ANTOOZA-BACKEND/Application/Features/Api/Stocks/GetLendingHistory/Handler.cs

using Application.Abstractions.Data;
using Application.Abstractions.Messaging;
using Microsoft.EntityFrameworkCore;
using SharedKernel.Results;

namespace Application.Features.Api.Stocks.GetLendingHistory;

internal sealed class Handler(IAppDbContext db) : IQueryHandler<Query, Result<Response>>
{
    private const ushort MaxPerPage = 500;

    public async Task<Result<Response>> Handle(Query request, CancellationToken ct)
    {
        var input = request.CodeOrIsin?.Trim();
        if (string.IsNullOrEmpty(input))
        {
            return Result.Failure<Response>(Error.Problem("Stock.CodeRequired", "종목 코드가 필요합니다."));
        }

        // 단축코드(6자리)면 Stock 조인으로 ISIN 확보, 아니면 입력을 ISIN 으로 간주.
        var isin = await db.Stock.AsNoTracking().Where(c => c.Code == input && c.ISIN != null).Select(c => c.ISIN!).FirstOrDefaultAsync(ct) ?? input;

        var page = request.Page < 1 ? 1 : request.Page;
        var perPage = request.PerPage is 0 or > MaxPerPage ? (ushort)90 : request.PerPage;

        var query = db.SecuritiesLending.AsNoTracking().Where(c => c.Isin == isin);

        if (request.From.HasValue)
        {
            query = query.Where(c => c.StdDt >= request.From.Value);
        }

        if (request.To.HasValue)
        {
            query = query.Where(c => c.StdDt <= request.To.Value);
        }

        var total = await query.CountAsync(ct);

        var list = await query
            .OrderByDescending(c => c.StdDt)
            .Skip((page - 1) * perPage)
            .Take(perPage)
            .Select(c => new Response.Row
            {
                StdDt = c.StdDt,
                LendingBalanceQty = c.SlbTrRemQty,
                MatchedQty = c.MatcQty,
                RedeemedQty = c.RedQty,
                TradeQty = c.TrQty,
                ForeignLendRatio = c.FrinerLendRemRatio,
                NativeLendRatio = c.NativeLendRemRatio,
                ForeignBorrowRatio = c.FrinerBrwRemRatio,
                NativeBorrowRatio = c.NativeBrwRemRatio
            })
            .ToListAsync(ct);

        return new Response
        {
            Isin = isin,
            Total = total,
            List = list
        };
    }
}