import { execFile } from 'child_process';
import { existsSync } from 'fs';
import { join } from 'path';
import { promisify } from 'util';
import { Logger } from '@nestjs/common';
import { PrismaClient } from '@prisma/client';
import { runMigrations, runOnce } from './migrate';

const execFileAsync = promisify(execFile);

function resolveSeedScript(): string | undefined {
  const candidates = [
    process.env.SEED_SCRIPT,
    join(process.cwd(), 'seed.js'),
    join(__dirname, '..', '..', 'seed.js'),
  ].filter((p): p is string => Boolean(p));

  return candidates.find((file) => existsSync(file));
}

/**
 * Runs pending SQL migrations before Nest boots, then seeds once.
 *
 * Seeding is gated on a marker row written only after the seed succeeds, so an
 * interrupted seed is retried on the next boot (the seed itself upserts).
 * Set RUN_MIGRATIONS=false or RUN_SEED=false to skip.
 */
export async function prepareDatabase(): Promise<void> {
  if (process.env.RUN_MIGRATIONS === 'false') return;

  const logger = new Logger('DatabaseBootstrap');
  const prisma = new PrismaClient();

  try {
    const { applied } = await runMigrations(prisma);

    if (applied.length > 0) {
      logger.log(`Applied migrations: ${applied.join(', ')}`);
    } else {
      logger.log('No pending migrations');
    }

    if (process.env.RUN_SEED === 'false') return;

    const seedScript = resolveSeedScript();
    if (!seedScript) {
      logger.warn('No seed script found — skipping seed');
      return;
    }

    const seeded = await runOnce(prisma, 'seed:initial', async () => {
      const { stdout } = await execFileAsync(process.execPath, [seedScript]);
      if (stdout.trim()) logger.log(stdout.trim());
    });
    if (seeded) logger.log('Seed data inserted');
  } finally {
    await prisma.$disconnect();
  }
}