import { OHIF } from 'meteor/ohif:core';

class ObjectPath {

    /**
     * Set an object property based on "path" (namespace) supplied creating
     * ... intermediary objects if they do not exist.
     * @param object {Object} An object where the properties specified on path should be set.
     * @param path {String} A string representing the property to be set, e.g. "user.study.series.timepoint".
     * @param value {Any} The value of the property that will be set.
     * @return {Boolean} Returns "true" on success, "false" if any intermediate component of the supplied path
     * ... is not a valid Object, in which case the property cannot be set. No excpetions are thrown.
     */
    static set(object, path, value) {

        let components = ObjectPath.getPathComponents(path),
            length = components !== null ? components.length : 0,
            result = false;

        if (length > 0 && ObjectPath.isValidObject(object)) {

            let i = 0,
                last = length - 1,
                currentObject = object;

            while (i < last) {

                let field = components[i];

                if (field in currentObject) {
                    if (!ObjectPath.isValidObject(currentObject[field])) {
                        break;
                    }
                } else {
                    currentObject[field] = {};
                }

                currentObject = currentObject[field];
                i++;

            }

            if (i === last) {
                currentObject[components[last]] = value;
                result = true;
            }

        }

        return result;

    }

    /**
     * Get an object property based on "path" (namespace) supplied traversing the object
     * ... tree as necessary.
     * @param object {Object} An object where the properties specified might exist.
     * @param path {String} A string representing the property to be searched for, e.g. "user.study.series.timepoint".
     * @return {Any} The value of the property if found. By default, returns the special type "undefined".
     */
    static get(object, path) {

        let found, // undefined by default
            components = ObjectPath.getPathComponents(path),
            length = components !== null ? components.length : 0;

        if (length > 0 && ObjectPath.isValidObject(object)) {

            let i = 0,
                last = length - 1,
                currentObject = object;

            while (i < last) {

                let field = components[i];

                const isValid = ObjectPath.isValidObject(currentObject[field]);
                if (field in currentObject && isValid) {
                    currentObject = currentObject[field];
                    i++;
                } else {
                    break;
                }

            }

            if (i === last && components[last] in currentObject) {
                found = currentObject[components[last]];
            }

        }

        return found;

    }

    /**
     * Check if the supplied argument is a real JavaScript Object instance.
     * @param object {Any} The subject to be tested.
     * @return {Boolean} Returns "true" if the object is a real Object instance and "false" otherwise.
     */
    static isValidObject(object) {
        return (
            typeof object === 'object' &&
            object !== null &&
            object instanceof Object
        );
    }

    static getPathComponents(path) {
        return (typeof path === 'string' ? path.split('.') : null);
    }

}

OHIF.utils.ObjectPath = ObjectPath;