var unread_ops = (function () {

var exports = {};

exports.mark_all_as_read = function (cont) {
    unread.declare_bankruptcy();
    unread_ui.update_unread_counts();

    channel.post({
        url:      '/json/mark_all_as_read',
        idempotent: true,
        success:  cont});
};

function process_newly_read_message(message, options) {
    home_msg_list.show_message_as_read(message, options);
    message_list.all.show_message_as_read(message, options);
    if (message_list.narrowed) {
        message_list.narrowed.show_message_as_read(message, options);
    }
    notifications.close_notification(message);
}

exports.process_read_messages_event = function (message_ids) {
    /*
        This code has a lot in common with mark_messages_as_read,
        but there are subtle differences due to the fact that the
        server can tell us about unread messages that we didn't
        actually read locally (and which we may not have even
        loaded locally).
    */
    var options = {from: 'server'};

    message_ids = unread.get_unread_message_ids(message_ids);
    if (message_ids.length === 0) {
        return;
    }

    _.each(message_ids, function (message_id) {
        if (current_msg_list === message_list.narrowed) {
            // I'm not sure this entirely makes sense for all server
            // notifications.
            unread.messages_read_in_narrow = true;
        }

        unread.mark_as_read(message_id);

        var message = message_store.get(message_id);

        if (message) {
            process_newly_read_message(message, options);
        }
    });

    unread_ui.update_unread_counts();
};


// Takes a list of messages and marks them as read.
// Skips any messages that are already marked as read.
exports.mark_messages_as_read = function (messages, options) {
    options = options || {};

    messages = unread.get_unread_messages(messages);
    if (messages.length === 0) {
        return;
    }

    message_flags.send_read(messages);

    _.each(messages, function (message) {
        if (current_msg_list === message_list.narrowed) {
            unread.messages_read_in_narrow = true;
        }

        unread.mark_as_read(message.id);
        process_newly_read_message(message, options);
    });

    unread_ui.update_unread_counts();
};

exports.mark_message_as_read = function (message, options) {
    exports.mark_messages_as_read([message], options);
};

// If we ever materially change the algorithm for this function, we
// may need to update notifications.received_messages as well.
exports.process_visible = function () {
    if (! notifications.window_has_focus()) {
        return;
    }

    if (feature_flags.mark_read_at_bottom) {
        if (message_viewport.bottom_message_visible()) {
            exports.mark_current_list_as_read();
        }
    } else {
        exports.mark_messages_as_read(message_viewport.visible_messages(true));
    }
};

exports.mark_current_list_as_read = function (options) {
    exports.mark_messages_as_read(current_msg_list.all_messages(), options);
};

exports.mark_stream_as_read = function (stream_id, cont) {
    channel.post({
        url:      '/json/mark_stream_as_read',
        idempotent: true,
        data:     {stream_id: stream_id},
        success:  cont});
};

exports.mark_topic_as_read = function (stream_id, topic, cont) {
    channel.post({
    url:      '/json/mark_topic_as_read',
    idempotent: true,
    data:     {stream_id: stream_id, topic_name: topic},
    success:  cont});
};


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