import chokidar from 'chokidar';
import { exec } from 'node:child_process';
import type { ExecException } from 'node:child_process';
import nodemon from 'nodemon';

import { logger } from './src/utils/logger.ts';

const nodeEnv = process.env.NODE_ENV || 'dev_stage';
const childEnv = buildChildEnv(process.env, nodeEnv);
const log = logger.child({ module: 'watcher' });

function buildChildEnv(
  env: NodeJS.ProcessEnv,
  fallbackNodeEnv: string,
): Record<string, string> {
  const child: Record<string, string> = {};

  for (const [key, value] of Object.entries(env)) {
    if (value !== undefined) {
      child[key] = value;
    }
  }

  child.NODE_ENV = fallbackNodeEnv;
  return child;
}

function logCommandResult(
  error: ExecException | null,
  stdout: string,
  stderr: string,
  successMessage: string,
): void {
  const output = stdout.trim();
  const errorOutput = stderr.trim();

  if (output) {
    log.info({ output }, successMessage);
  }

  if (error) {
    log.error(
      { err: error, stderr: errorOutput },
      'Watched database command failed',
    );
  } else if (errorOutput) {
    log.warn({ stderr: errorOutput }, 'Watched database command wrote stderr');
  }
}

const migrationsWatcher = chokidar.watch('./src/db/migrations', {
  persistent: true,
  ignoreInitial: true,
  usePolling: true,
  interval: 1000,
});
migrationsWatcher.on('error', (error) => {
  log.error({ err: error }, 'Migrations watcher failed');
});
migrationsWatcher.on('add', (filePath) => {
  log.info({ filePath }, 'New migration file detected');
  exec('npm run db:migrate', { env: childEnv }, (error, stdout, stderr) => {
    logCommandResult(error, stdout, stderr, 'Migration command completed');
  });
});

const seedersWatcher = chokidar.watch('./src/db/seeders', {
  persistent: true,
  ignoreInitial: true,
  usePolling: true,
  interval: 1000,
});
seedersWatcher.on('error', (error) => {
  log.error({ err: error }, 'Seeders watcher failed');
});
seedersWatcher.on('add', (filePath) => {
  log.info({ filePath }, 'New seed file detected');
  exec('npm run db:seed', { env: childEnv }, (error, stdout, stderr) => {
    logCommandResult(error, stdout, stderr, 'Seeder command completed');
  });
});

nodemon({
  script: './src/index.ts',
  exec: 'node',
  env: childEnv,
  watch: ['./src'],
  ext: 'js,ts,json',
  ignore: [
    './src/db/migrations',
    './src/db/seeders',
    './dist',
    './node_modules',
  ],
  delay: 500,
});

nodemon.on('start', () => {
  log.info({ nodeEnv }, 'Nodemon started');
});

nodemon.on('restart', (files) => {
  log.info({ files }, 'Nodemon restarted due to file changes');
});

nodemon.on('crash', () => {
  log.error('Nodemon app crashed');
});