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

namespace Application.Features.Api.Paper.GetAccount;

internal sealed class Handler(IAppDbContext db) : IQueryHandler<Query, Response>
{
    public async Task<Response> Handle(Query request, CancellationToken ct)
    {
        var account = await db.PaperAccount.AsNoTracking().FirstOrDefaultAsync(c => c.MemberID == request.MemberID, ct);

        if (account is null)
        {
            return new Response(false, 0, 0, 0, 0, 0, 0);
        }

        var positions = await db.PaperPosition.AsNoTracking()
            .Where(c => c.AccountID == account.ID && c.Quantity > 0)
            .Select(c => new { c.StockCode, c.Quantity })
            .ToListAsync(ct);

        var codes = positions.Select(c => c.StockCode).Distinct().ToList();
        var latestCloses = await PaperValuation.GetLatestClosesAsync(db, codes, ct);

        var equity = PaperValuation.ComputeEquity(
            account.Token,
            account.ReservedToken,
            positions.Select(c => (c.StockCode, c.Quantity)),
            latestCloses);

        var nav = PaperValuation.ComputeNav(equity, account.Units);
        var cumReturnBp = (int)Math.Round((nav - 1m) * 10000m, MidpointRounding.AwayFromZero);

        return new Response(
            true,
            account.Token,
            account.ReservedToken,
            account.Units,
            equity,
            cumReturnBp,
            positions.Count);
    }
}