using Application.Abstractions.Data;
using Application.Abstractions.Messaging;
using Domain.Entities.Donations.ValueObject;
using SharedKernel.Results;
using Microsoft.EntityFrameworkCore;

namespace Application.Features.Api.DonationGoal.GetProgress;

internal sealed class Handler(IAppDbContext db) : IQueryHandler<Query, Result<Response>>
{
    public async Task<Result<Response>> Handle(Query request, CancellationToken ct)
    {
        var goal = await db.DonationGoalConfig.AsNoTracking().FirstOrDefaultAsync(g => g.ID == request.GoalConfigID && g.ChannelID == request.ChannelID && g.IsActive, ct);
        if (goal is null)
        {
            return Result.Failure<Response>(Error.NotFound("DonationGoal.NotFound", "목표 설정을 찾을 수 없습니다."));
        }

        // Period 기반 시간 범위 계산
        var now = DateTime.UtcNow;
        DateTime? rangeStart = goal.Period switch
        {
            RankPeriodType.Daily   => now.Date,
            RankPeriodType.Weekly  => now.Date.AddDays(-(int)now.DayOfWeek),
            RankPeriodType.Monthly => new DateTime(now.Year, now.Month, 1, 0, 0, 0, DateTimeKind.Utc),
            RankPeriodType.Yearly  => new DateTime(now.Year, 1, 1, 0, 0, 0, DateTimeKind.Utc),
            RankPeriodType.Custom  => goal.StartAt,
            _ => null  // AllTime
        };
        DateTime? rangeEnd = goal.Period == RankPeriodType.Custom ? goal.EndAt : null;

        var currentAmount = await db.Donation.AsNoTracking()
            .Where(d => d.ChannelID == request.ChannelID
                     && !d.IsTest
                     && (rangeStart == null || d.CreatedAt >= rangeStart)
                     && (rangeEnd == null || d.CreatedAt <= rangeEnd))
            .SumAsync(d => d.Amount, ct);

        var adjusted = currentAmount + goal.StartAmount;
        var percent = goal.TargetAmount > 0 ? Math.Min((decimal)adjusted / goal.TargetAmount * 100, 100) : 0;

        return Result.Success(new Response(goal.ID, goal.Title, goal.StartAmount, goal.TargetAmount, adjusted, Math.Round(percent, 1)));
    }
}