'use strict';

(function (root) {
    function getBluememeUtils() {
        var cordovaPlugin = root.cordova
            && root.cordova.plugins
            && root.cordova.plugins.bluememeUtils;
        var plugin = root.BluememeUtils || cordovaPlugin;

        if (!plugin) {
            throw new Error('BluememeUtils is not available. Run this flow after deviceready.');
        }
        return plugin;
    }

    function toPromise(work) {
        return new Promise(function (resolve, reject) {
            work(resolve, reject);
        });
    }

    function call(methodName) {
        var args = Array.prototype.slice.call(arguments, 1);

        return toPromise(function (resolve, reject) {
            var plugin = getBluememeUtils();
            plugin[methodName].apply(plugin, args.concat(resolve, reject));
        });
    }

    function isPushPermissionGranted(permission) {
        return !!permission && (permission.enabled === true || permission.granted === true);
    }

    function permissionRequiredError(permission) {
        return {
            code: 'PERMISSION_REQUIRED',
            message: 'Notification permission is required before Firebase messaging setup.',
            permission: permission || null
        };
    }

    function ensurePushPermission() {
        return call('getPushPermissionStatus').then(function (status) {
            if (isPushPermissionGranted(status)) {
                return status;
            }

            return call('requestPushPermission').then(function () {
                return call('getPushPermissionStatus');
            }).then(function (updatedStatus) {
                if (isPushPermissionGranted(updatedStatus)) {
                    return updatedStatus;
                }
                throw permissionRequiredError(updatedStatus);
            });
        });
    }

    function subscribeTopics(topics) {
        return (topics || []).reduce(function (chain, topic) {
            return chain.then(function (results) {
                return call('subscribeToTopic', topic).then(function () {
                    results.push(topic);
                    return results;
                });
            });
        }, Promise.resolve([]));
    }

    function startListener(onNotificationEvent, onError) {
        if (typeof onNotificationEvent !== 'function') {
            return;
        }

        getBluememeUtils().startNotificationListener(onNotificationEvent, onError);
    }

    function setupFirebaseMessaging(options, success, error) {
        options = options || {};

        var flow = ensurePushPermission()
            .then(function (permission) {
                startListener(options.onNotificationEvent, error || options.onError);
                return call('getFirebaseToken').then(function (tokenResult) {
                    return {
                        permission: permission,
                        token: tokenResult && tokenResult.token,
                        tokenResult: tokenResult
                    };
                });
            })
            .then(function (context) {
                return subscribeTopics(options.topics).then(function (topics) {
                    context.topics = topics;
                    return context;
                });
            })
            .then(function (context) {
                return call('getInitialNotification').then(function (initialNotification) {
                    context.initialNotification = initialNotification || null;
                    return context;
                });
            });

        if (typeof success === 'function' || typeof error === 'function') {
            flow.then(success, error);
        }

        return flow;
    }

    root.BluememePushFlow = {
        ensurePushPermission: ensurePushPermission,
        isPushPermissionGranted: isPushPermissionGranted,
        setupFirebaseMessaging: setupFirebaseMessaging
    };
})(window);