const router = require('express').Router();
const { query } = require('../db');
const { runEnrichTick, enrichWordsSync } = require('../lib/enrichWords');

const STATUSES = ['requested', 'translated', 'generated', 'blocked', 'published'];

const STATUS_TIMESTAMP = {
  requested:  'requested_at',
  published:  'published_at',
  blocked:    'blocked_at',
};

// POST /api/words/enrich-batch — manueller Trigger für Wort-Anreicherung
router.post('/enrich-batch', async (req, res, next) => {
  try {
    const sync = req.query.sync === 'true';
    if (sync) {
      const max = parseInt(req.query.max) || 500;
      return res.json(await enrichWordsSync({ max }));
    }
    res.json(await runEnrichTick());
  } catch (err) { next(err); }
});

// GET /api/words
router.get('/', async (req, res, next) => {
  try {
    const { status, titel_de, search, dom_pos, level, themenfeld_id, has_conc_m,
            limit = 50, offset = 0 } = req.query;
    const params = [Math.min(parseInt(limit), 500), parseInt(offset)];
    const conditions = [];
    if (status)        { conditions.push(`w.status = $${params.length + 1}`);                   params.push(status); }
    if (titel_de)      { conditions.push(`lower(w.titel_de) = lower($${params.length + 1})`);   params.push(titel_de); }
    if (dom_pos)       { conditions.push(`w.dom_pos = $${params.length + 1}`);                  params.push(dom_pos); }
    if (level)         { conditions.push(`w.level = $${params.length + 1}`);                    params.push(level); }
    if (themenfeld_id) { conditions.push(`w.themenfeld_id = $${params.length + 1}`);            params.push(themenfeld_id); }
    if (has_conc_m === 'true')  conditions.push(`w.conc_m IS NOT NULL`);
    if (has_conc_m === 'false') conditions.push(`w.conc_m IS NULL`);
    if (search) {
      const p = `%${search.toLowerCase()}%`;
      conditions.push(`(lower(w.titel_de) LIKE $${params.length + 1} OR lower(w.titel_en) LIKE $${params.length + 1} OR lower(w.titel_sv) LIKE $${params.length + 1})`);
      params.push(p);
    }
    const where = conditions.length ? `WHERE ${conditions.join(' AND ')}` : '';
    const result = await query(
      `SELECT w.*,
        COALESCE(json_agg(DISTINCT p.id) FILTER (WHERE p.id IS NOT NULL), '[]') AS picture_ids,
        COALESCE(json_agg(DISTINCT c.id) FILTER (WHERE c.id IS NOT NULL), '[]') AS category_ids,
        COUNT(DISTINCT wp2.picture_id)::int AS picture_count
       FROM words w
       LEFT JOIN word_pictures wp  ON wp.word_id  = w.id
       LEFT JOIN pictures p        ON p.id         = wp.picture_id
       LEFT JOIN word_categories wc ON wc.word_id  = w.id
       LEFT JOIN categories c       ON c.id         = wc.category_id
       LEFT JOIN word_pictures wp2  ON wp2.word_id  = w.id
       ${where}
       GROUP BY w.id
       ORDER BY w.created_at DESC
       LIMIT $1 OFFSET $2`,
      params
    );
    res.json(result.rows);
  } catch (err) { next(err); }
});

// Hilfsfunktion: wenn alle 3 Sprachen gefüllt sind und Status `requested`, auto → `translated`.
function autoTranslatedStatus(row) {
  return (row.titel_de && row.titel_en && row.titel_sv && row.status === 'requested') ? 'translated' : null;
}

// POST /api/words
router.post('/', async (req, res, next) => {
  try {
    const { titel_de, titel_en, titel_sv, difficulty_level, status, conc_m } = req.body;
    if (status && !STATUSES.includes(status))
      return res.status(400).json({ error: `status must be one of: ${STATUSES.join(', ')}` });
    // Auto: alle 3 Sprachen direkt mitgeliefert + kein expliziter Status → 'translated'
    const allLangs = titel_de && titel_en && titel_sv;
    const effectiveStatus = status || (allLangs ? 'translated' : 'requested');
    // Upsert: neu anlegen oder bei doppeltem titel_en nur conc_m aktualisieren
    let result = await query(
      `INSERT INTO words (titel_de, titel_en, titel_sv, difficulty_level, status, conc_m, requested_at)
       VALUES ($1, $2, $3, $4, $5, $6, NOW()) RETURNING *, true AS is_insert`,
      [titel_de || null, titel_en || null, titel_sv || null,
       difficulty_level || null, effectiveStatus, conc_m ?? null]
    ).catch(async err => {
      if (err.code === '23505' && titel_en) {
        // Duplikat auf titel_en → conc_m aktualisieren und bestehende Zeile zurückgeben
        const upd = await query(
          `UPDATE words SET conc_m = $1 WHERE titel_en = $2 RETURNING *, false AS is_insert`,
          [conc_m ?? null, titel_en]
        );
        return upd;
      }
      throw err;
    });
    const row = result.rows[0];
    const { is_insert, ...word } = row;
    res.status(is_insert ? 201 : 200).json({ ...word, picture_ids: [], category_ids: [] });
  } catch (err) { next(err); }
});

// PATCH /api/words/:id
router.patch('/:id', async (req, res, next) => {
  try {
    const allowed = ['titel_de', 'titel_en', 'titel_sv', 'status',
                     'difficulty_level', 'requested_at', 'published_at', 'blocked_at',
                     'conc_m', 'dom_pos', 'level', 'themenfeld_id'];
    const fields = Object.keys(req.body).filter(k => allowed.includes(k));
    if (!fields.length) return res.status(400).json({ error: 'No valid fields provided' });

    if (req.body.status && !STATUSES.includes(req.body.status))
      return res.status(400).json({ error: `status must be one of: ${STATUSES.join(', ')}` });

    // Auto-timestamp bei Statuswechsel
    const tsField = STATUS_TIMESTAMP[req.body.status];
    if (tsField && !req.body[tsField]) {
      fields.push(tsField);
      req.body[tsField] = new Date().toISOString();
    }

    const setClauses = fields.map((f, i) => `${f} = $${i + 1}`).join(', ');
    const values = [...fields.map(f => req.body[f]), req.params.id];
    const result = await query(
      `UPDATE words SET ${setClauses} WHERE id = $${fields.length + 1} RETURNING *`,
      values
    );
    if (!result.rows.length) return res.status(404).json({ error: 'Not found' });

    // Auto-Übergang: requested → translated wenn jetzt alle 3 Sprachen gefüllt sind
    let row = result.rows[0];
    const next = autoTranslatedStatus(row);
    if (next) {
      const upd = await query(`UPDATE words SET status = $1 WHERE id = $2 RETURNING *`, [next, row.id]);
      row = upd.rows[0];
    }
    res.json(row);
  } catch (err) { next(err); }
});

// DELETE /api/words/:id
router.delete('/:id', async (req, res, next) => {
  try {
    const result = await query('DELETE FROM words WHERE id = $1 RETURNING id', [req.params.id]);
    if (!result.rows.length) return res.status(404).json({ error: 'Not found' });
    res.status(204).end();
  } catch (err) { next(err); }
});

// GET /api/words/:id — AFTER sub-routes to avoid shadowing
router.get('/:id', async (req, res, next) => {
  try {
    const result = await query(
      `SELECT w.*,
        COALESCE(json_agg(DISTINCT p.id) FILTER (WHERE p.id IS NOT NULL), '[]') AS picture_ids,
        COALESCE(json_agg(DISTINCT c.id) FILTER (WHERE c.id IS NOT NULL), '[]') AS category_ids,
        COUNT(DISTINCT wp2.picture_id)::int AS picture_count
       FROM words w
       LEFT JOIN word_pictures wp   ON wp.word_id  = w.id
       LEFT JOIN pictures p         ON p.id         = wp.picture_id
       LEFT JOIN word_categories wc ON wc.word_id   = w.id
       LEFT JOIN categories c       ON c.id          = wc.category_id
       LEFT JOIN word_pictures wp2  ON wp2.word_id   = w.id
       WHERE w.id = $1
       GROUP BY w.id`,
      [req.params.id]
    );
    if (!result.rows.length) return res.status(404).json({ error: 'Not found' });
    res.json(result.rows[0]);
  } catch (err) { next(err); }
});

// GET /api/words/:id/pictures — verknüpfte Bilder laden
router.get('/:id/pictures', async (req, res, next) => {
  try {
    const result = await query(
      `SELECT p.* FROM pictures p
       JOIN word_pictures wp ON wp.picture_id = p.id
       WHERE wp.word_id = $1
       ORDER BY p.created_at DESC`,
      [req.params.id]
    );
    res.json(result.rows);
  } catch (err) { next(err); }
});

// GET /api/words/:id/categories — verknüpfte Kategorien laden
router.get('/:id/categories', async (req, res, next) => {
  try {
    const result = await query(
      `SELECT c.* FROM categories c
       JOIN word_categories wc ON wc.category_id = c.id
       WHERE wc.word_id = $1
       ORDER BY c.name_de`,
      [req.params.id]
    );
    res.json(result.rows);
  } catch (err) { next(err); }
});

// POST /api/words/:id/pictures/:pictureId — Bild verknüpfen
router.post('/:id/pictures/:pictureId', async (req, res, next) => {
  try {
    await query(
      `INSERT INTO word_pictures (word_id, picture_id) VALUES ($1, $2) ON CONFLICT DO NOTHING`,
      [req.params.id, req.params.pictureId]
    );
    res.status(204).end();
  } catch (err) { next(err); }
});

// DELETE /api/words/:id/pictures/:pictureId — Bild-Verknüpfung entfernen
router.delete('/:id/pictures/:pictureId', async (req, res, next) => {
  try {
    await query(
      `DELETE FROM word_pictures WHERE word_id = $1 AND picture_id = $2`,
      [req.params.id, req.params.pictureId]
    );
    res.status(204).end();
  } catch (err) { next(err); }
});

// POST /api/words/:id/categories/:categoryId — Kategorie verknüpfen
router.post('/:id/categories/:categoryId', async (req, res, next) => {
  try {
    await query(
      `INSERT INTO word_categories (word_id, category_id) VALUES ($1, $2) ON CONFLICT DO NOTHING`,
      [req.params.id, req.params.categoryId]
    );
    res.status(204).end();
  } catch (err) { next(err); }
});

// DELETE /api/words/:id/categories/:categoryId — Kategorie-Verknüpfung entfernen
router.delete('/:id/categories/:categoryId', async (req, res, next) => {
  try {
    await query(
      `DELETE FROM word_categories WHERE word_id = $1 AND category_id = $2`,
      [req.params.id, req.params.categoryId]
    );
    res.status(204).end();
  } catch (err) { next(err); }
});

module.exports = router;