using FsCheck;
using FsCheck.Xunit;
using OfficeOpenXml;
using WorkCameraExport.Models;
using WorkCameraExport.Services;
using Xunit;

namespace WorkCameraExport.Tests
{
    /// <summary>
    /// ExportService 属性测试
    /// Feature: work-camera-2.0.1
    /// </summary>
    public class ExportServicePropertyTests : IDisposable
    {
        private readonly string _testOutputDir;

        public ExportServicePropertyTests()
        {
            _testOutputDir = Path.Combine(Path.GetTempPath(), $"ExportService_Test_{Guid.NewGuid():N}");
            Directory.CreateDirectory(_testOutputDir);
            ExcelPackage.LicenseContext = LicenseContext.NonCommercial;
        }

        public void Dispose()
        {
            try
            {
                if (Directory.Exists(_testOutputDir))
                {
                    Directory.Delete(_testOutputDir, true);
                }
            }
            catch
            {
                // 忽略清理错误
            }
        }

        #region Property 6: 分页数据获取

        /// <summary>
        /// Property 6: 分页数据获取
        /// For any 分页查询，每页返回的数据量应不超过 pageSize（50），且所有页的数据合并后应等于总记录数。
        /// Validates: Requirements 6.3
        /// </summary>
        [Property(MaxTest = 100)]
        public Property PaginatedData_PageSize_ShouldNotExceedLimit()
        {
            return Prop.ForAll(
                Arb.From<PositiveInt>(),
                Arb.From<PositiveInt>(),
                (totalCountGen, pageSizeGen) =>
                {
                    var totalCount = (totalCountGen.Get % 200) + 1; // 1-200 条记录
                    var pageSize = (pageSizeGen.Get % 50) + 1; // 1-50 每页

                    // 模拟分页
                    var pages = SimulatePagination(totalCount, pageSize);

                    // 验证每页数据量不超过 pageSize
                    var allPagesValid = pages.All(p => p.Count <= pageSize);
                    
                    // 验证总数据量等于 totalCount
                    var totalFromPages = pages.Sum(p => p.Count);

                    return (allPagesValid && totalFromPages == totalCount)
                        .Label($"All pages should have <= {pageSize} items and total should be {totalCount}, got {totalFromPages}");
                });
        }

        /// <summary>
        /// Property 6 扩展: 分页后的数据应保持顺序
        /// </summary>
        [Property(MaxTest = 100)]
        public Property PaginatedData_Order_ShouldBePreserved()
        {
            return Prop.ForAll(
                Arb.From<PositiveInt>(),
                (totalCountGen) =>
                {
                    var totalCount = (totalCountGen.Get % 100) + 1;
                    var pageSize = 50;

                    // 生成有序数据
                    var allData = Enumerable.Range(1, totalCount).ToList();
                    
                    // 模拟分页获取
                    var pages = SimulatePaginationWithData(allData, pageSize);
                    
                    // 合并所有页
                    var merged = pages.SelectMany(p => p).ToList();

                    // 验证顺序
                    var orderPreserved = merged.SequenceEqual(allData);

                    return orderPreserved.Label("Data order should be preserved after pagination");
                });
        }

        #endregion

        #region 辅助方法

        /// <summary>
        /// 模拟分页
        /// </summary>
        private List<List<int>> SimulatePagination(int totalCount, int pageSize)
        {
            var pages = new List<List<int>>();
            var remaining = totalCount;
            var pageNum = 0;

            while (remaining > 0)
            {
                var count = Math.Min(remaining, pageSize);
                pages.Add(Enumerable.Range(pageNum * pageSize + 1, count).ToList());
                remaining -= count;
                pageNum++;
            }

            return pages;
        }

        /// <summary>
        /// 模拟分页（带数据）
        /// </summary>
        private List<List<int>> SimulatePaginationWithData(List<int> data, int pageSize)
        {
            var pages = new List<List<int>>();
            
            for (int i = 0; i < data.Count; i += pageSize)
            {
                pages.Add(data.Skip(i).Take(pageSize).ToList());
            }

            return pages;
        }

        #endregion
    }
}