using System.Collections.Generic;
using System.Linq;
using System.Security.Claims;
using DataModel.Models;
using Microsoft.AspNet.Identity;

namespace WebInterface.Security
{
    /// <summary>
    /// Custom user identity for tracking user-related data
    /// </summary>
    public sealed class UserIdentity : ClaimsIdentity
    {
        /// <summary>
        /// Constuctor
        /// </summary>
        /// <param name="claims">Claims for identity</param>
        /// <param name="authenticationType">Type of authentication for identity</param>
        public UserIdentity(IEnumerable<Claim> claims, string authenticationType = DefaultAuthenticationTypes.ApplicationCookie)
            : base(claims, authenticationType)
        {
        }

        /// <summary>
        /// Constuctor
        /// </summary>
        /// <param name="claimsIdentity">Identity to parse from</param>
        public UserIdentity(ClaimsIdentity claimsIdentity)
            : base(claimsIdentity.Claims, claimsIdentity.AuthenticationType)
        {
        }

        /// <summary>
        /// Extracts the keyed claims to generate LDAPEntry for user
        /// </summary>
        /// <returns>LDAPEntry for current user</returns>
        public LDAPEntry ToLDAPEntry()
        {
            return new LDAPEntry()
            {
                DN = GetClaimValue(ClaimTypes.NameIdentifier),
                Username = GetClaimValue(ClaimTypes.WindowsAccountName),
                FirstName = GetClaimValue(ClaimTypes.GivenName),
                LastName = GetClaimValue(ClaimTypes.Surname),
                Title = GetClaimValue(ClaimTypes.Role),
                EmailAddress = GetClaimValue(ClaimTypes.Email)
            };
        }

        /// <summary>
        /// Gets the value assigned to the designated claim
        /// </summary>
        /// <param name="claimID">Type/ID of claim to get value for</param>
        /// <returns>Value of designed claim</returns>
        private string GetClaimValue(string claimID)
        {
            Claim claim = Claims.FirstOrDefault(c => c.Type == claimID);
            return claim == null ? string.Empty : claim.Value;
        }

        /// <summary>
        /// Generates user identify from LDAP entry
        /// </summary>
        /// <param name="ldapEntry">LDAP entry to get values for claims</param>
        /// <returns>User identity with claims for LDAP entry values</returns>
        public static UserIdentity FromLDAPEntry(LDAPEntry ldapEntry)
        {
            //Create claims from LDAP entry values
            List<Claim> claims = new List<Claim> {
                new Claim(ClaimTypes.NameIdentifier, ldapEntry.DN),
                new Claim(ClaimTypes.WindowsAccountName, ldapEntry.Username),
                new Claim(ClaimTypes.GivenName, ldapEntry.FirstName),
                new Claim(ClaimTypes.Surname, ldapEntry.LastName),
                new Claim(ClaimTypes.Role, ldapEntry.Title),
                new Claim(ClaimTypes.Email, ldapEntry.EmailAddress)
            };
            return new UserIdentity(claims);
        }
    }
}