/**
 *
 * Copyright 2003-2007 Jive Software.
 *
 * 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.smack.roster.packet;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Locale;
import java.util.Set;
import java.util.concurrent.CopyOnWriteArraySet;

import org.jivesoftware.smack.packet.ExtensionElement;
import org.jivesoftware.smack.packet.IQ;
import org.jivesoftware.smack.packet.Stanza;
import org.jivesoftware.smack.util.EqualsUtil;
import org.jivesoftware.smack.util.HashCode;
import org.jivesoftware.smack.util.Objects;
import org.jivesoftware.smack.util.StringUtils;
import org.jivesoftware.smack.util.XmlStringBuilder;

import org.jxmpp.jid.BareJid;

/**
 * Represents XMPP roster packets.
 *
 * @author Matt Tucker
 * @author Florian Schmaus
 */
public final class RosterPacket extends IQ {

    public static final String ELEMENT = QUERY_ELEMENT;
    public static final String NAMESPACE = "jabber:iq:roster";

    private final List<Item> rosterItems = new ArrayList<>();
    private String rosterVersion;

    public RosterPacket() {
        super(ELEMENT, NAMESPACE);
    }

    /**
     * Adds a roster item to the packet.
     *
     * @param item a roster item.
     */
    public void addRosterItem(Item item) {
        synchronized (rosterItems) {
            rosterItems.add(item);
        }
    }

    /**
     * Returns the number of roster items in this roster packet.
     *
     * @return the number of roster items.
     */
    public int getRosterItemCount() {
        synchronized (rosterItems) {
            return rosterItems.size();
        }
    }

    /**
     * Returns a copied list of the roster items in the packet.
     *
     * @return a copied list of the roster items in the packet.
     */
    public List<Item> getRosterItems() {
        synchronized (rosterItems) {
            return new ArrayList<>(rosterItems);
        }
    }

    @Override
    protected IQChildElementXmlStringBuilder getIQChildElementBuilder(IQChildElementXmlStringBuilder buf) {
        buf.optAttribute("ver", rosterVersion);
        buf.rightAngleBracket();

        synchronized (rosterItems) {
            for (Item entry : rosterItems) {
                buf.append(entry.toXML());
            }
        }
        return buf;
    }

    public String getVersion() {
        return rosterVersion;
    }

    public void setVersion(String version) {
        rosterVersion = version;
    }

    /**
     * A roster item, which consists of a JID, their name, the type of subscription, and
     * the groups the roster item belongs to.
     */
    // TODO Make this class immutable.
    public static final class Item implements ExtensionElement {

        /**
         * The constant value "{@value}".
         */
        public static final String ELEMENT = Stanza.ITEM;

        public static final String GROUP = "group";

        private final BareJid jid;

        /**
         * TODO describe me. With link to the RFC. Is ask= attribute.
         */
        private boolean subscriptionPending;

        // TODO Make immutable.
        private String name;
        private ItemType itemType = ItemType.none;
        private boolean approved;
        private final Set<String> groupNames;

        /**
         * Creates a new roster item.
         *
         * @param jid TODO javadoc me please
         * @param name TODO javadoc me please
         */
        public Item(BareJid jid, String name) {
            this(jid, name, false);
        }

        /**
         * Creates a new roster item.
         *
         * @param jid the jid.
         * @param name the user's name.
         * @param subscriptionPending TODO javadoc me please
         */
        public Item(BareJid jid, String name, boolean subscriptionPending) {
            this.jid = Objects.requireNonNull(jid);
            this.name = name;
            this.subscriptionPending = subscriptionPending;
            groupNames = new CopyOnWriteArraySet<>();
        }

        @Override
        public String getElementName() {
            return ELEMENT;
        }

        @Override
        public String getNamespace() {
            return NAMESPACE;
        }

        /**
         * Returns the user.
         *
         * @return the user.
         * @deprecated use {@link #getJid()} instead.
         */
        @Deprecated
        public String getUser() {
            return jid.toString();
        }

        /**
         * Returns the JID of this item.
         *
         * @return the JID.
         */
        public BareJid getJid() {
            return jid;
        }

        /**
         * Returns the user's name.
         *
         * @return the user's name.
         */
        public String getName() {
            return name;
        }

        /**
         * Sets the user's name.
         *
         * @param name the user's name.
         */
        public void setName(String name) {
            this.name = name;
        }

        /**
         * Returns the roster item type.
         *
         * @return the roster item type.
         */
        public ItemType getItemType() {
            return itemType;
        }

        /**
         * Sets the roster item type.
         *
         * @param itemType the roster item type.
         */
        public void setItemType(ItemType itemType) {
            this.itemType = Objects.requireNonNull(itemType, "itemType must not be null");
        }

        public void setSubscriptionPending(boolean subscriptionPending) {
            this.subscriptionPending = subscriptionPending;
        }

        public boolean isSubscriptionPending() {
            return subscriptionPending;
        }

        /**
         * Returns the roster item pre-approval state.
         *
         * @return the pre-approval state.
         */
        public boolean isApproved() {
            return approved;
        }

        /**
         * Sets the roster item pre-approval state.
         *
         * @param approved the pre-approval flag.
         */
        public void setApproved(boolean approved) {
            this.approved = approved;
        }

        /**
         * Returns an unmodifiable set of the group names that the roster item
         * belongs to.
         *
         * @return an unmodifiable set of the group names.
         */
        public Set<String> getGroupNames() {
            return Collections.unmodifiableSet(groupNames);
        }

        /**
         * Adds a group name.
         *
         * @param groupName the group name.
         */
        public void addGroupName(String groupName) {
            groupNames.add(groupName);
        }

        /**
         * Removes a group name.
         *
         * @param groupName the group name.
         */
        public void removeGroupName(String groupName) {
            groupNames.remove(groupName);
        }

        @Override
        public XmlStringBuilder toXML(org.jivesoftware.smack.packet.XmlEnvironment enclosingNamespace) {
            XmlStringBuilder xml = new XmlStringBuilder(this, enclosingNamespace);
            xml.attribute("jid", jid);
            xml.optAttribute("name", name);
            xml.optAttribute("subscription", itemType);
            if (subscriptionPending) {
                xml.append(" ask='subscribe'");
            }
            xml.optBooleanAttribute("approved", approved);
            xml.rightAngleBracket();

            for (String groupName : groupNames) {
                xml.openElement(GROUP).escape(groupName).closeElement(GROUP);
            }
            xml.closeElement(this);
            return xml;
        }

        @Override
        public int hashCode() {
            return HashCode.builder()
                .append(groupNames)
                .append(subscriptionPending)
                .append(itemType)
                .append(name)
                .append(jid)
                .append(approved)
                .build();
        }

        @Override
        public boolean equals(Object obj) {
            return EqualsUtil.equals(this, obj, (e, o) ->
                e.append(groupNames, o.groupNames)
                 .append(subscriptionPending, o.subscriptionPending)
                 .append(itemType, o.itemType)
                 .append(name, o.name)
                 .append(jid, o.jid)
                 .append(approved, o.approved)
            );
        }

    }

    public enum ItemType {

        /**
         * The user does not have a subscription to the contact's presence, and the contact does not
         * have a subscription to the user's presence; this is the default value, so if the
         * subscription attribute is not included then the state is to be understood as "none".
         */
        none('⊥'),

        /**
         * The user has a subscription to the contact's presence, but the contact does not have a
         * subscription to the user's presence.
         */
        to('←'),

        /**
         * The contact has a subscription to the user's presence, but the user does not have a
         * subscription to the contact's presence.
         */
        from('→'),

        /**
         * The user and the contact have subscriptions to each other's presence (also called a
         * "mutual subscription").
         */
        both('↔'),

        /**
         * The user wishes to stop receiving presence updates from the subscriber.
         */
        remove('⚡'),
        ;


        private static final char ME = '●';

        private final String symbol;

        ItemType(char secondSymbolChar) {
            StringBuilder sb = new StringBuilder(2);
            sb.append(ME).append(secondSymbolChar);
            symbol = sb.toString();
        }

        public static ItemType fromString(String string) {
            if (StringUtils.isNullOrEmpty(string)) {
                return none;
            }
            return ItemType.valueOf(string.toLowerCase(Locale.US));
        }

        /**
         * Get a String containing symbols representing the item type. The first symbol in the
         * string is a big dot, representing the local entity. The second symbol represents the
         * established subscription relation and is typically an arrow. The head(s) of the arrow
         * point in the direction presence messages are sent. For example, if there is only a head
         * pointing to the big dot, then the local user will receive presence information from the
         * remote entity.
         *
         * @return the symbolic representation of this item type.
         */
        public String asSymbol() {
            return symbol;
        }
    }
}