ANTOOZA-BACKEND/Application/Features/Api/Paper/GetMyLeaderboardRank/Handler.cs

using Application.Abstractions.Data;
using Application.Abstractions.Messaging;
using Application.Abstractions.Paper;
using Application.Helpers;
using Microsoft.EntityFrameworkCore;

namespace Application.Features.Api.Paper.GetMyLeaderboardRank;

/// <summary>
/// 내 리더보드 순위·지표 (인증) — 미등재(등재요건 미달·계좌/스냅샷 없음)면 HasRank=false (d4 M3 리더보드 백엔드 구현).
/// </summary>
internal sealed class Handler(IAppDbContext db, IPaperLeaderboardCache cache) : IQueryHandler<Query, Response>
{
    public async Task<Response> Handle(Query request, CancellationToken ct)
    {
        var sort = PaperLeaderboardMetrics.ParseSort(request.Sort);
        var period = PaperLeaderboardMetrics.ParsePeriod(request.Period);
        var sortStr = PaperLeaderboardMetrics.SortToString(sort);
        var periodStr = PaperLeaderboardMetrics.PeriodToString(period);

        var minFillsForRank = await db.Config.AsNoTracking().OrderByDescending(c => c.ID).Select(c => c.Paper.MinFillsForRank).FirstOrDefaultAsync(ct);

        if (minFillsForRank <= 0)
        {
            minFillsForRank = 3;
        }

        var my = await cache.GetMyRankAsync(sort, period, request.MemberID, db, minFillsForRank, ct);

        if (my is null)
        {
            return new Response(sortStr, periodStr, false, 0, 0, 0, 0, 0, 0);
        }

        var metrics = await PaperLeaderboardMetrics.ComputeAllAsync(db, period, minFillsForRank, ct);
        var metric = metrics.FirstOrDefault(c => c.MemberID == request.MemberID);

        return new Response(
            sortStr,
            periodStr,
            true,
            my.Rank + 1,
            my.Total,
            metric?.ReturnBp ?? 0,
            metric?.WinRateBp ?? 0,
            metric?.MddBp ?? 0,
            metric?.FillCount ?? 0);
    }
}