ANTOOZA-BACKEND/Application/Features/Api/Stocks/Watch/List/Handler.cs

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

namespace Application.Features.Api.Stocks.Watch.List;

/// <summary>
/// 회원 관심종목 목록 — StockWatch(회원) 최근 등록순으로 Stock 을 Code 조인, 종목명·시장·최근 종가/등락률(denorm) 반환.
/// enum→문자열 변환은 EF 번역 불가라 조회 후 메모리에서 매핑(GetList 패턴).
/// </summary>
internal sealed class Handler(IAppDbContext db) : IQueryHandler<Query, Response>
{
    public async Task<Response> Handle(Query request, CancellationToken ct)
    {
        var raw = await db.StockWatch.AsNoTracking()
            .Where(w => w.MemberID == request.MemberID)
            .OrderByDescending(w => w.CreatedAt)
            .Join(db.Stock.AsNoTracking(), w => w.StockCode, s => s.Code, (w, s) => new
            {
                s.Code,
                s.Name,
                s.Market,
                s.LastClosePrice,
                s.LastChangeRate
            })
            .ToListAsync(ct);

        return new Response
        {
            List = [..raw.Select(c => new Response.Row
            {
                Code = c.Code,
                Name = c.Name,
                Market = c.Market.ToString(),
                ClosePrice = c.LastClosePrice,
                ChangeRate = c.LastChangeRate
            })]
        };
    }
}