import { mkdtempSync } from 'node:fs';
import { tmpdir } from 'node:os';
import { join } from 'node:path';

import { INestApplication } from '@nestjs/common';
import { Test, TestingModuleBuilder } from '@nestjs/testing';
import type { NestExpressApplication } from '@nestjs/platform-express';
import cookieParser from 'cookie-parser';

import { AppModule } from '../app.module';

/**
 * Boots the full application for e2e tests, mirroring main.ts middleware.
 * Requires TEST_DATABASE_URL; DATABASE_URL is pointed at it so the app
 * under test uses the test database. `customize` can override providers
 * (e.g. inject a fake converter for the conversion queue tests, issue #62).
 */
export async function createTestApp(
  customize?: (builder: TestingModuleBuilder) => TestingModuleBuilder,
): Promise<INestApplication> {
  process.env.NODE_ENV = 'test';
  if (process.env.TEST_DATABASE_URL) {
    process.env.DATABASE_URL = process.env.TEST_DATABASE_URL;
  }
  process.env.DATABASE_URL ??= 'postgresql://nobody:nothing@127.0.0.1:59999/absent';
  // Fresh scratch directory per test file so upload tests never touch the
  // repository or collide with each other.
  process.env.UPLOADS_DIR ??= mkdtempSync(join(tmpdir(), 'dorfteich-uploads-'));
  process.env.PLUGINS_DIR ??= mkdtempSync(join(tmpdir(), 'dorfteich-plugins-'));

  const base = Test.createTestingModule({ imports: [AppModule] });
  const moduleRef = await (customize ? customize(base) : base).compile();
  const app = moduleRef.createNestApplication<NestExpressApplication>();
  app.use(cookieParser());
  // Mirrors main.ts: base64 Yjs page state needs more than Express's 100kb default.
  app.useBodyParser('json', { limit: '8mb' });
  // Mirrors main.ts: the public API (issue #104) declares its full path.
  app.setGlobalPrefix('api/v1', {
    exclude: ['api/public/v1', 'api/public/v1/{*path}', 'api/mcp'],
  });
  await app.init();
  return app;
}

/** Extracts the dt_session cookie pair ("name=value") from a response. */
export function sessionCookieOf(res: { headers: Record<string, unknown> }): string {
  const header = res.headers['set-cookie'];
  const cookies = Array.isArray(header) ? header : [header].filter(Boolean);
  const session = (cookies as string[]).find((c) => c.startsWith('dt_session='));
  if (!session) throw new Error('response carries no dt_session cookie');
  return session.split(';')[0]!;
}