server.js

const fastify = require('fastify')({ logger: { level: 'error' } });
const Database = require('better-sqlite3');
const path = require('path');
const fs = require('fs');

const PORT = 3000;
const DATA_DIR = path.join(__dirname, 'data');

// Add CORS
fastify.register(require('@fastify/cors'), {
    origin: '*',
    methods: ['GET']
});

// Auto-detect mbtiles file
let mbtilesFile = 'local.mbtiles';
try {
    if (fs.existsSync(DATA_DIR)) {
        const files = fs.readdirSync(DATA_DIR).filter(file => file.endsWith('.mbtiles'));
        if (files.length > 0) mbtilesFile = files[0];
    }
} catch (e) {
    console.error('Failed to scan data directory:', e.message);
}

const MBTILES_PATH = path.join(DATA_DIR, mbtilesFile);

if (!fs.existsSync(MBTILES_PATH)) {
    console.error(`Error: No .mbtiles file found at ${MBTILES_PATH}`);
    process.exit(1);
}

console.log(`Serving tiles from: ${mbtilesFile}`);

const db = new Database(MBTILES_PATH, { readonly: true });
const getTileStmt = db.prepare('SELECT tile_data FROM tiles WHERE zoom_level = ? AND tile_column = ? AND tile_row = ?');

// Determine content type
let contentType = 'application/octet-stream';
try {
    const formatRow = db.prepare('SELECT value FROM metadata WHERE name = ?').get('format');
    if (formatRow) {
        switch (formatRow.value) {
            case 'pbf': contentType = 'application/x-protobuf'; break;
            case 'png': contentType = 'image/png'; break;
            case 'jpg': case 'jpeg': contentType = 'image/jpeg'; break;
            case 'webp': contentType = 'image/webp'; break;
        }
    }
} catch (err) {
    console.warn('Metadata read failed, defaulting to application/octet-stream');
}

fastify.get('/', async (req, reply) => {
    return { status: 'running', service: 'local-map-tiler', tiles_endpoint: '/tiles/{z}/{x}/{y}' };
});

fastify.get('/tiles/:z/:x/:y', async (req, reply) => {
    const { z, x, y } = req.params;

    // TMS Y-coordinate flip: (2^z - 1) - y
    const zInt = parseInt(z);
    const xInt = parseInt(x);
    const yInt = parseInt(y); // Fastify handles standard int parsing, but we can be safe

    // Handle extension if present (e.g. 123.png)
    const yVal = isNaN(yInt) ? parseInt(y.split('.')[0]) : yInt;
    const tileRow = (Math.pow(2, zInt) - 1) - yVal;

    try {
        const row = getTileStmt.get(zInt, xInt, tileRow);

        if (!row || !row.tile_data) {
            return reply.code(404).send('Not Found');
        }

        const buffer = row.tile_data;

        reply.header('Content-Type', contentType);
        reply.header('Cache-Control', 'public, max-age=31536000');

        // GZIP detection (0x1f 0x8b)
        if (buffer.length >= 2 && buffer[0] === 0x1f && buffer[1] === 0x8b) {
            reply.header('Content-Encoding', 'gzip');
        }

        return reply.send(buffer);
    } catch (err) {
        req.log.error(err);
        return reply.code(500).send('Internal Server Error');
    }
});

const start = async () => {
    try {
        await fastify.listen({ port: PORT, host: '0.0.0.0' });
        console.log(`Server running at http://localhost:${PORT}`);
    } catch (err) {
        console.error(err);
        process.exit(1);
    }
};

start();