/**
 * v0.6.3 修复回归测试 — 原子性/一致性/资源治理
 *
 * 覆盖：
 * - B7: KVStore writeBatch 混合 put+delete 单条日志记录（真原子）
 * - B8: WAL full 模式写入失败抛错（不再吞错）
 * - B6: MemoryEngine SET NULL 级联索引残留（虚假 UNIQUE_VIOLATION）
 * - B10: delete 级联两阶段（RESTRICT 预检，无部分级联）
 * - B13: BufferPool 驱逐同步清理 pages Map（内存预算真实生效）
 * - B11: LSM.flush 不再重复入链（无重复 SSTable）
 * - B12: rollbackToSavepoint 重建受影响表二级索引
 */

import { MemoryEngine } from '../src/engine/memory';
import { KVStoreEngine } from '../src/engine/kvstore_engine';
import { AriaEngine } from '../src/engine/aria/index';
import { createSchema } from '../src/table/schema';
import { KVStore } from '../src/engine/kvstore/index';
import { SharedMemoryBackend } from '../src/engine/kvstore/shared_memory_medium';
import { parseLogRecords, KVLogOp } from '../src/engine/kvstore/log';
import { WAL } from '../src/engine/aria/wal/log';
import { BufferPool } from '../src/engine/aria/buffer/pool';

function uniqueDB(): string {
  return `v063-${Date.now()}-${Math.random().toString(36).slice(2, 8)}`;
}

/** 断言 Promise 以指定错误码拒绝 */
async function expectCode(promise: Promise<unknown>, code: string): Promise<void> {
  try {
    await promise;
  } catch (e) {
    expect((e as { code?: string }).code).toBe(code);
    return;
  }
  throw new Error(`Expected rejection with code "${code}", but promise resolved`);
}

describe('v0.6.3 — KVStore writeBatch 混合原子（B7）', () => {
  it('put+delete 编码进同一条日志记录', async () => {
    const kv = new KVStore(new SharedMemoryBackend(), 0);
    await kv.open(uniqueDB());
    await kv.put('keep', new TextEncoder().encode('k').buffer);
    await kv.writeBatch(
      { a: new TextEncoder().encode('1').buffer, b: new TextEncoder().encode('2').buffer },
      ['old1', 'old2'],
    );
    // 直接读取日志文件字节：解析应为 2 条记录（put keep + 混合记录），
    // 混合记录包含 2 PUT + 2 DELETE 条目
    const medium = (kv as any).medium as SharedMemoryBackend;
    const raw = await medium.read('__kv_log');
    expect(raw).not.toBeNull();
    const records: { entries: { op: KVLogOp }[] }[] = [];
    parseLogRecords(new Uint8Array(raw!), (r) => records.push(r as never));
    expect(records).toHaveLength(2);
    const mixed = records[1].entries.map((e) => e.op);
    expect(mixed.filter((op) => op === KVLogOp.PUT)).toHaveLength(2);
    expect(mixed.filter((op) => op === KVLogOp.DELETE)).toHaveLength(2);
    await kv.close();
  });

  it('KVStoreEngine delete（SET NULL 级联）混合写为单记录', async () => {
    const name = uniqueDB();
    const eng = new KVStoreEngine();
    await eng.open(name, 1);
    await eng.createTable(createSchema('users', {
      id: { type: 'string', primaryKey: true },
    }));
    await eng.createTable(createSchema('orders', {
      id: { type: 'string', primaryKey: true },
      user_id: { type: 'string', references: 'users.id', onDelete: 'SET NULL' },
    }));
    await eng.insert('users', [{ id: 'u1' }]);
    await eng.insert('orders', [{ id: 'o1', user_id: 'u1' }]);
    await eng.delete('users', { table: 'users', where: { id: 'u1' } });

    // 日志未 checkpoint：最后一条记录应同时含 orders 行重写（PUT）与 users 行删除（DELETE）
    const kv = (eng as any).kv as KVStore;
    const medium = (kv as any).medium as SharedMemoryBackend;
    const raw = await medium.read('__kv_log');
    const records: { entries: { op: KVLogOp }[] }[] = [];
    parseLogRecords(new Uint8Array(raw!), (r) => records.push(r as never));
    const last = records[records.length - 1].entries.map((e) => e.op);
    expect(last).toContain(KVLogOp.PUT);
    expect(last).toContain(KVLogOp.DELETE);
    await eng.close();

    // 重开后效果完整（SET NULL + 父行删除均生效）
    const eng2 = new KVStoreEngine();
    await eng2.open(name, 1);
    const orders = await eng2.find('orders', { table: 'orders' });
    expect(orders).toHaveLength(1);
    expect(orders[0].user_id).toBeNull();
    expect(await eng2.count('users')).toBe(0);
    await eng2.close();
  });
});

describe('v0.6.3 — WAL 写入失败传播（B8）', () => {
  class FailingStore {
    async append(_d: Uint8Array): Promise<void> { throw new Error('disk full'); }
    async readAll(): Promise<Uint8Array> { return new Uint8Array(0); }
    async truncate(): Promise<void> {}
    async exists(): Promise<boolean> { return false; }
  }

  it("full 模式 append 失败 reject（不再 console.warn 吞错）", async () => {
    const wal = new WAL(new FailingStore() as never, true, 'full');
    await expect(wal.append({
      type: 1, txnId: 0, tableName: 't', key: '1', data: { v: 1 },
    })).rejects.toThrow('disk full');
    await expect(wal.appendBatch([{
      type: 1, txnId: 0, tableName: 't', key: '2', data: { v: 2 },
    }])).rejects.toThrow('disk full');
  });
});

describe('v0.6.3 — MemoryEngine SET NULL 索引清理（B6）', () => {
  it('级联 SET NULL 后旧值可被复用（不再虚假 UNIQUE_VIOLATION）', async () => {
    const eng = new MemoryEngine();
    await eng.open(uniqueDB(), 1);
    await eng.createTable(createSchema('users', {
      id: { type: 'string', primaryKey: true },
    }));
    await eng.createTable(createSchema('orders', {
      id: { type: 'string', primaryKey: true },
      user_id: { type: 'string', references: 'users.id', onDelete: 'SET NULL', unique: true },
    }));
    await eng.insert('users', [{ id: 'u1' }]);
    await eng.insert('orders', [{ id: 'o1', user_id: 'u1' }]);
    await eng.delete('users', { table: 'users', where: { id: 'u1' } });
    // 旧值 u1 的索引条目应被完整清理（含空 Set 移除）
    await eng.insert('orders', [{ id: 'o2', user_id: 'u1' }]);
    const rows = await eng.find('orders', { table: 'orders' });
    expect(rows).toHaveLength(2);
    // 索引查询旧值返回正确
    const byIdx = await eng.find('orders', { table: 'orders', where: { user_id: 'u1' } });
    expect(byIdx).toHaveLength(1);
    expect(byIdx[0].id).toBe('o2');
  });
});

describe('v0.6.3 — delete 级联两阶段（B10）', () => {
  async function buildMemory(): Promise<MemoryEngine> {
    const eng = new MemoryEngine();
    await eng.open(uniqueDB(), 1);
    await eng.createTable(createSchema('parents', {
      id: { type: 'string', primaryKey: true },
    }));
    await eng.createTable(createSchema('cascade_child', {
      id: { type: 'string', primaryKey: true },
      pid: { type: 'string', references: 'parents.id', onDelete: 'CASCADE' },
    }));
    await eng.createTable(createSchema('restrict_child', {
      id: { type: 'string', primaryKey: true },
      pid: { type: 'string', references: 'parents.id', onDelete: 'RESTRICT' },
    }));
    return eng;
  }

  it('Memory: 多行删除含 RESTRICT 违规则整体拒绝（无部分级联）', async () => {
    const eng = await buildMemory();
    await eng.insert('parents', [{ id: 'p1' }, { id: 'p2' }]);
    await eng.insert('cascade_child', [{ id: 'c1', pid: 'p1' }]);
    await eng.insert('restrict_child', [{ id: 'r2', pid: 'p2' }]);
    await expectCode(eng.delete('parents', { table: 'parents' }), 'FOREIGN_KEY_VIOLATION');
    // p1 的级联子行必须仍在（修复前：p1 子行已删、父行未删）
    expect(await eng.count('parents')).toBe(2);
    expect(await eng.count('cascade_child')).toBe(1);
    expect(await eng.count('restrict_child')).toBe(1);
  });

  it('Aria: 多行删除含 RESTRICT 违规则整体拒绝（无部分级联）', async () => {
    const eng = new AriaEngine({ storageBackend: 'memory' });
    await eng.open(uniqueDB(), 1);
    await eng.createTable(createSchema('parents', {
      id: { type: 'string', primaryKey: true },
    }));
    await eng.createTable(createSchema('cascade_child', {
      id: { type: 'string', primaryKey: true },
      pid: { type: 'string', references: 'parents.id', onDelete: 'CASCADE' },
    }));
    await eng.createTable(createSchema('restrict_child', {
      id: { type: 'string', primaryKey: true },
      pid: { type: 'string', references: 'parents.id', onDelete: 'RESTRICT' },
    }));
    await eng.insert('parents', [{ id: 'p1' }, { id: 'p2' }]);
    await eng.insert('cascade_child', [{ id: 'c1', pid: 'p1' }]);
    await eng.insert('restrict_child', [{ id: 'r2', pid: 'p2' }]);
    await expectCode(eng.delete('parents', { table: 'parents' }), 'FOREIGN_KEY_VIOLATION');
    expect(await eng.count('parents')).toBe(2);
    expect(await eng.count('cascade_child')).toBe(1);
    expect(await eng.count('restrict_child')).toBe(1);
    await eng.close();
  });

  it('深层 CASCADE 链末端的 RESTRICT 也被预检拦截', async () => {
    const eng = await buildMemory();
    await eng.createTable(createSchema('deep_child', {
      id: { type: 'string', primaryKey: true },
      cid: { type: 'string', references: 'cascade_child.id', onDelete: 'RESTRICT' },
    }));
    await eng.insert('parents', [{ id: 'p1' }]);
    await eng.insert('cascade_child', [{ id: 'c1', pid: 'p1' }]);
    await eng.insert('deep_child', [{ id: 'd1', cid: 'c1' }]);
    await expectCode(eng.delete('parents', { table: 'parents', where: { id: 'p1' } }), 'FOREIGN_KEY_VIOLATION');
    expect(await eng.count('parents')).toBe(1);
    expect(await eng.count('cascade_child')).toBe(1);
    expect(await eng.count('deep_child')).toBe(1);
  });

  it('无 RESTRICT 违规时级联删除照常完整执行', async () => {
    const eng = await buildMemory();
    await eng.insert('parents', [{ id: 'p1' }, { id: 'p2' }]);
    await eng.insert('cascade_child', [{ id: 'c1', pid: 'p1' }, { id: 'c2', pid: 'p2' }]);
    const count = await eng.delete('parents', { table: 'parents' });
    expect(count).toBe(4); // 2 父 + 2 级联子
    expect(await eng.count('parents')).toBe(0);
    expect(await eng.count('cascade_child')).toBe(0);
  });
});

describe('v0.6.3 — BufferPool 内存预算（B13）', () => {
  it('驱逐同步清理 pages Map（容量约束真实生效）', async () => {
    const pageIO = {
      readPage: async (id: number) => {
        const b = new ArrayBuffer(4096);
        new DataView(b).setUint32(0, id);
        new DataView(b).setUint8(4, 1);
        return b;
      },
      writePage: async () => {},
      allocatePageId: async () => 0,
      freePageId: async () => {},
    };
    const pool = new BufferPool(pageIO, 2);
    for (let i = 1; i <= 20; i++) {
      const p = await pool.getPage(i);
      pool.unpin(p!);
    }
    expect((pool as any).pages.size).toBeLessThanOrEqual(2);
    // 驱逐后再次访问能重新加载（正确性不受影响）
    const p = await pool.getPage(20);
    expect(p).not.toBeNull();
    pool.unpin(p!);
  });
});

describe('v0.6.3 — LSM.flush 不重复入链（B11）', () => {
  it('2 行 + 中间冻结 + flush → 恰好 2 个 SSTable（无重复产物）', async () => {
    const eng = new AriaEngine({ storageBackend: 'memory' });
    await eng.open(uniqueDB(), 1);
    await eng.createTable(createSchema('t', {
      id: { type: 'string', primaryKey: true },
      v: { type: 'string' },
    }));
    const lsm = (eng as any).lsm;
    await eng.insert('t', [{ id: '1', v: 'a' }]);
    lsm.freezeMemtable();
    await eng.insert('t', [{ id: '2', v: 'b' }]);
    await lsm.flush();
    const metas = lsm.levels[0] as { id: number; minKey: string; maxKey: string }[];
    expect(metas).toHaveLength(2);
    const keys = metas.flatMap((m) => [m.minKey, m.maxKey]).sort();
    expect(keys).toEqual(['t:1', 't:1', 't:2', 't:2']);
    const rows = await eng.find('t', { table: 't' });
    expect(rows).toHaveLength(2);
    await eng.close();
  });
});

describe('v0.6.3 — rollbackToSavepoint 索引重建（B12）', () => {
  it('savepoint 回滚后索引不含过期条目', async () => {
    const eng = new AriaEngine({ storageBackend: 'memory' });
    await eng.open(uniqueDB(), 1);
    await eng.createTable(createSchema('t', {
      id: { type: 'string', primaryKey: true },
      tag: { type: 'string', index: true },
    }));
    await eng.insert('t', [{ id: '1', tag: 'x' }]);
    await eng.beginTransaction();
    await (eng as any).savepoint('sp1');
    await eng.insert('t', [{ id: '2', tag: 'x' }]);
    await (eng as any).rollbackToSavepoint('sp1');
    await eng.commitTransaction();
    // 数据只有 1 行
    expect(await eng.count('t')).toBe(1);
    // 索引查询 x 只返回 id=1（savepoint 后插入的 id=2 索引条目已清理）
    const rows = await eng.find('t', { table: 't', where: { tag: 'x' } });
    expect(rows).toHaveLength(1);
    expect(rows[0].id).toBe('1');
    await eng.close();
  });
});