var notifications = (function () {

var exports = {};

var notice_memory = {};
var window_has_focus = true;
var asked_permission_already = false;
var names;
var supports_sound;

function browser_desktop_notifications_on () {
    return (window.webkitNotifications &&
            // Firefox on Ubuntu claims to do webkitNotifications but its notifications are terrible
            $.browser.webkit &&
            // 0 is PERMISSION_ALLOWED
            window.webkitNotifications.checkPermission() === 0);
}

exports.initialize = function () {
    $(window).focus(function () {
        window_has_focus = true;
        exports.update_title_count();

        $.each(notice_memory, function (index, notice_mem_entry) {
           notice_mem_entry.obj.cancel();
        });


        process_visible_unread_messages();
    }).blur(function () {
        window_has_focus = false;
    });

    if (!window.webkitNotifications) {
        return;
    }

    $(document).click(function () {
        if (!page_params.desktop_notifications_enabled || asked_permission_already) {
            return;
        }
        if (window.webkitNotifications.checkPermission() !== 0) { // 0 is PERMISSION_ALLOWED
            window.webkitNotifications.requestPermission(function () {});
            asked_permission_already = true;
        }
    });
    var audio = $("<audio>");
    if (audio[0].canPlayType === undefined) {
        supports_sound = false;
    } else {
        supports_sound = true;
        $("#notifications-area").append(audio);
        if (audio[0].canPlayType('audio/ogg; codecs="vorbis"')) {
            audio.append($("<source>").attr("type", "audio/ogg")
                                      .attr("loop", "yes")
                                      .attr("src", "/static/audio/humbug.ogg"));
        } else {
            audio.append($("<source>").attr("type", "audio/mpeg")
                                      .attr("loop", "yes")
                                      .attr("src", "/static/audio/humbug.mp3"));
        }
    }
};

exports.update_title_count = function () {
    // Update window title and favicon to reflect unread messages in current view
    var n;

    var new_message_count = unread_in_current_view();
    var new_title = (new_message_count ? ("(" + new_message_count + ") ") : "")
        + page_params.domain + " - Humbug";

    if (document.title === new_title) {
        return;
    }

    document.title = new_title;

    // IE doesn't support PNG favicons, *shrug*
    if (! $.browser.msie) {
        // Indicate the message count in the favicon
        if (new_message_count) {
            // Make sure we're working with a number, as a defensive programming
            // measure.  And we don't have images above 99, so display those as
            // 'infinite'.
            n = (+new_message_count);
            if (n > 99)
                n = 'infinite';

            util.set_favicon('/static/images/favicon/favicon-'+n+'.png');
        } else {
            util.set_favicon('/static/favicon.ico?v=2');
        }
    }
};

exports.window_has_focus = function () {
    return window_has_focus;
};

function gravatar_url(message) {
    return "https://secure.gravatar.com/avatar/" + message.gravatar_hash +
           "?d=identicon&s=30?stamp=" + ui.get_gravatar_stamp();
}

function process_desktop_notification(message) {
    var i, notification_object, key;
    var title = message.sender_full_name;
    var content = $('<div/>').html(message.content).text();
    var other_recipients;
    var msg_count = 1;

    if (message.type === "private") {
        key = message.display_reply_to;
        other_recipients = message.display_reply_to;
        // Remove the sender from the list of other recipients
        other_recipients = other_recipients.replace(", " + message.sender_full_name, "");
        other_recipients = other_recipients.replace(message.sender_full_name + ", ", "");
    } else {
        key = message.sender_full_name + " to " +
              message.stream + " > " + message.subject;
    }

    if (content.length > 150) {
        // Truncate content at a word boundary
        for (i = 150; i > 0; i--) {
            if (content[i] === ' ') {
                break;
            }
        }
        content = content.substring(0, i);
        content += " [...]";
    }

    if (notice_memory[key] !== undefined) {
        msg_count = notice_memory[key].msg_count + 1;
        title = msg_count + " messages from " + title;
        notification_object = notice_memory[key].obj;
        // We must remove the .onclose so that it does not trigger on .cancel
        notification_object.onclose = function () {};
        notification_object.onclick = function () {};
        notification_object.cancel();
    }

    if (message.type === "private" && message.display_recipient.length > 2) {
        // If the message has too many recipients to list them all...
        if (content.length + title.length + other_recipients.length > 230) {
            // Then count how many people are in the conversation and summarize
            // by saying the conversation is with "you and [number] other people"
            other_recipients = other_recipients.replace(/[^,]/g, "").length +
                               " other people";
        }
        title += " (to you and " + other_recipients + ")";
    }
    if (message.type === "stream") {
        title += " (to " + message.stream + " > " + message.subject + ")";
    }

    notice_memory[key] = {
        obj: window.webkitNotifications.createNotification(
                gravatar_url(message), title, content),
        msg_count: msg_count
    };
    notification_object = notice_memory[key].obj;
    notification_object.onclick = function () {
        notification_object.cancel();
        window.focus();
    };
    notification_object.onclose = function () {
        delete notice_memory[key];
    };
    notification_object.show();
}

exports.speaking_at_me = function (message) {
    if (message === undefined || message.flags === undefined) {
        return false;
    }
    return message.flags.indexOf('mentioned') > -1;
};

function message_is_notifiable(message) {
    // based purely on message contents, can we notify the user about the message?
    return (message.type === "private" ||
            exports.speaking_at_me(message) ||
           (message.type === "stream" &&
            subs.receives_notifications(message.stream)));
}

exports.received_messages = function (messages) {
    var i;

    $.each(messages, function (index, message) {
        if (message.sender_email !== page_params.email &&
            narrow.message_in_home(message)) {

            // We send notifications for messages which the user has
            // configured as notifiable, as long as they haven't been
            // marked as read by process_visible_unread_messages
            // (which occurs if the message arrived onscreen while the
            // window had focus).
            if (!(message_is_notifiable(message) && unread.message_unread(message))) {
                return;
            }
            if (page_params.desktop_notifications_enabled &&
                browser_desktop_notifications_on()) {
                process_desktop_notification(message);
            }
            if (page_params.sounds_enabled && supports_sound) {
                $("#notifications-area").find("audio")[0].play();
            }
        }
    });
};

return exports;

}());