// -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
import Clutter from 'gi://Clutter';
import Gio from 'gi://Gio';
import GLib from 'gi://GLib';
import GObject from 'gi://GObject';
import St from 'gi://St';

let Tpl = null;
let Tp = null;
try {
    ({default: Tp} = await import('gi://TelepathyGlib'));
    ({default: Tpl} = await import('gi://TelepathyLogger'));

    Gio._promisify(Tp.Channel.prototype, 'close_async');
    Gio._promisify(Tp.TextChannel.prototype, 'send_message_async');
    Gio._promisify(Tp.ChannelDispatchOperation.prototype, 'claim_with_async');
    Gio._promisify(Tpl.LogManager.prototype, 'get_filtered_events_async');
} catch {
    console.debug('Skipping chat support, telepathy not found');
}

import * as History from '../../misc/history.js';
import * as Main from '../main.js';
import * as MessageList from '../messageList.js';
import * as MessageTray from '../messageTray.js';
import * as Params from '../../misc/params.js';
import * as Util from '../../misc/util.js';

const HAVE_TP = Tp != null && Tpl != null;

// See Notification.appendMessage
const SCROLLBACK_IMMEDIATE_TIME = 3 * 60; // 3 minutes
const SCROLLBACK_RECENT_TIME = 15 * 60; // 15 minutes
const SCROLLBACK_RECENT_LENGTH = 20;
const SCROLLBACK_IDLE_LENGTH = 5;

// See Source._displayPendingMessages
const SCROLLBACK_HISTORY_LINES = 10;

// See Notification._onEntryChanged
const COMPOSING_STOP_TIMEOUT = 5;

const CHAT_EXPAND_LINES = 12;

const NotificationDirection = {
    SENT: 'chat-sent',
    RECEIVED: 'chat-received',
};

const ChatMessage = HAVE_TP ? GObject.registerClass({
    Properties: {
        'message-type': GObject.ParamSpec.int(
            'message-type', 'message-type', 'message-type',
            GObject.ParamFlags.READWRITE | GObject.ParamFlags.CONSTRUCT_ONLY,
            Math.min(...Object.values(Tp.ChannelTextMessageType)),
            Math.max(...Object.values(Tp.ChannelTextMessageType)),
            Tp.ChannelTextMessageType.NORMAL),
        'text': GObject.ParamSpec.string(
            'text', 'text', 'text',
            GObject.ParamFlags.READWRITE | GObject.ParamFlags.CONSTRUCT_ONLY,
            null),
        'sender': GObject.ParamSpec.string(
            'sender', 'sender', 'sender',
            GObject.ParamFlags.READWRITE | GObject.ParamFlags.CONSTRUCT_ONLY,
            null),
        'timestamp': GObject.ParamSpec.int64(
            'timestamp', 'timestamp', 'timestamp',
            GObject.ParamFlags.READWRITE | GObject.ParamFlags.CONSTRUCT_ONLY,
            0, Number.MAX_SAFE_INTEGER, 0),
        'direction': GObject.ParamSpec.string(
            'direction', 'direction', 'direction',
            GObject.ParamFlags.READWRITE | GObject.ParamFlags.CONSTRUCT_ONLY,
            null),
    },
}, class ChatMessageClass extends GObject.Object {
    static newFromTpMessage(tpMessage, direction) {
        return new ChatMessage({
            'message-type': tpMessage.get_message_type(),
            'text': tpMessage.to_text()[0],
            'sender': tpMessage.sender.alias,
            'timestamp': direction === NotificationDirection.RECEIVED
                ? tpMessage.get_received_timestamp() : tpMessage.get_sent_timestamp(),
            direction,
        });
    }

    static newFromTplTextEvent(tplTextEvent) {
        let direction =
            tplTextEvent.get_sender().get_entity_type() === Tpl.EntityType.SELF
                ? NotificationDirection.SENT : NotificationDirection.RECEIVED;

        return new ChatMessage({
            'message-type': tplTextEvent.get_message_type(),
            'text': tplTextEvent.get_message(),
            'sender': tplTextEvent.get_sender().get_alias(),
            'timestamp': tplTextEvent.get_timestamp(),
            direction,
        });
    }
}) : null;


class TelepathyComponent {
    constructor() {
        this._client = null;

        if (!HAVE_TP)
            return; // Telepathy isn't available

        this._client = new TelepathyClient();
    }

    enable() {
        if (!this._client)
            return;

        try {
            this._client.register();
        } catch (e) {
            throw new Error(`Could not register Telepathy client. Error: ${e}`);
        }

        if (!this._client.account_manager.is_prepared(Tp.AccountManager.get_feature_quark_core()))
            this._client.account_manager.prepare_async(null, null);
    }

    disable() {
        if (!this._client)
            return;

        this._client.unregister();
    }
}

const TelepathyClient = HAVE_TP ? GObject.registerClass(
class TelepathyClient extends Tp.BaseClient {
    _init() {
        // channel path -> ChatSource
        this._chatSources = {};
        this._chatState = Tp.ChannelChatState.ACTIVE;

        // account path -> AccountNotification
        this._accountNotifications = {};

        // Define features we want
        this._accountManager = Tp.AccountManager.dup();
        let factory = this._accountManager.get_factory();
        factory.add_account_features([Tp.Account.get_feature_quark_connection()]);
        factory.add_connection_features([Tp.Connection.get_feature_quark_contact_list()]);
        factory.add_channel_features([Tp.Channel.get_feature_quark_contacts()]);
        factory.add_contact_features([
            Tp.ContactFeature.ALIAS,
            Tp.ContactFeature.AVATAR_DATA,
            Tp.ContactFeature.PRESENCE,
            Tp.ContactFeature.SUBSCRIPTION_STATES,
        ]);

        // Set up a SimpleObserver, which will call _observeChannels whenever a
        // channel matching its filters is detected.
        // The second argument, recover, means _observeChannels will be run
        // for any existing channel as well.
        super._init({
            name: 'GnomeShell',
            account_manager: this._accountManager,
            uniquify_name: true,
        });

        // We only care about single-user text-based chats
        let filter = {};
        filter[Tp.PROP_CHANNEL_CHANNEL_TYPE] = Tp.IFACE_CHANNEL_TYPE_TEXT;
        filter[Tp.PROP_CHANNEL_TARGET_HANDLE_TYPE] = Tp.HandleType.CONTACT;

        this.set_observer_recover(true);
        this.add_observer_filter(filter);
        this.add_approver_filter(filter);
        this.add_handler_filter(filter);

        // Allow other clients (such as Empathy) to preempt our channels if
        // needed
        this.set_delegated_channels_callback(
            this._delegatedChannelsCb.bind(this));
    }

    vfunc_observe_channels(...args) {
        let [account, conn, channels, dispatchOp_, requests_, context] = args;
        let len = channels.length;
        for (let i = 0; i < len; i++) {
            let channel = channels[i];
            let [targetHandle_, targetHandleType] = channel.get_handle();

            if (channel.get_invalidated())
                continue;

            /* Only observe contact text channels */
            if (!(channel instanceof Tp.TextChannel) ||
               targetHandleType != Tp.HandleType.CONTACT)
                continue;

            this._createChatSource(account, conn, channel, channel.get_target_contact());
        }

        context.accept();
    }

    _createChatSource(account, conn, channel, contact) {
        if (this._chatSources[channel.get_object_path()])
            return;

        let source = new ChatSource(account, conn, channel, contact, this);

        this._chatSources[channel.get_object_path()] = source;
        source.connect('destroy', () => {
            delete this._chatSources[channel.get_object_path()];
        });
    }

    vfunc_handle_channels(...args) {
        let [account, conn, channels, requests_, userActionTime_, context] = args;
        this._handlingChannels(account, conn, channels, true);
        context.accept();
    }

    _handlingChannels(account, conn, channels, notify) {
        let len = channels.length;
        for (let i = 0; i < len; i++) {
            let channel = channels[i];

            // We can only handle text channel, so close any other channel
            if (!(channel instanceof Tp.TextChannel)) {
                channel.close_async();
                continue;
            }

            if (channel.get_invalidated())
                continue;

            // 'notify' will be true when coming from an actual HandleChannels
            // call, and not when from a successful Claim call. The point is
            // we don't want to notify for a channel we just claimed which
            // has no new messages (for example, a new channel which only has
            // a delivery notification). We rely on _displayPendingMessages()
            // and _messageReceived() to notify for new messages.

            // But we should still notify from HandleChannels because the
            // Telepathy spec states that handlers must foreground channels
            // in HandleChannels calls which are already being handled.

            if (notify && this.is_handling_channel(channel)) {
                // We are already handling the channel, display the source
                let source = this._chatSources[channel.get_object_path()];
                if (source)
                    source.showNotification();
            }
        }
    }

    vfunc_add_dispatch_operation(...args) {
        let [account, conn, channels, dispatchOp, context] = args;
        let channel = channels[0];
        let chanType = channel.get_channel_type();

        if (channel.get_invalidated()) {
            context.fail(new Tp.Error({
                code: Tp.Error.INVALID_ARGUMENT,
                message: 'Channel is invalidated',
            }));
            return;
        }

        if (chanType == Tp.IFACE_CHANNEL_TYPE_TEXT) {
            this._approveTextChannel(account, conn, channel, dispatchOp, context);
        } else {
            context.fail(new Tp.Error({
                code: Tp.Error.INVALID_ARGUMENT,
                message: 'Unsupported channel type',
            }));
        }
    }

    async _approveTextChannel(account, conn, channel, dispatchOp, context) {
        let [targetHandle_, targetHandleType] = channel.get_handle();

        if (targetHandleType != Tp.HandleType.CONTACT) {
            context.fail(new Tp.Error({
                code: Tp.Error.INVALID_ARGUMENT,
                message: 'Unsupported handle type',
            }));
            return;
        }

        context.accept();

        // Approve private text channels right away as we are going to handle it
        try {
            await dispatchOp.claim_with_async(this);
            this._handlingChannels(account, conn, [channel], false);
        } catch (err) {
            log(`Failed to claim channel: ${err}`);
        }
    }

    _delegatedChannelsCb(_client, _channels) {
        // Nothing to do as we don't make a distinction between observed and
        // handled channels.
    }
}) : null;

const ChatSource = HAVE_TP ? GObject.registerClass(
class ChatSource extends MessageTray.Source {
    _init(account, conn, channel, contact, client) {
        this._account = account;
        this._contact = contact;
        this._client = client;

        super._init(contact.get_alias());

        this.isChat = true;
        this._pendingMessages = [];

        this._conn = conn;
        this._channel = channel;

        this._notifyTimeoutId = 0;

        this._presence = contact.get_presence_type();

        this._channel.connectObject(
            'invalidated', this._channelClosed.bind(this),
            'message-sent', this._messageSent.bind(this),
            'message-received', this._messageReceived.bind(this),
            'pending-message-removed', this._pendingRemoved.bind(this), this);

        this._contact.connectObject(
            'notify::alias', this._updateAlias.bind(this),
            'notify::avatar-file', this._updateAvatarIcon.bind(this),
            'presence-changed', this._presenceChanged.bind(this), this);

        // Add ourselves as a source.
        Main.messageTray.add(this);

        this._getLogMessages();
    }

    _ensureNotification() {
        if (this._notification)
            return;

        this._notification = new ChatNotification(this);
        this._notification.connectObject(
            'activated', this.open.bind(this),
            'destroy', () => (this._notification = null),
            'updated', () => {
                if (this._banner && this._banner.expanded)
                    this._ackMessages();
            }, this);
        this.pushNotification(this._notification);
    }

    _createPolicy() {
        if (this._account.protocol_name == 'irc')
            return new MessageTray.NotificationApplicationPolicy('org.gnome.Polari');
        return new MessageTray.NotificationApplicationPolicy('empathy');
    }

    createBanner() {
        this._banner = new ChatNotificationBanner(this._notification);

        // We ack messages when the user expands the new notification
        this._banner.connectObject(
            'expanded', this._ackMessages.bind(this),
            'destroy', () => (this._banner = null), this);

        return this._banner;
    }

    _updateAlias() {
        let oldAlias = this.title;
        let newAlias = this._contact.get_alias();

        if (oldAlias == newAlias)
            return;

        this.setTitle(newAlias);
        if (this._notification)
            this._notification.appendAliasChange(oldAlias, newAlias);
    }

    getIcon() {
        let file = this._contact.get_avatar_file();
        if (file)
            return new Gio.FileIcon({file});
        else
            return new Gio.ThemedIcon({name: 'avatar-default'});
    }

    getSecondaryIcon() {
        let iconName;
        let presenceType = this._contact.get_presence_type();

        switch (presenceType) {
        case Tp.ConnectionPresenceType.AVAILABLE:
            iconName = 'user-available';
            break;
        case Tp.ConnectionPresenceType.BUSY:
            iconName = 'user-busy';
            break;
        case Tp.ConnectionPresenceType.OFFLINE:
            iconName = 'user-offline';
            break;
        case Tp.ConnectionPresenceType.HIDDEN:
            iconName = 'user-invisible';
            break;
        case Tp.ConnectionPresenceType.AWAY:
            iconName = 'user-away';
            break;
        case Tp.ConnectionPresenceType.EXTENDED_AWAY:
            iconName = 'user-idle';
            break;
        default:
            iconName = 'user-offline';
        }
        return new Gio.ThemedIcon({name: iconName});
    }

    _updateAvatarIcon() {
        this.iconUpdated();
        if (this._notification) {
            this._notification.update(this._notification.title,
                                      this._notification.bannerBodyText,
                                      {gicon: this.getIcon()});
        }
    }

    open() {
        Main.overview.hide();
        Main.panel.closeCalendar();

        if (this._client.is_handling_channel(this._channel)) {
            // We are handling the channel, try to pass it to Empathy or Polari
            // (depending on the channel type)
            // We don't check if either app is available - mission control will
            // fallback to something else if activation fails

            let target;
            if (this._channel.connection.protocol_name == 'irc')
                target = 'org.freedesktop.Telepathy.Client.Polari';
            else
                target = 'org.freedesktop.Telepathy.Client.Empathy.Chat';
            this._client.delegate_channels_async([this._channel], global.get_current_time(), target, null);
        } else {
            // We are not the handler, just ask to present the channel
            let dbus = Tp.DBusDaemon.dup();
            let cd = Tp.ChannelDispatcher.new(dbus);

            cd.present_channel_async(this._channel, global.get_current_time(), null);
        }
    }

    async _getLogMessages() {
        let logManager = Tpl.LogManager.dup_singleton();
        let entity = Tpl.Entity.new_from_tp_contact(this._contact, Tpl.EntityType.CONTACT);

        const [events] = await logManager.get_filtered_events_async(
            this._account, entity,
            Tpl.EventTypeMask.TEXT, SCROLLBACK_HISTORY_LINES,
            null);

        let logMessages = events.map(e => ChatMessage.newFromTplTextEvent(e));
        this._ensureNotification();

        let pendingTpMessages = this._channel.get_pending_messages();
        let pendingMessages = [];

        for (let i = 0; i < pendingTpMessages.length; i++) {
            let message = pendingTpMessages[i];

            if (message.get_message_type() == Tp.ChannelTextMessageType.DELIVERY_REPORT)
                continue;

            pendingMessages.push(ChatMessage.newFromTpMessage(message,
                NotificationDirection.RECEIVED));

            this._pendingMessages.push(message);
        }

        this.countUpdated();

        let showTimestamp = false;

        for (let i = 0; i < logMessages.length; i++) {
            let logMessage = logMessages[i];
            let isPending = false;

            // Skip any log messages that are also in pendingMessages
            for (let j = 0; j < pendingMessages.length; j++) {
                let pending = pendingMessages[j];
                if (logMessage.timestamp == pending.timestamp && logMessage.text == pending.text) {
                    isPending = true;
                    break;
                }
            }

            if (!isPending) {
                showTimestamp = true;
                this._notification.appendMessage(logMessage, true, ['chat-log-message']);
            }
        }

        if (showTimestamp)
            this._notification.appendTimestamp();

        for (let i = 0; i < pendingMessages.length; i++)
            this._notification.appendMessage(pendingMessages[i], true);

        if (pendingMessages.length > 0)
            this.showNotification();
    }

    destroy(reason) {
        if (this._client.is_handling_channel(this._channel)) {
            this._ackMessages();
            // The chat box has been destroyed so it can't
            // handle the channel any more.
            this._channel.close_async();
        } else {
            // Don't indicate any unread messages when the notification
            // that represents them has been destroyed.
            this._pendingMessages = [];
            this.countUpdated();
        }

        // Keep source alive while the channel is open
        if (reason != MessageTray.NotificationDestroyedReason.SOURCE_CLOSED)
            return;

        if (this._destroyed)
            return;

        this._destroyed = true;
        this._channel.disconnectObject(this);
        this._contact.disconnectObject(this);

        super.destroy(reason);
    }

    _channelClosed() {
        this.destroy(MessageTray.NotificationDestroyedReason.SOURCE_CLOSED);
    }

    /* All messages are new messages for Telepathy sources */
    get count() {
        return this._pendingMessages.length;
    }

    get unseenCount() {
        return this.count;
    }

    get countVisible() {
        return this.count > 0;
    }

    _messageReceived(channel, message) {
        if (message.get_message_type() == Tp.ChannelTextMessageType.DELIVERY_REPORT)
            return;

        this._ensureNotification();
        this._pendingMessages.push(message);
        this.countUpdated();

        message = ChatMessage.newFromTpMessage(message,
            NotificationDirection.RECEIVED);
        this._notification.appendMessage(message);

        // Wait a bit before notifying for the received message, a handler
        // could ack it in the meantime.
        if (this._notifyTimeoutId != 0)
            GLib.source_remove(this._notifyTimeoutId);
        this._notifyTimeoutId = GLib.timeout_add(GLib.PRIORITY_DEFAULT, 500,
            this._notifyTimeout.bind(this));
        GLib.Source.set_name_by_id(this._notifyTimeoutId, '[gnome-shell] this._notifyTimeout');
    }

    _notifyTimeout() {
        if (this._pendingMessages.length != 0)
            this.showNotification();

        this._notifyTimeoutId = 0;

        return GLib.SOURCE_REMOVE;
    }

    // This is called for both messages we send from
    // our client and other clients as well.
    _messageSent(channel, message, _flags, _token) {
        this._ensureNotification();
        message = ChatMessage.newFromTpMessage(message,
            NotificationDirection.SENT);
        this._notification.appendMessage(message);
    }

    showNotification() {
        super.showNotification(this._notification);
    }

    respond(text) {
        let type;
        if (text.slice(0, 4) == '/me ') {
            type = Tp.ChannelTextMessageType.ACTION;
            text = text.slice(4);
        } else {
            type = Tp.ChannelTextMessageType.NORMAL;
        }

        let msg = Tp.ClientMessage.new_text(type, text);
        this._channel.send_message_async(msg, 0);
    }

    setChatState(state) {
        // We don't want to send COMPOSING every time a letter is typed into
        // the entry. We send the state only when it changes. Telepathy/Empathy
        // might change it behind our back if the user is using both
        // gnome-shell's entry and the Empathy conversation window. We could
        // keep track of it with the ChatStateChanged signal but it is good
        // enough right now.
        if (state != this._chatState) {
            this._chatState = state;
            this._channel.set_chat_state_async(state, null);
        }
    }

    _presenceChanged(_contact, _presence, _status, _message) {
        if (this._notification) {
            this._notification.update(this._notification.title,
                                      this._notification.bannerBodyText,
                                      {secondaryGIcon: this.getSecondaryIcon()});
        }
    }

    _pendingRemoved(channel, message) {
        let idx = this._pendingMessages.indexOf(message);

        if (idx >= 0) {
            this._pendingMessages.splice(idx, 1);
            this.countUpdated();
        }

        if (this._pendingMessages.length == 0 &&
            this._banner && !this._banner.expanded)
            this._banner.hide();
    }

    _ackMessages() {
        // Don't clear our messages here, tp-glib will send a
        // 'pending-message-removed' for each one.
        this._channel.ack_all_pending_messages_async(null);
    }
}) : null;

const ChatNotificationMessage = HAVE_TP ? GObject.registerClass(
class ChatNotificationMessage extends GObject.Object {
    _init(props = {}) {
        super._init();
        this.set(props);
    }
}) : null;

const ChatNotification = HAVE_TP ? GObject.registerClass({
    Signals: {
        'message-removed': {param_types: [ChatNotificationMessage.$gtype]},
        'message-added': {param_types: [ChatNotificationMessage.$gtype]},
        'timestamp-changed': {param_types: [ChatNotificationMessage.$gtype]},
    },
}, class ChatNotification extends MessageTray.Notification {
    _init(source) {
        super._init(source, source.title, null,
            {secondaryGIcon: source.getSecondaryIcon()});
        this.setUrgency(MessageTray.Urgency.HIGH);
        this.setResident(true);

        this.messages = [];
        this._timestampTimeoutId = 0;
    }

    destroy(reason) {
        if (this._timestampTimeoutId)
            GLib.source_remove(this._timestampTimeoutId);
        this._timestampTimeoutId = 0;
        super.destroy(reason);
    }

    /**
     * appendMessage:
     * @param {Object} message: An object with the properties
     *   {string} message.text: the body of the message,
     *   {Tp.ChannelTextMessageType} message.messageType: the type
     *   {string} message.sender: the name of the sender,
     *   {number} message.timestamp: the time the message was sent
     *   {NotificationDirection} message.direction: a #NotificationDirection
     *
     * @param {bool} noTimestamp: Whether to add a timestamp. If %true,
     *   no timestamp will be added, regardless of the difference since
     *   the last timestamp
     */
    appendMessage(message, noTimestamp) {
        let messageBody = GLib.markup_escape_text(message.text, -1);
        let styles = [message.direction];

        if (message.messageType == Tp.ChannelTextMessageType.ACTION) {
            let senderAlias = GLib.markup_escape_text(message.sender, -1);
            messageBody = `<i>${senderAlias}</i> ${messageBody}`;
            styles.push('chat-action');
        }

        if (message.direction == NotificationDirection.RECEIVED) {
            this.update(this.source.title, messageBody, {
                datetime: GLib.DateTime.new_from_unix_local(message.timestamp),
                bannerMarkup: true,
            });
        }

        let group = message.direction == NotificationDirection.RECEIVED
            ? 'received' : 'sent';

        this._append({
            body: messageBody,
            group,
            styles,
            timestamp: message.timestamp,
            noTimestamp,
        });
    }

    _filterMessages() {
        if (this.messages.length < 1)
            return;

        let lastMessageTime = this.messages[0].timestamp;
        let currentTime = Date.now() / 1000;

        // Keep the scrollback from growing too long. If the most
        // recent message (before the one we just added) is within
        // SCROLLBACK_RECENT_TIME, we will keep
        // SCROLLBACK_RECENT_LENGTH previous messages. Otherwise
        // we'll keep SCROLLBACK_IDLE_LENGTH messages.

        let maxLength = lastMessageTime < currentTime - SCROLLBACK_RECENT_TIME
            ? SCROLLBACK_IDLE_LENGTH : SCROLLBACK_RECENT_LENGTH;

        let filteredHistory = this.messages.filter(item => item.realMessage);
        if (filteredHistory.length > maxLength) {
            let lastMessageToKeep = filteredHistory[maxLength];
            let expired = this.messages.splice(this.messages.indexOf(lastMessageToKeep));
            for (let i = 0; i < expired.length; i++)
                this.emit('message-removed', expired[i]);
        }
    }

    /**
     * _append:
     * @param {Object} props: An object with the properties:
     *  {string} props.body: The text of the message.
     *  {string} props.group: The group of the message, one of:
     *         'received', 'sent', 'meta'.
     *  {string[]} props.styles: Style class names for the message to have.
     *  {number} props.timestamp: The timestamp of the message.
     *  {bool} props.noTimestamp: suppress timestamp signal?
     */
    _append(props) {
        let currentTime = Date.now() / 1000;
        props = Params.parse(props, {
            body: null,
            group: null,
            styles: [],
            timestamp: currentTime,
            noTimestamp: false,
        });
        const {noTimestamp} = props;
        delete props.noTimestamp;

        // Reset the old message timeout
        if (this._timestampTimeoutId)
            GLib.source_remove(this._timestampTimeoutId);
        this._timestampTimeoutId = 0;

        let message = new ChatNotificationMessage({
            realMessage: props.group !== 'meta',
            showTimestamp: false,
            ...props,
        });

        this.messages.unshift(message);
        this.emit('message-added', message);

        if (!noTimestamp) {
            let timestamp = props.timestamp;
            if (timestamp < currentTime - SCROLLBACK_IMMEDIATE_TIME) {
                this.appendTimestamp();
            } else {
                // Schedule a new timestamp in SCROLLBACK_IMMEDIATE_TIME
                // from the timestamp of the message.
                this._timestampTimeoutId = GLib.timeout_add_seconds(
                    GLib.PRIORITY_DEFAULT,
                    SCROLLBACK_IMMEDIATE_TIME - (currentTime - timestamp),
                    this.appendTimestamp.bind(this));
                GLib.Source.set_name_by_id(this._timestampTimeoutId, '[gnome-shell] this.appendTimestamp');
            }
        }

        this._filterMessages();
    }

    appendTimestamp() {
        this._timestampTimeoutId = 0;

        this.messages[0].showTimestamp = true;
        this.emit('timestamp-changed', this.messages[0]);

        this._filterMessages();

        return GLib.SOURCE_REMOVE;
    }

    appendAliasChange(oldAlias, newAlias) {
        oldAlias = GLib.markup_escape_text(oldAlias, -1);
        newAlias = GLib.markup_escape_text(newAlias, -1);

        /* Translators: this is the other person changing their old IM name to their new
           IM name. */
        const message = `<i>${
            _('%s is now known as %s').format(oldAlias, newAlias)}</i>`;

        this._append({
            body: message,
            group: 'meta',
            styles: ['chat-meta-message'],
        });

        this._filterMessages();
    }
}) : null;

const ChatLineBox = GObject.registerClass(
class ChatLineBox extends St.BoxLayout {
    vfunc_get_preferred_height(forWidth) {
        let [, natHeight] = super.vfunc_get_preferred_height(forWidth);
        return [natHeight, natHeight];
    }
});

const ChatNotificationBanner = GObject.registerClass(
class ChatNotificationBanner extends MessageTray.NotificationBanner {
    _init(notification) {
        super._init(notification);

        this._responseEntry = new St.Entry({
            style_class: 'chat-response',
            x_expand: true,
            can_focus: true,
        });
        this._responseEntry.clutter_text.connect('activate', this._onEntryActivated.bind(this));
        this._responseEntry.clutter_text.connect('text-changed', this._onEntryChanged.bind(this));
        this.setActionArea(this._responseEntry);

        this._responseEntry.clutter_text.connect('key-focus-in', () => {
            this.focused = true;
        });
        this._responseEntry.clutter_text.connect('key-focus-out', () => {
            this.focused = false;
            this.emit('unfocused');
        });

        this._scrollArea = new St.ScrollView({
            style_class: 'chat-scrollview vfade',
            vscrollbar_policy: St.PolicyType.AUTOMATIC,
            hscrollbar_policy: St.PolicyType.NEVER,
            visible: this.expanded,
        });
        this._contentArea = new St.BoxLayout({
            style_class: 'chat-body',
            vertical: true,
        });
        this._scrollArea.add_actor(this._contentArea);

        this.setExpandedBody(this._scrollArea);
        this.setExpandedLines(CHAT_EXPAND_LINES);

        this._lastGroup = null;

        // Keep track of the bottom position for the current adjustment and
        // force a scroll to the bottom if things change while we were at the
        // bottom
        this._oldMaxScrollValue = this._scrollArea.vscroll.adjustment.value;
        this._scrollArea.vscroll.adjustment.connect('changed', adjustment => {
            if (adjustment.value == this._oldMaxScrollValue)
                this.scrollTo(St.Side.BOTTOM);
            this._oldMaxScrollValue = Math.max(adjustment.lower, adjustment.upper - adjustment.page_size);
        });

        this._inputHistory = new History.HistoryManager({entry: this._responseEntry.clutter_text});

        this._composingTimeoutId = 0;

        this._messageActors = new Map();

        this.notification.connectObject(
            'timestamp-changed', (n, message) => this._updateTimestamp(message),
            'message-added', (n, message) => this._addMessage(message),
            'message-removed', (n, message) => {
                let actor = this._messageActors.get(message);
                if (this._messageActors.delete(message))
                    actor.destroy();
            }, this);

        for (let i = this.notification.messages.length - 1; i >= 0; i--)
            this._addMessage(this.notification.messages[i]);
    }

    scrollTo(side) {
        let adjustment = this._scrollArea.vscroll.adjustment;
        if (side == St.Side.TOP)
            adjustment.value = adjustment.lower;
        else if (side == St.Side.BOTTOM)
            adjustment.value = adjustment.upper;
    }

    hide() {
        this.emit('done-displaying');
    }

    _addMessage(message) {
        let body = new MessageList.URLHighlighter(message.body, true, true);

        let styles = message.styles;
        for (let i = 0; i < styles.length; i++)
            body.add_style_class_name(styles[i]);

        let group = message.group;
        if (group != this._lastGroup) {
            this._lastGroup = group;
            body.add_style_class_name('chat-new-group');
        }

        let lineBox = new ChatLineBox();
        lineBox.add(body);
        this._contentArea.add_actor(lineBox);
        this._messageActors.set(message, lineBox);

        this._updateTimestamp(message);
    }

    _updateTimestamp(message) {
        let actor = this._messageActors.get(message);
        if (!actor)
            return;

        while (actor.get_n_children() > 1)
            actor.get_child_at_index(1).destroy();

        if (message.showTimestamp) {
            let lastMessageTime = message.timestamp;
            let lastMessageDate = new Date(lastMessageTime * 1000);

            let timeLabel = Util.createTimeLabel(lastMessageDate);
            timeLabel.style_class = 'chat-meta-message';
            timeLabel.x_expand = timeLabel.y_expand = true;
            timeLabel.x_align = timeLabel.y_align = Clutter.ActorAlign.END;

            actor.add_actor(timeLabel);
        }
    }

    _onEntryActivated() {
        let text = this._responseEntry.get_text();
        if (text == '')
            return;

        this._inputHistory.addItem(text);

        // Telepathy sends out the Sent signal for us.
        // see Source._messageSent
        this._responseEntry.set_text('');
        this.notification.source.respond(text);
    }

    _composingStopTimeout() {
        this._composingTimeoutId = 0;

        this.notification.source.setChatState(Tp.ChannelChatState.PAUSED);

        return GLib.SOURCE_REMOVE;
    }

    _onEntryChanged() {
        let text = this._responseEntry.get_text();

        // If we're typing, we want to send COMPOSING.
        // If we empty the entry, we want to send ACTIVE.
        // If we've stopped typing for COMPOSING_STOP_TIMEOUT
        //    seconds, we want to send PAUSED.

        // Remove composing timeout.
        if (this._composingTimeoutId > 0) {
            GLib.source_remove(this._composingTimeoutId);
            this._composingTimeoutId = 0;
        }

        if (text != '') {
            this.notification.source.setChatState(Tp.ChannelChatState.COMPOSING);

            this._composingTimeoutId = GLib.timeout_add_seconds(
                GLib.PRIORITY_DEFAULT,
                COMPOSING_STOP_TIMEOUT,
                this._composingStopTimeout.bind(this));
            GLib.Source.set_name_by_id(this._composingTimeoutId, '[gnome-shell] this._composingStopTimeout');
        } else {
            this.notification.source.setChatState(Tp.ChannelChatState.ACTIVE);
        }
    }
});

export const Component = TelepathyComponent;