import { describe, expect, test } from "bun:test";
import { existsSync, mkdirSync, readdirSync, rmSync } from "node:fs";
import { tmpdir } from "node:os";
import { join } from "node:path";

import type { MigrationRecord } from "../../../src/server/db/load-migrations";

import { createDatabase } from "../../../src/server/db/connection";
import { runMigrations } from "../../../src/server/db/migrate";
import { createMemoryLogger } from "../../../src/server/logger";

function makeTempDir(): string {
  const dir = join(tmpdir(), `migration-test-${Date.now()}-${Math.random().toString(36).slice(2)}`);
  mkdirSync(dir, { recursive: true });
  return dir;
}

const MIGRATION_001: MigrationRecord = {
  checksum: "fake-checksum-001",
  id: "0001_initial",
  sql: `
    CREATE TABLE test_table (id TEXT PRIMARY KEY, name TEXT NOT NULL);
  `,
};

const MIGRATION_002: MigrationRecord = {
  checksum: "fake-checksum-002",
  id: "0002_add_desc",
  sql: `
    ALTER TABLE test_table ADD COLUMN description TEXT DEFAULT '';
  `,
};

describe("migration 执行器", () => {
  test("应用待执行 migration 并记录", () => {
    const dir = makeTempDir();
    const logger = createMemoryLogger();
    try {
      const db = createDatabase(dir, logger);
      runMigrations(db, [MIGRATION_001], dir, logger);

      const rows = db.query("SELECT id, checksum FROM schema_migrations").all() as Array<{
        checksum: string;
        id: string;
      }>;
      expect(rows.length).toBe(1);
      expect(rows[0]!.id).toBe("0001_initial");
      expect(rows[0]!.checksum).toBe("fake-checksum-001");

      db.exec("INSERT INTO test_table (id, name) VALUES ('1', 'test')");
      db.close();
    } finally {
      rmSync(dir, { force: true, recursive: true });
    }
  });

  test("跳过已应用的 migration", () => {
    const dir = makeTempDir();
    const logger = createMemoryLogger();
    try {
      const db = createDatabase(dir, logger);
      runMigrations(db, [MIGRATION_001], dir, logger);
      runMigrations(db, [MIGRATION_001], dir, logger);

      const rows = db.query("SELECT id FROM schema_migrations").all() as Array<{ id: string }>;
      expect(rows.length).toBe(1);
      db.close();
    } finally {
      rmSync(dir, { force: true, recursive: true });
    }
  });

  test("按顺序应用多个 migration", () => {
    const dir = makeTempDir();
    const logger = createMemoryLogger();
    try {
      const db = createDatabase(dir, logger);
      runMigrations(db, [MIGRATION_001, MIGRATION_002], dir, logger);

      const rows = db.query("SELECT id FROM schema_migrations ORDER BY id").all() as Array<{ id: string }>;
      expect(rows.length).toBe(2);
      expect(rows[0]!.id).toBe("0001_initial");
      expect(rows[1]!.id).toBe("0002_add_desc");

      db.exec("INSERT INTO test_table (id, name, description) VALUES ('1', 'test', 'desc')");
      db.close();
    } finally {
      rmSync(dir, { force: true, recursive: true });
    }
  });

  test("无待执行 migration 时不做变更", () => {
    const dir = makeTempDir();
    const logger = createMemoryLogger();
    try {
      const db = createDatabase(dir, logger);
      runMigrations(db, [], dir, logger);

      const tableExists = db
        .query("SELECT name FROM sqlite_master WHERE type = 'table' AND name = 'schema_migrations'")
        .get();
      expect(tableExists).toBeNull();
      db.close();
    } finally {
      rmSync(dir, { force: true, recursive: true });
    }
  });

  test("执行 migration 前创建备份", () => {
    const dir = makeTempDir();
    const logger = createMemoryLogger();
    try {
      const db = createDatabase(dir, logger);
      db.exec("CREATE TABLE existing (id TEXT)");
      db.exec("INSERT INTO existing (id) VALUES ('x')");
      db.close();

      const db2 = createDatabase(dir, logger);
      runMigrations(db2, [MIGRATION_001], dir, logger);
      db2.close();

      const backupsDir = join(dir, "backups");
      expect(existsSync(backupsDir)).toBe(true);
      const backupFiles = readdirSync(backupsDir);
      expect(backupFiles.length).toBe(1);
      expect(backupFiles[0]!).toMatch(/^alfred-.*\.db$/);
    } finally {
      rmSync(dir, { force: true, recursive: true });
    }
  });

  test("失败的 migration 不留下部分记录", () => {
    const dir = makeTempDir();
    const logger = createMemoryLogger();
    const BAD_MIGRATION: MigrationRecord = {
      checksum: "bad",
      id: "0003_bad",
      sql: "INVALID SQL STATEMENT;",
    };
    try {
      const db = createDatabase(dir, logger);
      expect(() => {
        runMigrations(db, [MIGRATION_001, BAD_MIGRATION], dir, logger);
      }).toThrow();

      const rows = db.query("SELECT id FROM schema_migrations").all() as Array<{ id: string }>;
      expect(rows.length).toBe(0);
      db.close();
    } finally {
      rmSync(dir, { force: true, recursive: true });
    }
  });
});