/*
* Copyright (C) 1998-2023 by Northwoods Software Corporation
* All Rights Reserved.
*
* Go Local Storage
*/

import * as go from '../../release/go';
import * as gcs from './GoCloudStorage.js';

/**
 * Class for saving / loading GoJS {@link Model}s 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.
 *
 * **Note**: This class will not work with browsers that do not have Local Storage support
 * (like some old versions of Internet Explorer).
 * @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 {@link Diagram}s 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 {@link Model#toJson} 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 | Array<go.Diagram>, defaultModel?: string, iconsRelativeDirectory?: string) {
        super(managedDiagrams, defaultModel, null, iconsRelativeDirectory);
        try {
            this._localStorage = window.localStorage;
        } catch (e) {
            throw new Error('Cannot access localStorage. Make sure your browser supports localStorage.' +
                'If so, and this issue persists, try unblocking third-party cookies and site data in your browser settings');
        }
        this.ui.id = 'goLocalStorageCustomFilepicker';
        this._serviceName = 'Local Storage';
        this._className = 'GoLocalStorage';
    }

    /**
     * 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): Promise<any> {
        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:
     *   - New
     *   - Open
     *   - Save
     *   - Delete
     * @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;
        const maxFilesToShow: number = GoLocalStorage._MIN_FILES_IN_UI + numAdditionalFiles;
        ui.innerHTML = "<img class='icons' src='" + storage.iconsRelativeDirectory + "localStorage.png'></img>";
        const 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)
        const savedDiagrams: Array<Object> = [];
        const numFilesToCheck: number = GoLocalStorage._MIN_FILES_IN_UI + numAdditionalFiles;
        let numFilesChecked: number = 0;
        let hasCheckedAllFiles: boolean = false;
        if (storage.localStorage.length !== 0) {
            for (const key in storage.localStorage) {
                if (savedDiagrams.length < maxFilesToShow) {
                    numFilesChecked++;
                    const fileContent: string = storage.localStorage.getItem(key);
                    if (fileContent && (fileContent.indexOf('GraphLinksModel') !== -1 || fileContent.indexOf('TreeModel') !== -1)) {
                        const 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++) {
                const kvp: Object = savedDiagrams[i];
                const file: string = kvp['key'];
                const 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) {
            const 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) {
            const str: string = storage.currentDiagramFile.id.replace(/ /g, spacestring);
            const el: HTMLElement = document.getElementById(str + '-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:
     *   - Save
     *   - Load
     *   - Delete
     */
    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 ((radios[i] as HTMLInputElement).checked) {
                    selectedFile = radios[i].id.replace(/qwe45qw34/g, ' ');
                }
            }
            if (selectedFile) return selectedFile;
            else return null;
        }

        const file: string = getSelectedFile();
        switch (action) {
            case 'Save': {
                let name = (document.getElementById('userInput') as HTMLInputElement).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();
    }

    /**
     * Get information about a diagram file saved to Local Storage. This data includes:
     *   - content: The content of the saved file (a string respresentation of a GoJS Diagram Model)
     *   - id: The key of the file in local storage
     *   - name: Same as id value
     *   - path: Same as id value
     *
     * **Note:** Id, name, and path are all provided (despite being the same). They are required for creating valid {@link DiagramFile}s.
     * @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) {
            const fileContent: string = (!!window.localStorage.getItem(path)) ? window.localStorage.getItem(path) : null;
            const file: Object = { name: path, content: fileContent, path: path, id: path };
            resolve(file);
        });
    }

    /**
     * Check whether a file exists in Local Storage 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) {
            const 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';
                const item: string = storage.makeSaveFile();
                storage.localStorage.setItem(path, item);
                const 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) {
                const saveName: string = storage.currentDiagramFile['path'];
                const savedFile: gcs.DiagramFile = { name: saveName, path: saveName, id: saveName };
                const 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) {
                const fileContents: string = storage.localStorage.getItem(path);
                if (fileContents) {
                    storage.loadFromFileContents(fileContents);
                    const 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) {
                const 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);
        });
    }
}