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

namespace Application.Features.Api.Stocks.GetHistory;

internal sealed class Handler(IAppDbContext db) : IQueryHandler<Query, Result<Response>>
{
    private const ushort MaxPerPage = 200;

    public async Task<Result<Response>> Handle(Query request, CancellationToken ct)
    {
        var stockID = await db.Stock.AsNoTracking().Where(c => c.Code == request.Code).Select(c => (int?)c.ID).FirstOrDefaultAsync(ct);
        if (stockID is null)
        {
            return Result.Failure<Response>(Error.NotFound("Stock.NotFound", "종목을 찾을 수 없습니다."));
        }

        var page = request.Page < 1 ? 1 : request.Page;
        var perPage = request.PerPage is 0 or > MaxPerPage ? (ushort)30 : request.PerPage;

        var query = db.StockDailyPrice.AsNoTracking().Where(c => c.StockID == stockID.Value);

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

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

        var total = await query.CountAsync(ct);

        var list = await query
            .OrderByDescending(c => c.TradingDate)
            .Skip((page - 1) * perPage)
            .Take(perPage)
            .Select(c => new Response.Row
            {
                TradingDate = c.TradingDate,
                Open = c.Open,
                High = c.High,
                Low = c.Low,
                Close = c.Close,
                Volume = c.Volume,
                TradingValue = c.TradingValue,
                ChangeAmount = c.ChangeAmount,
                ChangeRate = c.ChangeRate,
                MarketCap = c.MarketCap
            })
            .ToListAsync(ct);

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