using Indotalent.Infrastructure.Database;
using MediatR;
using Microsoft.EntityFrameworkCore;

namespace Indotalent.Features.Leave.LeaveBalance.Cqrs;

public record SyncLeaveBalanceCommand() : IRequest<bool>;

public class SyncLeaveBalanceHandler : IRequestHandler<SyncLeaveBalanceCommand, bool>
{
    private readonly AppDbContext _context;

    public SyncLeaveBalanceHandler(AppDbContext context) => _context = context;

    public async Task<bool> Handle(SyncLeaveBalanceCommand request, CancellationToken cancellationToken)
    {
        var balances = await _context.LeaveBalance.ToListAsync(cancellationToken);

        if (!balances.Any()) return true;

        var allRequests = await _context.LeaveRequest
            .AsNoTracking()
            .ToListAsync(cancellationToken);

        foreach (var balance in balances)
        {
            var empRequests = allRequests
                .Where(x => x.EmployeeId == balance.EmployeeId &&
                            x.LeaveCategoryId == balance.LeaveCategoryId &&
                            x.StartDate.Year == balance.Year)
                .ToList();

            balance.Used = (int)empRequests.Where(x => x.Status == "Approved").Sum(x => x.Days);
            balance.Pending = (int)empRequests.Where(x => x.Status == "Pending").Sum(x => x.Days);
            balance.Remaining = (balance.Entitlement + balance.CarryForward) - balance.Used;
        }

        return await _context.SaveChangesAsync(cancellationToken) > 0;
    }
}