using YD_Event.Core.Enum;
using YD_Event.Core.Domain.Pricing.Models;

namespace YD_Event.Core.Domain.Pricing;

/// <summary>
/// 赛事定价计算服务
/// 所有金额计算均以此服务为准，确保计算结果的一致性
/// </summary>
public static class EventPricingService
{
    /// <summary>
    /// 计算赛事报名费用
    /// </summary>
    /// <param name="input">定价计算输入</param>
    /// <returns>定价计算结果</returns>
    public static PricingResult Calculate(PricingInput input)
    {
        var result = new PricingResult
        {
            TotalPersonCount = input.ParticipantCount
        };

        result.CalculationLogs.Add($"[{DateTime.Now:yyyy-MM-dd HH:mm:ss}] 开始计算费用，收费模式: {input.ChargeMode}, 人数: {input.ParticipantCount}");

        switch (input.ChargeMode)
        {
            case ChargeMode.Free:
                CalculateFreeMode(result);
                break;
            case ChargeMode.FixedPrice:
                CalculateFixedPriceMode(result, input);
                break;
            case ChargeMode.UnitPriceEvent:
                CalculateUnitPriceEventMode(result, input);
                break;
            case ChargeMode.UnitPriceProject:
                CalculateUnitPriceProjectMode(result, input);
                break;
        }

        result.TotalAmount = Math.Round(result.TotalAmount, 2, MidpointRounding.AwayFromZero);
        result.CalculationLogs.Add($"[{DateTime.Now:yyyy-MM-dd HH:mm:ss}] 最终总金额: {result.TotalAmount:F2} 元");

        return result;
    }

    /// <summary>
    /// 免费模式
    /// </summary>
    private static void CalculateFreeMode(PricingResult result)
    {
        result.TotalAmount = 0;
        result.Details.Add(new PricingDetailItem
        {
            ItemName = "报名费",
            UnitPrice = 0,
            Quantity = 1,
            Subtotal = 0,
            Remark = "免费"
        });
        result.CalculationLogs.Add($"[{DateTime.Now:yyyy-MM-dd HH:mm:ss}] 免费模式，总金额: 0 元");
    }

    /// <summary>
    /// 定价（赛事）模式：固定为赛事设定价格/场，无论参赛主体是个人还是单位，也无论参赛项目数量多少，均统一按固定价格计算
    /// </summary>
    private static void CalculateFixedPriceMode(PricingResult result, PricingInput input)
    {
        var price = input.EventPrice;
        result.TotalAmount = price;
        result.Details.Add(new PricingDetailItem
        {
            ItemName = "赛事报名费",
            UnitPrice = price,
            Quantity = 1,
            Subtotal = price,
            Remark = $"固定价格 {price:F2} 元/场，参赛人数: {input.ParticipantCount} 人"
        });
        result.CalculationLogs.Add($"[{DateTime.Now:yyyy-MM-dd HH:mm:ss}] 定价（赛事）模式: 固定价格 {price:F2} 元/场");
    }

    /// <summary>
    /// 单价（赛事）模式：按照赛事设定的单价乘以实际报名人数计算总金额
    /// </summary>
    private static void CalculateUnitPriceEventMode(PricingResult result, PricingInput input)
    {
        var unitPrice = input.EventPrice;
        var totalAmount = unitPrice * input.ParticipantCount;
        result.TotalAmount = totalAmount;
        result.Details.Add(new PricingDetailItem
        {
            ItemName = "赛事报名费",
            UnitPrice = unitPrice,
            Quantity = input.ParticipantCount,
            Subtotal = totalAmount,
            Remark = input.ParticipantCount == 1 
                ? $"个人参赛 {unitPrice:F2} 元" 
                : $"团队参赛 {unitPrice:F2} 元/人 × {input.ParticipantCount} 人"
        });
        result.CalculationLogs.Add($"[{DateTime.Now:yyyy-MM-dd HH:mm:ss}] 单价（赛事）模式: {unitPrice:F2} 元/人 × {input.ParticipantCount} 人 = {totalAmount:F2} 元");
    }

    /// <summary>
    /// 单价（项目）模式：根据每个项目的单独定价和报名人数进行计算。
    /// 每个项目独立计算：项目单价 × 对应人数，然后累加所有项目的金额
    /// </summary>
    private static void CalculateUnitPriceProjectMode(PricingResult result, PricingInput input)
    {
        decimal totalAmount = 0;

        foreach (var project in input.Projects)
        {
            var subtotal = project.UnitPrice * project.Quantity;
            totalAmount += subtotal;
            
            result.Details.Add(new PricingDetailItem
            {
                ItemName = project.ProjectName,
                UnitPrice = project.UnitPrice,
                Quantity = project.Quantity,
                Subtotal = subtotal,
                Remark = "项目单价"
            });
            result.CalculationLogs.Add($"[{DateTime.Now:yyyy-MM-dd HH:mm:ss}] 项目: {project.ProjectName}, 单价: {project.UnitPrice:F2} 元, 人数: {project.Quantity}, 小计: {subtotal:F2} 元");
        }

        result.TotalAmount = totalAmount;
        result.CalculationLogs.Add($"[{DateTime.Now:yyyy-MM-dd HH:mm:ss}] 单价（项目）模式: 总金额 {totalAmount:F2} 元");
    }
}