/**
 *
 * Copyright 2003-2007 Jive Software, 2014-2017 Florian Schmaus
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.jivesoftware.smackx.jingle.element;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import org.jivesoftware.smack.packet.IQ;
import org.jivesoftware.smack.util.Objects;
import org.jivesoftware.smack.util.StringUtils;

import org.jxmpp.jid.FullJid;

/**
 * The Jingle element.
 *
 * @author Florian Schmaus
 */
public final class Jingle extends IQ {

    public static final String NAMESPACE = "urn:xmpp:jingle:1";

    public static final String ACTION_ATTRIBUTE_NAME = "action";

    public static final String INITIATOR_ATTRIBUTE_NAME = "initiator";

    public static final String RESPONDER_ATTRIBUTE_NAME = "responder";

    public static final String SESSION_ID_ATTRIBUTE_NAME = "sid";

    public static final String ELEMENT = "jingle";

    /**
     * The session ID related to this session. The session ID is a unique identifier generated by the initiator. This
     * should match the XML Nmtoken production so that XML character escaping is not needed for characters such as &.
     */
    private final String sessionId;

    /**
     * The jingle action. This attribute is required.
     */
    private final JingleAction action;

    private final FullJid initiator;

    private final FullJid responder;

    private final JingleReason reason;

    private final List<JingleContent> contents;

    private Jingle(String sessionId, JingleAction action, FullJid initiator, FullJid responder, JingleReason reason,
                    List<JingleContent> contents) {
        super(ELEMENT, NAMESPACE);
        this.sessionId = StringUtils.requireNotNullOrEmpty(sessionId, "Jingle session ID must not be null");
        this.action = Objects.requireNonNull(action, "Jingle action must not be null");
        this.initiator = initiator;
        this.responder = responder;
        this.reason = reason;
        if (contents != null) {
            this.contents = Collections.unmodifiableList(contents);
        }
        else {
            this.contents = Collections.emptyList();
        }
        setType(Type.set);
    }

    /**
     * Get the initiator. The initiator will be the full JID of the entity that has initiated the flow (which may be
     * different to the "from" address in the IQ)
     *
     * @return the initiator
     */
    public FullJid getInitiator() {
        return initiator;
    }

    /**
     * Get the responder. The responder is the full JID of the entity that has replied to the initiation (which may be
     * different to the "to" address in the IQ).
     *
     * @return the responder
     */
    public FullJid getResponder() {
        return responder;
    }

    /**
     * Returns the session ID related to the session. The session ID is a unique identifier generated by the initiator.
     * This should match the XML Nmtoken production so that XML character escaping is not needed for characters such as
     * &amp;.
     *
     * @return Returns the session ID related to the session.
     */
    public String getSid() {
        return sessionId;
    }

    /**
     * Get the action specified in the jingle IQ.
     *
     * @return the action.
     */
    public JingleAction getAction() {
        return action;
    }

    public JingleReason getReason() {
        return reason;
    }

    /**
     * Get a List of the contents.
     *
     * @return the contents.
     */
    public List<JingleContent> getContents() {
        return contents;
    }

    /**
     * Get the only jingle content if one exists, or <code>null</code>. This method will throw an
     * {@link IllegalStateException} if there is more than one jingle content.
     *
     * @return a JingleContent instance or <code>null</code>.
     * @throws IllegalStateException if there is more than one jingle content.
     */
    public JingleContent getSoleContentOrThrow() {
        if (contents.isEmpty()) {
            return null;
        }

        if (contents.size() > 1) {
            throw new IllegalStateException();
        }

        return contents.get(0);
    }

    @Override
    protected IQChildElementXmlStringBuilder getIQChildElementBuilder(IQChildElementXmlStringBuilder xml) {
        xml.optAttribute(INITIATOR_ATTRIBUTE_NAME, getInitiator());
        xml.optAttribute(RESPONDER_ATTRIBUTE_NAME, getResponder());
        xml.optAttribute(ACTION_ATTRIBUTE_NAME, getAction());
        xml.optAttribute(SESSION_ID_ATTRIBUTE_NAME, getSid());
        xml.rightAngleBracket();

        xml.optElement(reason);

        xml.append(contents);

        return xml;
    }

    public static Builder getBuilder() {
        return new Builder();
    }

    public static final class Builder {
        private String sid;

        private JingleAction action;

        private FullJid initiator;

        private FullJid responder;

        private JingleReason reason;

        private List<JingleContent> contents;

        private Builder() {
        }

        public Builder setSessionId(String sessionId) {
            StringUtils.requireNotNullOrEmpty(sessionId, "Session ID must not be null or empty");
            this.sid = sessionId;
            return this;
        }

        public Builder setAction(JingleAction action) {
            this.action = action;
            return this;
        }

        public Builder setInitiator(FullJid initator) {
            this.initiator = initator;
            return this;
        }

        public Builder setResponder(FullJid responder) {
            this.responder = responder;
            return this;
        }

        public Builder addJingleContent(JingleContent content) {
            if (contents == null) {
                contents = new ArrayList<>(1);
            }
            contents.add(content);
            return this;
        }

        public Builder setReason(JingleReason.Reason reason) {
            this.reason = new JingleReason(reason);
            return this;
        }

        public Builder setReason(JingleReason reason) {
            this.reason = reason;
            return this;
        }

        public Jingle build() {
            return new Jingle(sid, action, initiator, responder, reason, contents);
        }
    }
}