const express = require('express');
const https = require('https');
const path = require('path');
const fs = require('fs');

const app = express();
app.use(express.json());
app.use(express.static(path.join(__dirname, 'public')));

const POINTS_FILE = path.join(__dirname, 'data', 'points.json');
const TILES_DIR = path.join(__dirname, 'tiles');

const SHOM_BASE = 'https://services.data.shom.fr/clevisu/wmts?layer=RASTER_MARINE_3857_WMTS&style=normal&tilematrixset=3857&Service=WMTS&Request=GetTile&Version=1.0.0&Format=image%2Fpng';
const SHOM_HEADERS = {
  'Referer': 'https://data.shom.fr',
  'Origin': 'https://data.shom.fr',
  'User-Agent': 'Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/114.0',
  'Accept': 'image/png'
};

let db = null;
let mbtilesMeta = {};
let tileStmt = null;

async function initMbtiles() {
  try {
    const files = fs.readdirSync(TILES_DIR).filter(f => f.endsWith('.mbtiles'));
    if (files.length === 0) return;
    const initSqlJs = require('sql.js');
    const SQL = await initSqlJs();
    const buf = fs.readFileSync(path.join(TILES_DIR, files[0]));
    db = new SQL.Database(buf);
    db.each('SELECT name, value FROM metadata', [], (row) => {
      mbtilesMeta[row.name] = row.value;
    });
    tileStmt = db.prepare(
      'SELECT tile_data FROM tiles WHERE zoom_level=? AND tile_column=? AND tile_row=?'
    );
    console.log(`✓ MBTiles : ${files[0]} (zoom ${mbtilesMeta.minzoom}–${mbtilesMeta.maxzoom})`);
  } catch (e) {
    console.log('Pas de MBTiles local, utilisation du flux SHOM en ligne.');
  }
}

function proxyShom(z, x, y, res) {
  const url = `${SHOM_BASE}&TileMatrix=${z}&TileCol=${x}&TileRow=${y}`;
  https.get(url, { headers: SHOM_HEADERS }, (upstream) => {
    if (upstream.statusCode !== 200) return res.status(upstream.statusCode).end();
    res.set('Content-Type', 'image/png');
    res.set('Cache-Control', 'public, max-age=86400');
    upstream.pipe(res);
  }).on('error', () => res.status(502).end());
}

initMbtiles().then(startServer);

app.get('/api/status', (req, res) => {
  res.json({
    hasMbtiles: !!db,
    name: mbtilesMeta.name || null,
    minZoom: parseInt(mbtilesMeta.minzoom) || 6,
    maxZoom: parseInt(mbtilesMeta.maxzoom) || 17
  });
});

app.get('/tiles/:z/:x/:y', (req, res) => {
  const z = parseInt(req.params.z);
  const x = parseInt(req.params.x);
  const y = parseInt(req.params.y);

  if (tileStmt) {
    const tmsY = (1 << z) - 1 - y;
    try {
      tileStmt.bind([z, x, tmsY]);
      if (!tileStmt.step()) { tileStmt.reset(); return proxyShom(z, x, y, res); }
      const row = tileStmt.getAsObject();
      tileStmt.reset();
      const fmt = mbtilesMeta.format || 'png';
      res.set('Content-Type', fmt === 'jpg' || fmt === 'jpeg' ? 'image/jpeg' : 'image/png');
      res.set('Cache-Control', 'public, max-age=86400');
      res.send(Buffer.from(row.tile_data));
    } catch (e) {
      tileStmt.reset();
      proxyShom(z, x, y, res);
    }
  } else {
    proxyShom(z, x, y, res);
  }
});

function loadPoints() {
  if (!fs.existsSync(POINTS_FILE)) return [];
  try { return JSON.parse(fs.readFileSync(POINTS_FILE, 'utf8')); }
  catch { return []; }
}

function savePoints(pts) {
  fs.writeFileSync(POINTS_FILE, JSON.stringify(pts, null, 2));
}

app.get('/api/points', (req, res) => res.json(loadPoints()));

app.post('/api/points', (req, res) => {
  const pts = loadPoints();
  const pt = { id: `${Date.now()}-${Math.random().toString(36).slice(2, 7)}`, ...req.body };
  pts.push(pt);
  savePoints(pts);
  res.json(pt);
});

app.put('/api/points/:id', (req, res) => {
  const pts = loadPoints();
  const i = pts.findIndex(p => p.id === req.params.id);
  if (i === -1) return res.status(404).json({ error: 'Not found' });
  pts[i] = { ...pts[i], ...req.body };
  savePoints(pts);
  res.json(pts[i]);
});

app.delete('/api/points/:id', (req, res) => {
  savePoints(loadPoints().filter(p => p.id !== req.params.id));
  res.json({ ok: true });
});

function startServer() {
  app.listen(4242, () => console.log('\n⚓  Saint-Malo Quiz → http://localhost:4242\n'));
}