using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;
using FoodsharingSiegen.Contracts;
using FoodsharingSiegen.Contracts.Entity;
using FoodsharingSiegen.Server.Data;
using FoodsharingSiegen.Server.Data.Service;
using FoodsharingSiegen.Server.Service;
using Microsoft.AspNetCore.Components.Authorization;
using Microsoft.EntityFrameworkCore;
using Microsoft.IdentityModel.Tokens;

namespace FoodsharingSiegen.Server.Auth
{
    /// <summary>
    /// The auth service class (a. beging, 04.04.2022)
    /// </summary>
    /// <seealso cref="ServiceBase"/>
    public class AuthService : ServiceBase
    {
        #region Public Properties

        /// <summary>
        /// Gets or sets the value of the user (ab)
        /// </summary>
        public User? User { get; set; }

        #endregion

        #region Private Fields

        /// <summary>
        /// The authentication state provider
        /// </summary>
        private readonly AuthenticationStateProvider _authenticationStateProvider;

        /// <summary>
        /// The local storage service
        /// </summary>
        private readonly LocalStorageService _localStorageService;

        #endregion

        #region Setup/Teardown

        /// <summary>
        /// Initializes a new instance of the <see cref="AuthService"/> class
        /// </summary>
        /// <param name="context">The context</param>
        /// <param name="localStorageService">The local storage service</param>
        /// <param name="authenticationStateProvider">The authentication state provider</param>
        public AuthService(FsContext context, LocalStorageService localStorageService, AuthenticationStateProvider authenticationStateProvider) : base(context)
        {
            _localStorageService = localStorageService;
            _authenticationStateProvider = authenticationStateProvider;
        }

        #endregion

        #region Public Method Login

        /// <summary>
        /// Logins the mail address (a. beging, 04.04.2022)
        /// </summary>
        /// <param name="mailAddress">The mail address</param>
        /// <param name="password">The password</param>
        /// <returns>A task containing the operation result</returns>
        public async Task<OperationResult> Login(string mailAddress, string password)
        {
            #region Ensure Admin

            var existingTroogS = await Context.Users.AnyAsync(x => x.Mail == "fs@beging.de");
            if (!existingTroogS)
            {
                var troogs = new User
                {
                    Name = "Andre",
                    Mail = "fs@beging.de",
                    Type = UserType.Admin,
                    Created = DateTime.UtcNow,
                    EncryptedPassword = "qSIxTZo7J8M="
                };

                await Context.Users.AddAsync(troogs);
                await Context.SaveChangesAsync();
            }

            #endregion Ensure Admin
            
            var encryptedPassword = AuthHelper.Encrypt(password);

            User = await Context.Users.FirstOrDefaultAsync(x => x.Mail.ToLower() == mailAddress.ToLower() && x.EncryptedPassword == encryptedPassword);
            
            if (User != null)
            {
                
                
                // Daten korrekt
                var tokenHandler = new JwtSecurityTokenHandler();
                var tokenDescriptor = new SecurityTokenDescriptor
                {
                    Subject = new ClaimsIdentity(new[]
                    {
                        new Claim(ClaimTypes.NameIdentifier, User.Id.ToString()),
                    }),
                    Expires = DateTime.UtcNow.AddDays(30),
                    Issuer = "FS-Siegen",
                    Audience = "FS-Siegen",
                    SigningCredentials = new SigningCredentials(AuthHelper.GetSigningKey(), SecurityAlgorithms.HmacSha256Signature)
                };
                
                var token = tokenHandler.CreateToken(tokenDescriptor);
                var serializedToken = tokenHandler.WriteToken(token);
                
                await _localStorageService.SetItem(StorageKeys.TokenKey, serializedToken);

                return new OperationResult();
            }

            return new OperationResult(new Exception("Invalid"));
        }

        #endregion

        #region Public Method Logout

        /// <summary>
        /// Logouts this instance (a. beging, 04.04.2022)
        /// </summary>
        /// <returns>A task containing the operation result</returns>
        public async Task<OperationResult> Logout()
        {
            try
            {
                await _localStorageService.RemoveItem(StorageKeys.TokenKey);
                User = null;
                ((TokenAuthStateProvider) _authenticationStateProvider).MarkUserAsLoggedOut();
                return new OperationResult();
            }
            catch (Exception e)
            {
                return new OperationResult(e);
            }
        }

        #endregion
    }
}