// <auto-generated/> // disable StyleCop on this file
//-----------------------------------------------------------------------
// <copyright file="Protocol.cs" company="Outercurve Foundation">
//     Copyright (c) Outercurve Foundation. All rights reserved.
// </copyright>
//-----------------------------------------------------------------------

namespace DotNetOpenAuth.OpenId {
	using System;
	using System.Collections.Generic;
	using DotNetOpenAuth.Messaging;
	using System.Globalization;
	using System.Diagnostics.CodeAnalysis;
	using System.Diagnostics;
	using Validation;

	/// <summary>
	/// An enumeration of the OpenID protocol versions supported by this library.
	/// </summary>
	public enum ProtocolVersion {
		/// <summary>
		/// OpenID Authentication 1.0
		/// </summary>
		V10,
		/// <summary>
		/// OpenID Authentication 1.1
		/// </summary>
		V11,
		/// <summary>
		/// OpenID Authentication 2.0
		/// </summary>
		V20,
	}

	/// <summary>
	/// Tracks the several versions of OpenID this library supports and the unique
	/// constants to each version used in the protocol.
	/// </summary>
	[DebuggerDisplay("OpenID {Version}")]
	internal sealed class Protocol {
		/// <summary>
		/// The value of the openid.ns parameter in the OpenID 2.0 specification.
		/// </summary>
		internal const string OpenId2Namespace = "http://specs.openid.net/auth/2.0";

		/// <summary>
		/// The parameter of the callback parameter we tack onto the return_to URL
		/// to store the replay-detection nonce.
		/// </summary>
		internal const string ReturnToNonceParameter = OpenIdUtilities.CustomParameterPrefix + "request_nonce";

		/// <summary>
		/// Scans a list for matches with some element of the OpenID protocol,
		/// searching from newest to oldest protocol for the first and best match.
		/// </summary>
		/// <typeparam name="T">The type of element retrieved from the <see cref="Protocol"/> instance.</typeparam>
		/// <param name="elementOf">Takes a <see cref="Protocol"/> instance and returns an element of it.</param>
		/// <param name="list">The list to scan for matches.</param>
		/// <returns>The protocol with the element that matches some item in the list.</returns>
		internal static Protocol FindBestVersion<T>(Func<Protocol, T> elementOf, IEnumerable<T> list) {
			foreach (var protocol in Protocol.AllVersions) {
				foreach (var item in list) {
					if (item != null && item.Equals(elementOf(protocol)))
						return protocol;
				}
			}
			return null;
		}

		Protocol(QueryParameters queryBits) {
			openidnp = queryBits;
			openid = new QueryParameters(queryBits);
		}

		// Well-known, supported versions of the OpenID spec.
		public static readonly Protocol V10 = new Protocol(new QueryParameters()) {
			Version = new Version(1, 0),
			XmlNamespace = "http://openid.net/xmlns/1.0",
			QueryDeclaredNamespaceVersion = null,
			ClaimedIdentifierServiceTypeURI = "http://openid.net/signon/1.0",
			OPIdentifierServiceTypeURI = null, // not supported
			ClaimedIdentifierForOPIdentifier = null, // not supported
			RPReturnToTypeURI = null, // not supported
			HtmlDiscoveryProviderKey = "openid.server",
			HtmlDiscoveryLocalIdKey = "openid.delegate",
		};
		public static readonly Protocol V11 = new Protocol(new QueryParameters()) {
			Version = new Version(1, 1),
			XmlNamespace = "http://openid.net/xmlns/1.0",
			QueryDeclaredNamespaceVersion = null,
			ClaimedIdentifierServiceTypeURI = "http://openid.net/signon/1.1",
			OPIdentifierServiceTypeURI = null, // not supported
			ClaimedIdentifierForOPIdentifier = null, // not supported
			RPReturnToTypeURI = null, // not supported
			HtmlDiscoveryProviderKey = "openid.server",
			HtmlDiscoveryLocalIdKey = "openid.delegate",
		};
		public static readonly Protocol V20 = new Protocol(new QueryParameters() {
			Realm = "realm",
			op_endpoint = "op_endpoint",
			response_nonce = "response_nonce",
			error_code = "error_code",
			user_setup_url = null,
		}) {
			Version = new Version(2, 0),
			XmlNamespace = null, // no longer applicable
			QueryDeclaredNamespaceVersion = Protocol.OpenId2Namespace,
			ClaimedIdentifierServiceTypeURI = "http://specs.openid.net/auth/2.0/signon",
			OPIdentifierServiceTypeURI = "http://specs.openid.net/auth/2.0/server",
			ClaimedIdentifierForOPIdentifier = "http://specs.openid.net/auth/2.0/identifier_select",
			RPReturnToTypeURI = "http://specs.openid.net/auth/2.0/return_to",
			HtmlDiscoveryProviderKey = "openid2.provider",
			HtmlDiscoveryLocalIdKey = "openid2.local_id",
			Args = new QueryArguments() {
				SessionType = new QueryArguments.SessionTypes() {
					NoEncryption = "no-encryption",
					DH_SHA256 = "DH-SHA256",
					DH_SHA384 = "DH-SHA384",
					DH_SHA512 = "DH-SHA512",
				},
				SignatureAlgorithm = new QueryArguments.SignatureAlgorithms() {
					HMAC_SHA256 = "HMAC-SHA256",
					HMAC_SHA384 = "HMAC-SHA384",
					HMAC_SHA512 = "HMAC-SHA512",
				},
				Mode = new QueryArguments.Modes() {
					setup_needed = "setup_needed",
				},
			},
		};

		/// <summary>
		/// A list of all supported OpenID versions, in order starting from newest version.
		/// </summary>
		public readonly static List<Protocol> AllVersions = new List<Protocol>() { V20, V11, V10 };

		/// <summary>
		/// A list of all supported OpenID versions, in order starting from newest version.
		/// V1.1 and V1.0 are considered the same and only V1.1 is in the list.
		/// </summary>
		public readonly static List<Protocol> AllPracticalVersions = new List<Protocol>() { V20, V11 };

		/// <summary>
		/// The default (or most recent) supported version of the OpenID protocol.
		/// </summary>
		public readonly static Protocol Default = AllVersions[0];
		public static Protocol Lookup(Version version) {
			foreach (Protocol protocol in AllVersions) {
				if (protocol.Version == version) return protocol;
			}
			throw new ArgumentOutOfRangeException("version");
		}
		public static Protocol Lookup(ProtocolVersion version) {
			switch (version) {
				case ProtocolVersion.V10: return Protocol.V10;
				case ProtocolVersion.V11: return Protocol.V11;
				case ProtocolVersion.V20: return Protocol.V20;
				default: throw new ArgumentOutOfRangeException("version");
			}
		}
		/// <summary>
		/// Attempts to detect the right OpenID protocol version based on the contents
		/// of an incoming OpenID <i>indirect</i> message or <i>direct request</i>.
		/// </summary>
		internal static Protocol Detect(IDictionary<string, string> query) {
			Requires.NotNull(query, "query");
			return query.ContainsKey(V20.openid.ns) ? V20 : V11;
		}
		/// <summary>
		/// Attempts to detect the right OpenID protocol version based on the contents
		/// of an incoming OpenID <i>direct</i> response message.
		/// </summary>
		internal static Protocol DetectFromDirectResponse(IDictionary<string, string> query) {
			Requires.NotNull(query, "query");
			return query.ContainsKey(V20.openidnp.ns) ? V20 : V11;
		}
		/// <summary>
		/// Attemps to detect the highest OpenID protocol version supported given a set
		/// of XRDS Service Type URIs included for some service.
		/// </summary>
		internal static Protocol Detect(IEnumerable<string> serviceTypeURIs) {
			Requires.NotNull(serviceTypeURIs, "serviceTypeURIs");
			return FindBestVersion(p => p.OPIdentifierServiceTypeURI, serviceTypeURIs) ??
				   FindBestVersion(p => p.ClaimedIdentifierServiceTypeURI, serviceTypeURIs) ??
				   FindBestVersion(p => p.RPReturnToTypeURI, serviceTypeURIs);
		}

		/// <summary>
		/// The OpenID version that this <see cref="Protocol"/> instance describes.
		/// </summary>
		public Version Version;
		/// <summary>
		/// Returns the <see cref="ProtocolVersion"/> enum value for the <see cref="Protocol"/> instance.
		/// </summary>
		public ProtocolVersion ProtocolVersion {
			get {
				switch (Version.Major) {
					case 1: return ProtocolVersion.V11;
					case 2: return ProtocolVersion.V20;
					default: throw new ArgumentException(null); // this should never happen
				}
			}
		}
		/// <summary>
		/// The namespace of OpenId 1.x elements in XRDS documents.
		/// </summary>
		public string XmlNamespace;
		/// <summary>
		/// The value of the openid.ns parameter that appears on the query string
		/// whenever data is passed between relying party and provider for OpenID 2.0
		/// and later.
		/// </summary>
		public string QueryDeclaredNamespaceVersion;
		/// <summary>
		/// The XRD/Service/Type value discovered in an XRDS document when
		/// "discovering" on a Claimed Identifier (http://andrewarnott.yahoo.com)
		/// </summary>
		public string ClaimedIdentifierServiceTypeURI;
		/// <summary>
		/// The XRD/Service/Type value discovered in an XRDS document when
		/// "discovering" on an OP Identifier rather than a Claimed Identifier.
		/// (http://yahoo.com)
		/// </summary>
		public string OPIdentifierServiceTypeURI;
		/// <summary>
		/// The XRD/Service/Type value discovered in an XRDS document when
		/// "discovering" on a Realm URL and looking for the endpoint URL
		/// that can receive authentication assertions.
		/// </summary>
		public string RPReturnToTypeURI;
		/// <summary>
		/// Used as the Claimed Identifier and the OP Local Identifier when
		/// the User Supplied Identifier is an OP Identifier.
		/// </summary>
		public string ClaimedIdentifierForOPIdentifier;
		/// <summary>
		/// The value of the 'rel' attribute in an HTML document's LINK tag
		/// when the same LINK tag's HREF attribute value contains the URL to an
		/// OP Endpoint URL.
		/// </summary>
		public string HtmlDiscoveryProviderKey;
		/// <summary>
		/// The value of the 'rel' attribute in an HTML document's LINK tag
		/// when the same LINK tag's HREF attribute value contains the URL to use
		/// as the OP Local Identifier.
		/// </summary>
		public string HtmlDiscoveryLocalIdKey;
		/// <summary>
		/// Parts of the protocol that define parameter names that appear in the 
		/// query string.  Each parameter name is prefixed with 'openid.'.
		/// </summary>
		public readonly QueryParameters openid;
		/// <summary>
		/// Parts of the protocol that define parameter names that appear in the 
		/// query string.  Each parameter name is NOT prefixed with 'openid.'.
		/// </summary>
		public readonly QueryParameters openidnp;
		/// <summary>
		/// The various 'constants' that appear as parameter arguments (values).
		/// </summary>
		public QueryArguments Args = new QueryArguments();

		internal sealed class QueryParameters {
			/// <summary>
			/// The value "openid."
			/// </summary>
			public readonly string Prefix = "openid.";
			[SuppressMessage("Microsoft.Performance", "CA1805:DoNotInitializeUnnecessarily")]
			public QueryParameters() { }
			[SuppressMessage("Microsoft.Performance", "CA1805:DoNotInitializeUnnecessarily")]
			public QueryParameters(QueryParameters addPrefixTo) {
				ns = addPrefix(addPrefixTo.ns);
				return_to = addPrefix(addPrefixTo.return_to);
				Realm = addPrefix(addPrefixTo.Realm);
				mode = addPrefix(addPrefixTo.mode);
				error = addPrefix(addPrefixTo.error);
				error_code = addPrefix(addPrefixTo.error_code);
				identity = addPrefix(addPrefixTo.identity);
				op_endpoint = addPrefix(addPrefixTo.op_endpoint);
				response_nonce = addPrefix(addPrefixTo.response_nonce);
				claimed_id = addPrefix(addPrefixTo.claimed_id);
				expires_in = addPrefix(addPrefixTo.expires_in);
				assoc_type = addPrefix(addPrefixTo.assoc_type);
				assoc_handle = addPrefix(addPrefixTo.assoc_handle);
				session_type = addPrefix(addPrefixTo.session_type);
				is_valid = addPrefix(addPrefixTo.is_valid);
				sig = addPrefix(addPrefixTo.sig);
				signed = addPrefix(addPrefixTo.signed);
				user_setup_url = addPrefix(addPrefixTo.user_setup_url);
				invalidate_handle = addPrefix(addPrefixTo.invalidate_handle);
				dh_modulus = addPrefix(addPrefixTo.dh_modulus);
				dh_gen = addPrefix(addPrefixTo.dh_gen);
				dh_consumer_public = addPrefix(addPrefixTo.dh_consumer_public);
				dh_server_public = addPrefix(addPrefixTo.dh_server_public);
				enc_mac_key = addPrefix(addPrefixTo.enc_mac_key);
				mac_key = addPrefix(addPrefixTo.mac_key);
			}
			string addPrefix(string original) {
				return (original != null) ? Prefix + original : null;
			}
			// These fields default to 1.x specifications, and are overridden
			// as necessary by later versions in the Protocol class initializers.
			// Null values in any version suggests that that feature is absent from that version.
			public string ns = "ns";
			public string return_to = "return_to";
			public string Realm = "trust_root";
			public string mode = "mode";
			public string error = "error";
			public string error_code = null;
			public string identity = "identity";
			public string op_endpoint = null;
			public string response_nonce = null;
			public string claimed_id = "claimed_id";
			public string expires_in = "expires_in";
			public string assoc_type = "assoc_type";
			public string assoc_handle = "assoc_handle";
			public string session_type = "session_type";
			public string is_valid = "is_valid";
			public string sig = "sig";
			public string signed = "signed";
			public string user_setup_url = "user_setup_url";
			public string invalidate_handle = "invalidate_handle";
			public string dh_modulus = "dh_modulus";
			public string dh_gen = "dh_gen";
			public string dh_consumer_public = "dh_consumer_public";
			public string dh_server_public = "dh_server_public";
			public string enc_mac_key = "enc_mac_key";
			public string mac_key = "mac_key";

#if CONTRACTS_FULL
			/// <summary>
			/// Verifies conditions that should be true for any valid state of this object.
			/// </summary>
			[SuppressMessage("Microsoft.Performance", "CA1822:MarkMembersAsStatic", Justification = "Called by code contracts.")]
			[SuppressMessage("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode", Justification = "Called by code contracts.")]
			[ContractInvariantMethod]
			private void ObjectInvariant() {
				Contract.Invariant(!string.IsNullOrEmpty(this.Prefix));
			}
#endif
		}

		internal sealed class QueryArguments {
			public ErrorCodes ErrorCode = new ErrorCodes();
			public SessionTypes SessionType = new SessionTypes();
			public SignatureAlgorithms SignatureAlgorithm = new SignatureAlgorithms();
			public Modes Mode = new Modes();
			public IsValidValues IsValid = new IsValidValues();

			internal sealed class ErrorCodes {
				public string UnsupportedType = "unsupported-type";
			}
			internal sealed class SessionTypes {
				/// <summary>
				/// A preference order list of all supported session types.
				/// </summary>
				public string[] All { get { return new[] { DH_SHA512, DH_SHA384, DH_SHA256, DH_SHA1, NoEncryption }; } }
				public string[] AllDiffieHellman { get { return new[] { DH_SHA512, DH_SHA384, DH_SHA256, DH_SHA1 }; } }
				public string DH_SHA1 = "DH-SHA1";
				public string DH_SHA256;
				public string DH_SHA384;
				public string DH_SHA512;
				public string NoEncryption = string.Empty;
				public string Best {
					get {
						foreach (string algorithmName in All) {
							if (algorithmName != null) {
								return algorithmName;
							}
						}
						throw new ProtocolException(); // really bad... we have no signing algorithms at all
					}
				}
			}
			internal sealed class SignatureAlgorithms {
				/// <summary>
				/// A preference order list of signature algorithms we support.
				/// </summary>
				public string[] All { get { return new[] { HMAC_SHA512, HMAC_SHA384, HMAC_SHA256, HMAC_SHA1 }; } }
				public string HMAC_SHA1 = "HMAC-SHA1";
				public string HMAC_SHA256;
				public string HMAC_SHA384;
				public string HMAC_SHA512;
				public string Best {
					get {
						foreach (string algorithmName in All) {
							if (algorithmName != null) {
								return algorithmName;
							}
						}
						throw new ProtocolException(); // really bad... we have no signing algorithms at all
					}
				}
			}
			internal sealed class Modes {
				public string cancel = "cancel";
				public string error = "error";
				public string id_res = "id_res";
				public string checkid_immediate = "checkid_immediate";
				public string checkid_setup = "checkid_setup";
				public string check_authentication = "check_authentication";
				public string associate = "associate";
				public string setup_needed = "id_res"; // V2 overrides this
			}
			internal sealed class IsValidValues {
				public string True = "true";
				public string False = "false";
			}
		}

		/// <summary>
		/// The maximum time a user can be allowed to take to complete authentication.
		/// </summary>
		/// <remarks>
		/// This is used to calculate the length of time that nonces are stored.
		/// This is internal until we can decide whether to leave this static, or make
		/// it an instance member, or put it inside the IConsumerApplicationStore interface.
		/// </remarks>
		internal static TimeSpan MaximumUserAgentAuthenticationTime = TimeSpan.FromMinutes(5);
		/// <summary>
		/// The maximum permissible difference in clocks between relying party and 
		/// provider web servers, discounting time zone differences.
		/// </summary>
		/// <remarks>
		/// This is used when storing/validating nonces from the provider.
		/// If it is conceivable that a server's clock could be up to five minutes
		/// off from true UTC time, then the maximum time skew should be set to 
		/// ten minutes to allow one server to be five minutes ahead and the remote
		/// server to be five minutes behind and still be able to communicate.
		/// </remarks>
		internal static TimeSpan MaximumAllowableTimeSkew = TimeSpan.FromMinutes(10);

		/// <summary>
		/// Checks whether a given Protocol version practically equals this one
		/// for purposes of verifying a match for assertion verification.
		/// </summary>
		/// <param name="other">The other version to check against this one.</param>
		/// <returns><c>true</c> if this and the given Protocol versions are essentially the same.</returns>
		/// <remarks>
		/// OpenID v1.0 never had a spec, and 1.0 and 1.1 are indistinguishable because of that.
		/// Therefore for assertion verification, 1.0 and 1.1 are considered equivalent.
		/// </remarks>
		public bool EqualsPractically(Protocol other) {
			if (other == null) {
				return false;
			}

			// Exact version match is definitely equality.
			if (this.Version == other.Version) {
				return true;
			}

			// If both protocol versions are 1.x, it doesn't matter if one
			// is 1.0 and the other is 1.1 for assertion verification purposes.
			if (this.Version.Major == 1 && other.Version.Major == 1) {
				return true;
			}

			// Different version.
			return false;
		}

		public override bool Equals(object obj) {
			Protocol other = obj as Protocol;
			if (other == null) {
				return false;
			}

			return this.Version == other.Version;
		}
		public override int GetHashCode() {
			return Version.GetHashCode();
		}
		public override string ToString() {
			return string.Format(CultureInfo.CurrentCulture, "OpenID Authentication {0}.{1}", Version.Major, Version.Minor);
		}
	}
}