var typing_events = (function () {
var exports = {};

// See docs/subsystems/typing-indicators.md for details on typing indicators.

// This code handles the inbound side of typing notifications.
// When another user is typing, we process the events here.
//
// We also handle the local event of re-narrowing.
// (For the outbound code, see typing.js.)

// How long before we assume a client has gone away
// and expire its typing status
var TYPING_STARTED_EXPIRY_PERIOD = 15000; // 15s

// Note!: There are also timing constants in typing_status.js
// that make typing indicators work.

function get_users_typing_for_narrow() {
    if (!narrow_state.narrowed_to_pms()) {
        // Narrow is neither pm-with nor is: private
        return [];
    }

    var first_term = narrow_state.operators()[0];
    if (first_term.operator === 'pm-with') {
        // Get list of users typing in this conversation
        var narrow_emails_string = first_term.operand;
        // TODO: Create people.emails_strings_to_user_ids.
        var narrow_user_ids_string = people.emails_strings_to_user_ids_string(narrow_emails_string);
        if (!narrow_user_ids_string) {
            blueslip.warn('Bad narrow for typing indicators: ' + narrow_emails_string);
            return [];
        }
        var narrow_user_ids = narrow_user_ids_string.split(',').map(function (user_id_string) {
            return parseInt(user_id_string, 10);
        });
        var group = narrow_user_ids.concat([page_params.user_id]);
        return typing_data.get_group_typists(group);
    }
    // Get all users typing (in all private conversations with current user)
    return typing_data.get_all_typists();
}

function render_notifications_for_narrow() {
    var user_ids = get_users_typing_for_narrow();
    var users_typing = user_ids.map(people.get_person_from_user_id);
    if (users_typing.length === 0) {
        $('#typing_notifications').hide();
    } else {
        $('#typing_notifications').html(templates.render('typing_notifications', {users: users_typing}));
        $('#typing_notifications').show();
    }
}

exports.hide_notification = function (event) {
    var recipients = event.recipients.map(function (user) {
        return user.user_id;
    });
    recipients.sort();

    typing_data.clear_inbound_timer(recipients);

    var removed = typing_data.remove_typist(recipients, event.sender.user_id);

    if (removed) {
        render_notifications_for_narrow();
    }
};

exports.display_notification = function (event) {
    var recipients = event.recipients.map(function (user) {
        return user.user_id;
    });
    recipients.sort();

    var sender_id = event.sender.user_id;
    event.sender.name = people.get_person_from_user_id(sender_id).full_name;

    typing_data.add_typist(recipients, sender_id);

    render_notifications_for_narrow();

    typing_data.kickstart_inbound_timer(
        recipients,
        TYPING_STARTED_EXPIRY_PERIOD,
        function () {
            exports.hide_notification(event);
        }
    );
};

$(document).on('narrow_activated.zulip', render_notifications_for_narrow);
$(document).on('narrow_deactivated.zulip', render_notifications_for_narrow);


return exports;
}());

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