/**
 * v0.4.2 深度审计回归测试（第二轮）
 * 覆盖：
 * - P0-A: compaction 不依赖缓存（缓存未命中不得丢数据/数据不可见）
 * - P0-B: flush/compaction 失败不得卡死 flushChain（写路径死锁）
 * - P1-A: 重开后二级索引恢复 + createIndex 幂等重建 + WAL 恢复后索引一致
 * - P1-B: ALTER TABLE 在 IndexedDB/Hybrid 引擎持久化
 * - P1-C: IndexedDB 事务内 DDL（建表/删表）commit 后磁盘一致
 */

import { AriaEngine } from '../src/engine/aria/index';
import { createSchema } from '../src/table/schema';
import { MemoryEngine } from '../src/engine/memory';
import { HybridEngine } from '../src/hybrid/index';
import { MetonaSqlark } from '../src/core';

import { resetOPFSMock } from './helpers/storage-harness';

beforeEach(() => { resetOPFSMock(); });

let idbCounter = 0;
function uniqueDB(): string {
  return `audit-${Date.now()}-${++idbCounter}-${Math.random().toString(36).slice(2, 8)}`;
}

// ===================================================================
//  P0-A: compaction 不得依赖 SSTable 缓存
// ===================================================================

describe('P0-A — Compaction 缓存独立性', () => {
  it('缓存上限小于单个 SSTable 时 compaction 不丢数据（此前数据不可见）', async () => {
    const engine = new AriaEngine({
      storageBackend: 'memory',
      // 缓存上限 4 页 = 16KB，memtable 32KB → 每次 flush 的文件都超出缓存上限被驱逐
      bufferPoolPages: 4,
      memtableSizeThreshold: 32 * 1024,
      checkpointInterval: 100000,
    });
    await engine.open(uniqueDB(), 1);
    await engine.createTable(createSchema('t', {
      id: { type: 'string', primaryKey: true },
      v: { type: 'number' },
      data: { type: 'string' },
    }));
    for (let i = 0; i < 400; i++) {
      await engine.insert('t', [{ id: `k${String(i).padStart(4, '0')}`, v: i, data: 'x'.repeat(200) }]);
    }
    // 等待 flush + compaction 链全部完成
    await (engine as any).lsm.flush();
    await new Promise((r) => setTimeout(r, 100));
    // 修复前：compaction 缓存未命中跳过全部文件并从 levels 移除 → 查询为空
    expect(await engine.count('t')).toBe(400);
    await engine.close();
  });

  it('多层级 compaction 后数据仍完整且可重开', async () => {
    const dbName = uniqueDB();
    const engine = new AriaEngine({
      storageBackend: 'opfs',
      bufferPoolPages: 8, // 32KB 缓存
      memtableSizeThreshold: 16 * 1024,
      checkpointInterval: 100000,
    });
    await engine.open(dbName, 1);
    await engine.createTable(createSchema('t', {
      id: { type: 'string', primaryKey: true },
      v: { type: 'number' },
    }));
    for (let i = 0; i < 300; i++) {
      await engine.insert('t', [{ id: `k${String(i).padStart(4, '0')}`, v: i }]);
    }
    await (engine as any).lsm.flush();
    await new Promise((r) => setTimeout(r, 150));
    const before = await engine.count('t');
    expect(before).toBe(300);
    await engine.close();

    // 重开：数据完整（meta/文件未被 compaction 破坏）
    const engine2 = new AriaEngine({
      storageBackend: 'opfs',
      bufferPoolPages: 8,
      memtableSizeThreshold: 16 * 1024,
      checkpointInterval: 100000,
    });
    await engine2.open(dbName, 1);
    expect(await engine2.count('t')).toBe(300);
    await engine2.close();
  });
});

// ===================================================================
//  P1-A: 二级索引跨重启恢复
// ===================================================================

describe('P1-A — 二级索引恢复', () => {
  it('Aria 重开后二级索引可用（索引 LSM 持久化恢复）', async () => {
    const dbName = uniqueDB();
    const engine = new AriaEngine({ storageBackend: 'opfs', checkpointInterval: 100000 });
    await engine.open(dbName, 1);
    await engine.createTable(createSchema('users', {
      id: { type: 'string', primaryKey: true },
      email: { type: 'string', index: true },
    }));
    await engine.insert('users', [
      { id: '1', email: 'a@x.com' },
      { id: '2', email: 'b@x.com' },
      { id: '3', email: 'a@x.com' },
    ]);
    await (engine as any).lsm.flush();
    await engine.close();

    // 重开：二级索引 LSM 应自动恢复（修复前为空 → 索引查询回退全表，createIndex 也静默跳过）
    const engine2 = new AriaEngine({ storageBackend: 'opfs', checkpointInterval: 100000 });
    await engine2.open(dbName, 1);
    // 强断言：索引 LSM 真实存在且数据完整（防止"索引缺失静默回退全表扫描"的假通过）
    const idxLsm = (engine2 as any).secondaryIndexes.get('users:idx:email');
    expect(idxLsm).toBeDefined();
    expect(idxLsm.getStats().sstableCount).toBeGreaterThan(0);
    await idxLsm.prefetchRange('', '\uffff');
    expect(idxLsm.rangeScan('', '\uffff')).toHaveLength(3);
    const byEmail = await engine2.find('users', { table: 'users', where: { email: 'a@x.com' } });
    expect(byEmail).toHaveLength(2);
    // createIndex 对已持久化的索引列应幂等可重建（不得静默跳过导致索引永久缺失）
    await engine2.createIndex('users', 'email');
    await engine2.close();
  });

  it('WAL 恢复后二级索引与主数据一致（崩溃前索引未更新）', async () => {
    const dbName = uniqueDB();
    const engine = new AriaEngine({ storageBackend: 'opfs', checkpointInterval: 100000 });
    await engine.open(dbName, 1);
    await engine.createTable(createSchema('users', {
      id: { type: 'string', primaryKey: true },
      city: { type: 'string', index: true },
    }));
    await engine.insert('users', [{ id: '1', city: 'Beijing' }]);
    await (engine as any).lsm.flush();
    // 写入 WAL 但强制不 flush（模拟崩溃：新行只在 WAL，索引 LSM 未更新）
    await engine.insert('users', [{ id: '2', city: 'Shanghai' }]);
    // 模拟异常退出（不 close）
    await (engine as any).backend.close();
    (engine as any).opened = false;

    const engine2 = new AriaEngine({ storageBackend: 'opfs', checkpointInterval: 100000 });
    await engine2.open(dbName, 1);
    // 强断言：索引 LSM 已恢复且包含 WAL 回放的行（崩溃前索引未更新，恢复后必须重建）
    const idxLsm = (engine2 as any).secondaryIndexes.get('users:idx:city');
    expect(idxLsm).toBeDefined();
    await idxLsm.prefetchRange('', '\uffff');
    expect(idxLsm.rangeScan('', '\uffff')).toHaveLength(2);
    // 索引查询应看到 WAL 恢复的行（修复前索引与主数据不一致 → 丢行）
    const byCity = await engine2.find('users', { table: 'users', where: { city: 'Shanghai' } });
    expect(byCity).toHaveLength(1);
    expect(byCity[0].id).toBe('2');
    await engine2.close();
  });

  it('createIndex 重开后仍可新建（schema 标记恢复后不阻塞）', async () => {
    const dbName = uniqueDB();
    const engine = new AriaEngine({ storageBackend: 'opfs', checkpointInterval: 100000 });
    await engine.open(dbName, 1);
    await engine.createTable(createSchema('t', {
      id: { type: 'string', primaryKey: true },
      name: { type: 'string' },
    }));
    await engine.insert('t', [{ id: '1', name: 'A' }]);
    await engine.close();

    const engine2 = new AriaEngine({ storageBackend: 'opfs', checkpointInterval: 100000 });
    await engine2.open(dbName, 1);
    await engine2.createIndex('t', 'name'); // 修复前 schema 无标记时正常；此处验证无标记场景
    const byName = await engine2.find('t', { table: 't', where: { name: 'A' } });
    expect(byName).toHaveLength(1);
    await engine2.close();
  });
});

// ===================================================================
//  P1-B: ALTER TABLE 跨引擎持久化
// ===================================================================

describe('P1-B — ALTER TABLE 持久化', () => {
  it('KVStoreEngine DROP COLUMN 后重启不复活', async () => {
    const dbName = uniqueDB();
    const db = new MetonaSqlark({ name: dbName, mode: 'disk', diskEngine: 'opfs' });
    await db.init();
    await db.defineTable('t', {
      id: { type: 'string', primaryKey: true },
      old_col: { type: 'string' },
      keep: { type: 'string' },
    });
    await db.table('t').insert({ id: '1', old_col: 'x', keep: 'y' });
    await db.query('ALTER TABLE t DROP COLUMN old_col');
    // 行数据中该列已移除
    const rows = await db.table('t').select().execute();
    expect(rows[0].old_col).toBeUndefined();
    await db.close();

    // 重启：schema 不复活，列定义已持久化
    const db2 = new MetonaSqlark({ name: dbName, mode: 'disk', diskEngine: 'opfs' });
    await db2.init();
    const schema2 = await db2.getEngine().getTableSchema('t');
    expect(schema2!.columns.old_col).toBeUndefined();
    expect(schema2!.columns.keep).toBeDefined();
    await db2.close();
  });

  it('HybridEngine ADD COLUMN 后重启保留', async () => {
    const dbName = uniqueDB();
    const db = new MetonaSqlark({ name: dbName, mode: 'hybrid', diskEngine: 'opfs' });
    await db.init();
    await db.defineTable('t', { id: { type: 'string', primaryKey: true } });
    await db.query('ALTER TABLE t ADD COLUMN phone STRING');
    await db.close();

    const db2 = new MetonaSqlark({ name: dbName, mode: 'hybrid', diskEngine: 'opfs' });
    await db2.init();
    const schema2 = await db2.getEngine().getTableSchema('t');
    expect(schema2!.columns.phone).toBeDefined();
    await db2.close();
  });
});

// ===================================================================
//  P1-C: KVStore 事务内 DDL
// ===================================================================

describe('P1-C — KVStore 事务内 DDL', () => {
  it('事务内建表 → commit 后磁盘一致（重启表存在且可查）', async () => {
    const dbName = uniqueDB();
    const db = new MetonaSqlark({ name: dbName, mode: 'hybrid', diskEngine: 'opfs' });
    await db.init();
    await db.defineTable('base', { id: { type: 'string', primaryKey: true } });
    await db.table('base').insert({ id: '1' });

    await db.transaction(async (trx) => {
      await trx.table('base').insert({ id: '2' });
      // 事务内建新表（此前 commit 时 IDB 无对应 store → 事务失败）
      await db.defineTable('created_in_tx', { id: { type: 'string', primaryKey: true } });
      await db.table('created_in_tx').insert({ id: 'tx1' });
    });

    expect(await db.table('created_in_tx').count()).toBe(1);
    await db.close();

    const db2 = new MetonaSqlark({ name: dbName, mode: 'hybrid', diskEngine: 'opfs' });
    await db2.init();
    expect(await db2.table('created_in_tx').count()).toBe(1);
    expect(await db2.table('base').count()).toBe(2);
    await db2.close();
  });

  it('事务内删表 → commit 后磁盘一致（重启无幽灵表）', async () => {
    const dbName = uniqueDB();
    const db = new MetonaSqlark({ name: dbName, mode: 'hybrid', diskEngine: 'opfs' });
    await db.init();
    await db.defineTable('ghost', { id: { type: 'string', primaryKey: true } });
    await db.table('ghost').insert({ id: '1' });

    await db.transaction(async () => {
      await db.dropTable('ghost');
    });

    await db.close();
    const db2 = new MetonaSqlark({ name: dbName, mode: 'hybrid', diskEngine: 'opfs' });
    await db2.init();
    const names = await db2.getTableNames();
    expect(names).not.toContain('ghost');
    await db2.close();
  });
});

// ===================================================================
//  各引擎 clearAll / repair / 元数据 一致性抽查
// ===================================================================

describe('全模式抽查 — 生命周期与元数据', () => {
  it('MemoryEngine clearAll/repair/getMeta/setMeta', async () => {
    const e = new MemoryEngine();
    await e.open('m', 1);
    await e.createTable({ name: 't', columns: { id: { type: 'string', primaryKey: true } } });
    await e.insert('t', [{ id: '1' }]);
    await e.setMeta('k', 'v');
    expect(await e.getMeta('k')).toBe('v');
    await e.repair();
    await e.clearAll();
    expect(await e.getTableNames()).toEqual([]);
    await e.close();
  });

  it('HybridEngine getMeta/setMeta 委托磁盘', async () => {
    const dbName = uniqueDB();
    const e = new HybridEngine('opfs');
    await e.open(dbName, 1);
    await e.setMeta('__metona_version', '7');
    expect(await e.getMeta('__metona_version')).toBe('7');
    await e.close();
    const e2 = new HybridEngine('opfs');
    await e2.open(dbName, 1);
    expect(await e2.getMeta('__metona_version')).toBe('7');
    await e2.close();
  });

  it('AriaEngine repair 幂等', async () => {
    const dbName = uniqueDB();
    const engine = new AriaEngine({ storageBackend: 'opfs' });
    await engine.open(dbName, 1);
    await engine.createTable(createSchema('t', { id: { type: 'string', primaryKey: true } }));
    await engine.insert('t', [{ id: '1' }]);
    await engine.repair();
    await engine.repair();
    expect(await engine.count('t')).toBe(1);
    await engine.close();
  });
});