import { cp, mkdtemp, readFile, rm, writeFile } from 'node:fs/promises';
import os from 'node:os';
import path from 'node:path';
import process from 'node:process';
import { spawn } from 'node:child_process';
import { fileURLToPath } from 'node:url';

const projectRoot = path.resolve(path.dirname(fileURLToPath(import.meta.url)), '..');
const siteSource = path.join(projectRoot, 'pages-dist');
const repository = process.env.GITHUB_PAGES_REPOSITORY ?? 'https://github.com/DD4SN/DD4SN.github.io.git';

if (!process.env.GITHUB_PAGES_TOKEN) {
  throw new Error('GITHUB_PAGES_TOKEN is required to publish Pages output.');
}

function runGit(args, options = {}) {
  return new Promise((resolve, reject) => {
    const child = spawn('git', args, {
      cwd: options.cwd ?? projectRoot,
      env: options.env ?? process.env,
      stdio: options.quiet ? 'ignore' : 'inherit',
      shell: false
    });
    child.on('error', reject);
    child.on('exit', (code) => resolve(code ?? 1));
  });
}

async function requireGit(args, options) {
  const code = await runGit(args, options);
  if (code !== 0) throw new Error(`git ${args[0]} failed with exit code ${code}.`);
}

const temporaryRoot = await mkdtemp(path.join(os.tmpdir(), 'holodori-pages-'));
const checkout = path.join(temporaryRoot, 'repository');
const askPass = path.join(temporaryRoot, process.platform === 'win32' ? 'askpass.cmd' : 'askpass.sh');
const askPassContents = process.platform === 'win32'
  ? '@echo off\necho %1 | findstr /I "Username" >nul\nif %errorlevel%==0 (echo x-access-token) else (echo %GITHUB_PAGES_TOKEN%)\n'
  : '#!/bin/sh\ncase "$1" in\n  *Username*) printf "%s\\n" "x-access-token" ;;\n  *) printf "%s\\n" "$GITHUB_PAGES_TOKEN" ;;\nesac\n';

try {
  await writeFile(askPass, askPassContents, { mode: 0o700 });
  const gitEnvironment = {
    ...process.env,
    GIT_ASKPASS: askPass,
    GIT_TERMINAL_PROMPT: '0'
  };

  await requireGit(['clone', repository, checkout], { env: gitEnvironment });

  const generatedPaths = ['site', 'assets', 'icons', 'index.html', 'README.txt', 'VERSION.txt', '.nojekyll'];
  await Promise.all(generatedPaths.map((generatedPath) => rm(path.join(checkout, generatedPath), { recursive: true, force: true })));
  await cp(siteSource, checkout, { recursive: true });
  await writeFile(path.join(checkout, '.nojekyll'), '');

  await requireGit(['config', 'user.name', 'HolodoriCalc deployment'], { cwd: checkout, env: gitEnvironment });
  await requireGit(['config', 'user.email', 'actions@users.noreply.github.com'], { cwd: checkout, env: gitEnvironment });
  await requireGit(['add', '--all', '--', '.'], { cwd: checkout, env: gitEnvironment });

  const diffCode = await runGit(['diff', '--cached', '--quiet'], { cwd: checkout, env: gitEnvironment, quiet: true });
  if (diffCode === 0) {
    process.stdout.write('GitHub Pages output is already up to date.\n');
  } else if (diffCode === 1) {
    const packageJson = JSON.parse(await readFile(path.join(projectRoot, 'package.json'), 'utf8'));
    await requireGit(['commit', '-m', `deploy: HolodoriCalc v${packageJson.version}`], { cwd: checkout, env: gitEnvironment });
    await requireGit(['push', 'origin', 'HEAD:main'], { cwd: checkout, env: gitEnvironment });
  } else {
    throw new Error(`git diff failed with exit code ${diffCode}.`);
  }
} finally {
  const resolvedTemporaryRoot = path.resolve(temporaryRoot);
  const resolvedSystemTemp = path.resolve(os.tmpdir());
  if (resolvedTemporaryRoot.startsWith(`${resolvedSystemTemp}${path.sep}`) && path.basename(resolvedTemporaryRoot).startsWith('holodori-pages-')) {
    await rm(resolvedTemporaryRoot, { recursive: true, force: true });
  }
}