class Helpers {

    constructor() {
        console.log("helpers constructor");
        // List of valid ID characters for use in an instance.
        this.ValidIDChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
        // List of valid extensions for VWF components.
        this.template_extensions = ["", ".yaml", ".json"];
        this.applicationRoot = "/"; //app
    }


    async Process(updatedURL) {
        var result =
            { 'public_path': "/", 'application': undefined, 'instance': undefined, 'private_path': undefined };
        var segments = this.GenerateSegments(updatedURL);
        var extension = undefined;

        while ((segments.length > 0) && (await this.IsExist(this.JoinPath(result['public_path'], segments[0])))) {
            result['public_path'] = this.JoinPath(result['public_path'], segments.shift());
        }

        if ((segments.length > 0) && (extension = await this.GetExtension(this.JoinPath(result['public_path'], segments[0])))) {
            result['application'] = segments.shift();
        } else if (extension = await this.GetExtension(this.JoinPath(result['public_path'], "index.vwf"))) {
            result['application'] = "index.vwf";
        }

        if (extension) {
            if ((segments.length > 0) && (this.IsInstanceID(segments[0]))) {
                result['instance'] = segments.shift();
            }
            if (segments.length > 0) {
                result['private_path'] = segments.join("/");
            }
        }

        return result;
    }

    // IsInstanceID tests if the passed in potential Instance ID 
    // is a valid instance id.
    IsInstanceID(potentialInstanceID) {
        if (potentialInstanceID.match(/^[0-9A-Za-z]{16}$/)) {
            return true;
        }
        return false;
    }

    // GenerateInstanceID function creates a randomly generated instance ID.
    GenerateInstanceID() {
        var text = "";

        for (var i = 0; i < 16; i++)
            text += this.ValidIDChars.charAt(Math.floor(Math.random() * this.ValidIDChars.length));

        return text;
    }

    // JoinPath
    // Takes multiple arguments, joins them together into one path.
    JoinPath( /* arguments */) {
        var result = "";
        if (arguments.length > 0) {
            if (arguments[0]) {
                result = arguments[0];
            }
            for (var index = 1; index < arguments.length; index++) {
                var newSegment = arguments[index];
                if (newSegment == undefined) {
                    newSegment = "";
                }

                if ((newSegment[0] == "/") && (result[result.length - 1] == "/")) {
                    result = result + newSegment.slice(1);
                } else if ((newSegment[0] == "/") || (result[result.length - 1] == "/")) {
                    result = result + newSegment;
                } else {
                    result = result + "/" + newSegment;
                }
                //result = libpath.join( result, newSegment );
            }
        }
        return result;
    }

    async IsFileExist(path) {

        var seperatorFixedPath = path.slice(1);//path.replace(/\//g, '/');
        let worldName = seperatorFixedPath.split('/')[0];
        let fileName = seperatorFixedPath.replace(worldName + '/', "");
        let doc = await _LCS_WORLD_USER.get('worlds').get(worldName).get(fileName).once().then();
        if (doc) {
            return true
        }
        return false
    }

    async IsExist(path) {

        var seperatorFixedPath = path.slice(1);//path.replace(/\//g, '/');
        let doc = await _LCS_WORLD_USER.get('worlds').get(seperatorFixedPath).once().then();
        if (doc) {
            return true
        }
        return false
    }


    // GenerateSegments takes a string, breaks it into
    // '/' separated segments, and removes potential
    // blank first and last segments. 
    GenerateSegments(argument) {
        var result = argument.split("/");
        if (result.length > 0) {
            if (result[0] == "") {
                result.shift();
            }
        }
        if (result.length > 0) {
            if (result[result.length - 1] == "") {
                result.pop();
            }
        }
        return result;
    }

    async GetExtension(path) {

        if (path.match(/\.vwf$/)) {

            for (const res of this.template_extensions) {
                let check = await this.IsFileExist(this.JoinPath(path + res).split(".").join("_"));
                if (check) return res
            }
        }

        return undefined;
    }

    get appPath() {
        return JSON.parse(localStorage.getItem('lcs_app')).path.public_path.slice(1)
    }

    get worldStateName() {

        let appConfig = JSON.parse(localStorage.getItem('lcs_app'));

        var saveName = appConfig.path.public_path.slice(1);
        let privatePath = appConfig.path.private_path;
        if (privatePath) {
            if (privatePath.indexOf('load') !== -1) {
                saveName = privatePath.split('/')[1];
            }
        }

        return saveName

    }

    getRoot(noUser) {
        var app = window.location.pathname;
        var pathSplit = app.split('/');
        if (pathSplit[0] == "") {
            pathSplit.shift();
        }
        if (pathSplit[pathSplit.length - 1] == "") {
            pathSplit.pop();
        }
        var inst = undefined;
        var instIndex = pathSplit.length - 1;
        if (pathSplit.length > 2) {
            if (pathSplit[pathSplit.length - 2] == "load") {
                instIndex = pathSplit.length - 3;
            }
        }
        if (pathSplit.length > 3) {
            if (pathSplit[pathSplit.length - 3] == "load") {
                instIndex = pathSplit.length - 4;
            }
        }

        inst = pathSplit[instIndex];

        var root = "";
        for (var i = 0; i < instIndex; i++) {
            if (root != "") {
                root = root + "/";
            }
            root = root + pathSplit[i];
        }

        if (root.indexOf('.vwf') != -1) root = root.substring(0, root.lastIndexOf('/'));

        if (noUser) {
            return {
                "root": root.replace(pathSplit[0] + '/', ""),
                "inst": inst
            }
        } else {

            return {
                "root": root,
                "inst": inst
            }
        }

    }

    get worldUser() {
        return this.getRoot(false).root.split('/')[0];
    }


    randId() {
        return '_' + Math.random().toString(36).substr(2, 9);
    }

    getRandomInt(min, max) {
        min = Math.ceil(min);
        max = Math.floor(max);
        return Math.floor(Math.random() * (max - min)) + min; //The maximum is exclusive and the minimum is inclusive
    }


    GUID() {
        var S4 = function () {
            return Math.floor(
                Math.random() * 0x10000 /* 65536 */
            ).toString(16);
        };

        return (
            S4() + S4() + "-" +
            S4() + "-" +
            S4() + "-" +
            S4() + "-" +
            S4() + S4() + S4()
        );
    }

    async sha256(message) {

        // encode as UTF-8
        const msgBuffer = new TextEncoder('utf-8').encode(message);

        // hash the message
        const hashBuffer = await crypto.subtle.digest('SHA-256', msgBuffer);

        // convert ArrayBuffer to Array
        const hashArray = Array.from(new Uint8Array(hashBuffer));

        // convert bytes to hex string
        const hashHex = hashArray.map(b => ('00' + b.toString(16)).slice(-2)).join('');
        return hashHex;
    }

    replaceSubStringALL(target, search, replacement) {
        return target.split(search).join(replacement);
    };


    async getHtmlText(url) {

        let file = await fetch(url, { method: 'get' });
        let text = await file.text();
        return text
    }


    removeProps(obj) {
        Object.keys(obj).forEach(key =>
            (key === 'id' || key === 'patches' || key === 'random' || key === 'sequence') && delete obj[key] ||
            (obj[key] && typeof obj[key] === 'object') && this.removeProps(obj[key])
        );
        return obj;
    };

    getNodeDef(nodeID) {
        let node = vwf.getNode(nodeID, true);
        let nodeDefPure = this.removeProps(node);
        let nodeDef = this.removeGrammarObj(nodeDefPure);
        return nodeDef
    }

    removeGrammarObj(obj) {
        Object.keys(obj).forEach(key =>
            (key === 'grammar' || key === 'semantics') && delete obj[key] ||
            (obj[key] && typeof obj[key] === 'object') && this.removeGrammarObj(obj[key])
        );
        return obj;
    };


    httpGet(url) {
        return new Promise(function (resolve, reject) {
            // do the usual Http request
            let request = new XMLHttpRequest();
            request.open('GET', url);

            request.onload = function () {
                if (request.status == 200) {
                    resolve(request.response);
                } else {
                    reject(Error(request.statusText));
                }
            };

            request.onerror = function () {
                reject(Error('Network Error'));
            };

            request.send();
        });
    }

    async httpGetJson(url) {
        // check if the URL looks like a JSON file and call httpGet.
        let regex = /\.(json)$/i;

        if (regex.test(url)) {
            // call the async function, wait for the result
            return await this.httpGet(url);
        } else {
            throw Error('Bad Url Format');
        }
    }

}

export { Helpers }