const pool = require('./db');

const VALID_TYPES = new Set(['artist', 'painting', 'movement']);

function parseTypes(typesParam) {
  if (!typesParam || typeof typesParam !== 'string') {
    return ['artist', 'movement', 'painting'];
  }
  const parsed = typesParam
    .split(',')
    .map((t) => t.trim().toLowerCase())
    .filter((t) => VALID_TYPES.has(t));
  return parsed.length > 0 ? parsed : ['artist', 'movement', 'painting'];
}

async function searchArtists(pattern, prefixPattern, perTypeLimit) {
  const { rows } = await pool.query(
    `SELECT a.id, a.name, a.birth_year, a.death_year,
            a.portrait_path, a.portrait_thumb_path,
            m.name AS movement_name,
            CASE WHEN a.name ILIKE $2 THEN 0 ELSE 1 END AS rank
     FROM artists a
     LEFT JOIN art_movements m ON a.movement_id = m.id
     WHERE a.name ILIKE $1
        OR a.wikipedia_title ILIKE $1
        OR m.name ILIKE $1
     ORDER BY rank, a.name
     LIMIT $3`,
    [pattern, prefixPattern, perTypeLimit]
  );
  return rows.map((row) => ({
    type: 'artist',
    id: row.id,
    name: row.name,
    birth_year: row.birth_year,
    death_year: row.death_year,
    movement_name: row.movement_name,
    portrait_path: row.portrait_path,
    portrait_thumb_path: row.portrait_thumb_path,
    rank: row.rank,
  }));
}

async function searchMovements(pattern, prefixPattern, perTypeLimit) {
  const { rows } = await pool.query(
    `SELECT m.id, m.name, m.color, m.start_year, m.end_year,
            e.name AS era_name,
            CASE WHEN m.name ILIKE $2 THEN 0 ELSE 1 END AS rank
     FROM art_movements m
     LEFT JOIN historical_eras e ON m.era_id = e.id
     WHERE m.name ILIKE $1
        OR e.name ILIKE $1
     ORDER BY rank, m.name
     LIMIT $3`,
    [pattern, prefixPattern, perTypeLimit]
  );
  return rows.map((row) => ({
    type: 'movement',
    id: row.id,
    name: row.name,
    color: row.color,
    start_year: row.start_year,
    end_year: row.end_year,
    era_name: row.era_name,
    rank: row.rank,
  }));
}

async function searchPaintings(pattern, prefixPattern, perTypeLimit) {
  const { rows } = await pool.query(
    `SELECT p.id, p.title, p.year, p.thumbnail_path, p.image_path,
            a.id AS artist_id, a.name AS artist_name,
            m.name AS movement_name,
            CASE WHEN p.title ILIKE $2 THEN 0 ELSE 1 END AS rank
     FROM paintings p
     JOIN artists a ON p.artist_id = a.id
     LEFT JOIN art_movements m ON a.movement_id = m.id
     WHERE p.title ILIKE $1
        OR p.wikipedia_title ILIKE $1
        OR a.name ILIKE $1
        OR m.name ILIKE $1
        OR CAST(p.year AS TEXT) ILIKE $1
     ORDER BY rank, p.year NULLS LAST, p.title
     LIMIT $3`,
    [pattern, prefixPattern, perTypeLimit]
  );
  return rows.map((row) => ({
    type: 'painting',
    id: row.id,
    title: row.title,
    year: row.year,
    artist_id: row.artist_id,
    artist_name: row.artist_name,
    movement_name: row.movement_name,
    thumbnail_path: row.thumbnail_path,
    image_path: row.image_path,
    rank: row.rank,
  }));
}

async function searchCatalog(query, options = {}) {
  const q = String(query || '').trim();
  if (q.length < 2) {
    return { q, results: [] };
  }

  const limit = Math.min(50, Math.max(1, Number(options.limit) || 20));
  const types = parseTypes(options.types);
  const perTypeLimit = Math.max(1, Math.ceil(limit / types.length));
  const pattern = `%${q}%`;
  const prefixPattern = `${q}%`;

  const tasks = [];
  if (types.includes('artist')) tasks.push(searchArtists(pattern, prefixPattern, perTypeLimit));
  if (types.includes('movement')) tasks.push(searchMovements(pattern, prefixPattern, perTypeLimit));
  if (types.includes('painting')) tasks.push(searchPaintings(pattern, prefixPattern, perTypeLimit));

  const groups = await Promise.all(tasks);
  const merged = groups
    .flat()
    .sort((a, b) => {
      if (a.rank !== b.rank) return a.rank - b.rank;
      const typeOrder = { artist: 0, movement: 1, painting: 2 };
      if (typeOrder[a.type] !== typeOrder[b.type]) return typeOrder[a.type] - typeOrder[b.type];
      const labelA = a.type === 'painting' ? a.title : a.name;
      const labelB = b.type === 'painting' ? b.title : b.name;
      return String(labelA).localeCompare(String(labelB));
    })
    .slice(0, limit)
    .map(({ rank: _rank, ...rest }) => rest);

  return { q, results: merged };
}

module.exports = { searchCatalog };