package com.nimbusds.oauth2.sdk.id;


import java.io.Serializable;

import com.nimbusds.oauth2.sdk.ParseException;
import com.nimbusds.oauth2.sdk.util.JSONObjectUtils;
import net.jcip.annotations.Immutable;
import net.minidev.json.JSONAware;
import net.minidev.json.JSONObject;


/**
 * Authorised actor in impersonation and delegation cases.
 */
@Immutable
public final class Actor implements Serializable, Comparable<Actor>, JSONAware {
        

        /**
         * The actor subject.
         */
        private final Subject subject;


        /**
         * Optional issuer for the actor subject.
         */
        private final Issuer issuer;


        /**
         * Optional parent for the actor.
         */
        private final Actor parent;


        /**
         * Creates a new actor.
         *
         * @param subject The subject. Must not be {@code null}.
         */
        public Actor(final Subject subject) {
                this(subject, null, null);
        }


        /**
         * Creates a new actor.
         *
         * @param subject The subject. Must not be {@code null}.
         * @param issuer  Optional issuer for the subject, {@code null} if
         *                not specified.
         * @param parent  Optional parent for the actor, {@code null} if none.
         */
        public Actor(final Subject subject, final Issuer issuer, final Actor parent) {
                if (subject == null) {
                        throw new IllegalArgumentException("The subject must not be null");
                }
                this.subject = subject;
                this.issuer = issuer;
                this.parent = parent;
        }


        /**
         * Returns the subject.
         *
         * @return The subject.
         */
        public Subject getSubject() {
                return subject;
        }


        /**
         * Returns the optional issuer for the subject.
         *
         * @return The issuer, {@code null} if not specified.
         */
        public Issuer getIssuer() {
                return issuer;
        }


        /**
         * Returns the optional parent for this actor.
         *
         * @return The optional parent for the actor, {@code null} if none.
         */
        public Actor getParent() {
                return parent;
        }


        /**
         * Returns a JSON object representation of this actor.
         *
         * <p>Simple example:
         *
         * <pre>
         * {
         *   "sub" : "[email protected]"
         * }
         * </pre>
         *
         * <p>With nesting:
         *
         * <pre>
         * {
         *   "sub" : "consumer.example.com-web-application",
         *   "iss" : "https://issuer.example.net",
         *   "act" : { "sub":"[email protected]" }
         * }
         * </pre>
         *
         * @return The JSON object.
         */
        public JSONObject toJSONObject() {

                JSONObject o = new JSONObject();
                o.put("sub", subject.getValue());

                if (issuer != null) {
                        o.put("iss", issuer.getValue());
                }

                if (parent != null) {
                        o.put("act", parent.toJSONObject());
                }

                return o;
        }


        @Override
        public int compareTo(final Actor other) {

                return toJSONString().compareTo(other.toJSONString());
        }


        @Override
        public String toJSONString() {
                return toJSONObject().toJSONString();
        }


        @Override
        public boolean equals(Object o) {
                if (this == o) return true;
                if (!(o instanceof Actor)) return false;

                Actor actor = (Actor) o;

                if (!subject.equals(actor.subject)) return false;
                if (issuer != null ? !issuer.equals(actor.issuer) : actor.issuer != null)
                        return false;
                return parent != null ? parent.equals(actor.parent) : actor.parent == null;

        }


        @Override
        public int hashCode() {
                int result = subject.hashCode();
                result = 31 * result + (issuer != null ? issuer.hashCode() : 0);
                result = 31 * result + (parent != null ? parent.hashCode() : 0);
                return result;
        }


        /**
         * Parses an actor from the specified JSON object representation.
         *
         * <p>Simple example:
         *
         * <pre>
         * {
         *   "sub" : "[email protected]"
         * }
         * </pre>
         *
         * <p>With nesting:
         *
         * <pre>
         * {
         *   "sub" : "consumer.example.com-web-application",
         *   "iss" : "https://issuer.example.net",
         *   "act" : { "sub":"[email protected]" }
         * }
         * </pre>
         *
         * @param jsonObject The JSON object. Must not be {@code null}.
         *
         * @return The actor.
         *
         * @throws ParseException If parsing failed.
         */
        public static Actor parse(final JSONObject jsonObject)
                throws ParseException {

                Subject sub = new Subject(JSONObjectUtils.getString(jsonObject, "sub"));

                Issuer iss = null;

                if (jsonObject.containsKey("iss")) {
                        iss = new Issuer(JSONObjectUtils.getString(jsonObject, "iss"));
                }

                Actor parent = parseTopLevel(jsonObject);

                return new Actor(sub, iss, parent);
        }


        /**
         * Parses an actor from the specified top-level JSON object contains
         * an optional actor JSON representation.
         *
         * <p>Simple example:
         *
         * <pre>
         * {
         *   "aud" : "https://consumer.example.com",
         *   "iss" : "https://issuer.example.com",
         *   "exp" : 1443904177,
         *   "nbf" : 1443904077,
         *   "sub" : "[email protected]",
         *   "act" : { "sub" : "[email protected]" }
         * }
         * </pre>
         *
         * <p>With nesting:
         * {
         *   "aud" : "https://backend.example.com",
         *   "iss" : "https://issuer.example.com",
         *   "exp" : 1443904100,
         *   "nbf" : 1443904000,
         *   "sub" : "[email protected]",
         *   "act" : { "sub" : "consumer.example.com-web-application",
         *             "iss" : "https://issuer.example.net",
         *             "act" : { "sub":"[email protected]" } }
         * }
         * <pre>
         *
         * </pre>
         *
         * @param jsonObject The top-level JSON object to parse. Must not be
         *                   {@code null}.
         *
         * @return The actor, {@code null} if not specified.
         *
         * @throws ParseException If parsing failed.
         */
        public static Actor parseTopLevel(final JSONObject jsonObject)
                throws ParseException {

                if (! jsonObject.containsKey("act")) {
                        return null;
                }

                return parse(JSONObjectUtils.getJSONObject(jsonObject, "act"));
        }
}