namespace Diligent.WebAPI.Business.Services
{
    public class ApplicantService : IApplicantService
    {
        private readonly DatabaseContext _context;
        private readonly IMapper _mapper;
        private readonly ILogger<ApplicantService> _logger;

        public ApplicantService(DatabaseContext context, IMapper mapper, ILogger<ApplicantService> logger)
        {
            _context = context;
            _mapper = mapper;
            _logger = logger;
        }

        public async Task<QueryResultDto<ApplicantViewDto>> GetFilteredApplicants(ApplicantFilterDto applicantFilterDto)
        {
            _logger.LogInformation("Start getting filtered applicants");
            _logger.LogInformation("Getting data from DB and filter");
            var filteredApplicants = (await _context.Applicants
                .Include(c => c.Ads)
                .Include(x => x.TechnologyApplicants)
                .ThenInclude(x => x.Technology).ToListAsync())
                .FilterApplicants(applicantFilterDto);

            int totalNumberOfItems = filteredApplicants.Count;
            _logger.LogInformation($"Got {totalNumberOfItems} applicants");

            filteredApplicants = PaginationExtension.ApplyPagging(filteredApplicants, new Pagination
            {
                CurrentPage = applicantFilterDto.CurrentPage,
                PageSize = applicantFilterDto.PageSize
            });

            _logger.LogInformation($"Return list of applicants");
            return new QueryResultDto<ApplicantViewDto>
            {
                Items = _mapper.Map<List<ApplicantViewDto>>(filteredApplicants),
                Total = totalNumberOfItems
            };
        }

        public async Task<ApplicantViewDto> GetById(int id)
        {
            _logger.LogInformation($"Start searching Applicant with id = {id}");
            var applicant = await _context.Applicants
                .Include(x => x.Ads)
                .ThenInclude(x => x.Technologies)
                .Include(x => x.TechnologyApplicants)
                .ThenInclude(x => x.Technology)
                .Include(x => x.Comments)
                .ThenInclude(t => t.User)
                .FirstOrDefaultAsync(x => x.ApplicantId == id);

            if (applicant is null)
            {
                _logger.LogError($"Applicant with id = {id} not found");
                throw new EntityNotFoundException("Applicant not found");
            }
            _logger.LogInformation($"Mapping Applicant with id = {id}");
            var result = _mapper.Map<ApplicantViewDto>(applicant);
            _logger.LogInformation($"Applicant with id = {id} mapped successfully");
            return result;
        }

        public async Task<ApplicantViewDto> GetApplicantWithSelectionProcessesById(int id)
        {
            var applicant = await _context.Applicants
                .Include(a => a.SelectionProcesses).ThenInclude(sp => sp.SelectionLevel)
                .Include(a => a.SelectionProcesses).ThenInclude(sp => sp.Scheduler)
                .FirstOrDefaultAsync(a => a.ApplicantId == id);

            if (applicant is null)
                throw new EntityNotFoundException("Applicant not found");

            return _mapper.Map<ApplicantViewDto>(applicant);
        }

        public async Task DeleteApplicant(int id)
        {
            _logger.LogInformation($"Start searching Applicant with id = {id}");
            var applicant = await _context.Applicants.FindAsync(id);

            if (applicant is null)
            {
                _logger.LogError($"Applicant with id = {id} not found");
                throw new EntityNotFoundException("Applicant not found");
            }

            _logger.LogInformation($"Removing Applicant with id = {id}");
            _context.Applicants.Remove(applicant);
            var result = _context.SaveChangesAsync();
            _logger.LogInformation($"Applicant with id = {id} is removed successfully");
            await result;
        }

        public async Task<List<AdApplicantsViewDto>> GetAllAdsApplicants(ApplicantFilterDto applicantFilterDto)
        {
            _logger.LogInformation("Start getting filtered applicants");
            _logger.LogInformation("Getting data from DB and filter");
            var adsApplicants = (await _context.Ads
                .Include(a => a.Applicants)
                .ThenInclude(a => a.TechnologyApplicants)
                .ThenInclude(a => a.Technology)
                .ToListAsync())
                .FilterAdApplicants(applicantFilterDto);

            _logger.LogInformation($"Got {adsApplicants.Count} ads");

            var result = _mapper.Map<List<AdApplicantsViewDto>>(adsApplicants);
            return result;
        }

        public async Task<List<ApplicantOptionsDTO>> GetOptions()
        {
            var res = await _context.Applicants.ToListAsync();
            return _mapper.Map<List<ApplicantOptionsDTO>>(res);
        }

        public async Task<ServiceResponseDTO<object>> InitializeProcess(ApplicantProcessRequestDTO model)
        {
            var applicant = await _context.Applicants.Include(n => n.SelectionProcesses).Where(n=> n.ApplicantId ==model.ApplicantId).FirstOrDefaultAsync();

            if (applicant == null)
                return new ServiceResponseDTO<object>
                {
                    IsError = true,
                    ErrorMessage = "Applicant does not exist."
                };

            applicant.SelectionProcesses.Add(new SelectionProcess
            {
                Name = StringGenerator.GenerateRandomPassword(),
                SchedulerId = model.SchedulerId,
                SelectionLevelId = 1,
                Status = model.Appointment != null ? "Zakazan" : "Čeka na zakazivanje",
                Date = model.Appointment
            });

            await _context.SaveChangesAsync();

            return new ServiceResponseDTO<object>
            {
                Data = true
            };
        }

        //public async Task CreateApplicant(ApplicantCreateDto applicantCreateDto)
        //{
        //    var applicant = _mapper.Map<Applicant>(applicantCreateDto);
        //    await _context.Applicants.AddAsync(applicant);

        //    await _context.SaveChangesAsync();
        //}


        //public async Task UpdateApplicant(int id, ApplicantUpdateDto applicantUpdateDto)
        //{
        //    var applicant = await _context.Applicants.FindAsync(id);
        //    if (applicant is null)
        //        throw new EntityNotFoundException("Applicant not found");

        //    _mapper.Map(applicantUpdateDto, applicant);

        //    _context.Entry(applicant).State = EntityState.Modified;
        //    await _context.SaveChangesAsync();
        //}

    }
}