using Common.ExpandFun;
using Microsoft.EntityFrameworkCore;
using Sharp.Data;
using Sharp.Data.Context;

namespace Data.Test;

/// <summary>
/// 演示 05: 分页查询
///
/// 本测试类演示:
/// 1. 基础分页查询
/// 2. 带条件的分页
/// 3. 带排序的分页
/// 4. 分页结果的使用
/// 5. 复用 Common 模块的 PagedResult
/// </summary>
[TestClass]
public class _05_PaginationTests
{
    private IDataContext _db = null!;

    [TestInitialize]
    public async Task Setup()
    {
        var builder = new DataContextBuilder<TestDbContext>();
        builder.UseInMemoryDatabase($"PaginationDemo_{Guid.NewGuid()}");
        _db = builder.Build();

        // 添加测试数据：100 个产品
        var repo = _db.Repository<Product>();
        var products = new List<Product>();
        for (var i = 1; i <= 100; i++)
            products.Add(new Product
            {
                Name = $"产品{i:D3}",
                Price = (i % 10 + 1) * 100m,
                Stock = i * 5,
                Description = i % 2 == 0 ? "热门产品" : "普通产品"
            });
        await repo.AddRangeAsync(products);
        await _db.SaveChangesAsync();

        Console.WriteLine("✓ 初始化完成：创建了 100 个测试产品\n");
    }

    [TestCleanup]
    public void Cleanup()
    {
        _db?.Dispose();
    }

    /// <summary>
    /// 演示: 基础分页查询
    /// </summary>
    [TestMethod]
    public async Task Demo_BasicPagination()
    {
        var repo = _db.Repository<Product>();

        // 查询第 1 页，每页 10 条
        var page1 = await repo.GetPagedAsync(
            1,
            10);

        Console.WriteLine($"第 1 页:");
        Console.WriteLine($"  当前页: {page1.PageIndex}");
        Console.WriteLine($"  每页数量: {page1.PageSize}");
        Console.WriteLine($"  总记录数: {page1.TotalCount}");
        Console.WriteLine($"  总页数: {page1.TotalPages}");
        Console.WriteLine($"  是否有上一页: {page1.HasPreviousPage}");
        Console.WriteLine($"  是否有下一页: {page1.HasNextPage}");

        // 验证
        Assert.AreEqual(1, page1.PageIndex);
        Assert.AreEqual(10, page1.PageSize);
        Assert.AreEqual(100, page1.TotalCount);
        Assert.AreEqual(10, page1.TotalPages);
        Assert.AreEqual(10, page1.Items.Count);
        Assert.IsFalse(page1.HasPreviousPage);
        Assert.IsTrue(page1.HasNextPage);

        Console.WriteLine($"\n产品列表:");
        foreach (var product in page1.Items) Console.WriteLine($"  - {product.Name}: {product.Price:C}");
    }

    /// <summary>
    /// 演示: 遍历所有页
    /// </summary>
    [TestMethod]
    public async Task Demo_IterateAllPages()
    {
        var repo = _db.Repository<Product>();
        var pageSize = 15;
        var currentPage = 1;

        Console.WriteLine($"=== 遍历所有页（每页 {pageSize} 条）===\n");

        PagedResult<Product> pageResult;
        do
        {
            pageResult = await repo.GetPagedAsync(currentPage, pageSize);

            Console.WriteLine($"第 {currentPage} 页: {pageResult.Items.Count} 条记录");
            Console.WriteLine(
                $"  范围: {(currentPage - 1) * pageSize + 1} - {Math.Min(currentPage * pageSize, pageResult.TotalCount)}");

            // 处理当前页数据
            foreach (var product in pageResult.Items)
            {
                // 业务逻辑...
            }

            currentPage++;
        } while (pageResult.HasNextPage);

        Console.WriteLine($"\n✓ 总共遍历了 {currentPage - 1} 页");
        Assert.AreEqual(7, currentPage - 1); // 100 / 15 = 7 页
    }

    /// <summary>
    /// 演示: 带条件的分页查询
    /// </summary>
    [TestMethod]
    public async Task Demo_PaginationWithFilter()
    {
        var repo = _db.Repository<Product>();

        // 查询价格 > 500 的产品，第 1 页，每页 10 条
        var result = await repo.GetPagedAsync(
            1,
            10,
            p => p.Price > 500m);

        Console.WriteLine($"查询条件: 价格 > 500");
        Console.WriteLine($"  总记录数: {result.TotalCount}");
        Console.WriteLine($"  总页数: {result.TotalPages}");
        Console.WriteLine($"  当前页记录数: {result.Items.Count}");

        Console.WriteLine($"\n产品列表:");
        foreach (var product in result.Items)
        {
            Console.WriteLine($"  - {product.Name}: {product.Price:C}");
            Assert.IsTrue(product.Price > 500m);
        }
    }

    /// <summary>
    /// 演示: 带排序的分页查询
    /// </summary>
    [TestMethod]
    public async Task Demo_PaginationWithOrdering()
    {
        var repo = _db.Repository<Product>();

        // 按价格降序排列
        var result = await repo.GetPagedAsync(
            1,
            10,
            null,
            q => q.OrderByDescending(p => p.Price));

        Console.WriteLine($"排序: 按价格降序");
        Console.WriteLine($"\n前 10 个最贵的产品:");
        foreach (var product in result.Items) Console.WriteLine($"  - {product.Name}: {product.Price:C}");

        // 验证排序
        for (var i = 0; i < result.Items.Count - 1; i++)
            Assert.IsTrue(result.Items[i].Price >= result.Items[i + 1].Price);
    }

    /// <summary>
    /// 演示: 复杂分页查询 - 组合条件、排序、分页
    /// </summary>
    [TestMethod]
    public async Task Demo_ComplexPagination()
    {
        var repo = _db.Repository<Product>();

        // 查询热门产品，价格 > 300，按库存降序，第 2 页，每页 5 条
        var result = await repo.GetPagedAsync(
            2,
            5,
            p => p.Description == "热门产品" && p.Price > 300m,
            q => q.OrderByDescending(p => p.Stock));

        Console.WriteLine($"复杂查询:");
        Console.WriteLine($"  条件: 热门产品 AND 价格>300");
        Console.WriteLine($"  排序: 按库存降序");
        Console.WriteLine($"  分页: 第 2 页，每页 5 条");
        Console.WriteLine($"\n结果:");
        Console.WriteLine($"  总记录数: {result.TotalCount}");
        Console.WriteLine($"  总页数: {result.TotalPages}");
        Console.WriteLine($"  当前页码: {result.PageIndex}");

        Console.WriteLine($"\n产品列表:");
        foreach (var product in result.Items)
        {
            Console.WriteLine($"  - {product.Name}: {product.Price:C}, 库存: {product.Stock}");
            Assert.AreEqual("热门产品", product.Description);
            Assert.IsTrue(product.Price > 300m);
        }
    }

    /// <summary>
    /// 演示: 分页辅助信息的使用
    /// </summary>
    [TestMethod]
    public async Task Demo_PaginationHelpers()
    {
        var repo = _db.Repository<Product>();

        // 第 5 页，每页 10 条
        var result = await repo.GetPagedAsync(5, 10);

        Console.WriteLine($"=== 分页辅助信息 ===\n");
        Console.WriteLine($"当前页: {result.PageIndex}");
        Console.WriteLine($"每页数量: {result.PageSize}");
        Console.WriteLine($"总记录数: {result.TotalCount}");
        Console.WriteLine($"总页数: {result.TotalPages}");
        Console.WriteLine($"是否第一页: {result.PageIndex == 1}");
        Console.WriteLine($"是否最后一页: {result.PageIndex == result.TotalPages}");
        Console.WriteLine($"有上一页: {result.HasPreviousPage}");
        Console.WriteLine($"有下一页: {result.HasNextPage}");

        // 计算记录范围
        var startIndex = (result.PageIndex - 1) * result.PageSize + 1;
        var endIndex = Math.Min(result.PageIndex * result.PageSize, result.TotalCount);
        Console.WriteLine($"\n记录范围: {startIndex} - {endIndex}");

        // 验证
        Assert.AreEqual(5, result.PageIndex);
        Assert.AreEqual(41, startIndex);
        Assert.AreEqual(50, endIndex);
        Assert.IsTrue(result.HasPreviousPage);
        Assert.IsTrue(result.HasNextPage);
    }

    /// <summary>
    /// 演示: 空结果的分页
    /// </summary>
    [TestMethod]
    public async Task Demo_EmptyPageResult()
    {
        var repo = _db.Repository<Product>();

        // 查询不存在的条件
        var result = await repo.GetPagedAsync(
            1,
            10,
            p => p.Price > 99999m);

        Console.WriteLine($"查询不存在的记录:");
        Console.WriteLine($"  总记录数: {result.TotalCount}");
        Console.WriteLine($"  总页数: {result.TotalPages}");
        Console.WriteLine($"  当前页记录数: {result.Items.Count}");

        Assert.AreEqual(0, result.TotalCount);
        Assert.AreEqual(0, result.TotalPages);
        Assert.AreEqual(0, result.Items.Count);
        Assert.IsFalse(result.HasPreviousPage);
        Assert.IsFalse(result.HasNextPage);
    }

    /// <summary>
    /// 演示: 超出范围的页码
    /// </summary>
    [TestMethod]
    public async Task Demo_OutOfRangePage()
    {
        var repo = _db.Repository<Product>();

        // 请求第 999 页（超出实际页数）
        var result = await repo.GetPagedAsync(999, 10);

        Console.WriteLine($"请求超出范围的页码 (第 999 页):");
        Console.WriteLine($"  总记录数: {result.TotalCount}");
        Console.WriteLine($"  总页数: {result.TotalPages}");
        Console.WriteLine($"  当前页码: {result.PageIndex}");
        Console.WriteLine($"  当前页记录数: {result.Items.Count}");

        // 超出范围返回空列表
        Assert.AreEqual(0, result.Items.Count);
        Assert.AreEqual(999, result.PageIndex);
        Assert.IsFalse(result.HasNextPage);
    }

    /// <summary>
    /// 演示: 在 UI 中使用分页
    ///
    /// 模拟 Web API 或 WPF 应用的分页场景
    /// </summary>
    [TestMethod]
    public async Task Demo_PaginationInUI()
    {
        var repo = _db.Repository<Product>();

        // 模拟用户请求
        var requestedPage = 3;
        var pageSize = 20;
        var searchTerm = "产品0"; // 用户搜索

        Console.WriteLine($"=== UI 分页场景 ===");
        Console.WriteLine($"用户请求: 第 {requestedPage} 页, 每页 {pageSize} 条");
        Console.WriteLine($"搜索词: {searchTerm}\n");

        // 执行分页查询
        var result = await repo.GetPagedAsync(
            requestedPage,
            pageSize,
            string.IsNullOrEmpty(searchTerm)
                ? null
                : p => p.Name.Contains(searchTerm),
            q => q.OrderBy(p => p.Name));

        // 构建返回给前端的数据
        var uiData = new
        {
            Success = true,
            Data = new
            {
                Items = result.Items.Select(p => new
                {
                    p.Id,
                    p.Name,
                    p.Price,
                    p.Stock
                }).ToList(),
                Pagination = new
                {
                    result.PageIndex,
                    result.PageSize,
                    result.TotalCount,
                    result.TotalPages,
                    result.HasPreviousPage,
                    result.HasNextPage
                }
            }
        };

        Console.WriteLine($"返回数据:");
        Console.WriteLine($"  记录数: {uiData.Data.Items.Count}");
        Console.WriteLine($"  分页信息: {uiData.Data.Pagination.PageIndex}/{uiData.Data.Pagination.TotalPages}");
        Console.WriteLine($"\n✓ 可以直接序列化为 JSON 返回给前端");
    }

    /// <summary>
    /// 演示: PagedResult 来自 Common 模块
    ///
    /// Sharp.Data 复用 Common.ExpandFun.PagedResult<T>，避免重复定义
    /// </summary>
    [TestMethod]
    public async Task Demo_PagedResultFromCommonModule()
    {
        var repo = _db.Repository<Product>();

        var result = await repo.GetPagedAsync(1, 10);

        // PagedResult<T> 来自 Common.ExpandFun 命名空间
        Console.WriteLine($"✓ PagedResult<T> 的类型信息:");
        Console.WriteLine($"  类型: {result.GetType().FullName}");
        Console.WriteLine($"  命名空间: {result.GetType().Namespace}");
        Console.WriteLine($"\n✓ 复用 Common 模块，避免重复造轮子");

        Assert.AreEqual("Common.ExpandFun", result.GetType().Namespace);
    }

    /// <summary>
    /// 演示: 自定义扩展方法进行分页
    /// </summary>
    [TestMethod]
    public async Task Demo_CustomPaginationExtension()
    {
        // 使用 EF Core 的 IQueryable 直接分页
        var query = _db.Context.Set<Product>()
            .Where(p => p.Price > 500m)
            .OrderBy(p => p.Name);

        // 手动实现分页逻辑
        var page = 2;
        var pageSize = 10;

        var totalCount = await query.CountAsync();
        var items = await query
            .Skip((page - 1) * pageSize)
            .Take(pageSize)
            .ToListAsync();

        // 构建 PagedResult
        var result = new PagedResult<Product>
        {
            Items = items,
            TotalCount = totalCount,
            PageIndex = page,
            PageSize = pageSize
        };

        Console.WriteLine($"自定义分页:");
        Console.WriteLine($"  总记录数: {result.TotalCount}");
        Console.WriteLine($"  当前页: {result.PageIndex}");
        Console.WriteLine($"  记录数: {result.Items.Count}");

        Console.WriteLine($"\n✓ 可以直接使用 IQueryable 和 PagedResult 进行自定义分页");
    }
}