collectionapi.metmuseum.org/public/collection/v1/search?q=${encodeURIComponent(
        `${artistName} ${paintingTitle}`
      )}&hasImages=true`;
    const search = await fetchJson(searchUrl);
    const objectId = search?.objectIDs?.[0];
    if (!objectId) return results;

    const object = await fetchJson(
      `https://collectionapi.metmuseum.org/public/collection/v1/objects/${objectId}`
    );
    const text = [object.creditLine, object.culture, object.period, object.classification, object.medium]
      .filter(Boolean)
      .join('. ');

    for (const movement of detectMovements(text)) {
      results.push({
        type: 'movement',
        movement,
        period: { duringCreation: true },
        notes: `Met Museum object metadata for ${object.title || paintingTitle}.`,
        source: 'The Metropolitan Museum of Art',
        source_url: object.objectURL || `https://www.metmuseum.org/art/collection/search/${objectId}`,
        discovered_via: 'metmuseum',
        confidence: 'discovered',
      });
    }
  } catch {
    // skip
  }
  return results;
}

async function discoverInfluencesForWork({ artist, title, year }) {
  const artistName = normalizeArtist(artist);
  const chunks = await Promise.all([
    discoverFromWikipedia(artistName, title),
    discoverFromWikidata(artistName),
    discoverFromMet(artistName, title),
    discoverFromWebSearch(artistName, title),
  ]);

  return uniqueByKey(chunks.flat(), (item) =>
    item.type === 'movement'
      ? `movement:${item.movement}`
      : item.type === 'artist'
        ? `artist:${item.artist}`
        : `painting:${item.artist}:${item.title}`
  ).map((item) => ({
    ...item,
    period: item.period || (year ? { duringCreation: true } : undefined),
  }));
}

module.exports = {
  discoverInfluencesForWork,
  discoverFromWikipedia,
  discoverFromWikidata,
  discoverFromWebSearch,
  discoverFromMet,
  SEARCH_SITES,
};