using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Web.Script.Serialization;
using System.Net;
using System.IO;


namespace TradeIdeas.TIProGUI
{
    //This code is for the "sign in through google" for the desktop TIPro.
    //Source inspired from Linda Lawton's site/blog:  http://www.daimto.com/google-api-and-oath2/
    // Lots of modification by Kathy L.
    public class oAuthGoogle
    {
        private static string _clientId = "654054237352-39508qbhsgq1e0aj43q6g6c1lj1f8cs7.apps.googleusercontent.com";
        private static string _clientSecret = "LPcPsgO1MhCkQcAf_89IJ1UQ";
        private static  string _redirectURI = "urn:ietf:wg:oauth:2.0:oob";
        public string access_token { get; set; }
        public string refresh_token { get; set; }
        public string id_token { get; set; }

        /// <summary>
        /// Parse the json response 
        /// //  "{\n  \"access_token\" : \"ya29.kwFUj-la2lATSkrqFlJXBqQjCIZiTg51GYpKt8Me8AJO5JWf0Sx6-0ZWmTpxJjrBrxNS_JzVw969LA\",\n  \"token_type\" : \"Bearer\",\n  \"expires_in\" : 3600,\n  \"refresh_token\" : \"1/ejoPJIyBAhPHRXQ7pHLxJX2VfDBRz29hqS_i5DuC1cQ\"\n}"
        /// </summary>
        /// <param name="response"></param>
        /// <returns></returns>
        public static oAuthGoogle get(string response)
        {
            oAuthGoogle result = new JavaScriptSerializer().Deserialize<oAuthGoogle>(response);
            return result;
        }
        
        public static string refresh(string refreshToken)  //access tokens last about an hour, so each time we process data(getting email, user's name) we'll refresh it.
        {
            try
            {
                var request = (HttpWebRequest)WebRequest.Create("https://accounts.google.com/o/oauth2/token");
                string postData = string.Format("client_id={0}&client_secret={1}&refresh_token={2}&grant_type=refresh_token", _clientId, _clientSecret, refreshToken);
                var data = Encoding.ASCII.GetBytes(postData);

                request.Method = "POST";
                request.ContentType = "application/x-www-form-urlencoded";
                request.ContentLength = data.Length;

                using (var stream = request.GetRequestStream())
                {
                    stream.Write(data, 0, data.Length);
                }

                var response = (HttpWebResponse)request.GetResponse();
                var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();
                var refreshResponse = oAuthGoogle.get(responseString);

                return refreshResponse.access_token;
            }
            catch
            {
                return "";
            }
        }

        public static oAuthGoogle Exchange(string authCode)
        {
            try
            {
                var request = (HttpWebRequest)WebRequest.Create("https://www.googleapis.com/oauth2/v4/token");
                string postData = string.Format("code={0}&client_id={1}&client_secret={2}&redirect_uri={3}&grant_type=authorization_code", authCode, _clientId, _clientSecret, _redirectURI);
                var data = Encoding.ASCII.GetBytes(postData);

                request.Method = "POST";
                request.ContentType = "application/x-www-form-urlencoded";
                request.ContentLength = data.Length;

                using (var stream = request.GetRequestStream())
                {
                    stream.Write(data, 0, data.Length);
                }

                var response = (HttpWebResponse)request.GetResponse();
                var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();
                var x = oAuthGoogle.get(responseString);
                return x;
            }
            catch
            {
                return null;
            }
        }

        public static Uri GetAutenticationURI()
        {
            string scopes = "email profile";  //we just want the email for now
            string oauth = string.Format("https://accounts.google.com/o/oauth2/v2/auth?client_id={0}&redirect_uri={1}&scope={2}&response_type=code", _clientId, _redirectURI, scopes);
            return new Uri(oauth);
        }
    }
}