using AutoMapper;
using MediatR;
using ExpenseTracker.Application.Common.Exceptions;
using ExpenseTracker.Application.Common.Interfaces;
using ExpenseTracker.Application.Common.Interfaces.Repositories;
using ExpenseTracker.Domain.Entities;
using ExpenseTracker.Domain.Enums;

namespace ExpenseTracker.Application.Transactions.Commands.Update;

public class UpdateTransactionCommandHandler : IRequestHandler<UpdateTransactionCommand, TransactionDto>
{
    private readonly IMapper _mapper;
    private readonly IUnitOfWork _unitOfWork;

    public UpdateTransactionCommandHandler(IMapper mapper, IUnitOfWork unitOfWork)
    {
        _mapper = mapper;
        _unitOfWork = unitOfWork;
    }

    public async Task<TransactionDto> Handle(UpdateTransactionCommand request, CancellationToken cancellationToken)
    {
        var databaseEntity = _unitOfWork.TransactionRepository.Queryable.FirstOrDefault(e => e.Id == request.Id);

        if (databaseEntity == null)
        {
            throw new NotFoundException();
        }

        var updatedEntity = new Transaction()
        {
            Id = request.Id,
            Amount = request.Amount ?? databaseEntity.Amount,
            Category = Category.FromName(request.Category) ?? databaseEntity.Category,
            Time = request.Time ?? databaseEntity.Time,
            Description = request.Description,
            AccountId = request.AccountId
        };

        databaseEntity = await _unitOfWork.TransactionRepository.UpdateOneAsync(updatedEntity, cancellationToken);

        await _unitOfWork.SaveAsync(cancellationToken);

        return _mapper.Map<TransactionDto>(databaseEntity);
    }
}