var notifications = (function () {

var exports = {};

var notice_memory = {};

// When you start Zulip, window_has_focus should be true, but it might not be the
// case after a server-initiated reload.
var window_has_focus = document.hasFocus && document.hasFocus();

var supports_sound;

var unread_pms_favicon = '/static/images/favicon/favicon-pms.png';
var current_favicon;
var previous_favicon;
var flashing = false;

var notifications_api;
if (window.webkitNotifications) {
    notifications_api = window.webkitNotifications;
} else if (window.Notification) {
    // Build a shim to the new notification API
    notifications_api = {
        checkPermission: function checkPermission() {
            if (window.Notification.permission === 'granted') {
                return 0;
            }
            return 2;
        },
        requestPermission: window.Notification.requestPermission,
        createNotification: function createNotification(icon, title, content, tag) {
            var notification_object = new window.Notification(title, {icon: icon,
                                                                      body: content,
                                                                      tag: tag});
            notification_object.show = function () {};
            notification_object.cancel = function () { notification_object.close(); };
            return notification_object;
        },
    };
}


function browser_desktop_notifications_on() {
    return (notifications_api &&
            // Firefox on Ubuntu claims to do webkitNotifications but its notifications are terrible
            /webkit/i.test(navigator.userAgent) &&
            // 0 is PERMISSION_ALLOWED
            notifications_api.checkPermission() === 0) ||
        // window.bridge is the desktop client
        (window.bridge !== undefined);
}

function cancel_notification_object(notification_object) {
        // We must remove the .onclose so that it does not trigger on .cancel
        notification_object.onclose = function () {};
        notification_object.onclick = function () {};
        notification_object.cancel();
}

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

        _.each(notice_memory, function (notice_mem_entry) {
           cancel_notification_object(notice_mem_entry.obj);
        });
        notice_memory = {};

        // Update many places on the DOM to reflect unread
        // counts.
        unread_ops.process_visible();

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

    if (window.bridge !== undefined) {
        supports_sound = true;

        return;
    }

    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/zulip.ogg"));
        } else {
            audio.append($("<source>").attr("type", "audio/mpeg")
                                      .attr("loop", "yes")
                                      .attr("src", "/static/audio/zulip.mp3"));
        }
    }
};

exports.permission_state = function () {
    if (window.Notification === undefined) {
        // act like notifications are blocked if they do not have access to
        // the notification API.
        return "denied";
    }
    return window.Notification.permission;
};

// For web pages, the initial favicon is the same as the favicon we
// set for no unread messages and the initial page title is the same
// as the page title we set for no unread messages.  However, for the
// macOS app, the dock icon does not get its badge updated on initial
// page load.  If the badge icon was wrong right before a reload and
// we actually have no unread messages then we will never execute
// bridge.updateCount() until the unread count changes.  Therefore,
// we ensure that bridge.updateCount is always run at least once to
// synchronize it with the page title.  This can be done before the
// DOM is loaded.
if (window.bridge !== undefined) {
    window.bridge.updateCount(0);
}

var new_message_count = 0;

exports.update_title_count = function (count) {
    new_message_count = count;
    exports.redraw_title();
};

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

    var new_title = (new_message_count ? ("(" + new_message_count + ") ") : "")
        + narrow.narrow_title + " - "
        + page_params.realm_name + " - "
        + "Zulip";

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

    document.title = new_title;

    // IE doesn't support PNG favicons, *shrug*
    if (!/msie/i.test(navigator.userAgent)) {
        // 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';
            }

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

    // window.bridge is for the legacy QT desktop app; we'll likely
    // remove this code soon.
    if (window.bridge !== undefined) {
        // We don't use 'n' because we want the exact count. The bridge handles
        // which icon to show.
        window.bridge.updateCount(new_message_count);
    }

    // Notify the current desktop app's UI about the new unread count.
    if (window.electron_bridge !== undefined) {
        window.electron_bridge.send_event('total_unread_count', new_message_count);
    }
};

function flash_pms() {
    // When you have unread PMs, toggle the favicon between the unread count and
    // a special icon indicating that you have unread PMs.
    if (unread.get_counts().private_message_count > 0) {
        if (current_favicon === unread_pms_favicon) {
            favicon.set(previous_favicon);
            current_favicon = previous_favicon;
            previous_favicon = unread_pms_favicon;
        } else {
            favicon.set(unread_pms_favicon);
            previous_favicon = current_favicon;
            current_favicon = unread_pms_favicon;
        }
        // Toggle every 2 seconds.
        setTimeout(flash_pms, 2000);
    } else {
        flashing = false;
        // You have no more unread PMs, so back to only showing the unread
        // count.
        favicon.set(current_favicon);
    }
}

exports.update_pm_count = function (new_pm_count) {
    if (window.bridge !== undefined && window.bridge.updatePMCount !== undefined) {
        window.bridge.updatePMCount(new_pm_count);
    }
    if (!flashing) {
        flashing = true;
        flash_pms();
    }
};

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

function in_browser_notify(message, title, content, raw_operators, opts) {
    var notification_html = $(templates.render('notification', {
        gravatar_url: people.small_avatar_url(message),
        title: title,
        content: content,
        message_id: message.id,
    }));

    $(".top-right").notify({
        message: {
            html: notification_html,
        },
        fadeOut: {
            enabled: true,
            delay: 4000,
        },
    }).show();

    $(".notification[data-message-id='" + message.id + "']").expectOne().data("narrow", {
        raw_operators: raw_operators,
        opts_notif: opts,
    });
}

exports.notify_above_composebox = function (note, link_class, link_msg_id, link_text) {
    var notification_html = $(templates.render('compose_notification', {note: note,
                                                                        link_class: link_class,
                                                                        link_msg_id: link_msg_id,
                                                                        link_text: link_text}));
    exports.clear_compose_notifications();
    $('#out-of-view-notification').append(notification_html);
    $('#out-of-view-notification').show();
};

function process_notification(notification) {
    var i;
    var notification_object;
    var key;
    var content;
    var other_recipients;
    var message = notification.message;
    var title = message.sender_full_name;
    var msg_count = 1;
    var notification_source;
    var raw_operators = [];
    var opts = {select_first_unread: true, trigger: "notification click"};
    // Convert the content to plain text, replacing emoji with their alt text
    content = $('<div/>').html(message.content);
    ui.replace_emoji_with_text(content);
    content = content.text();

    if (message.is_me_message) {
        content = message.sender_full_name + content.slice(3);
    }

    if (message.type === "private") {
        if (page_params.pm_content_in_desktop_notifications !== undefined
            && !page_params.pm_content_in_desktop_notifications) {
            content = "New private message from " + message.sender_full_name;
        }
        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 + ", ", "");
        notification_source = 'pm';
    } else {
        key = message.sender_full_name + " to " +
              message.stream + " > " + message.subject;
        if (message.mentioned) {
            notification_source = 'mention';
        } else if (message.alerted) {
            notification_source = 'alert';
        } else {
            notification_source = 'stream';
        }
    }

    if (content.length > 150) {
        // Truncate content at a word boundary
        for (i = 150; i > 0; i -= 1) {
            if (content[i] === ' ') {
                break;
            }
        }
        content = content.substring(0, i);
        content += " [...]";
    }

    if (window.bridge === undefined && notice_memory[key] !== undefined) {
        msg_count = notice_memory[key].msg_count + 1;
        title = msg_count + " messages from " + title;
        notification_object = notice_memory[key].obj;
        cancel_notification_object(notification_object);
    }

    if (message.type === "private") {
        if (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 + ")";
        } else {
            title += " (to you)";
        }

        raw_operators = [{operand: message.reply_to, operator: "pm-with"}];
    }

    if (message.type === "stream") {
        title += " (to " + message.stream + " > " + message.subject + ")";
        raw_operators = [{operator: "stream", operand: message.stream},
                         {operator: "topic", operand: message.subject}];
    }

    if (window.bridge === undefined && notification.webkit_notify === true) {
        var icon_url = people.small_avatar_url(message);
        notice_memory[key] = {
            obj: notifications_api.createNotification(
                    icon_url, title, content, message.id),
            msg_count: msg_count,
            message_id: message.id,
        };
        notification_object = notice_memory[key].obj;
        notification_object.onclick = function () {
            notification_object.cancel();
            if (feature_flags.clicking_notification_causes_narrow) {
                narrow.by_subject(message.id, {trigger: 'notification'});
            }
            window.focus();
        };
        notification_object.onclose = function () {
            delete notice_memory[key];
        };
        notification_object.show();
    } else if (notification.webkit_notify === false && typeof Notification !== "undefined" && /mozilla/i.test(navigator.userAgent) === true) {
        Notification.requestPermission(function (perm) {
            if (perm === 'granted') {
                notification_object = new Notification(title, {
                    body: content,
                    iconUrl: people.small_avatar_url(message),
                    tag: message.id,
                });
                notification_object.onclick = function () {
                    // We don't need to bring the browser window into focus explicitly
                    // by calling `window.focus()` as well as don't need to clear the
                    // notification since it is the default behavior in Firefox.
                    if (feature_flags.clicking_notification_causes_narrow) {
                        narrow.by_subject(message.id, {trigger: 'notification'});
                    }
                };
            } else {
                in_browser_notify(message, title, content, raw_operators, opts);
            }
        });
    } else if (notification.webkit_notify === false) {
        in_browser_notify(message, title, content, raw_operators, opts);
    } else {
        // Shunt the message along to the desktop client
        window.bridge.desktopNotification(title, content, notification_source);
    }
}

exports.close_notification = function (message) {
    _.each(Object.keys(notice_memory), function (key) {
       if (notice_memory[key].message_id === message.id) {
           cancel_notification_object(notice_memory[key].obj);
           delete notice_memory[key];
       }
    });
};

exports.message_is_notifiable = function (message) {
    // Independent of the user's notification settings, are there
    // properties of the message that unconditionally mean we
    // shouldn't notify about it.

    if (message.sent_by_me) {
        return false;
    }

    // If a message is edited multiple times, we want to err on the side of
    // not spamming notifications.
    if (message.notification_sent) {
        return false;
    }

    // @-<username> mentions take precedence over muted-ness. Note
    // that @all mentions are still suppressed by muting.
    if (message.mentioned_me_directly) {
        return true;
    }

    // Messages to muted streams that don't mention us specifically
    // are not notifiable.
    if ((message.type === "stream") &&
        !stream_data.in_home_view(message.stream_id)) {
        return false;
    }

    if ((message.type === "stream") &&
        muting.is_topic_muted(message.stream, message.subject)) {
        return false;
    }

    // Everything else is on the table; next filter based on notification
    // settings.
    return true;
};

function should_send_desktop_notification(message) {
    // For streams, send if desktop notifications are enabled for this
    // stream.
    if ((message.type === "stream") &&
        stream_data.receives_desktop_notifications(message.stream)) {
        return true;
    }

    // For PMs and @-mentions, send if desktop notifications are
    // enabled.
    if ((message.type === "private") &&
        page_params.enable_desktop_notifications) {
        return true;
    }

    // For alert words and @-mentions, send if desktop notifications
    // are enabled.
    if (alert_words.notifies(message) &&
        page_params.enable_desktop_notifications) {
        return true;
    }

    if (message.mentioned &&
        page_params.enable_desktop_notifications) {
        return true;
    }

    return false;
}

function should_send_audible_notification(message) {
    // For streams, ding if sounds are enabled for this stream.
    if ((message.type === "stream") &&
        stream_data.receives_audible_notifications(message.stream)) {
        return true;
    }

    // For PMs and @-mentions, ding if sounds are enabled.
    if ((message.type === "private") && page_params.enable_sounds) {
        return true;
    }

    // For alert words and @-mentions, ding if sounds are enabled.
    if (alert_words.notifies(message) && page_params.enable_sounds) {
        return true;
    }

    if (message.mentioned && page_params.enable_sounds) {
        return true;
    }

    return false;
}

exports.granted_desktop_notifications_permission = function () {
    return (notifications_api &&
            // 0 is PERMISSION_ALLOWED
            notifications_api.checkPermission() === 0) ||
        // window.bridge is the legacy desktop app
        (window.bridge !== undefined);
};


exports.request_desktop_notifications_permission = function () {
    if (notifications_api) {
        return notifications_api.requestPermission();
    }
};

exports.received_messages = function (messages) {
    _.each(messages, function (message) {
        if (!exports.message_is_notifiable(message)) {
            return;
        }
        if (!unread.message_unread(message)) {
            // The message is already read; Zulip is currently in focus.
            return;
        }

        message.notification_sent = true;

        if (should_send_desktop_notification(message)) {
            if (browser_desktop_notifications_on()) {
                process_notification({message: message, webkit_notify: true});
            } else {
                process_notification({message: message, webkit_notify: false});
            }
        }
        if (should_send_audible_notification(message) && supports_sound) {
            if (window.bridge !== undefined) {
                window.bridge.bell();
            } else {
                $("#notifications-area").find("audio")[0].play();
            }
        }
    });
};

function get_message_header(message) {
    if (message.type === "stream") {
        return message.stream + ">" + message.subject;
    }
    if (message.display_recipient.length > 2) {
        return "group PM with " + message.display_reply_to;
    }
    if (people.is_current_user(message.reply_to)) {
        return "PM with yourself";
    }
    return "PM with " + message.display_reply_to;
}

exports.get_local_notify_mix_reason = function (message) {
    var row = current_msg_list.get_row(message.id);
    if (row.length > 0) {
        // If our message is in the current message list, we do
        // not have a mix, so we are happy.
        return;
    }

    if (message.type === "stream" && muting.is_topic_muted(message.stream, message.subject)) {
        return "Sent! Your message was sent to a topic you have muted.";
    }

    if (message.type === "stream" && !stream_data.in_home_view(message.stream_id)) {
        return "Sent! Your message was sent to a stream you have muted.";
    }

    // offscreen because it is outside narrow
    // we can only look for these on non-search (can_apply_locally) messages
    // see also: exports.notify_messages_outside_current_search
    return "Sent! Your message is outside your current narrow.";
};

exports.notify_local_mixes = function (messages) {
    /*
        This code should only be called when we are locally echoing
        messages.  It notifies users that their messages aren't
        actually in the view that they composed to.

        This code is called after we insert messages into our
        message list widgets.  All of the conditions here are
        checkable locally, so we may want to execute this code
        earlier in the codepath at some point and possibly punt
        on local rendering.
    */

    _.each(messages, function (message) {
        if (!people.is_my_user_id(message.sender_id)) {
            blueslip.warn('We did not expect messages sent by others to get here');
            return;
        }

        var reason = exports.get_local_notify_mix_reason(message);

        if (!reason) {
            // This is more than normal, just continue on.
            return;
        }

        var link_msg_id = message.id;
        var link_class = "compose_notification_narrow_by_subject";
        var link_text = "Narrow to " + get_message_header(message);

        exports.notify_above_composebox(reason, link_class, link_msg_id, link_text);
    });
};

// for callback when we have to check with the server if a message should be in
// the current_msg_list (!can_apply_locally; a.k.a. "a search").
exports.notify_messages_outside_current_search = function (messages) {
    _.each(messages, function (message) {
        if (!people.is_current_user(message.sender_email)) {
            return;
        }
        exports.notify_above_composebox("Sent! Your recent message is outside the current search.",
                                        "compose_notification_narrow_by_subject",
                                        message.id,
                                        "Narrow to " + get_message_header(message));
    });
};

exports.clear_compose_notifications = function () {
    $('#out-of-view-notification').empty();
    $('#out-of-view-notification').stop(true, true);
    $('#out-of-view-notification').hide();
};

$(function () {
    // Shim for Cocoa WebScript exporting top-level JS
    // objects instead of window.foo objects
    if (typeof(bridge) !== 'undefined' && window.bridge === undefined) {
        window.bridge = bridge;
    }

});

exports.reify_message_id = function (opts) {
    var old_id = opts.old_id;
    var new_id = opts.new_id;

    // If a message ID that we're currently storing (as a link) has changed,
    // update that link as well
    _.each($('#out-of-view-notification a'), function (e) {
        var elem = $(e);
        var msgid = elem.data('msgid');

        if (msgid === old_id) {
            elem.data('msgid', new_id);
        }
    });
};

exports.register_click_handlers = function () {
    $('#out-of-view-notification').on('click', '.compose_notification_narrow_by_subject', function (e) {
        var msgid = $(e.currentTarget).data('msgid');
        narrow.by_subject(msgid, {trigger: 'compose_notification'});
        e.stopPropagation();
        e.preventDefault();
    });
    $('#out-of-view-notification').on('click', '.compose_notification_scroll_to_message', function (e) {
        var msgid = $(e.currentTarget).data('msgid');
        current_msg_list.select_id(msgid);
        navigate.scroll_to_selected();
        e.stopPropagation();
        e.preventDefault();
    });
    $('#out-of-view-notification').on('click', '.out-of-view-notification-close', function (e) {
        exports.clear_compose_notifications();
        e.stopPropagation();
        e.preventDefault();
    });
};

exports.handle_global_notification_updates = function (notification_name, setting) {
    // Update the global settings checked when determining if we should notify
    // for a given message. These settings do not affect whether or not a
    // particular stream should receive notifications.
    if (settings_notifications.notification_settings.indexOf(notification_name) !== -1) {
        page_params[notification_name] = setting;
    }
};

return exports;

}());

if (typeof module !== 'undefined') {
    module.exports = notifications;
}
