using System.Linq;
using CleanArchitecture.Application.Common.Exceptions;
using CleanArchitecture.Application.Common.Interfaces;
using CleanArchitecture.Domain.Entities;
using MediatR;
using System.Threading;
using System.Threading.Tasks;
using CleanArchitecture.WebUI.Controllers;
using FluentValidation;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;

namespace CleanArchitecture.Application.TodoLists.Commands.UpdateTodoList
{
    [Authorize]
    public class UpdateTodoListController : ApiControllerBase
    {
        [HttpPut("{id}")]
        public async Task<ActionResult> Update(int id, UpdateTodoListCommand command)
        {
            if (id != command.Id)
            {
                return BadRequest();
            }

            await Mediator.Send(command);

            return NoContent();
        }
    }

    public class UpdateTodoListCommand : IRequest
    {
        public int Id { get; set; }

        public string Title { get; set; }
    }

    public class UpdateTodoListCommandValidator : AbstractValidator<UpdateTodoListCommand>
    {
        private readonly IApplicationDbContext _context;

        public UpdateTodoListCommandValidator(IApplicationDbContext context)
        {
            _context = context;

            RuleFor(v => v.Title)
                .NotEmpty().WithMessage("Title is required.")
                .MaximumLength(200).WithMessage("Title must not exceed 200 characters.")
                .MustAsync(BeUniqueTitle).WithMessage("The specified title already exists.");
        }

        public async Task<bool> BeUniqueTitle(UpdateTodoListCommand model, string title, CancellationToken cancellationToken)
        {
            return await _context.TodoLists
                .Where(l => l.Id != model.Id)
                .AllAsync(l => l.Title != title);
        }
    }

    public class UpdateTodoListCommandHandler : IRequestHandler<UpdateTodoListCommand>
    {
        private readonly IApplicationDbContext _context;

        public UpdateTodoListCommandHandler(IApplicationDbContext context)
        {
            _context = context;
        }

        public async Task<Unit> Handle(UpdateTodoListCommand request, CancellationToken cancellationToken)
        {
            var entity = await _context.TodoLists.FindAsync(request.Id);

            if (entity == null)
            {
                throw new NotFoundException(nameof(TodoList), request.Id);
            }

            entity.Title = request.Title;

            await _context.SaveChangesAsync(cancellationToken);

            return Unit.Value;
        }
    }
}