/**
 * ISO Build Orchestration
 *
 * Builds the EcoOS custom Ubuntu ISO
 */

import * as path from '@std/path';

const ROOT = path.dirname(path.dirname(path.fromFileUrl(import.meta.url)));
const DAEMON_DIR = path.join(path.dirname(ROOT), 'ecoos_daemon');
const BUILD_DIR = path.join(ROOT, 'build');
const OUTPUT_DIR = path.join(ROOT, 'output');
const CONFIG_DIR = path.join(ROOT, 'config');

export async function build(): Promise<void> {
  console.log('=== EcoOS ISO Builder ===\n');

  // Step 1: Check prerequisites
  console.log('[1/7] Checking prerequisites...');
  await checkPrerequisites();

  // Step 2: Bundle the daemon
  console.log('[2/7] Bundling ecoos_daemon...');
  await bundleDaemon();

  // Step 3: Prepare build directory
  console.log('[3/7] Preparing build directory...');
  await prepareBuildDir();

  // Step 4: Configure live-build
  console.log('[4/7] Configuring live-build...');
  await configureLiveBuild();

  // Step 5: Copy package lists
  console.log('[5/7] Copying package lists...');
  await copyPackageLists();

  // Step 6: Copy daemon and configs to chroot includes
  console.log('[6/7] Preparing chroot includes...');
  await prepareChrootIncludes();

  // Step 7: Build ISO
  console.log('[7/7] Building ISO (this may take a while)...');
  await buildIso();

  console.log('\n=== Build Complete ===');
  console.log(`ISO: ${OUTPUT_DIR}/ecoos.iso`);
}

async function checkPrerequisites(): Promise<void> {
  const commands = ['lb', 'debootstrap', 'xorriso'];

  for (const cmd of commands) {
    try {
      const result = await run('which', [cmd]);
      if (!result.success) {
        throw new Error(`${cmd} not found`);
      }
    } catch {
      console.error(`Missing prerequisite: ${cmd}`);
      console.error('Install with: sudo apt install live-build debootstrap xorriso');
      Deno.exit(1);
    }
  }

  console.log('  All prerequisites found.');
}

async function bundleDaemon(): Promise<void> {
  // Compile the daemon to a single executable
  const bundleDir = path.join(DAEMON_DIR, 'bundle');
  await Deno.mkdir(bundleDir, { recursive: true });

  const result = await run('deno', [
    'compile',
    '--allow-all',
    '--output', path.join(bundleDir, 'eco-daemon'),
    path.join(DAEMON_DIR, 'mod.ts'),
  ], { cwd: DAEMON_DIR });

  if (!result.success) {
    console.error('Failed to bundle daemon');
    console.error(result.stderr);
    Deno.exit(1);
  }

  console.log('  Daemon bundled successfully.');
}

async function prepareBuildDir(): Promise<void> {
  // Clean and create build directory
  try {
    await Deno.remove(BUILD_DIR, { recursive: true });
  } catch {
    // Directory may not exist
  }

  await Deno.mkdir(BUILD_DIR, { recursive: true });
  console.log('  Build directory prepared.');
}

async function configureLiveBuild(): Promise<void> {
  // Initialize live-build config
  const result = await run('lb', ['config'], { cwd: BUILD_DIR });

  if (!result.success) {
    console.error('Failed to initialize live-build');
    console.error(result.stderr);
    Deno.exit(1);
  }

  // Copy our auto/config
  const autoDir = path.join(BUILD_DIR, 'auto');
  await Deno.mkdir(autoDir, { recursive: true });

  const configSrc = path.join(CONFIG_DIR, 'live-build', 'auto', 'config');
  const configDst = path.join(autoDir, 'config');

  await Deno.copyFile(configSrc, configDst);
  await Deno.chmod(configDst, 0o755);

  // Re-run lb config with our settings
  const result2 = await run('lb', ['config'], { cwd: BUILD_DIR });
  if (!result2.success) {
    console.error('Failed to configure live-build');
    Deno.exit(1);
  }

  console.log('  live-build configured.');
}

async function copyPackageLists(): Promise<void> {
  const srcDir = path.join(CONFIG_DIR, 'live-build', 'package-lists');
  const dstDir = path.join(BUILD_DIR, 'config', 'package-lists');

  await Deno.mkdir(dstDir, { recursive: true });

  for await (const entry of Deno.readDir(srcDir)) {
    if (entry.isFile && entry.name.endsWith('.list.chroot')) {
      const src = path.join(srcDir, entry.name);
      const dst = path.join(dstDir, entry.name);
      await Deno.copyFile(src, dst);
    }
  }

  console.log('  Package lists copied.');
}

async function prepareChrootIncludes(): Promise<void> {
  const includesDir = path.join(BUILD_DIR, 'config', 'includes.chroot');

  // Create directory structure
  await Deno.mkdir(path.join(includesDir, 'opt', 'eco', 'bin'), { recursive: true });
  await Deno.mkdir(path.join(includesDir, 'opt', 'eco', 'daemon'), { recursive: true });
  await Deno.mkdir(path.join(includesDir, 'etc', 'systemd', 'system'), { recursive: true });

  // Copy bundled daemon
  const daemonSrc = path.join(DAEMON_DIR, 'bundle', 'eco-daemon');
  const daemonDst = path.join(includesDir, 'opt', 'eco', 'bin', 'eco-daemon');

  try {
    await Deno.copyFile(daemonSrc, daemonDst);
    await Deno.chmod(daemonDst, 0o755);
  } catch (e) {
    console.error('Failed to copy daemon bundle:', e);
    // Fall back to copying source files
    console.log('  Copying daemon source files instead...');
    await copyDir(path.join(DAEMON_DIR, 'ts'), path.join(includesDir, 'opt', 'eco', 'daemon'));
    await Deno.copyFile(
      path.join(DAEMON_DIR, 'mod.ts'),
      path.join(includesDir, 'opt', 'eco', 'daemon', 'mod.ts')
    );
  }

  // Copy systemd service
  const serviceSrc = path.join(CONFIG_DIR, 'systemd', 'eco-daemon.service');
  const serviceDst = path.join(includesDir, 'etc', 'systemd', 'system', 'eco-daemon.service');
  await Deno.copyFile(serviceSrc, serviceDst);

  // Copy autoinstall config
  const autoinstallDir = path.join(BUILD_DIR, 'config', 'includes.binary');
  await Deno.mkdir(autoinstallDir, { recursive: true });

  const userDataSrc = path.join(CONFIG_DIR, 'autoinstall', 'user-data');
  const userDataDst = path.join(autoinstallDir, 'autoinstall', 'user-data');
  await Deno.mkdir(path.dirname(userDataDst), { recursive: true });
  await Deno.copyFile(userDataSrc, userDataDst);

  // Create empty meta-data file (required for cloud-init)
  await Deno.writeTextFile(path.join(path.dirname(userDataDst), 'meta-data'), '');

  console.log('  Chroot includes prepared.');
}

async function buildIso(): Promise<void> {
  const result = await run('sudo', ['lb', 'build'], {
    cwd: BUILD_DIR,
    stdout: 'inherit',
    stderr: 'inherit',
  });

  if (!result.success) {
    console.error('ISO build failed');
    Deno.exit(1);
  }

  // Move ISO to output directory
  await Deno.mkdir(OUTPUT_DIR, { recursive: true });

  for await (const entry of Deno.readDir(BUILD_DIR)) {
    if (entry.isFile && entry.name.endsWith('.iso')) {
      const src = path.join(BUILD_DIR, entry.name);
      const dst = path.join(OUTPUT_DIR, 'ecoos.iso');
      await Deno.rename(src, dst);
      break;
    }
  }
}

async function run(
  cmd: string,
  args: string[],
  options: { cwd?: string; stdout?: 'piped' | 'inherit'; stderr?: 'piped' | 'inherit' } = {}
): Promise<{ success: boolean; stdout: string; stderr: string }> {
  const command = new Deno.Command(cmd, {
    args,
    cwd: options.cwd,
    stdout: options.stdout ?? 'piped',
    stderr: options.stderr ?? 'piped',
  });

  const result = await command.output();

  return {
    success: result.success,
    stdout: new TextDecoder().decode(result.stdout),
    stderr: new TextDecoder().decode(result.stderr),
  };
}

async function copyDir(src: string, dst: string): Promise<void> {
  await Deno.mkdir(dst, { recursive: true });

  for await (const entry of Deno.readDir(src)) {
    const srcPath = path.join(src, entry.name);
    const dstPath = path.join(dst, entry.name);

    if (entry.isDirectory) {
      await copyDir(srcPath, dstPath);
    } else {
      await Deno.copyFile(srcPath, dstPath);
    }
  }
}