const express = require('express');
const cors = require('cors');
const path = require('path');
const fs = require('fs');
require('dotenv').config();

const pool = require('./db');
const { ensurePaintingImages, preloadArtistImagesLocal, IMAGE_DIR } = require('./image-service');

const app = express();
const PORT = process.env.PORT || 3001;

app.use(cors());
app.use(express.json());
app.use('/images', express.static(IMAGE_DIR));

// Timeline: eras + movements for a year range
app.get('/api/timeline', async (req, res) => {
  try {
    const { start, end } = req.query;
    const startYear = parseInt(start) || -3000;
    const endYear = parseInt(end) || 2100;

    const [eras, movements] = await Promise.all([
      pool.query(
        `SELECT * FROM historical_eras
         WHERE end_year >= $1 AND start_year <= $2
         ORDER BY sort_order, start_year`,
        [startYear, endYear]
      ),
      pool.query(
        `SELECT DISTINCT m.*, e.name as era_name
         FROM art_movements m
         LEFT JOIN historical_eras e ON m.era_id = e.id
         INNER JOIN artists a ON a.movement_id = m.id
         WHERE m.end_year >= $1 AND m.start_year <= $2
           AND (a.death_year IS NULL OR a.death_year >= $1)
           AND (a.birth_year IS NULL OR a.birth_year <= $2)
         ORDER BY m.start_year`,
        [startYear, endYear]
      ),
    ]);

    res.json({ eras: eras.rows, movements: movements.rows });
  } catch (err) {
    console.error(err);
    res.status(500).json({ error: 'Failed to fetch timeline' });
  }
});

// Artists for a movement in a time range
app.get('/api/movements/:id/artists', async (req, res) => {
  try {
    const { id } = req.params;
    const result = await pool.query(
      `SELECT id, name, birth_year, death_year, portrait_path, bio_short
       FROM artists WHERE movement_id = $1
       ORDER BY birth_year`,
      [id]
    );
    res.json(result.rows);
  } catch (err) {
    console.error(err);
    res.status(500).json({ error: 'Failed to fetch artists' });
  }
});

// All artists in a year range (for timeline portrait placement)
app.get('/api/artists', async (req, res) => {
  try {
    const { start, end, movement_id } = req.query;
    let query = `
      SELECT a.*, m.name as movement_name, m.color as movement_color
      FROM artists a
      LEFT JOIN art_movements m ON a.movement_id = m.id
      WHERE 1=1`;
    const params = [];

    if (start) {
      params.push(parseInt(start));
      query += ` AND (a.death_year IS NULL OR a.death_year >= $${params.length})`;
    }
    if (end) {
      params.push(parseInt(end));
      query += ` AND (a.birth_year IS NULL OR a.birth_year <= $${params.length})`;
    }
    if (movement_id) {
      params.push(parseInt(movement_id));
      query += ` AND a.movement_id = $${params.length}`;
    }

    query += ' ORDER BY a.birth_year';
    const result = await pool.query(query, params);
    res.json(result.rows);
  } catch (err) {
    console.error(err);
    res.status(500).json({ error: 'Failed to fetch artists' });
  }
});

// Artist detail with periods and paintings
app.get('/api/artists/:id/navigation', async (req, res) => {
  try {
    const artistId = parseInt(req.params.id, 10);

    const groupByMovement = (rows) => {
      const map = new Map();
      for (const row of rows) {
        const key = row.movement_id ?? 0;
        if (!map.has(key)) {
          map.set(key, {
            movement_id: row.movement_id,
            movement_name: row.movement_name || 'Other',
            movement_color: row.movement_color || '#8B7355',
            artists: [],
          });
        }
        const group = map.get(key);
        if (!group.artists.some((a) => a.id === row.id)) {
          group.artists.push({
            id: row.id,
            name: row.name,
            birth_year: row.birth_year,
            death_year: row.death_year,
            portrait_path: row.portrait_path,
          });
        }
      }
      return Array.from(map.values()).sort((a, b) =>
        a.movement_name.localeCompare(b.movement_name)
      );
    };

    const [predecessors, successors] = await Promise.all([
      pool.query(
        `SELECT DISTINCT a.id, a.name, a.birth_year, a.death_year, a.portrait_path,
                m.id AS movement_id, m.name AS movement_name, m.color AS movement_color
         FROM painting_influences pi
         JOIN paintings p_work ON pi.painting_id = p_work.id
         JOIN paintings p_pred ON pi.influenced_by_painting_id = p_pred.id
         JOIN artists a ON p_pred.artist_id = a.id
         LEFT JOIN art_movements m ON a.movement_id = m.id
         WHERE p_work.artist_id = $1 AND a.id <> $1
         ORDER BY m.name NULLS LAST, a.birth_year NULLS LAST, a.name`,
        [artistId]
      ),
      pool.query(
        `SELECT DISTINCT a.id, a.name, a.birth_year, a.death_year, a.portrait_path,
                m.id AS movement_id, m.name AS movement_name, m.color AS movement_color
         FROM painting_influences pi
         JOIN paintings p_src ON pi.influenced_by_painting_id = p_src.id
         JOIN paintings p_work ON pi.painting_id = p_work.id
         JOIN artists a ON p_work.artist_id = a.id
         LEFT JOIN art_movements m ON a.movement_id = m.id
         WHERE p_src.artist_id = $1 AND a.id <> $1
         ORDER BY m.name NULLS LAST, a.birth_year NULLS LAST, a.name`,
        [artistId]
      ),
    ]);

    res.json({
      predecessors: groupByMovement(predecessors.rows),
      successors: groupByMovement(successors.rows),
    });
  } catch (err) {
    console.error(err);
    res.status(500).json({ error: 'Failed to fetch artist navigation' });
  }
});

// Artist detail with periods and paintings
app.get('/api/artists/:id', async (req, res) => {
  try {
    const { id } = req.params;
    const [artist, periods, paintings] = await Promise.all([
      pool.query(
        `SELECT a.*, m.name as movement_name
         FROM artists a
         LEFT JOIN art_movements m ON a.movement_id = m.id
         WHERE a.id = $1`,
        [id]
      ),
      pool.query(
        `SELECT * FROM artist_periods WHERE artist_id = $1 ORDER BY sort_order, start_year`,
        [id]
      ),
      pool.query(
        `SELECT p.*,
                EXISTS (
                  SELECT 1 FROM painting_influences pi
                  WHERE pi.painting_id = p.id OR pi.influenced_by_painting_id = p.id
                ) AS has_influence_links
         FROM paintings p
         WHERE p.artist_id = $1
         ORDER BY p.sort_order, p.year`,
        [id]
      ),
    ]);

    if (artist.rows.length === 0) {
      return res.status(404).json({ error: 'Artist not found' });
    }

    res.json({
      artist: artist.rows[0],
      periods: periods.rows,
      paintings: paintings.rows,
    });
  } catch (err) {
    console.error(err);
    res.status(500).json({ error: 'Failed to fetch artist' });
  }
});

// Painting detail with influences
app.get('/api/paintings/:id', async (req, res) => {
  try {
    const { id } = req.params;

    const painting = await pool.query(
      `SELECT p.*, a.name as artist_name, a.id as artist_id, a.portrait_path as artist_portrait,
              EXISTS (
                SELECT 1 FROM painting_influences pi
                WHERE pi.painting_id = p.id OR pi.influenced_by_painting_id = p.id
              ) AS has_influence_links
       FROM paintings p
       JOIN artists a ON p.artist_id = a.id
       WHERE p.id = $1`,
      [id]
    );

    if (painting.rows.length === 0) {
      return res.status(404).json({ error: 'Painting not found' });
    }

    const [influencedBy, influenced] = await Promise.all([
      pool.query(
        `SELECT pi.notes, pi.source, pi.aspects, pi.quote, pi.source_author, pi.source_url,
                p.id, p.title, p.year, p.image_path, a.name as artist_name, a.id as artist_id
         FROM painting_influences pi
         JOIN paintings p ON pi.influenced_by_painting_id = p.id
         JOIN artists a ON p.artist_id = a.id
         WHERE pi.painting_id = $1`,
        [id]
      ),
      pool.query(
        `SELECT pi.notes, pi.source, pi.aspects, pi.quote, pi.source_author, pi.source_url,
                p.id, p.title, p.year, p.image_path, a.name as artist_name, a.id as artist_id
         FROM painting_influences pi
         JOIN paintings p ON pi.painting_id = p.id
         JOIN artists a ON p.artist_id = a.id
         WHERE pi.influenced_by_painting_id = $1`,
        [id]
      ),
    ]);

    res.json({
      painting: painting.rows[0],
      influencedBy: influencedBy.rows,
      influenced: influenced.rows,
    });
  } catch (err) {
    console.error(err);
    res.status(500).json({ error: 'Failed to fetch painting' });
  }
});

// Fast preload: link local image files only (no external downloads)
app.post('/api/artists/:id/preload-images', async (req, res) => {
  try {
    const artistId = parseInt(req.params.id, 10);
    const result = await preloadArtistImagesLocal(artistId);
    res.json(result);
  } catch (err) {
    console.error('Preload error:', err.message);
    res.status(500).json({ error: 'Preload failed' });
  }
});

// On-demand painting image (resolves, caches, serves thumb or full)
app.get('/api/paintings/:id/image', async (req, res) => {
  try {
    const { id } = req.params;
    const size = req.query.size === 'full' ? 'full' : 'thumb';
    const relPath = await ensurePaintingImages(parseInt(id, 10), size);

    if (!relPath) {
      return res.status(404).json({ error: 'Image not found' });
    }

    const absPath = path.join(IMAGE_DIR, relPath);
    if (!fs.existsSync(absPath)) {
      return res.status(404).json({ error: 'Image file missing' });
    }

    res.setHeader('Cache-Control', 'public, max-age=86400');
    res.sendFile(absPath);
  } catch (err) {
    console.error('Image fetch error:', err.message);
    res.status(500).json({ error: 'Image fetch failed' });
  }
});

// Year range bounds
app.get('/api/bounds', async (req, res) => {
  try {
    const result = await pool.query(`
      SELECT
        (SELECT MIN(start_year) FROM art_movements) as min_year,
        GREATEST(
          (SELECT MAX(end_year) FROM historical_eras),
          (SELECT MAX(end_year) FROM art_movements),
          (SELECT MAX(death_year) FROM artists WHERE death_year IS NOT NULL)
        ) as max_year
    `);
    res.json(result.rows[0]);
  } catch (err) {
    console.error(err);
    res.status(500).json({ error: 'Failed to fetch bounds' });
  }
});

const CLIENT_DIST = path.join(__dirname, '..', 'client', 'dist');
if (fs.existsSync(CLIENT_DIST)) {
  app.use(express.static(CLIENT_DIST));
  app.get(/^(?!\/api|\/images).*/, (_req, res) => {
    res.sendFile(path.join(CLIENT_DIST, 'index.html'));
  });
}

app.listen(PORT, () => {
  console.log(`Gallery running on http://localhost:${PORT}`);
});