/**
 * Build a standalone app.asar + checksums.sha256 for minor (patch) updates.
 *
 * Replicates what electron-builder packs into the asar (dist/ + package.json +
 * required node_modules) without running the full installer build.
 *
 * Automatically resolves transitive dependencies so sub-deps are never missed.
 *
 * Usage:
 *   npm run build:asar                     # default (github) update source
 *   UPDATE_SOURCE=gitea npm run build:asar  # gitea update source
 */

const { execSync } = require('child_process');
const { cpSync, mkdirSync, rmSync, readFileSync, writeFileSync, createReadStream, existsSync } = require('fs');
const { join } = require('path');
const { createHash } = require('crypto');
const asar = require('@electron/asar');

const ROOT = join(__dirname, '..');
const STAGING = join(ROOT, 'out', 'asar-staging');
const OUTPUT = join(ROOT, 'out', 'asar');

// Top-level packages to include (same as electron-builder.yml)
const SEED_MODULES = [
    'electron-store', 'conf', 'dot-prop', 'type-fest', 'pkg-up',
    'find-up', 'locate-path', 'p-locate', 'p-limit', 'yocto-queue',
    'path-exists', 'env-paths', 'json-schema-typed', 'ajv', 'ajv-formats',
    'atomically', 'debounce-fn', 'mimic-fn', 'semver', 'onetime',
];

/**
 * Walk the dependency tree starting from seed modules and collect all
 * transitive production dependencies.
 */
function resolveAllDeps(seeds) {
    const resolved = new Set();
    const queue = [...seeds];

    while (queue.length > 0) {
        const mod = queue.shift();
        if (resolved.has(mod)) continue;

        // Check if module exists in top-level node_modules
        const modDir = join(ROOT, 'node_modules', mod);
        if (!existsSync(modDir)) {
            console.warn(`  Warning: ${mod} not found in node_modules, skipping`);
            continue;
        }

        resolved.add(mod);

        // Read its dependencies and enqueue them
        const pkgPath = join(modDir, 'package.json');
        if (existsSync(pkgPath)) {
            try {
                const pkg = JSON.parse(readFileSync(pkgPath, 'utf8'));
                const deps = Object.keys(pkg.dependencies || {});
                for (const dep of deps) {
                    if (!resolved.has(dep)) queue.push(dep);
                }
            } catch { /* ignore malformed package.json */ }
        }
    }

    return resolved;
}

function shouldExclude(src) {
    return src.endsWith('.ts') || src.endsWith('.map');
}

async function main() {
    // 1. Run Vite build (pass UPDATE_SOURCE through env)
    const env = { ...process.env };
    if (env.UPDATE_SOURCE) {
        console.log(`Building with UPDATE_SOURCE=${env.UPDATE_SOURCE}`);
    }
    execSync('npm run build', { cwd: ROOT, stdio: 'inherit', env });

    // 2. Resolve all dependencies (including transitive)
    console.log('\nResolving dependencies...');
    const allModules = resolveAllDeps(SEED_MODULES);
    console.log(`Found ${allModules.size} modules (${SEED_MODULES.length} seed + ${allModules.size - SEED_MODULES.length} transitive)`);

    // 3. Prepare staging directory
    rmSync(STAGING, { recursive: true, force: true });
    mkdirSync(STAGING, { recursive: true });

    // Copy dist/
    cpSync(join(ROOT, 'dist'), join(STAGING, 'dist'), { recursive: true });

    // Copy package.json (Electron reads "main" from it)
    cpSync(join(ROOT, 'package.json'), join(STAGING, 'package.json'));

    // Copy all resolved node_modules (excluding .ts and .map files)
    for (const mod of allModules) {
        const src = join(ROOT, 'node_modules', mod);
        const dest = join(STAGING, 'node_modules', mod);

        // Some packages have nested node_modules with their own deps
        // (hoisted vs non-hoisted). Check both the top-level and nested locations.
        if (existsSync(src)) {
            cpSync(src, dest, {
                recursive: true,
                filter: (s) => !shouldExclude(s),
            });
        }
    }

    // 4. Pack into asar
    mkdirSync(OUTPUT, { recursive: true });
    const asarPath = join(OUTPUT, 'app.asar');
    await asar.createPackage(STAGING, asarPath);
    console.log('\nCreated:', asarPath);

    // 5. Generate checksums.sha256
    const hex = await fileHash(asarPath);
    const checksumsPath = join(OUTPUT, 'checksums.sha256');
    writeFileSync(checksumsPath, `${hex}  app.asar\n`);
    console.log(`SHA-256: ${hex}`);
    console.log('Created:', checksumsPath);

    // 6. Cleanup staging
    rmSync(STAGING, { recursive: true, force: true });

    // Print size and module list
    const size = readFileSync(asarPath).length;
    console.log(`\napp.asar size: ${(size / 1024).toFixed(1)} KB`);
    console.log('Modules:', [...allModules].sort().join(', '));
}

function fileHash(filePath) {
    return new Promise((resolve, reject) => {
        const hash = createHash('sha256');
        const stream = createReadStream(filePath);
        stream.on('data', (chunk) => hash.update(chunk));
        stream.on('end', () => resolve(hash.digest('hex')));
        stream.on('error', reject);
    });
}

main().catch((err) => {
    console.error('build-asar failed:', err);
    process.exit(1);
});