using System;
using System.Collections.Generic;
using System.IdentityModel.Tokens.Jwt;
using System.Linq;
using System.Security.Claims;
using System.Text;
using System.Threading.Tasks;
using AutoMapper;
using Flexitime.DataAccess.Objects;
using Flexitime.Interfaces;
using Flexitime.Objects;
using FlexitimeAPI.Exceptions;
using FlexitimeAPI.Interfaces;
using FlexitimeAPI.Models;
using Microsoft.Extensions.Options;
using Microsoft.IdentityModel.Tokens;
using Newtonsoft.Json;
using RandomNameGeneratorLibrary;

namespace FlexitimeAPI.Services
{
    public interface IUserService
    {
        Task<LoginResponse> Authenticate(LoginRequest model);
        Task<IEnumerable<User>> GetAll();
        Task<User> GetById(Guid id);
        Task<User> Add(User newUser);
        Task<bool> UsernameIsValid(string username);
        Task<User> Update(User user);
    }

    public class UserService : IUserService
    {
        private readonly IDataAccess _dataSource;
        private readonly ILoginService _loginService;

        public UserService(IDataAccess dataSource, ILoginService loginService)
        {
            _dataSource = dataSource;
            _loginService = loginService;
        }

        public async Task<LoginResponse> Authenticate(LoginRequest model)
        {
            var user = (await _dataSource.GetUsers()).SingleOrDefault(x => x.UserName == model.Username && x.Password == model.Password);

            // return null if user not found
            if (user == null) return null;

            // authentication successful so generate jwt token
            var token = _loginService.GenerateJwtToken(user);

            return new LoginResponse(user, token);
        }

        public async Task<IEnumerable<User>> GetAll()
        {
            return await _dataSource.GetUsers();
        }

        public async Task<User> GetById(Guid id)
        {
            return await _dataSource.GetUserById(id);
        }

        public async Task<User> Add(User newUser)
        {
            var userNameIsValid = await UsernameIsValid(newUser.UserName);
            if (!userNameIsValid)
            {
                throw new InvalidUserNameException(newUser.UserName);
            }

            return await _dataSource.AddUser(newUser);
        }

        public async Task<bool> UsernameIsValid(string userName)
        {
            if (string.IsNullOrWhiteSpace(userName))
            {
                return false;
            }

            //TODO: blacklisted username check

            var existingUser = await _dataSource.GetUserByUsername(userName);

            return existingUser == null;
        }

        public async Task<User> Update(User user)
        {
            if (user == null) return null;

            if ((await GetById(user.Id)) == null)
            {
                return null;
            }

            
            return await _dataSource.UpdateUser(user);
        }
    }
}