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

namespace Application.Features.Api.Stocks.GetSriBonds;

/// <summary>
/// 사회책임투자채권 목록 — 지정일(미지정 시 최신 TradeDate) 스냅샷을 발행금액 내림차순으로 페이징 (KRX 사회책임투자채권 수집, 익명).
/// BondType(SRI_BND_TP_NM 채권종류) 지정 시 해당 종류만 필터한다.
/// </summary>
internal sealed class Handler(IAppDbContext db) : IQueryHandler<Query, Response>
{
    private const ushort MaxPerPage = 100;

    public async Task<Response> Handle(Query request, CancellationToken ct)
    {
        var page = request.Page < 1 ? 1 : request.Page;
        var perPage = request.PerPage is 0 or > MaxPerPage ? (ushort)20 : request.PerPage;

        var targetDate = request.Date;
        if (targetDate is null)
        {
            targetDate = await db.SriBond.AsNoTracking()
                .OrderByDescending(c => c.TradeDate)
                .Select(c => (DateOnly?)c.TradeDate)
                .FirstOrDefaultAsync(ct);
        }

        if (targetDate is null)
        {
            return new Response
            {
                Total = 0,
                TradeDate = null,
                List = []
            };
        }

        var query = db.SriBond.AsNoTracking().Where(c => c.TradeDate == targetDate.Value);

        if (!string.IsNullOrWhiteSpace(request.BondType))
        {
            var bondType = request.BondType.Trim();
            query = query.Where(c => c.SriBondType == bondType);
        }

        var total = await query.CountAsync(ct);

        var list = await query
            .OrderByDescending(c => c.IssueAmount).ThenBy(c => c.Code)
            .Skip((page - 1) * perPage)
            .Take(perPage)
            .Select(c => new Response.Row
            {
                Code = c.Code,
                IssuerName = c.IssuerName,
                SriBondType = c.SriBondType,
                Name = c.Name,
                ListDate = c.ListDate,
                IssueDate = c.IssueDate,
                RedemptionDate = c.RedemptionDate,
                CouponRate = c.CouponRate,
                IssueAmount = c.IssueAmount,
                ListAmount = c.ListAmount,
                BondType = c.BondType
            })
            .ToListAsync(ct);

        return new Response
        {
            Total = total,
            TradeDate = targetDate.Value,
            List = list
        };
    }
}