using FluentValidation;
using TakeoutSaaS.Application.App.Billings.Commands;

namespace TakeoutSaaS.Application.App.Billings.Validators;

/// <summary>
/// 创建账单命令验证器。
/// </summary>
public sealed class CreateBillingCommandValidator : AbstractValidator<CreateBillingCommand>
{
    public CreateBillingCommandValidator()
    {
        // 1. 租户 ID 必填
        RuleFor(x => x.TenantId)
            .GreaterThan(0)
            .WithMessage("租户 ID 必须大于 0");

        // 2. 账单类型必填
        RuleFor(x => x.BillingType)
            .IsInEnum()
            .WithMessage("账单类型无效");

        // 3. 应付金额必须大于 0
        RuleFor(x => x.AmountDue)
            .GreaterThan(0)
            .WithMessage("应付金额必须大于 0");

        // 4. 到期日必须是未来时间
        RuleFor(x => x.DueDate)
            .GreaterThan(DateTime.UtcNow)
            .WithMessage("到期日必须是未来时间");

        // 5. 账单明细至少包含一项
        RuleFor(x => x.LineItems)
            .NotEmpty()
            .WithMessage("账单明细不能为空");

        // 6. 账单明细项验证
        RuleForEach(x => x.LineItems)
            .ChildRules(lineItem =>
            {
                lineItem.RuleFor(x => x.ItemType)
                    .NotEmpty()
                    .WithMessage("账单明细类型不能为空")
                    .MaximumLength(50)
                    .WithMessage("账单明细类型不能超过 50 个字符");

                lineItem.RuleFor(x => x.Description)
                    .NotEmpty()
                    .WithMessage("账单明细描述不能为空")
                    .MaximumLength(200)
                    .WithMessage("账单明细描述不能超过 200 个字符");

                lineItem.RuleFor(x => x.Quantity)
                    .GreaterThan(0)
                    .WithMessage("账单明细数量必须大于 0");

                lineItem.RuleFor(x => x.UnitPrice)
                    .GreaterThanOrEqualTo(0)
                    .WithMessage("账单明细单价不能为负数");

                lineItem.RuleFor(x => x.Amount)
                    .GreaterThanOrEqualTo(0)
                    .WithMessage("账单明细金额不能为负数");
            });

        // 7. 备注长度限制（可选）
        RuleFor(x => x.Notes)
            .MaximumLength(500)
            .WithMessage("备注不能超过 500 个字符")
            .When(x => !string.IsNullOrWhiteSpace(x.Notes));
    }
}
