using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using AsbCloudApp.Data;
using AsbCloudApp.Exceptions;
using AsbCloudApp.Repositories;
using AsbCloudApp.Requests;

namespace AsbCloudApp.Services.Notifications;

/// <summary>
/// Сервис для работы с уведомлениями
/// </summary>
public class NotificationService
{
    private readonly ICrudRepository<NotificationCategoryDto> notificationCategoryRepository;
    private readonly IUserRepository userRepository;
    private readonly INotificationRepository notificationRepository;
    private readonly IEnumerable<INotificationTransportService> notificationTransportServices;

    /// <summary>
    /// Сервис для работы с уведомлениями
    /// </summary>
    /// <param name="notificationCategoryRepository"></param>
    /// <param name="userRepository"></param>
    /// <param name="notificationRepository"></param>
    /// <param name="notificationTransportServices"></param>
    public NotificationService(ICrudRepository<NotificationCategoryDto> notificationCategoryRepository,
        IUserRepository userRepository,
        INotificationRepository notificationRepository,
        IEnumerable<INotificationTransportService> notificationTransportServices)
    {
        this.userRepository = userRepository;
        this.notificationCategoryRepository = notificationCategoryRepository;
        this.notificationRepository = notificationRepository;
        this.notificationTransportServices = notificationTransportServices;
    }
    
    /// <summary>
    /// Отправка нового уведомления
    /// </summary>
    /// <param name="request"></param>
    /// <param name="cancellationToken"></param>
    public async Task NotifyAsync(NotifyRequest request,
        CancellationToken cancellationToken)
    {
        var notificationCategory = await notificationCategoryRepository
                                       .GetOrDefaultAsync(request.IdNotificationCategory, cancellationToken)
                                   ?? throw new ArgumentInvalidException("Категория уведомления не найдена", nameof(request.IdNotificationCategory));

        var user = await userRepository.GetOrDefaultAsync(request.IdUser, cancellationToken)
            ?? throw new ArgumentInvalidException("Пользователь не найден" , nameof(request.IdUser));
        
        var notification = new NotificationDto
        {
            IdUser = request.IdUser,
            RegistrationDate = DateTime.UtcNow,
            IdNotificationCategory = request.IdNotificationCategory,
            Title = request.Title,
            Message = request.Message,
            IdTransportType = request.IdTransportType,
        };

        notification.Id = await notificationRepository.InsertAsync(notification, cancellationToken);
        notification.NotificationCategory = notificationCategory;
        notification.User = user;
        
        var notificationTransportService = GetNotificationTransportService(request.IdTransportType);

        await notificationTransportService.SendAsync(notification, cancellationToken);
    }

    /// <summary>
    /// Обновление уведомления
    /// </summary>
    /// <param name="idNotification"></param>
    /// <param name="isRead"></param>
    /// <param name="cancellationToken"></param>
    /// <returns></returns>
    public async Task UpdateNotificationAsync(int idNotification,
        bool isRead,
        CancellationToken cancellationToken)
    {
        var notification = await notificationRepository.GetOrDefaultAsync(idNotification,
            cancellationToken)
            ?? throw new ArgumentInvalidException("Уведомление не найдено", nameof(idNotification));

        if (isRead)
        {
            if (notification.SentDate == null)
                throw new ArgumentInvalidException("Уведомление не может быть прочитано", nameof(isRead));

            notification.ReadDate = DateTime.UtcNow;
        }

        await notificationRepository.UpdateAsync(notification,
            cancellationToken);
    }

    /// <summary>
    /// Отправка уведомлений, которые не были отправлены
    /// </summary>
    /// <param name="idUser"></param>
    /// <param name="request"></param>
    /// <param name="cancellationToken"></param>
    /// <returns></returns>
    public async Task ResendNotificationAsync(int idUser,
        NotificationRequest request,
        CancellationToken cancellationToken)
    {
        if (!request.IdTransportType.HasValue)
            throw new ArgumentInvalidException("Id типа доставки уведомления должен иметь значение",
                nameof(request.IdTransportType));

        var result = await notificationRepository.GetNotificationsAsync(idUser,
            request,
            cancellationToken);

        var notificationTransportService = GetNotificationTransportService(request.IdTransportType.Value);

        await notificationTransportService.SendRangeAsync(result.Items,
            cancellationToken);
    }

    private INotificationTransportService GetNotificationTransportService(int idTransportType)
    {
        var notificationTransportService = notificationTransportServices
            .FirstOrDefault(s => s.IdTransportType == idTransportType)
            ?? throw new ArgumentInvalidException("Доставщик уведомлений не найден", nameof(idTransportType));

        return notificationTransportService;
    }
}