using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Text;
using System.Net;
using System.Web.Services.Protocols;
using System.IO;


namespace Google.Accounts
{
	public class ClientLoginRequest : HttpPostClientProtocol
	{
		public const string DefaultService = "xapi";
		public const string DefaultAccountType = "HOSTED";
		public const string DefaultSource = "Company-ApplicationName-Version";
		
		public ClientLoginRequest()
		{
			Service = DefaultService;
			AccountType = DefaultAccountType;
			Source = DefaultSource;
			
			this.Url = "https://www.google.com/accounts/ClientLogin";
			this.Timeout = (int) new TimeSpan(0, 0, 15).TotalMilliseconds;
		}
		
		public string AccountType { get; set; }
		public string Email { get; set; } 
		public string Password { get; set; } 
		public string Service { get; set; } 
		public string Source { get; set; } 
		public Captcha Captcha {get; set; } 
		public ClientSecurityToken Login()
		{
			if (Email == null)
				throw new InvalidOperationException("The email must be set");
			if (Password == null)
				throw new InvalidOperationException("The password must be set");
			if (Source == null)
				throw new InvalidOperationException("The source must be set");
			if (Service == null)
				throw new InvalidOperationException("The service must be set");
			try
			{
				string email = this.Email.IndexOf('@') == -1 ? this.Email + "@gmail.com" : this.Email;

				ClientSecurityToken token = LoginRaw (
					this.AccountType,
					email, this.Password,
					this.Service, this.Source,
					this.Captcha != null ? this.Captcha.Token : null,
					this.Captcha != null ? this.Captcha.Answer : null);
				token.Email = email;
				return token;
			}
			catch (WebException ex)
			{
				HttpWebResponse response = (HttpWebResponse) ex.Response;
				if (response !=null && response.StatusCode == HttpStatusCode.Forbidden)
				{
					ReadClientLoginFailureResponse(response);
				}
				throw;
			}
		}

		[HttpMethod(typeof(TextReturnReader), typeof(HtmlFormParameterWriter))]
		public ClientSecurityToken LoginRaw(string accountType, string Email, string Passwd,
			string service, string source,
			string logintoken, string logincaptcha)
		{
			ClientSecurityToken result = (ClientSecurityToken) this.Invoke(
				"LoginRaw",
				this.Url,
				new object[] {accountType, Email, Passwd, service, source, logintoken, logincaptcha });

			return result;
		}

		internal static void ReadClientLoginFailureResponse(HttpWebResponse response)
		{
			TextReturnReader r = new TextReturnReader();
			r.Initialize(new PatternMatcher(typeof(ClientLoginException)));
			using (Stream stream = response.GetResponseStream())
			{
				throw (ClientLoginException)r.Read(response, stream);
			}
		}
	}
	
	[Serializable]
	public class ClientSecurityToken
	{
		public string Email { get; set; } 
		[Match(@"Auth=(\S+)")]
		public string Auth { get; set; } 

		[Match(@"SID=(\S+)")]
		public string SID { get; set; } 
		[Match(@"LSID=(\S+)")]
		public string LSID { get; set; }
	}

	public class ClientLoginException : Exception
	{
		[Match(@"(?<!Captcha)Url=(\S+)")]
		public string URL { get; set; }
		[Match(@"Error=(\S+)")]
		public ClientLoginErrorCode ErrorCode { get; set; } 
		[Match(@"CaptchaToken=(\S+)")]
		public string CaptchaToken { get; set; }
		[Match(@"CaptchaUrl=(\S+)")]
		public string CaptchaURL { get; set; } 
		public Captcha GetCaptcha()
		{
			if (this.ErrorCode == ClientLoginErrorCode.CaptchaRequired || 
			    (this.CaptchaToken != null && this.CaptchaURL != null))
			{
				if (this.CaptchaToken == null || this.CaptchaURL == null)
					throw new InvalidOperationException("The captcha is incomplete.");
				return new Captcha(this.CaptchaToken, new Uri(this.CaptchaURL));
			}
			else
				return null;
		}
		public override string Message
		{
			get
			{
				return string.Format("The client login attempt failed with status {0}", this.ErrorCode);
			}
		}
	}

	public enum ClientLoginErrorCode
	{
		BadAuthentication,
		NotVerified,
		TermsNotAgreed,
		CaptchaRequired,
		Unknown,
		AccountDeleted,
		AccountDisabled,
		ServiceUnavailable
	} 
	#endregion

	public class Captcha
	{
		internal Captcha(string token, Uri imageUrl)
		{
			this.Token = token;
			this.ImageUrl = imageUrl;
			Answer = "";
		}
		public string Token { get; set; }

		public Uri ImageUrl { get; set; } 
		public string Answer { get; set; } 
	}
}