package com.nimbusds.oauth2.sdk.client;


import java.net.URI;
import java.util.Collections;
import java.util.Date;
import java.util.HashSet;
import java.util.Set;

import net.jcip.annotations.Immutable;

import net.minidev.json.JSONObject;

import com.nimbusds.oauth2.sdk.ParseException;
import com.nimbusds.oauth2.sdk.auth.Secret;
import com.nimbusds.oauth2.sdk.id.ClientID;
import com.nimbusds.oauth2.sdk.token.BearerAccessToken;
import com.nimbusds.oauth2.sdk.util.JSONObjectUtils;


/**
 * Client information. Encapsulates the registration and metadata details of 
 * an OAuth 2.0 client:
 * 
 * <ul>
 *     <li>The client identifier.
 *     <li>The client metadata.
 *     <li>The optional client secret for a confidential client.
 *     <li>The optional registration URI and access token if dynamic client
 *         registration is permitted.
 * </ul>
 *
 * <p>Related specifications:
 *
 * <ul>
 *     <li>OAuth 2.0 Dynamic Client Registration Protocol
 *         (draft-ietf-oauth-dyn-reg-18), section 4.1.
 *     <li>OAuth 2.0 Dynamic Client Registration Management Protocol
 *         (draft-ietf-oauth-dyn-reg-management-02), section 3.1.
 * </ul>
 */
@Immutable
public class ClientInformation {


        /**
         * The registered parameter names.
         */
        private static final Set<String> REGISTERED_PARAMETER_NAMES;


        /**
         * Initialises the registered parameter name set.
         */
        static {
                Set<String> p = new HashSet<>(ClientMetadata.getRegisteredParameterNames());

                p.add("client_id");
                p.add("client_id_issued_at");
                p.add("client_secret");
                p.add("client_secret_expires_at");
                p.add("registration_access_token");
                p.add("registration_client_uri");

                REGISTERED_PARAMETER_NAMES = Collections.unmodifiableSet(p);
        }


        /**
         * The registered client ID.
         */
        private final ClientID id;


        /**
         * The date the client ID was issued at.
         */
        private final Date issueDate;


        /**
         * The client metadata.
         */
        private final ClientMetadata metadata;


        /**
         * The optional client secret.
         */
        private final Secret secret;


        /**
         * The client registration URI.
         */
        private final URI registrationURI;


        /**
         * The client registration access token.
         */
        private final BearerAccessToken accessToken;


        /**
         * Creates a new client information instance.
         *
         * @param id              The client identifier. Must not be
         *                        {@code null}.
         * @param issueDate       The issue date of the client identifier,
         *                        {@code null} if not specified.
         * @param metadata        The client metadata. Must not be
         *                        {@code null}.
         * @param secret          The optional client secret, {@code null} if
         *                        not specified.
         */
        public ClientInformation(final ClientID id,
                                 final Date issueDate,
                                 final ClientMetadata metadata,
                                 final Secret secret) {

                this(id, issueDate, metadata, secret, null, null);
        }


        /**
         * Creates a new client information instance permitting dynamic client
         * registration management.
         * 
         * @param id              The client identifier. Must not be 
         *                        {@code null}.
         * @param issueDate       The issue date of the client identifier,
         *                        {@code null} if not specified.
         * @param metadata        The client metadata. Must not be
         *                        {@code null}.
         * @param secret          The optional client secret, {@code null} if
         *                        not specified.
         * @param registrationURI The client registration URI, {@code null} if
         *                        not specified.
         * @param accessToken     The client registration access token,
         *                        {@code null} if not specified.
         */
        public ClientInformation(final ClientID id,
                                 final Date issueDate,
                                 final ClientMetadata metadata,
                                 final Secret secret,
                                 final URI registrationURI,
                                 final BearerAccessToken accessToken) {

                if (id == null)
                        throw new IllegalArgumentException("The client identifier must not be null");
                
                this.id = id;

                this.issueDate = issueDate;

                if (metadata == null)
                        throw new IllegalArgumentException("The client metadata must not be null");

                this.metadata = metadata;

                this.secret = secret;

                this.registrationURI = registrationURI;

                this.accessToken = accessToken;
        }


        /**
         * Gets the registered client metadata parameter names.
         *
         * @return The registered parameter names, as an unmodifiable set.
         */
        public static Set<String> getRegisteredParameterNames() {

                return REGISTERED_PARAMETER_NAMES;
        }


        /**
         * Gets the client ID. Corresponds to the {@code client_id} client
         * registration parameter.
         *
         * @return The client ID.
         */
        public ClientID getID() {

                return id;
        }


        /**
         * Gets the issue date of the client identifier. Corresponds to the
         * {@code client_id_issued_at} client registration parameter.
         *
         * @return The issue date, {@code null} if not specified.
         */
        public Date getIDIssueDate() {

                return issueDate;
        }
        
        
        /**
         * Gets the client metadata.
         * 
         * @return The client metadata.
         */
        public ClientMetadata getMetadata() {
                
                return metadata;
        }


        /**
         * Gets the client secret. Corresponds to the {@code client_secret} and
         * {@code client_secret_expires_at} client registration parameters.
         *
         * @return The client secret, {@code null} if not specified.
         */
        public Secret getSecret() {

                return secret;
        }


        /**
         * Gets the URI of the client registration. Corresponds to the
         * {@code registration_client_uri} client registration parameter.
         *
         * @return The registration URI, {@code null} if not specified.
         */
        public URI getRegistrationURI() {

                return registrationURI;
        }


        /**
         * Gets the registration access token. Corresponds to the
         * {@code registration_access_token} client registration parameter.
         *
         * @return The registration access token, {@code null} if not
         *         specified.
         */
        public BearerAccessToken getRegistrationAccessToken() {

                return accessToken;
        }


        /**
         * Returns the JSON object representation of this client information 
         * instance.
         *
         * @return The JSON object.
         */
        public JSONObject toJSONObject() {

                JSONObject o = metadata.toJSONObject();

                o.put("client_id", id.getValue());

                if (issueDate != null) {

                        o.put("client_id_issued_at", issueDate.getTime() / 1000);
                }

                if (secret != null) {
                        o.put("client_secret", secret.getValue());

                        if (secret.getExpirationDate() != null) {
                                o.put("client_secret_expires_at", secret.getExpirationDate().getTime() / 1000);
                        } else {
                                o.put("client_secret_expires_at", 0l);
                        }
                }

                if (registrationURI != null) {

                        o.put("registration_client_uri", registrationURI.toString());
                }

                if (accessToken != null) {

                        o.put("registration_access_token", accessToken.getValue());
                }

                return o;
        }


        /**
         * Parses a client information instance from the specified JSON object.
         *
         * @param jsonObject The JSON object to parse. Must not be 
         *                   {@code null}.
         *
         * @return The client information.
         *
         * @throws ParseException If the JSON object couldn't be parsed to a
         *                        client information instance.
         */
        public static ClientInformation parse(final JSONObject jsonObject)
                throws ParseException {

                ClientID id = new ClientID(JSONObjectUtils.getString(jsonObject, "client_id"));

                Date issueDate = null;

                if (jsonObject.containsKey("client_id_issued_at")) {

                        issueDate = new Date(JSONObjectUtils.getLong(jsonObject, "client_id_issued_at") * 1000);
                }

                ClientMetadata metadata = ClientMetadata.parse(jsonObject);

                Secret secret = null;

                if (jsonObject.containsKey("client_secret")) {

                        String value = JSONObjectUtils.getString(jsonObject, "client_secret");

                        Date exp = null;

                        if (jsonObject.containsKey("client_secret_expires_at")) {

                                final long t = JSONObjectUtils.getLong(jsonObject, "client_secret_expires_at");

                                if (t > 0) {
                                        exp = new Date(t * 1000);
                                }
                        }

                        secret = new Secret(value, exp);
                }

                URI registrationURI = null;

                if (jsonObject.containsKey("registration_client_uri")) {

                        registrationURI = JSONObjectUtils.getURI(jsonObject, "registration_client_uri");
                }
                
                BearerAccessToken accessToken = null;

                if (jsonObject.containsKey("registration_access_token")) {

                        accessToken = new BearerAccessToken(
                                JSONObjectUtils.getString(jsonObject, "registration_access_token"));
                }
                
                return new ClientInformation(id, issueDate, metadata, secret, registrationURI, accessToken);
        }
}