/**
 * KVStoreEngine — 大规模压力测试（10 万级）
 *
 * 验证生产级可靠性：
 * 1. 10 万 key 批量写入 + checkpoint + 重开全量验证
 * 2. 混合操作（insert/update/delete）5 万级 + 崩溃模拟（不 checkpoint 断开）→ 重开验证已确认写入
 * 3. 多 checkpoint 循环下数据不丢
 */
import { KVStoreEngine } from '../../src/engine/kvstore_engine';
import { SharedMemoryBackend } from '../../src/engine/kvstore/shared_memory_medium';
import { createSchema } from '../../src/table/schema';

let counter = 0;
function uniqueDB(): string {
  return `stress-${Date.now()}-${++counter}-${Math.random().toString(36).slice(2, 6)}`;
}

beforeEach(() => {
  SharedMemoryBackend.clearRegistry();
});

describe('KVStoreEngine — 10 万级压力', () => {
  it('10 万 key 写入 + checkpoint + 重开全量验证', async () => {
    const dbName = uniqueDB();
    const engine = new KVStoreEngine(new SharedMemoryBackend());
    await engine.open(dbName, 1);
    await engine.createTable(createSchema('big', {
      id: { type: 'string', primaryKey: true },
      val: { type: 'number' },
      name: { type: 'string' },
    }));

    const TOTAL = 100000;
    // 分批写入（每批 1000）
    for (let batch = 0; batch < TOTAL / 1000; batch++) {
      const rows = [] as Record<string, unknown>[];
      for (let i = 0; i < 1000; i++) {
        const idx = batch * 1000 + i;
        rows.push({ id: `k${idx}`, val: idx, name: `User${idx}` });
      }
      await engine.insert('big', rows);
      // 每 20 批 checkpoint 一次
      if ((batch + 1) % 20 === 0) {
        await (engine as any).kv.checkpoint();
      }
    }
    expect(await engine.count('big')).toBe(TOTAL);
    await engine.close();

    // 重开：全量验证
    const engine2 = new KVStoreEngine(new SharedMemoryBackend());
    await engine2.open(dbName, 1);
    expect(await engine2.count('big')).toBe(TOTAL);
    // 抽样验证
    for (const id of ['k0', 'k49999', 'k99999', 'k12345']) {
      const rows = await engine2.find('big', { table: 'big', where: { id } });
      expect(rows).toHaveLength(1);
      expect(Number(rows[0].val)).toBe(Number(id.slice(1)));
    }
    await engine2.close();
  }, 120000);

  it('5 万混合操作 + 崩溃模拟（不 checkpoint）→ 重开全部已确认写入可见', async () => {
    const dbName = uniqueDB();
    const engine = new KVStoreEngine(new SharedMemoryBackend());
    await engine.open(dbName, 1);
    await engine.createTable(createSchema('ops', {
      id: { type: 'string', primaryKey: true },
      val: { type: 'number' },
    }));

    let seed = 42;
    const rand = () => { seed = (seed * 1103515245 + 12345) & 0x7fffffff; return seed / 0x7fffffff; };
    const confirmed = new Map<string, number>();

    const TOTAL = 50000;
    for (let i = 0; i < TOTAL; i++) {
      const r = rand();
      const id = `k${Math.floor(rand() * 20000)}`;
      if (r < 0.6) {
        const val = Math.floor(rand() * 1000000);
        try {
          await engine.insert('ops', [{ id, val }]);
          confirmed.set(id, val);
        } catch (e) {
          if ((e as { code?: string }).code !== 'DUPLICATE_KEY') throw e;
        }
      } else if (r < 0.8) {
        const val = Math.floor(rand() * 1000000);
        await engine.update('ops', { table: 'ops', where: { id } }, { val });
        if (confirmed.has(id)) confirmed.set(id, val);
      } else {
        await engine.delete('ops', { table: 'ops', where: { id } });
        confirmed.delete(id);
      }
      // 每 5000 次 checkpoint
      if ((i + 1) % 5000 === 0) {
        await (engine as any).kv.checkpoint();
      }
    }

    // 崩溃模拟：直接断开（不 close → 数据在 KVStore 日志/快照）
    await engine.close();
    const engine2 = new KVStoreEngine(new SharedMemoryBackend());
    await engine2.open(dbName, 1);
    expect(await engine2.count('ops')).toBe(confirmed.size);
    // 抽样验证值
    let sampled = 0;
    for (const [id, val] of confirmed) {
      if (sampled++ > 1000) break;
      const rows = await engine2.find('ops', { table: 'ops', where: { id } });
      expect(rows[0].val).toBe(val);
    }
    await engine2.close();
  }, 120000);

  it('多次 checkpoint 循环（500 次）数据不丢', async () => {
    const dbName = uniqueDB();
    const engine = new KVStoreEngine(new SharedMemoryBackend(), 0);
    await engine.open(dbName, 1);
    await engine.createTable(createSchema('t', {
      id: { type: 'string', primaryKey: true },
      v: { type: 'number' },
    }));

    for (let i = 0; i < 500; i++) {
      await engine.insert('t', [{ id: `k${i}`, v: i }]);
      await (engine as any).kv.checkpoint();
    }
    await engine.close();

    const engine2 = new KVStoreEngine(new SharedMemoryBackend(), 0);
    await engine2.open(dbName, 1);
    expect(await engine2.count('t')).toBe(500);
    const last = await engine2.find('t', { table: 't', where: { id: 'k499' } });
    expect(last[0].v).toBe(499);
    await engine2.close();
  }, 60000);
});