/**
 * AriaEngine Page 格式单元测试
 * 覆盖: PageHeader / Slot / Tuple 编解码 + PageFormat 整合
 */
import {
  PAGE_SIZE, PageType, PAGE_HEADER_SIZE, SLOT_ENTRY_SIZE,
} from '../../src/engine/aria/types';
import {
  encodePageHeader, decodePageHeader, initPageHeader, getPageType,
  getSlotCount, getFreeStart, setFreeStart, setFreeEnd,
} from '../../src/engine/aria/page/header';
import {
  getSlotEntry, setSlotEntry, getSlotDirectorySize,
  getFreeSpace, hasEnoughSpace, allocateSlot, readSlotData, freeSlot,
} from '../../src/engine/aria/page/slot';
import {
  encodeTuple, decodeTuple, getColumnEncodingMap,
} from '../../src/engine/aria/page/tuple';
import { ColumnEncoding } from '../../src/engine/aria/types';
import {
  createPage, pageFromBuffer, pageInsertRow, pageReadRow,
  pageDeleteRow, pageUpdateRow, computeChecksum, verifyChecksum, updateChecksum,
} from '../../src/engine/aria/page/format';

// ===================================================================
//  PageHeader
// ===================================================================
describe('AriaEngine Page — Header', () => {
  let buf: ArrayBuffer;

  beforeEach(() => {
    buf = new ArrayBuffer(PAGE_SIZE);
  });

  it('initPageHeader 初始化头部字段', () => {
    initPageHeader(buf, 42, PageType.DATA);
    const h = decodePageHeader(buf);
    expect(h.pageId).toBe(42);
    expect(h.type).toBe(PageType.DATA);
    expect(h.slotCount).toBe(0);
    expect(h.freeStart).toBe(PAGE_HEADER_SIZE);
    expect(h.freeEnd).toBe(PAGE_SIZE);
  });

  it('initPageHeader — INDEX 类型页面', () => {
    initPageHeader(buf, 99, PageType.INDEX);
    expect(getPageType(buf)).toBe(PageType.INDEX);
  });

  it('encodePageHeader + decodePageHeader 往返一致', () => {
    const header = { pageId: 7, type: PageType.META, freeStart: 32, freeEnd: 4000, slotCount: 5, checksum: 0xdeadbeef };
    encodePageHeader(header, buf);
    const decoded = decodePageHeader(buf);
    expect(decoded.pageId).toBe(7);
    expect(decoded.type).toBe(PageType.META);
    expect(decoded.freeStart).toBe(32);
    expect(decoded.freeEnd).toBe(4000);
    expect(decoded.slotCount).toBe(5);
  });

  it('不同 pageId 正确编解码', () => {
    for (const id of [0, 1, 255, 65535, 0xffffffff]) {
      initPageHeader(buf, id, PageType.DATA);
      expect(decodePageHeader(buf).pageId).toBe(id >>> 0);
    }
  });

  it('setFreeStart / setFreeEnd 修改字段', () => {
    initPageHeader(buf, 1, PageType.DATA);
    setFreeStart(buf, 100);
    setFreeEnd(buf, 3000);
    expect(getFreeStart(buf)).toBe(100);
    expect(decodePageHeader(buf).freeEnd).toBe(3000);
  });
});

// ===================================================================
//  Slot Directory
// ===================================================================
describe('AriaEngine Page — Slot', () => {
  let buf: ArrayBuffer;

  beforeEach(() => {
    buf = new ArrayBuffer(PAGE_SIZE);
    initPageHeader(buf, 1, PageType.DATA);
  });

  it('getSlotEntry — 空页面 slotCount 为 0', () => {
    expect(getSlotCount(buf)).toBe(0);
  });

  it('setSlotEntry + getSlotEntry 往返', () => {
    // 手动写一个 slot（不通过 allocateSlot）
    new DataView(buf).setUint16(9, 1, false); // slotCount = 1
    setSlotEntry(buf, 0, { offset: 1000, length: 50 });
    const entry = getSlotEntry(buf, 0);
    expect(entry.offset).toBe(1000);
    expect(entry.length).toBe(50);
  });

  it('getSlotDirectorySize 计算正确', () => {
    expect(getSlotDirectorySize(0)).toBe(0);
    expect(getSlotDirectorySize(1)).toBe(SLOT_ENTRY_SIZE);
    expect(getSlotDirectorySize(10)).toBe(10 * SLOT_ENTRY_SIZE);
  });

  it('getFreeSpace — 空页面有最大空闲空间', () => {
    const free = getFreeSpace(buf);
    expect(free).toBe(PAGE_SIZE - PAGE_HEADER_SIZE);
  });

  it('hasEnoughSpace — 小数据返回 true', () => {
    expect(hasEnoughSpace(buf, 100)).toBe(true);
  });

  it('hasEnoughSpace — 超大数据返回 false', () => {
    expect(hasEnoughSpace(buf, PAGE_SIZE * 2)).toBe(false);
  });

  it('allocateSlot 分配并写入数据', () => {
    const data = new Uint8Array([1, 2, 3, 4, 5]);
    const idx = allocateSlot(buf, data);
    expect(idx).toBe(0);
    expect(getSlotCount(buf)).toBe(1);

    const readBack = readSlotData(buf, 0);
    expect(readBack).not.toBeNull();
    expect(Array.from(readBack!)).toEqual([1, 2, 3, 4, 5]);
  });

  it('allocateSlot 多次分配', () => {
    for (let i = 0; i < 10; i++) {
      const data = new Uint8Array([i, i + 1]);
      const idx = allocateSlot(buf, data);
      expect(idx).toBe(i);
    }
    expect(getSlotCount(buf)).toBe(10);

    // 验证每个 slot 数据正确
    for (let i = 0; i < 10; i++) {
      const data = readSlotData(buf, i);
      expect(Array.from(data!)).toEqual([i, i + 1]);
    }
  });

  it('freeSlot 标记为删除', () => {
    const data = new Uint8Array([10, 20, 30]);
    allocateSlot(buf, data);
    freeSlot(buf, 0);
    const entry = getSlotEntry(buf, 0);
    expect(entry.offset).toBe(0);
    expect(entry.length).toBe(0);
  });

  it('readSlotData — 已删除 slot 返回 null', () => {
    allocateSlot(buf, new Uint8Array([1]));
    freeSlot(buf, 0);
    expect(readSlotData(buf, 0)).toBeNull();
  });

  it('allocateSlot — 空间不足返回 -1', () => {
    // 填满页面
    const big = new Uint8Array(PAGE_SIZE - PAGE_HEADER_SIZE - SLOT_ENTRY_SIZE);
    const idx1 = allocateSlot(buf, big);
    expect(idx1).toBe(0);
    const idx2 = allocateSlot(buf, new Uint8Array([1]));
    expect(idx2).toBe(-1);
  });
});

// ===================================================================
//  Tuple Codec
// ===================================================================
describe('AriaEngine Page — Tuple', () => {
  const colOrder = ['id', 'name', 'age', 'active', 'data'];
  const colTypes: Record<string, string> = {
    id: 'string', name: 'string', age: 'number', active: 'boolean', data: 'json',
  };

  it('encodeTuple + decodeTuple 完整往返', () => {
    const row = { id: '1', name: 'Alice', age: 30, active: true, data: { x: 1 } };
    const encoded = encodeTuple(row, colOrder, colTypes);
    expect(encoded.byteLength).toBeGreaterThan(0);

    const decoded = decodeTuple(encoded, colOrder, colTypes);
    expect(decoded).not.toBeNull();
    expect(decoded!.id).toBe('1');
    expect(decoded!.name).toBe('Alice');
    expect(decoded!.age).toBe(30);
    expect(decoded!.active).toBe(true);
    expect(decoded!.data).toEqual({ x: 1 });
  });

  it('encodeTuple — null 值正确处理', () => {
    const row = { id: '2', name: null, age: 25, active: null, data: null };
    const encoded = encodeTuple(row, colOrder, colTypes);
    const decoded = decodeTuple(encoded, colOrder, colTypes);
    expect(decoded!.name).toBeNull();
    expect(decoded!.active).toBeNull();
    expect(decoded!.data).toBeNull();
  });

  it('encodeTuple — undefined 值按 null 处理', () => {
    const row = { id: '3', age: 30 } as any;
    const encoded = encodeTuple(row, colOrder, colTypes);
    const decoded = decodeTuple(encoded, colOrder, colTypes);
    expect(decoded!.id).toBe('3');
    expect(decoded!.name).toBeNull();
  });

  it('encodeTuple — date 类型', () => {
    const order = ['ts'];
    const types = { ts: 'date' };
    const row = { ts: '2024-01-15T00:00:00.000Z' };
    const encoded = encodeTuple(row, order, types);
    const decoded = decodeTuple(encoded, order, types);
    expect(decoded!.ts).toBe('2024-01-15T00:00:00.000Z');
  });

  it('encodeTuple — boolean false', () => {
    const order = ['flag'];
    const types = { flag: 'boolean' };
    const encoded = encodeTuple({ flag: false }, order, types);
    const decoded = decodeTuple(encoded, order, types);
    expect(decoded!.flag).toBe(false);
  });

  it('encodeTuple — 负数', () => {
    const order = ['val'];
    const types = { val: 'number' };
    const encoded = encodeTuple({ val: -42.5 }, order, types);
    const decoded = decodeTuple(encoded, order, types);
    expect(decoded!.val).toBe(-42.5);
  });

  it('encodeTuple — 空字符串', () => {
    const order = ['s'];
    const types = { s: 'string' };
    const encoded = encodeTuple({ s: '' }, order, types);
    const decoded = decodeTuple(encoded, order, types);
    expect(decoded!.s).toBe('');
  });

  it('encodeTuple — 长字符串', () => {
    const order = ['s'];
    const types = { s: 'string' };
    const long = 'x'.repeat(10000);
    const encoded = encodeTuple({ s: long }, order, types);
    const decoded = decodeTuple(encoded, order, types);
    expect(decoded!.s).toBe(long);
  });

  it('getColumnEncodingMap 返回正确映射', () => {
    const map = getColumnEncodingMap(colOrder, colTypes);
    expect(map.get('id')).toBe(ColumnEncoding.STRING);
    expect(map.get('age')).toBe(ColumnEncoding.NUMBER);
    expect(map.get('active')).toBe(ColumnEncoding.BOOLEAN);
    expect(map.get('data')).toBe(ColumnEncoding.JSON);
  });

  it('decodeTuple — 损坏数据返回 null', () => {
    const broken = new Uint8Array([0xff, 0xff, 0xff]);
    expect(decodeTuple(broken, colOrder, colTypes)).toBeNull();
  });
});

// ===================================================================
//  Page Format 整合
// ===================================================================
describe('AriaEngine Page — Format', () => {
  const colOrder = ['id', 'name'];
  const colTypes: Record<string, string> = { id: 'string', name: 'string' };

  it('createPage 创建合法页面', () => {
    const page = createPage(100, PageType.DATA);
    expect(page.pageId).toBe(100);
    expect(page.type).toBe(PageType.DATA);
    expect(page.pins).toBe(0);
    expect(page.dirty).toBe(true);
  });

  it('pageInsertRow + pageReadRow 往返', () => {
    const page = createPage(1, PageType.DATA);
    const row = { id: 'u1', name: 'Test' };
    const idx = pageInsertRow(page, row, colOrder, colTypes);
    expect(idx).toBe(0);

    const read = pageReadRow(page, 0, colOrder, colTypes);
    expect(read).not.toBeNull();
    expect(read!.id).toBe('u1');
    expect(read!.name).toBe('Test');
  });

  it('pageInsertRow — 多次插入', () => {
    const page = createPage(1, PageType.DATA);
    for (let i = 0; i < 50; i++) {
      const idx = pageInsertRow(page, { id: `${i}`, name: `User${i}` }, colOrder, colTypes);
      expect(idx).toBe(i);
    }
    for (let i = 0; i < 50; i++) {
      const row = pageReadRow(page, i, colOrder, colTypes);
      expect(row!.id).toBe(`${i}`);
    }
  });

  it('pageDeleteRow 标记删除', () => {
    const page = createPage(1, PageType.DATA);
    pageInsertRow(page, { id: '1', name: 'A' }, colOrder, colTypes);
    pageInsertRow(page, { id: '2', name: 'B' }, colOrder, colTypes);
    pageDeleteRow(page, 0);
    expect(page.dirty).toBe(true);
    // 已删除的行读取失败
    const row = pageReadRow(page, 0, colOrder, colTypes);
    expect(row).toBeNull();
    // 未删除的行仍然可读
    const row2 = pageReadRow(page, 1, colOrder, colTypes);
    expect(row2!.id).toBe('2');
  });

  it('pageFromBuffer 从 ArrayBuffer 恢复', () => {
    const page = createPage(5, PageType.INDEX);
    const restored = pageFromBuffer(5, page.data);
    expect(restored.pageId).toBe(5);
    expect(restored.type).toBe(PageType.INDEX);
    expect(restored.dirty).toBe(false);
  });

  it('computeChecksum + verifyChecksum', () => {
    const page = createPage(1, PageType.DATA);
    updateChecksum(page);
    expect(verifyChecksum(page)).toBe(true);

    // 修改页面 → 校验和失效
    new Uint8Array(page.data)[100] = 0xff;
    expect(verifyChecksum(page)).toBe(false);
  });
});