using System;
using Newtonsoft.Json.Linq;
/// <summary>
/// Contains static methods that allow to extract user's information from a <see cref="JObject"/>
/// instance retrieved from Google after a successful authentication process.
/// </summary>
public static class GoogleHelper
    {
        /// <summary>
        /// Gets the Google user ID.
        /// </summary>
        public static string GetId(JObject user)
        {
            if (user == null)
            {
                throw new ArgumentNullException(nameof(user));
            }

            return user.Value<string>("id");
        }

        /// <summary>
        /// Gets the user's name.
        /// </summary>
        public static string GetName(JObject user)
        {
            if (user == null)
            {
                throw new ArgumentNullException(nameof(user));
            }

            return user.Value<string>("displayName");
        }

        /// <summary>
        /// Gets the user's given name.
        /// </summary>
        public static string GetGivenName(JObject user)
        {
            if (user == null)
            {
                throw new ArgumentNullException(nameof(user));
            }

            return TryGetValue(user, "name", "givenName");
        }

        /// <summary>
        /// Gets the user's family name.
        /// </summary>
        public static string GetFamilyName(JObject user)
        {
            if (user == null)
            {
                throw new ArgumentNullException(nameof(user));
            }

            return TryGetValue(user, "name", "familyName");
        }

        /// <summary>
        /// Gets the user's profile link.
        /// </summary>
        public static string GetProfile(JObject user)
        {
            if (user == null)
            {
                throw new ArgumentNullException(nameof(user));
            }

            return user.Value<string>("url");
        }

        /// <summary>
        /// Gets the user's email.
        /// </summary>
        public static string GetEmail(JObject user)
        {
            if (user == null)
            {
                throw new ArgumentNullException(nameof(user));
            }

            return TryGetFirstValue(user, "emails", "value");
        }

        // Get the given subProperty from a property.
        private static string TryGetValue(JObject user, string propertyName, string subProperty)
        {
            JToken value;
            if (user.TryGetValue(propertyName, out value))
            {
                var subObject = JObject.Parse(value.ToString());
                if (subObject != null && subObject.TryGetValue(subProperty, out value))
                {
                    return value.ToString();
                }
            }
            return null;
        }

#if  GoogleApisAuthOAuth2
        public static ServiceAccountCredential GetGoogleApiCredentials (string[] scopes)
        {
            String serviceAccountEmail = "SERVICE_ACCOUNT_EMAIL_HERE";

            string private_key = Startup.GoogleSettings.Account.private_key;
            
            string secret = Startup.GoogleSettings.ClientSecret;


            var certificate = new X509Certificate2(@"key.p12", secret, X509KeyStorageFlags.Exportable);

            return new ServiceAccountCredential(
               new ServiceAccountCredential.Initializer(serviceAccountEmail)
               {
                   Scopes = scopes
               }.FromCertificate(certificate));
        }
#endif
        // Get the given subProperty from a list property.
        private static string TryGetFirstValue(JObject user, string propertyName, string subProperty)
        {
            JToken value;
            if (user.TryGetValue(propertyName, out value))
            {
                var array = JArray.Parse(value.ToString());
                if (array != null && array.Count > 0)
                {
                    var subObject = JObject.Parse(array.First.ToString());
                    if (subObject != null)
                    {
                        if (subObject.TryGetValue(subProperty, out value))
                        {
                            return value.ToString();
                        }
                    }
                }
            }
            return null;
        }
    }