using Diligent.WebAPI.Contracts.DTOs.Stats;

namespace Diligent.WebAPI.Business.Services
{
    public class SelectionProcessService : ISelectionProcessService
    {
        private readonly DatabaseContext _context;
        private readonly IMapper _mapper;
        private readonly UserManager<User> _userManager;
        private readonly ILogger<SelectionProcessService> _logger;

        public SelectionProcessService(UserManager<User> userManager,DatabaseContext context, IMapper mapper, ILogger<SelectionProcessService> logger)
        {
            _context = context;
            _mapper = mapper;
            _logger = logger;
            _userManager = userManager;
        }

        public async Task<List<SelectionProcessResposneDto>> GetAllAsync()
        {
            _logger.LogInformation("Start getting all Selection Processes");
            _logger.LogInformation("Getting data from DB");
            var fromDB = await _context.SelectionProcesses.ToListAsync();
            _logger.LogInformation($"Received {fromDB.Count} processes from db.");
            _logger.LogInformation($"Mapping received ads to SelectionProcessResposneDto");
            var result = _mapper.Map<List<SelectionProcessResposneDto>>(fromDB);
            _logger.LogInformation($"Processes has been mapped and received to client: {result.Count} mapped processes");
            return result;
        }
        public async Task<bool> FinishSelectionProcess(SelectionProcessCreateDto model)
        {
            _logger.LogInformation($"Start finishing selection process with {model.Id}");
            var sp = await _context.SelectionProcesses.FindAsync(model.Id);

            if (sp is null)
            {
                _logger.LogError($"Process with id = {model.Id} not found");
                throw new EntityNotFoundException("Selection process not found");
            }

            _logger.LogInformation($"Changing status for {model.Id}");
            sp.Status = "Odrađen";

            _logger.LogInformation($"Skipping throught levels to come to next level");
            if (sp.SelectionLevelId == _context.SelectionLevels.OrderBy(n => n.Id).Last().Id)
            {
                _logger.LogError($"Applicant is in the last selection level");
                throw new EntityNotFoundException("Candidate came to the last selection level");
            }
            var nextLevel = _context.SelectionLevels.AsEnumerable()
                .SkipWhile(obj => obj.Id != sp.SelectionLevelId)
                .Skip(1).First();


            SelectionProcess newProcess = new SelectionProcess
            {
                Name = model.Name,
                SelectionLevelId = nextLevel.Id,
                Status = "Čeka na zakazivanje",
                ApplicantId = sp.ApplicantId
            };
            _context.SelectionProcesses.Add(newProcess);
            _logger.LogInformation($"Create and add new selection process");
            var result = await _context.SaveChangesAsync() > 0;
            _logger.LogInformation($"Saved changes to db");
            return result;
        }

        public async Task UpdateSelectionProcessStatusAsync(int id, SelectionProcessUpdateStatusDto selectionProcessUpdateStatusDto)
        {
            _logger.LogInformation($"Start searching Ad with id = {id}");
            var selectionProcess = await _context.SelectionProcesses.FindAsync(id);

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

            _logger.LogInformation($"Mapping Selection process with id = {id}");
            _mapper.Map(selectionProcessUpdateStatusDto, selectionProcess);
            _logger.LogInformation($"Selection process with id = {id} mapped successfully");

            _context.Entry(selectionProcess).State = EntityState.Modified;

            var result = _context.SaveChangesAsync();
            _logger.LogInformation($"Selection process saved to DB");
            await result;
        }
        public async Task StatusUpdate(StatusChangeDTO model)
        {
            _logger.LogInformation($"Start searching process with id = {model.ProcessId}");
            var process = await _context.SelectionProcesses.FindAsync(model.ProcessId);

            if (process is null)
            {
                _logger.LogError($"Process with id = {model.ProcessId} not found");
                throw new EntityNotFoundException("Process does not exist.");
            }

            _logger.LogInformation($"Check which status is going to be set.");
            if (model.NewStatus == "Zakazan" && model.SchedulerId is not null)
            {
                _logger.LogInformation($"Start searching user with id = {model.SchedulerId}");
                var user = await _userManager.FindByIdAsync(model.SchedulerId.ToString());

                if (user is null)
                    throw new EntityNotFoundException("Scheduler does not exist.");

                _logger.LogInformation($"Setting user {user.FirstName} {user.LastName} as scheduler for process with id = {model.ProcessId}");
                process.SchedulerId = user.Id;
            }

            process.Status = model.NewStatus;
            process.Date = model.Appointment;
            process.Comment = model.Comment;

            _logger.LogInformation($"Processing changes.");
            await _context.SaveChangesAsync();
        }

        public async Task InterviewerUpdate(InterviewerUpdateDTO model)
        {
            _logger.LogInformation($"Start searching process with id = {model.ProcessId}");
            var process = await _context.SelectionProcesses.FindAsync(model.ProcessId);

            if (process is null)
                throw new EntityNotFoundException("Process does not exist.");

            _logger.LogInformation($"Start searching user with id = {model.SchedulerId}");
            var user = await _userManager.FindByIdAsync(model.SchedulerId.ToString());

            if (user is null)
                throw new EntityNotFoundException("Scheduler does not exist.");

            _logger.LogInformation($"Setting user {user.FirstName} {user.LastName} as scheduler for process with id = {model.ProcessId}");
            process.SchedulerId = user.Id;

            _logger.LogInformation("Processing changes...");
            await _context.SaveChangesAsync();
        }
    }
}