using LdapLoginLib.Data;
using LdapLoginLib.Models;
using System.DirectoryServices.Protocols;

namespace LdapLoginLib
{
    public class LDAP
    {
        private static readonly LdapConfig _ldap = new();

        //public LDAP()
        //{
        //    _ldap = new LdapConfig();
        //}

        public bool Login(string password, string? document = null, string? username = null, string? email = null)
        {

            using (LdapConnection ldapConnection = _ldap.Connection())
            {
                try
                {
                    UserInfo userInfo = GetUserInfo(
                        document: document,
                        username: username,
                        email: email);

                    //Si el usuario está inactivo...
                    if (userInfo.Activo == false) return false;

                    // Set LDAP connection options
                    ldapConnection.SessionOptions.SecureSocketLayer = false;
                    ldapConnection.AuthType = AuthType.Basic;
                    ldapConnection.Credential = _ldap.UserCredentials(userInfo.Usuario!, password);

                    // Attempt to bind (authenticate) the user
                    ldapConnection.Bind();

                    return true;

                }
                catch (LdapException ldapEx)
                {
                    //Console.WriteLine($"Authentication failed: {ldapEx.Message}");
                    throw new Exception(_getErrorMessage(ldapEx.ErrorCode, ldapEx.Message));
                }
                catch
                {
                    //Console.WriteLine($"An error occurred: {ex.Message}");
                    //throw new Exception($"Ocurrió un error: {ex.Message}");
                    throw;
                }

            }
        }

        public static UserInfo GetUserInfo(string? document = null, string? username = null, string? email = null)
        {
            if (
                string.IsNullOrEmpty(document?.Trim()) &&
                string.IsNullOrEmpty(username?.Trim()) &&
                string.IsNullOrEmpty(email?.Trim())
                )
            {
                throw new Exception("Usuario, correo o documento son requeridos");
            }

            #region Query String Builder
            var ldapFilterArgs = new List<string>();

            //uid=APPuser163,ou=services,o=unal.edu.co
            if (string.IsNullOrEmpty(document?.Trim()) == false)
            {
                ldapFilterArgs.Add($"(employeeNumber={document.Trim()})");
            }

            if (string.IsNullOrEmpty(username?.Trim()) == false)
            {
                ldapFilterArgs.Add($"(uid={username.Trim()})");
            }

            if (string.IsNullOrEmpty(email?.Trim()) == false)
            {
                ldapFilterArgs.Add($"(mail={email.Trim()})");
            }

            //ldapFilter.Append("ou=People,o=unal.edu.co");

            #endregion

            using (LdapConnection ldapConnection = _ldap.Connection())
            {
                try
                {
                    // Admin login
                    ldapConnection.SessionOptions.SecureSocketLayer = false;
                    ldapConnection.AuthType = AuthType.Basic;
                    ldapConnection.Credential = _ldap.AdminCredential();
                    ldapConnection.Bind();


                    //Query
                    string searchBase = $"o=unal.edu.co";
                    string[] attributesToReturn = {
                        "uid",
                        "employeeNumber",
                        "cn",
                        "givenName",
                        "sn",
                        "mail",
                        "inetUserStatus",
                        "o",
                        "nuip"
                    };

                    string ldapFilter = $"(&{String.Join("", ldapFilterArgs.ToArray())})";

                    SearchRequest searchRequest = new(
                        searchBase,
                        ldapFilter,
                        SearchScope.Subtree,
                        attributesToReturn
                    );

                    searchRequest.SizeLimit = 1; // Buscar solo el primero

                    SearchResponse searchResponse = (SearchResponse)ldapConnection.SendRequest(searchRequest);

                    if (searchResponse != null && searchResponse.Entries.Count > 0)
                    {
                        SearchResultEntry entry = searchResponse.Entries[0];

                        LdapUserInfo ldapUserInfo = new()
                        {
                            Uid = entry.Attributes["uid"]?[0].ToString(),
                            EmployeeNumber = entry.Attributes["employeeNumber"]?[0].ToString(),
                            Cn = entry.Attributes["cn"]?[0].ToString(),
                            GivenName = entry.Attributes["givenName"]?[0].ToString(),
                            Sn = entry.Attributes["sn"]?[0].ToString(),
                            Mail = entry.Attributes["mail"]?[0].ToString(),
                            InetUserStatus = entry.Attributes["inetUserStatus"][0].ToString(),
                            O = entry.Attributes["o"]?[0].ToString(),
                            MailAlternateAddress = entry.Attributes["mailAlternateAddress"]?[0].ToString(),
                            //IsActive = entry.Attributes["uid"][0].ToString(),
                            //NUIP = entry.Attributes["NUIP"]?[0].ToString(),
                        };

                        ldapUserInfo.IsActive = _isActive(ldapUserInfo.InetUserStatus);

                        return (UserInfo)ldapUserInfo;

                    }
                    else
                    {
                        throw new Exception("Usuario no encontrado o no se recuperaron datos.");
                    }

                }
                catch (LdapException ldapEx)
                {
                    Console.WriteLine($"Authentication failed: {ldapEx.Message}");
                    Console.WriteLine($"Authentication failed: {ldapEx.ErrorCode}");
                    Console.WriteLine($"Authentication failed: {ldapEx.ServerErrorMessage}");
                    throw new Exception(ldapEx.Message);
                }
                catch // (Exception ex)
                {
                    //Console.WriteLine($"An error occurred: {ex.Message}");
                    //throw new Exception($"Ocurrió un error: {ex.Message}");
                    throw;
                }
            }

        }


        private static bool _isActive(string? inetUserStatus)
        {
            if (String.IsNullOrEmpty(inetUserStatus?.Trim()) == false)
            {
                return inetUserStatus.ToLower().Trim() == "active" ? true : false;
            }
            return false;
        }

        private static string _getErrorMessage(int errorCode, string errorMessage)
        {
            // Map LDAP error codes to error messages

            switch (errorCode)
            {
                case 49:
                    return "Error de credenciales: nombre de usuario o contraseña incorrectos";
                case 52:
                    return "Error de autenticación: cuenta está deshabilitada";
                case 81:
                    return "Error de servidor: no disponible";
                default:
                    return errorMessage;
            }
        }


    }
}