using FsCheck;
using FsCheck.Xunit;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Diagnostics;
using Microsoft.Extensions.Logging;
using Moq;
using VendingMachine.Application.DTOs.Points;
using VendingMachine.Application.Services;
using VendingMachine.Domain.Entities;
using VendingMachine.Infrastructure.Data;
using VendingMachine.Infrastructure.Services;

namespace VendingMachine.Tests;

/// <summary>
/// 积分模块属性测试
/// </summary>
public class PointsPropertyTests
{
    // Feature: vending-machine-app, Property 10: 积分转换计算
    // 对于任意支付金额和转换比，计算出的积分应等于 Math.Floor(金额 * 转换比)。
    // **Validates: Requirements 5.1**
    [Property(MaxTest = 100)]
    public bool PointsConversion_ShouldMatchFloorFormula(PositiveInt amountRaw, PositiveInt rateRaw)
    {
        // 生成合理范围的金额（0.01 ~ 10000.00）和转换比（0.1 ~ 10.0）
        var amount = (decimal)(amountRaw.Get % 1000000 + 1) / 100m;
        var rate = (decimal)(rateRaw.Get % 100 + 1) / 10m;

        var points = IPointsService.CalculatePoints(amount, rate);
        var expected = (int)Math.Floor(amount * rate);

        return points == expected;
    }

    [Property(MaxTest = 100)]
    public bool PointsConversion_ShouldAlwaysBeNonNegative(PositiveInt amountRaw, PositiveInt rateRaw)
    {
        var amount = (decimal)(amountRaw.Get % 1000000 + 1) / 100m;
        var rate = (decimal)(rateRaw.Get % 100 + 1) / 10m;

        var points = IPointsService.CalculatePoints(amount, rate);
        return points >= 0;
    }

    // Feature: vending-machine-app, Property 11: 积分记录渲染完整性
    // 对于任意积分记录，获取记录应包含来源、时间和增加数量；使用记录应包含使用方式、时间和减少数量。
    // **Validates: Requirements 5.4, 5.5**
    [Property(MaxTest = 100)]
    public bool EarnRecord_ShouldContainAllRequiredFields(
        NonEmptyString source, PositiveInt amount)
    {
        var record = new PointRecordDto
        {
            Id = Guid.NewGuid().ToString(),
            Type = "earn",
            Amount = amount.Get,
            Source = source.Get,
            CreatedAt = DateTime.UtcNow
        };

        // 获取记录应包含来源、时间和增加数量
        return !string.IsNullOrEmpty(record.Source)
            && record.CreatedAt != default
            && record.Amount > 0
            && record.Type == "earn";
    }

    [Property(MaxTest = 100)]
    public bool SpendRecord_ShouldContainAllRequiredFields(
        NonEmptyString source, PositiveInt amount)
    {
        var record = new PointRecordDto
        {
            Id = Guid.NewGuid().ToString(),
            Type = "spend",
            Amount = amount.Get,
            Source = source.Get,
            CreatedAt = DateTime.UtcNow
        };

        // 使用记录应包含使用方式、时间和减少数量
        return !string.IsNullOrEmpty(record.Source)
            && record.CreatedAt != default
            && record.Amount > 0
            && record.Type == "spend";
    }

    // Feature: vending-machine-app, Property 12: 赠送积分守恒
    // 对于任意积分赠送操作，如果发送方积分充足，则发送方减少的积分等于接收方增加的积分（总积分守恒）；
    // 如果发送方积分不足，则双方积分均不变。
    // **Validates: Requirements 5.6, 5.7**
    [Property(MaxTest = 100)]
    public bool GiftPoints_WhenSufficientBalance_TotalPointsConserved(PositiveInt balanceRaw, PositiveInt giftRaw)
    {
        // 确保发送方积分充足
        var balance = balanceRaw.Get % 10000 + 1;
        var giftAmount = (giftRaw.Get % balance) + 1;

        var options = new DbContextOptionsBuilder<AppDbContext>()
            .UseInMemoryDatabase(databaseName: $"GiftSufficient_{Guid.NewGuid()}")
            .ConfigureWarnings(w => w.Ignore(InMemoryEventId.TransactionIgnoredWarning))
            .Options;

        using var db = new AppDbContext(options);
        var logger = Mock.Of<ILogger<PointsService>>();

        var sender = new User { Uid = "sender000001", Phone = "13800000001", AreaCode = "+86", Nickname = "发送方", PointsBalance = balance };
        var receiver = new User { Uid = "receiver0001", Phone = "13800000002", AreaCode = "+86", Nickname = "接收方", PointsBalance = 0 };
        db.Users.AddRange(sender, receiver);
        db.SaveChanges();

        var totalBefore = sender.PointsBalance + receiver.PointsBalance;

        var service = new PointsService(db, logger);
        var result = service.GiftPointsAsync("sender000001", new GiftPointsRequest
        {
            TargetUid = "receiver0001",
            Amount = giftAmount
        }).GetAwaiter().GetResult();

        db.Entry(sender).Reload();
        db.Entry(receiver).Reload();

        var totalAfter = sender.PointsBalance + receiver.PointsBalance;

        // 总积分守恒
        return result.Success
            && totalBefore == totalAfter
            && sender.PointsBalance == balance - giftAmount
            && receiver.PointsBalance == giftAmount;
    }

    [Property(MaxTest = 100)]
    public bool GiftPoints_WhenInsufficientBalance_BothUnchanged(PositiveInt balanceRaw, PositiveInt extraRaw)
    {
        // 确保发送方积分不足
        var balance = balanceRaw.Get % 100 + 1;
        var giftAmount = balance + (extraRaw.Get % 1000) + 1;

        var options = new DbContextOptionsBuilder<AppDbContext>()
            .UseInMemoryDatabase(databaseName: $"GiftInsufficient_{Guid.NewGuid()}")
            .ConfigureWarnings(w => w.Ignore(InMemoryEventId.TransactionIgnoredWarning))
            .Options;

        using var db = new AppDbContext(options);
        var logger = Mock.Of<ILogger<PointsService>>();

        var sender = new User { Uid = "sender000001", Phone = "13800000001", AreaCode = "+86", Nickname = "发送方", PointsBalance = balance };
        var receiver = new User { Uid = "receiver0001", Phone = "13800000002", AreaCode = "+86", Nickname = "接收方", PointsBalance = 50 };
        db.Users.AddRange(sender, receiver);
        db.SaveChanges();

        var senderBefore = sender.PointsBalance;
        var receiverBefore = receiver.PointsBalance;

        var service = new PointsService(db, logger);
        var result = service.GiftPointsAsync("sender000001", new GiftPointsRequest
        {
            TargetUid = "receiver0001",
            Amount = giftAmount
        }).GetAwaiter().GetResult();

        db.Entry(sender).Reload();
        db.Entry(receiver).Reload();

        // 积分不足时双方积分均不变
        return !result.Success
            && sender.PointsBalance == senderBefore
            && receiver.PointsBalance == receiverBefore;
    }
}