/*
* Copyright (C) 1998-2017 by Northwoods Software Corporation
* All Rights Reserved.
*
* Go Local Storage
*/

import * as go from "../../release/go";
import * as gcs from "./GoCloudStorage";
import {Promise} from "es6-promise";

/**
 * <p>Class for saving / loading <a href="http://gojs.net/latest/api/symbols/Diagram.html">Diagram</a> <a href="http://gojs.net/latest/api/symbols/Model.html">models</a> 
 * to / from Local Storage. GoLocalStorage is the only {@link GoCloudStorage} subclass than can be used in a local page; that is, one not served by a web server.</p> 
 * <p><b>Note</b>: that this class will not work with browsers that do not have Local Storage support (like some old versions of Internet Explorer).</p>
 * @category Storage
 */
export class GoLocalStorage extends gcs.GoCloudStorage {
    
    private _localStorage: Storage;
    /** 
     * The number of files to display in {@link ui} before loading more
     */
    private static _MIN_FILES_IN_UI = 100; 

    /**
     * @constructor
     * @param {go.Diagram|go.Diagram[]} managedDiagrams An array of GoJS <a href="http://gojs.net/latest/api/symbols/Diagram.html">Diagrams</a> whose model(s) will be saved to
     * / loaded from Local Storage. Can also be a single Diagram. 
     * @param {string} defaultModel String representation of the default model data for new diagrams. If this is null, default new
     * diagrams will be empty. Usually a value given by calling <a href="https://gojs.net/latest/api/symbols/Model.html#toJson">.toJson()</a> on a GoJS Diagram's Model. 
     * @param {string} iconsRelativeDirectory The directory path relative to the page in which this instance of GoLocalStorage exists, in which
     * the storage service brand icons can be found. The default value is "../goCloudStorageIcons/".
     */
    constructor(managedDiagrams: go.Diagram|go.Diagram[], defaultModel?: string, iconsRelativeDirectory?: string) {
        super(managedDiagrams, defaultModel);
        this._localStorage = window.localStorage;
        this.ui.id = "goLocalStorageCustomFilepicker";
        this._serviceName = "Local Storage";
    }

    /**
     * Get the browser window's <a href="https://developer.mozilla.org/en-US/docs/Web/API/Window/localStorage">Local Storage</a> property.
     * @function.
     * @return {Storage}
     */
    get localStorage(): Storage { return this._localStorage }

    /**
     * Check if Local Storage is supported by the current browser. 
     * @param {boolean} refreshToken This parameter can be ignored. It exists only to maintain GoCloudStorage system structure
     * @return {Promise<boolean>} Returns a Promise that resolves with a boolean (true if local storage is supported, false if not)
     */
    public authorize(refreshToken: boolean = false) {
        const storage = this;
        return new Promise(function(resolve: Function, reject: Function){
            try {
                storage.localStorage.setItem('item', 'item');
                storage.localStorage.removeItem('item');
                resolve(true);
            } catch (e) {
                // local storage not supported
                resolve(false);
            }
        });
    }

    /**
     * Show the custom Go Local Storage filepicker {@link ui}. 
     * @param {string} action Clarify what action is being done after file selection. Must be one of the following:
     * <ul>
     *  <li>New</li>
     *  <li>Open</li>
     *  <li>Save</li>
     *  <li>Delete</li>
     * </ul>
     * @param {number} numAdditionalFiles Optional: Number of files to show in UI, in addition to a static numerical property (that can only be 
     * modified by changing source code). This prevents long wait times while the UI loads if there are a large number of diagram files stored in Local Storage.
     * @return {Promise<any>} Returns a Promise that resolves (in {@link save}, {@link load}, or {@link remove} with an {@link DiagramFile} 
     * representing the saved/loaded/deleted file
     */
    public showUI(action: string, numAdditionalFiles?: number) {
        const storage = this;
        const ui = storage.ui;
        const spacestring = "qwe45qw34"; // used as a placeholder for spaces in IDs
        if (!numAdditionalFiles) numAdditionalFiles = 0;
        let maxFilesToShow: number = GoLocalStorage._MIN_FILES_IN_UI + numAdditionalFiles;
        ui.innerHTML = "<img class='icons' src='" + storage.iconsRelativeDirectory + "localStorage.png'></img>";
        let title: string = action + " Diagram File";
        ui.innerHTML += "<strong>" + title + "</strong><hr></hr>";

        document.getElementsByTagName('body')[0].appendChild(ui);
        ui.style.visibility = 'visible';
        const filesDiv = document.createElement('div');
        filesDiv.id = 'fileOptions';

        // filter out non-diagram files in local storage (only until max allowed files is reached)
        let savedDiagrams: Object[] = [];
        let numFilesToCheck: number = GoLocalStorage._MIN_FILES_IN_UI + numAdditionalFiles;
        let numFilesChecked: number = 0;
        let hasCheckedAllFiles: boolean = false;
        if (storage.localStorage.length !== 0) {
            for (let key in storage.localStorage) {
                if (savedDiagrams.length < maxFilesToShow) {
                    numFilesChecked++;
                    let fileContent: string = storage.localStorage.getItem(key);
                    if (fileContent && fileContent.indexOf("GraphLinksModel" || "TreeModel") !== -1) {
                        let file: Object = { key: key, model: fileContent };
                        savedDiagrams.push(file);
                    }
                    if (numFilesChecked === storage.localStorage.length) hasCheckedAllFiles = true;
                }
            }
        } else hasCheckedAllFiles = true;
        if (savedDiagrams.length !== 0) {
            // list diagram files in local storage as selectable files (as many as MIN_FILES_IN_UI + additionalFiles param)
            for (let i = 0; i < savedDiagrams.length; i++) {
                let kvp: Object = savedDiagrams[i];
                let file: string = kvp['key'];
                let fileId: string = file.replace(/ /g, spacestring);
                if (action !== 'Save') {
                    filesDiv.innerHTML +=
                        "<div class='fileOption'>" +
                            "<input id=" + fileId + " type='radio' name='localStorageFile' />" +
                            "<label id =" + fileId + "-label" + " for='" + fileId + "'>" + file + "</label>" +
                        "</div>";
                } else {
                    filesDiv.innerHTML +=
                        "<div class='fileOption'>" +
                            "<label id =" + fileId + "-label" + " for='" + fileId + "'>" + file + "</label>" +
                        "</div>";
                }
            }
        }

        // If there may be more diagram files to show, say so and provide user with option to try loading more in the UI
        if (!hasCheckedAllFiles) {
            let num: number = numAdditionalFiles + 50;
            filesDiv.innerHTML += "<p>There may be more diagram files not shown. <a id='localStorageLoadMoreFiles'>Click here</a> to try loading more.</p>"
            document.getElementById("localStorageLoadMoreFiles").onclick = function () {
                storage.showUI(action, num);
            }
        }
        ui.appendChild(filesDiv);

        // italicize currently open file, if a file is currently open
        if (storage.currentDiagramFile.id) {
            let string: string = storage.currentDiagramFile.id.replace(/ /g, spacestring);
            let el: HTMLElement = document.getElementById(string + '-label');
            if (el) el.style.fontStyle = "italic";
        }

        // user input div (only for save)
        if (action === 'Save') {
            const userInputDiv = document.createElement('div');
            userInputDiv.id = 'userInputDiv';
            userInputDiv.innerHTML += '<span>Save Diagram As </span><input id="userInput" placeholder="Enter filename"></input>';
            ui.appendChild(userInputDiv);
        }

        const submitDiv = document.createElement('div');
        submitDiv.id = "submitDiv";
        const actionButton = document.createElement('button');
        actionButton.textContent = action;
        actionButton.id = 'actionButton';
        actionButton.onclick = function () {
            storage.processUIResult(action);
        }
        submitDiv.appendChild(actionButton);
        ui.appendChild(submitDiv);


        const cancelDiv = document.createElement('div');
        const cancelButton = document.createElement('button');
        cancelButton.id = 'cancelButton';
        cancelButton.textContent = 'Cancel';
        cancelButton.onclick = function () {
            storage.hideUI(true);
        }
        cancelDiv.appendChild(cancelButton);
        ui.appendChild(cancelDiv);

        return storage._deferredPromise['promise']; // will not resolve until action (save, load, delete) completes 
    }

    /**
     * @private
     * @hidden
     * Process the result of pressing the action button on the custom GoLocalStorage filepicker {@link ui}. 
     * @param {string} action The action being done. Acceptable values: 
     * <ul>
     *  <li>Save</li>
     *  <li>Load</li>
     *  <li>Delete</li>
     * </ul>
     */
    public processUIResult(action: string) {
        const storage = this;
        // Helper: Return key of the file selected from the custom localstorage filepicker menu
        function getSelectedFile() {
            const radios = document.getElementsByName('localStorageFile');
            let selectedFile: string = null;
            for (let i = 0; i < radios.length; i++) {
                if ((<HTMLInputElement>radios[i]).checked) {
                    selectedFile = radios[i].id.replace(/qwe45qw34/g, ' ');
                }
            }
            if (selectedFile) return selectedFile;
            else return null;
        }

        let file: string = getSelectedFile();
        switch (action) {
            case 'Save': {
                var name = (<HTMLInputElement>document.getElementById('userInput')).value;
                if (name) {
                    name += '.diagram';
                    storage.save(name);
                } else {
                    // handle bad name
                }
                break;
            }
            case 'Load': {
                storage.load(file);
                break;
            }
            case 'Delete': {
                storage.remove(file);
                break;
            }
        }
        storage.hideUI();
    }

    /**
     * <p>Get information about a diagram file saved to local storage. This data includes:</p>
     * <ul>
     *  <li>content: The content of the saved file (a string respresentation of a GoJS Diagram Model)</li>
     *  <li>id: The key of the file in local storage</li>
     *  <li>name: Same as id value</li>
     *  <li>path: Same as id value</li> 
     * <ul>
     * <p><b>Note:</b> Id, name, and path are all provided (despite being the same). They are requisite for creating valid {@link DiagramFile}s. </p>
     * @param {string} path A valid key corresponding to a saved diagram file in Local Storage
     * @return {Promise<any>} Returns a Promise that resolves with information about a diagram file saved to local storage
     */
    public getFile(path: string) {
        if (path.indexOf('.diagram') === -1) path += '.diagram';
            return new Promise(function (resolve, reject) {
                let fileContent: string = (!!window.localStorage.getItem(path)) ? window.localStorage.getItem(path) : null;
                let file: Object = { name: path, content: fileContent, path: path, id: path };
                resolve(file);
            });
    }

    /**
     * Check whether a file exists in LocalStorage at a given path.
     * @param {string} path A valid key corresponding to a saved diagram file in Local Storage
     * @return {Promise<any>} Returns a Promise that resolves with a boolean stating whether a file exists in LocalStorage at a given path
     */
    public checkFileExists(path: string) {
        if (path.indexOf('.diagram') === -1) path += '.diagram';
        return new Promise(function (resolve, reject) {
            let fileExists: boolean = !!(window.localStorage.getItem(path));
            resolve(fileExists);
        });
    }

    /**
     * Save the current {@link managedDiagrams}'s model data to Local Storage using the custom filepicker {@link ui}. 
     * @return {Promise<any>} Returns a Promise that resolves with a {@link DiagramFile} representing the saved file
     */
    public saveWithUI() {
        const storage = this;
        return new Promise(function (resolve: Function, reject: Function) {
            resolve(storage.showUI('Save'));
        });
    }

    /**
     * Save {@link managedDiagrams}' model data to Local Storage. If path is supplied save to that path. If no path is supplied but {@link currentDiagramFile} has non-null,
     * valid properties, update saved diagram file content at the key in Local Storage corresponding to currentDiagramFile.path with current managedDiagrams' model data. 
     * If no path is supplied and currentDiagramFile is null or has null properties, this calls {@link saveWithUI}.
     * @param {string} path A string to save diagram model data to (becomes the key for the file in Local Storage)
     * @return {Promise<any>} Returns a Promise that resolves with a {@link DiagramFile} representing the saved file
     */
    public save(path?: string) {
        const storage = this;
        return new Promise(function (resolve: Function, reject: Function) {
            if (path) {
                if (path.indexOf('.diagram') === -1) path += '.diagram';
                let item: string = storage.makeSaveFile();
                storage.localStorage.setItem(path, item);
                let savedFile: gcs.DiagramFile = { name: path, id: path, path: path };
                storage.currentDiagramFile = savedFile;
                resolve(savedFile); // used if saveDiagramAs was called without UI

                // if saveDiagramAs has been called in processUIResult, need to resolve / reset the Deferred Promise instance variable
                storage._deferredPromise['promise'].resolve(savedFile);
                storage._deferredPromise['promise'] = storage.makeDeferredPromise();
            } else if (storage.currentDiagramFile.path) {
                let saveName: string = storage.currentDiagramFile['path'];
                let savedFile: gcs.DiagramFile = { name: saveName, path: saveName, id: saveName };
                let item: string = storage.makeSaveFile();
                storage.localStorage.setItem(saveName, item);
                resolve(saveName);
            } else {
                resolve(storage.saveWithUI());
            }
        });
    }

    /**
     * Get the contents of a given file; load to {@link managedDiagrams} model. Use the custom filepicker {@link ui}. 
     * @return {Promise<any>} Returns a Promise that resolves with a {@link DiagramFile} representing the loaded file
     */
    public loadWithUI() {
        const storage = this;
        return new Promise(function (resolve: Function, reject: Function) {
            resolve(storage.showUI('Load'));
        }).catch(function(e: any){
            throw Error(e);
        });
    }

    /**
     * Get the contents of a given file; load to {@link managedDiagrams} model. 
     * @param {string} path A valid localstorage key to load diagram model data from
     * @return {Promise<any>} Returns a Promise that resolves with a {@link DiagramFile} representing the loaded file
     */
    public load(path: string) {
        const storage = this;
        return new Promise(function (resolve: Function, reject: Function) {
            if (path) {
                let fileContents: string = storage.localStorage.getItem(path);
                if (fileContents) {
                    storage.loadFromFileContents(fileContents);
                    let loadedFile: gcs.DiagramFile = { name: path, id: path, path: path };
                    storage.currentDiagramFile = loadedFile;
                    resolve(loadedFile); // used if loadDiagram was called without UI

                    // if loadDiagram has been called in processUIResult, need to resolve / reset the Deferred Promise instance variable
                    storage._deferredPromise.promise.resolve(loadedFile);
                    storage._deferredPromise.promise = storage.makeDeferredPromise();
                } else throw Error('Cannot load file from local storage with path ' + path);
            } else throw Error('Cannot load file from local storage with path ' + path);
        }).catch(function(e: any) {
            //console.error(e);
            throw Error(e);
        });
    }

    /**
     * Delete a diagram from Local Storage using the custom filepicker menu {@link ui}. 
     * @return {Promise<any>} Returns a Promise that resolves with a {@link DiagramFile} representing the deleted file
     */
    public removeWithUI() {
        const storage = this;
        return new Promise(function (resolve: Function, reject: Function) {
            resolve(storage.showUI('Delete'));
        });
    }

    /**
     * Delete a given diagram from Local Storage. 
     * @param {string} path A valid localstorage key to delete diagram model data from
     * @return {Promise<any>} Returns a Promise that resolves with a {@link DiagramFile} representing the deleted file
     */
    public remove(path: string) {
        const storage = this;
        return new Promise(function (resolve: Function, reject: Function) {
            if (path) {
                let deletedFile: gcs.DiagramFile = { name: path, path: path, id: path };
                if (storage.currentDiagramFile && path === storage.currentDiagramFile['name']) storage.currentDiagramFile = {name: null, path: null, id: null};
                storage.localStorage.removeItem(path); // remove file from local storage
                resolve(deletedFile); // used if deleteDiagram was called without UI

                // if deleteDiagram has been called in processUIResult, need to resolve / reset the Deferred Promise instance variable
                storage._deferredPromise['promise'].resolve(deletedFile);
                storage._deferredPromise['promise'] = storage.makeDeferredPromise();
            } else throw Error('Cannot delete file from local storage with path ' + path);
        });
    }
}