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

namespace Application.Features.Api.Stocks.GetForeignCustody;

internal sealed class Handler(IAppDbContext db) : IQueryHandler<Query, Result<Response>>
{
    public async Task<Result<Response>> Handle(Query request, CancellationToken ct)
    {
        var query = db.ForeignCustodyNation.AsNoTracking();

        var nation = request.Nation?.Trim();
        if (!string.IsNullOrEmpty(nation))
        {
            query = query.Where(c => c.NationCd == nation);
        }

        var secnTpcd = request.SecnTpcd?.Trim();
        var filterBySecnTpcd = !string.IsNullOrEmpty(secnTpcd);
        if (filterBySecnTpcd)
        {
            query = query.Where(c => c.SecnTpcd == secnTpcd);
        }

        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 rows = await query
            .Select(c => new
            {
                c.NationCd,
                c.SecnTpcd,
                c.StdDt,
                c.FrsecCusAmt
            })
            .ToListAsync(ct);

        List<Response.Series> series;

        if (filterBySecnTpcd)
        {
            // 종목구분 지정 → 국가×종목구분별 시계열 (개별 유지)
            series = rows
                .GroupBy(c => new { c.NationCd, c.SecnTpcd })
                .Select(g => new Response.Series
                {
                    NationCd = g.Key.NationCd,
                    SecnTpcd = g.Key.SecnTpcd,
                    Points = g
                        .OrderBy(c => c.StdDt)
                        .Select(c => new Response.Point { StdDt = c.StdDt, CustodyAmount = c.FrsecCusAmt ?? 0m })
                        .ToList()
                })
                .OrderBy(c => c.NationCd)
                .ToList();
        }
        else
        {
            // 미지정 → 국가별로 같은 기준일의 종목구분 금액을 합산
            series = rows
                .GroupBy(c => c.NationCd)
                .Select(g => new Response.Series
                {
                    NationCd = g.Key,
                    SecnTpcd = null,
                    Points = g
                        .GroupBy(c => c.StdDt)
                        .OrderBy(p => p.Key)
                        .Select(p => new Response.Point { StdDt = p.Key, CustodyAmount = p.Sum(c => c.FrsecCusAmt ?? 0m) })
                        .ToList()
                })
                .OrderBy(c => c.NationCd)
                .ToList();
        }

        return new Response { Nations = series };
    }
}