/* * Copyright (C) 2023 Yomitan Authors * Copyright (C) 2020-2022 Yomichan Authors * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <https://www.gnu.org/licenses/>. */ import {EventDispatcher, generateId, isObject} from '../core.js'; /** * @augments EventDispatcher<import('display-history').EventType> */ export class DisplayHistory extends EventDispatcher { /** * @param {{clearable?: boolean, useBrowserHistory?: boolean}} details */ constructor({clearable=true, useBrowserHistory=false}) { super(); /** @type {boolean} */ this._clearable = clearable; /** @type {boolean} */ this._useBrowserHistory = useBrowserHistory; /** @type {Map<string, import('display-history').Entry>} */ this._historyMap = new Map(); const historyState = history.state; const {id, state} = isObject(historyState) ? historyState : {id: null, state: null}; /** @type {import('display-history').Entry} */ this._current = this._createHistoryEntry(id, location.href, state, null, null); } /** @type {?import('display-history').EntryState} */ get state() { return this._current.state; } /** @type {?import('display-history').EntryContent} */ get content() { return this._current.content; } /** @type {boolean} */ get useBrowserHistory() { return this._useBrowserHistory; } set useBrowserHistory(value) { this._useBrowserHistory = value; } /** @type {boolean} */ get clearable() { return this._clearable; } set clearable(value) { this._clearable = value; } /** */ prepare() { window.addEventListener('popstate', this._onPopState.bind(this), false); } /** * @returns {boolean} */ hasNext() { return this._current.next !== null; } /** * @returns {boolean} */ hasPrevious() { return this._current.previous !== null; } /** */ clear() { if (!this._clearable) { return; } this._clear(); } /** * @returns {boolean} */ back() { return this._go(false); } /** * @returns {boolean} */ forward() { return this._go(true); } /** * @param {?import('display-history').EntryState} state * @param {?import('display-history').EntryContent} content * @param {string} [url] */ pushState(state, content, url) { if (typeof url === 'undefined') { url = location.href; } const entry = this._createHistoryEntry(null, url, state, content, this._current); this._current.next = entry; this._current = entry; this._updateHistoryFromCurrent(!this._useBrowserHistory); } /** * @param {?import('display-history').EntryState} state * @param {?import('display-history').EntryContent} content * @param {string} [url] */ replaceState(state, content, url) { if (typeof url === 'undefined') { url = location.href; } this._current.url = url; this._current.state = state; this._current.content = content; this._updateHistoryFromCurrent(true); } /** */ _onPopState() { this._updateStateFromHistory(); this._triggerStateChanged(false); } /** * @param {boolean} forward * @returns {boolean} */ _go(forward) { if (this._useBrowserHistory) { if (forward) { history.forward(); } else { history.back(); } } else { const target = forward ? this._current.next : this._current.previous; if (target === null) { return false; } this._current = target; this._updateHistoryFromCurrent(true); } return true; } /** * @param {boolean} synthetic */ _triggerStateChanged(synthetic) { this.trigger('stateChanged', /** @type {import('display-history').StateChangedEvent} */ ({synthetic})); } /** * @param {boolean} replace */ _updateHistoryFromCurrent(replace) { const {id, state, url} = this._current; if (replace) { history.replaceState({id, state}, '', url); } else { history.pushState({id, state}, '', url); } this._triggerStateChanged(true); } /** */ _updateStateFromHistory() { let state = history.state; let id = null; if (isObject(state)) { id = state.id; if (typeof id === 'string') { const entry = this._historyMap.get(id); if (typeof entry !== 'undefined') { // Valid this._current = entry; return; } } // Partial state recovery state = state.state; } else { state = null; } // Fallback this._current.id = (typeof id === 'string' ? id : this._generateId()); this._current.state = state; this._current.content = null; this._clear(); } /** * @param {unknown} id * @param {string} url * @param {?import('display-history').EntryState} state * @param {?import('display-history').EntryContent} content * @param {?import('display-history').Entry} previous * @returns {import('display-history').Entry} */ _createHistoryEntry(id, url, state, content, previous) { /** @type {import('display-history').Entry} */ const entry = { id: typeof id === 'string' ? id : this._generateId(), url, next: null, previous, state, content }; this._historyMap.set(entry.id, entry); return entry; } /** * @returns {string} */ _generateId() { return generateId(16); } /** */ _clear() { this._historyMap.clear(); this._historyMap.set(this._current.id, this._current); this._current.next = null; this._current.previous = null; } }