/**
 * Universal OTA Bundle Creator
 * Packs FW (Provider.bin) and WWW (www_v*.bin) into a single .bundle file.
 */

import { readFileSync, writeFileSync, readdirSync, existsSync, mkdirSync } from 'fs';
import { resolve, dirname } from 'path';
import { fileURLToPath } from 'url';

const __dirname = dirname(fileURLToPath(import.meta.url));
const projectRoot = resolve(__dirname, '..');
const providerRoot = resolve(projectRoot, '..');
const binDir = resolve(projectRoot, 'bin');

// Paths
const fwFile = resolve(providerRoot, 'build', 'Provider.bin');
const bundleDir = resolve(projectRoot, 'bundles');

if (!existsSync(bundleDir)) {
    mkdirSync(bundleDir, { recursive: true });
}

console.log('--- Universal Bundle Packaging ---');

// 1. Find the latest www.bin with proper semantic version sorting
const binFiles = readdirSync(binDir)
    .filter(f => f.startsWith('www_v') && f.endsWith('.bin'))
    .sort((a, b) => {
        const getParts = (s) => {
            const m = s.match(/v(\d+)\.(\d+)\.(\d+)/);
            return m ? m.slice(1).map(Number) : [0, 0, 0];
        };
        const [aMajor, aMinor, aRev] = getParts(a);
        const [bMajor, bMinor, bRev] = getParts(b);
        return (bMajor - aMajor) || (bMinor - aMinor) || (bRev - aRev);
    });

if (binFiles.length === 0) {
    console.error('Error: No www_v*.bin found in frontend/bin/. Run "npm run ota:package" first.');
    process.exit(1);
}

const wwwFile = resolve(binDir, binFiles[0]);

if (!existsSync(fwFile)) {
    console.error(`Error: Firmware binary not found at ${fwFile}. Run "idf.py build" first.`);
    process.exit(1);
}

try {
    console.log(`Packing Firmware: ${fwFile}`);
    console.log(`Packing Frontend: ${wwwFile}`);

    const fwBuf = readFileSync(fwFile);
    const wwwBuf = readFileSync(wwwFile);

    // Create 12-byte header
    // Magic: BNDL (4 bytes)
    // FW Size: uint32 (4 bytes)
    // WWW Size: uint32 (4 bytes)
    const header = Buffer.alloc(12);
    header.write('BNDL', 0);
    header.writeUInt32LE(fwBuf.length, 4);
    header.writeUInt32LE(wwwBuf.length, 8);

    const bundleBuf = Buffer.concat([header, fwBuf, wwwBuf]);
    const outputFile = resolve(bundleDir, `universal_v${binFiles[0].replace('www_v', '').replace('.bin', '')}.bundle`);

    writeFileSync(outputFile, bundleBuf);

    console.log('-------------------------------');
    console.log(`Success: Bundle created at ${outputFile}`);
    console.log(`Total size: ${(bundleBuf.length / 1024 / 1024).toFixed(2)} MB`);
    console.log('-------------------------------');

} catch (e) {
    console.error('Error creating bundle:', e.message);
    process.exit(1);
}