/*
 * Copyright (c) 2006-2017 DMDirc Developers
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
 * documentation files (the "Software"), to deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
 * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS
 * OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

package com.dmdirc;

import com.dmdirc.interfaces.GroupChat.PartReason;
import com.dmdirc.parser.common.ChannelJoinRequest;
import com.dmdirc.parser.common.DefaultStringConverter;
import com.dmdirc.parser.interfaces.StringConverter;

import java.util.Collection;
import java.util.Collections;
import java.util.Map;
import java.util.Optional;
import java.util.concurrent.ConcurrentSkipListMap;
import java.util.stream.Collectors;

import static com.google.common.base.Preconditions.checkNotNull;

/**
 * Utility class that maintains a map of channel names to channels.
 */
public class ChannelMap {

    /** Map of lowercased channel names to channel objects. */
    private final Map<String, Channel> channels = new ConcurrentSkipListMap<>();
    /** String converter to use to lowercase names. */
    private StringConverter converter = new DefaultStringConverter();

    /**
     * Sets the string converter that will be used for any future case conversions. If the map is
     * non-empty and the converter is changed, duplicate entries may be created.
     *
     * @param converter The new converter to use.
     */
    public void setStringConverter(final StringConverter converter) {
        this.converter = checkNotNull(converter);
    }

    /**
     * Gets the specified channel, if it exists.
     *
     * @param channel The channel to retrieve.
     *
     * @return An optional channel.
     */
    public Optional<Channel> get(final String channel) {
        return Optional.ofNullable(channels.get(converter.toLowerCase(channel)));
    }

    /**
     * Gets all known channels.
     *
     * @return A collection of all known channels.
     */
    public Collection<Channel> getAll() {
        return Collections.unmodifiableCollection(channels.values());
    }

    /**
     * Adds a channel to the map. If a channel with the same name (when lowercased) is present, it
     * will be replaced.
     *
     * @param channel The new channel to be added.
     */
    public void add(final Channel channel) {
        channels.put(converter.toLowerCase(channel.getName()), channel);
    }

    /**
     * Removes a channel from the map.
     *
     * @param channel The channel to be removed.
     */
    public void remove(final String channel) {
        channels.remove(converter.toLowerCase(channel));
    }

    /**
     * Closes all channels in the map.
     */
    public void closeAll() {
        channels.values().forEach(Channel::close);
    }

    /**
     * Resets the state of all channels in the map.
     */
    public void resetAll() {
        channels.values().forEach(c -> c.resetWindow(PartReason.DISCONNECTED));
    }

    /**
     * Gets a representation of the channels in this map as a collection of join requests.
     * Channels that have been parted explicitly (rather than because of a disconnection) will not
     * be included.
     *
     * @return A collection of join requests corresponding to channels in this map that were left
     * due to a disconnection.
     */
    public Collection<ChannelJoinRequest> asJoinRequests() {
        return channels.values().stream()
                .filter(channel -> channel.getPartReason() == PartReason.DISCONNECTED)
                .map(channel -> new ChannelJoinRequest(channel.getName()))
                .collect(Collectors.toList());
    }

}