import { existsSync, rmSync } from 'node:fs';
import { mkdtemp } from 'node:fs/promises';
import { tmpdir } from 'node:os';
import { join } from 'node:path';
import { setupTestDatabaseFile } from './database';

/**
 * Integration test context with isolated database and data directory
 */
export interface IntegrationTestContext {
  /** Path to test database file */
  dbPath: string;
  /** Path to test data directory */
  dataDir: string;
  /**
   * Path to the bus event sqlite db. Tests that need to attach a
   * bus responder fixture can pass this to `startBusResponderFixture`
   * so the responder shares the bus with the celilo CLI subprocess.
   */
  busDbPath: string;
  /** CLI command prefix with environment variables */
  cli: string;
  /** Cleanup function (closes DB and removes temp directories) */
  cleanup: () => Promise<void>;
}

/**
 * Setup complete integration test environment
 *
 * Creates:
 * - Isolated test database (file-based for CLI access)
 * - Isolated data directory
 * - Runs migrations
 * - Returns CLI command prefix with proper env vars
 *
 * @returns Integration test context with cleanup function
 *
 * @example
 * ```typescript
 * let ctx: IntegrationTestContext;
 *
 * beforeEach(async () => {
 *   ctx = await setupIntegrationTest();
 * });
 *
 * afterEach(async () => {
 *   await ctx.cleanup();
 * });
 *
 * test('my test', () => {
 *   const output = runCli(ctx.cli, 'system config get');
 *   expect(output).toContain('...');
 * });
 * ```
 */
export async function setupIntegrationTest(): Promise<IntegrationTestContext> {
  // celilo#1246: the shell on a dev host carries CELILO_HOME pointing at the
  // live install (DB and master.key included). Every CLI child this harness
  // spawns would inherit it, and isolation would then rest on the per-run
  // CELILO_DB_PATH / CELILO_DATA_DIR overrides below never being missed.
  // Unset it once, here, so no child ever sees the live home.
  delete process.env.CELILO_HOME;

  // Setup isolated database
  const testDb = await setupTestDatabaseFile();
  const dbPath = testDb.path;
  const dbCleanup = testDb.cleanup;

  // Setup isolated data directory (use mkdtemp to avoid timestamp collisions in parallel tests)
  const dataDir = await mkdtemp(join(tmpdir(), 'celilo-test-'));

  // The celilo CLI's getEventBusPath() falls back to <dataDir>/events.db
  // when EVENT_BUS_DB isn't set. Tests that attach a responder need
  // the same path so subprocess + responder share the bus DB.
  const busDbPath = join(dataDir, 'events.db');

  // CLI with isolated environment. CELILO_SUPPRESS_DEPRECATION silences
  // the legacy-path banners (e.g. on `celilo system init`) so they
  // don't pollute test output — the banners are an operator-UX concern,
  // not a CI signal.
  const cli = `CELILO_DB_PATH="${dbPath}" CELILO_DATA_DIR="${dataDir}" CELILO_SUPPRESS_DEPRECATION=1 bun run src/cli/index.ts`;

  // Note: Migrations are auto-run by createDbClient() in setupTestDatabaseFile()

  // Unified cleanup function
  const cleanup = async () => {
    // Cleanup data directory
    if (existsSync(dataDir)) {
      rmSync(dataDir, { recursive: true, force: true });
    }

    // Cleanup database
    await dbCleanup();
  };

  return {
    dbPath,
    dataDir,
    busDbPath,
    cli,
    cleanup,
  };
}