using System;
using System.Diagnostics;
using System.Linq;
using System.Threading.Tasks;
using AutoMapper;
using InternshipSystem.Api.Queries;
using InternshipSystem.Api.Security;
using InternshipSystem.Core;
using InternshipSystem.Repository;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;

namespace InternshipSystem.Api.Controllers
{
    [ApiController]
    [Route("document")]
    public class DocumentsController : ControllerBase
    {
        private InternshipDbContext Context { get; }
        private IMapper Mapper { get; }

        public DocumentsController(InternshipDbContext context, IMapper mapper)
        {
            Context = context;
            Mapper = mapper;
        }

        /// <summary>
        /// Fill out required document, 
        /// </summary>
        /// <param name="documentRequest">Documents Scan and description, and Id of filled document</param>
        /// <returns></returns>
        /// <response code="200">If change was successfully registered</response>
        /// <response code="400">If the provided query was malformed</response>
        /// <response code="404">Id doesn't match any required document</response>
        /// <response code="401">This action is only available for authorized student registered for current edition</response>
        [HttpPost]
        [ProducesResponseType(StatusCodes.Status200OK)]
        [ProducesResponseType(StatusCodes.Status400BadRequest)]
        [ProducesResponseType(StatusCodes.Status404NotFound)]
        [ProducesResponseType(StatusCodes.Status401Unauthorized)]
        [Authorize(Policy = Policies.RegisteredOnly)]
        public async Task<ActionResult> AddDocumentToInternship([FromBody] DocumentPublishRequest documentRequest, User user)
        {
            var validator = new DocumentPublishRequest.Validator();
            var validationResult = await validator.ValidateAsync(documentRequest);
            
            if (!validationResult.IsValid)
            {
                return BadRequest(validationResult.ToString());
            }

            var edition =
                await Context.Editions
                    .FindAsync(user.EditionId.Value);

            var internship = await Context.Entry(edition)
                .Collection(e => e.Internships)
                .Query()
                .SingleAsync(i => i.Student.Id == user.PersonNumber);

            var document = Mapper.Map<Document>(documentRequest);
            
            if (documentRequest.Id.HasValue)
            {                
                try
                {
                    internship.UpdateDocument(document);
                }
                catch (InvalidOperationException)
                {
                    return NotFound();
                }
            }
            else
            {
                internship.AddNewDocument(document);
            }

            await Context.SaveChangesAsync();
            return Ok();
        }
    }
}