using System.IdentityModel.Tokens;
using System.IdentityModel.Tokens.Jwt;
using System.Linq;
using System.Security.Claims;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;

using Microsoft.AspNetCore.Mvc;
using Microsoft.IdentityModel.Tokens;
using Newtonsoft.Json;

using TextSender_API.Models;
using TextSender_API.Repositories;

namespace TextSender_API.Controllers;

[ApiController]
[Route("api/v1/user")]
public class UsersController : ControllerBase
{
    #region Fields
    private readonly ILogger<UsersController> _logger;
    private IConfiguration _config;
    #endregion


    #region Constructors        

    public UsersController(ILogger<UsersController> logger, IConfiguration config)
    {
        this._logger = logger;
        this._config = config;
    }
    #endregion

    #region Methods
    private string AllScopes()
    {
        var allScopes = new List<String>()
        {
            "create:contact"
        };

        var scopes = string.Empty;

        for (var i = 0; i < allScopes.Count; i++)
        {
            if (i == allScopes.Count - 1)
            {
                scopes += allScopes[i];
            }
            else
            {
                scopes += allScopes[i] + " ";
            }
        }

        return scopes;
    }

    private List<Claim> Payload()
    {
        var expLimit = 30;
        var currentDate = DateTime.Now;
        var expiredDate = currentDate.AddMinutes(expLimit);
        var issued = Math.Floor((currentDate - DateTime.UnixEpoch).TotalSeconds);
        var expires = Math.Floor((expiredDate - DateTime.UnixEpoch).TotalSeconds);
        var issuer = this._config["JWT:Issuer"];
        var audience = this._config["JWT:Audience"];
        var subject = this._config["JWT:Subject"];

        var claim = new List<System.Security.Claims.Claim>()
        {
            new System.Security.Claims.Claim("scope", AllScopes(), "string"),
            new System.Security.Claims.Claim(JwtRegisteredClaimNames.Exp, expiredDate.ToString(), "string"),
            new System.Security.Claims.Claim(JwtRegisteredClaimNames.Aud, audience!),
            new System.Security.Claims.Claim(JwtRegisteredClaimNames.Iss, issuer!),
            new Claim(JwtRegisteredClaimNames.Sub, subject!)
        };

        return claim;
    }

    [HttpPost("login")]
    public IActionResult Login([FromBody] User userRequest)
    {
        var response = new LoginResponse();

        try
        {
            var connString = this._config.GetConnectionString("MongoDBURI");
            var userRepo = new UsersRepository(connString!);
            var saltRepo = new SaltRepository(connString!);
            var pwdVerify = new PasswordVerification(userRepo, saltRepo);
            var result = userRepo.Exists(userRequest);

            if (result.Item1 && pwdVerify.VerifyPassword(result.Item2, userRequest.Password!))
            {
                var user = result.Item2;
                var token = new Token();
                token.Issued = DateTime.Now;
                token.UserId = user.Id;
                token.TokenType = "JWT";

                var payload = Payload();
                payload.Add(new System.Security.Claims.Claim("user_id", user.Id!, ClaimValueTypes.String));

                var key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(this._config["JWT:Secret"]!));
                var signIn = new SigningCredentials(key, SecurityAlgorithms.HmacSha256);

                var tok = new JwtSecurityToken(
                    this._config["JWT:Issuer"],
                    this._config["JWT:Audience"],
                    payload,
                    expires: DateTime.UtcNow.AddMinutes(30),
                    signingCredentials: signIn);

                token.AccessToken = new JwtSecurityTokenHandler().WriteToken(tok);

                var expClaim = payload.FirstOrDefault(cl =>
                {
                    return cl.Type.Equals("exp");
                });

                if (expClaim != null)
                {
                    var expiredDate = DateTime.Parse(expClaim!.Value);
                    var exp = Math.Floor((expiredDate - DateTime.UnixEpoch).TotalSeconds);
                }

                response.Data.Add(token);
                Ok(response);
            }
            else
            {
                return NotFound(response);
            }
        }
        catch (Exception ex)
        {
            this._logger.LogError($"An error occurred: {ex.Message}");
        }

        return Ok(response);
    }

    [HttpPost("register"), DisableRequestSizeLimit]
    public IActionResult Upload([FromBody] User userRequest)
    {
        var response = new RegisterUserResponse();

        try
        {
            var connString = this._config.GetConnectionString("MongoDBURI");
            var userRepo = new UsersRepository(connString!);
            var saltRepo = new SaltRepository(connString!);
            var allUsers = userRepo.RetrieveAllUsers();
            var result = allUsers.Exists(ea => ea.Username!.Equals(userRequest.Username));

            if (!result)
            {
                var pwdVerify = new PasswordVerification(userRepo, saltRepo);
                var salt = pwdVerify.CreateSalt(userRequest);
                var hashedPassword = pwdVerify.HashPassword(userRequest, salt);

                this._logger.LogInformation("Creating user");
                userRequest.Password = hashedPassword;
                userRequest.DateCreated = DateTime.Now;
                userRepo.CreateUser(userRequest);

                response.Data.Add(userRequest);

                salt.UserId = userRequest.Id;
                saltRepo.Create(salt);
            }
            else
            {
                this._logger.LogInformation("User already exists");
            }
        }
        catch (Exception ex)
        {
            this._logger.LogError($"An error occurred: {ex.Message}");
        }

        return Ok(response);
    }
    #endregion

    #region Responses
    public class LoginResponse
    {
        #region Properties
        [JsonProperty("data")]
        public List<Token> Data { get; set; }
        #endregion

        #region Constructors
        public LoginResponse()
        {
            this.Data = new List<Token>();
        }
        #endregion

        #region Methods
        #endregion
    }

    public class RegisterUserResponse
    {
        #region Properties
        [JsonProperty("data")]
        public List<User> Data { get; set; }
        #endregion

        #region Constructors
        public RegisterUserResponse()
        {
            this.Data = new List<User>();
        }
        #endregion

        #region Methods
        #endregion
    }
    #endregion
}