import { execFile } from 'node:child_process';
import { access, mkdtemp, readFile, rm, writeFile } from 'node:fs/promises';
import os from 'node:os';
import path from 'node:path';
import { promisify } from 'node:util';
import toolInvocation from '../src/shared/tool-invocation.cjs';

const exec = promisify(execFile);
const { npmProbeCandidates } = toolInvocation;
const packageJson = JSON.parse(await readFile(new URL('../package.json', import.meta.url), 'utf8'));
const checks = [];
const jsonMode = process.argv.includes('--json');

function add(id, name, ok, detail, help = '') {
  checks.push({ id, name, status: ok ? 'pass' : 'fail', ok, detail, help });
}

const major = Number(process.versions.node.split('.')[0]);
add('node', 'Node.js', major >= 22, process.version, 'Install Node.js 22 or newer.');

try {
  const failures = [];
  let version = '';
  let source = '';
  for (const candidate of npmProbeCandidates()) {
    try {
      const { stdout } = await exec(candidate.file, candidate.args, { windowsHide: true });
      version = stdout.trim();
      source = candidate.source;
      if (version) break;
    } catch (error) {
      failures.push(`${candidate.source}: ${error.message}`);
    }
  }
  if (!version) throw new Error(failures.join(' | ') || 'No npm invocation candidate succeeded.');
  add('npm', 'npm', true, `${version} (${source})`);
} catch (error) {
  add('npm', 'npm', false, error.message, 'Install npm together with Node.js and ensure npm.cmd is available on PATH.');
}

try {
  const { stdout } = await exec('git', ['--version']);
  add('git', 'Git', true, stdout.trim());
  const [name, email] = await Promise.all([
    exec('git', ['config', '--global', '--get', 'user.name']).then((result) => result.stdout.trim()).catch(() => ''),
    exec('git', ['config', '--global', '--get', 'user.email']).then((result) => result.stdout.trim()).catch(() => '')
  ]);
  add('git-identity', 'Git identity', Boolean(name && email), name && email ? `${name} <${email}>` : 'user.name or user.email is missing', 'Configure git config --global user.name and user.email.');
} catch (error) {
  add('git', 'Git', false, error.message, 'Install Git and ensure git is on PATH.');
}

try {
  await access(new URL('../node_modules/electron/package.json', import.meta.url));
  add('electron', 'Electron dependency', true, 'installed');
} catch {
  add('electron', 'Electron dependency', false, 'not installed', 'Run npm install.');
}

let markerDirectory = null;
try {
  markerDirectory = await mkdtemp(path.join(os.tmpdir(), 'forgeflow-doctor-'));
  await writeFile(path.join(markerDirectory, 'write-test'), 'ok');
  add('temp-storage', 'Local diagnostic storage', true, markerDirectory.replace(os.homedir(), '<HOME>'));
} catch (error) {
  add('temp-storage', 'Local diagnostic storage', false, error.message, 'Check local disk permissions and free space.');
} finally {
  if (markerDirectory) await rm(markerDirectory, { recursive: true, force: true }).catch(() => {});
}

const report = {
  product: 'ForgeFlow',
  version: packageJson.version,
  generatedAt: new Date().toISOString(),
  platform: process.platform,
  arch: process.arch,
  ready: checks.every((check) => check.ok),
  checks
};

if (jsonMode) console.log(JSON.stringify(report, null, 2));
else {
  console.log('ForgeFlow doctor\n');
  for (const check of checks) console.log(`${check.ok ? 'PASS' : 'FAIL'}  ${check.name.padEnd(26)} ${check.detail}`);
  console.log(`\n${report.ready ? 'Environment is ready.' : 'Resolve failed checks before starting ForgeFlow.'}`);
}

if (!report.ready) process.exitCode = 1;