1 files changed, 297 insertions, 0 deletions
diff --git a/ext/js/input/hotkey-util.js b/ext/js/input/hotkey-util.js
new file mode 100644
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+++ b/ext/js/input/hotkey-util.js
@@ -0,0 +1,297 @@
+/*
+ * Copyright (C) 2021  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 <http://www.gnu.org/licenses/>.
+ */
+
+/**
+ * Utility class to help display hotkeys and convert to/from commands.
+ */
+class HotkeyUtil {
+    /**
+     * Creates a new instance.
+     */
+    constructor(os=null) {
+        this._os = os;
+        this._inputSeparator = ' + ';
+        this._modifierKeyNames = new Map();
+        this._mouseInputNamePattern = /^mouse(\d+)$/;
+        this._modifierPriorities = new Map([
+            ['meta', -4],
+            ['ctrl', -3],
+            ['alt', -2],
+            ['shift', -1]
+        ]);
+        this._stringComparer = new Intl.Collator('en-US'); // Invariant locale
+
+        this._updateModifierKeyNames();
+    }
+
+    /**
+     * Gets the operating system for this instance.
+     * The operating system is used to display system-localized modifier key names.
+     */
+    get os() {
+        return this._os;
+    }
+
+    /**
+     * Sets the operating system for this instance.
+     * @param value The value to assign.
+     *   Valid values are: win, mac, linux, openbsd, cros, android.
+     */
+    set os(value) {
+        if (this._os === value) { return; }
+        this._os = value;
+        this._updateModifierKeyNames();
+    }
+
+    /**
+     * Gets a display string for a key and a set of modifiers.
+     * @param key The key code string, or `null` for no key.
+     * @param modifiers An array of modifiers.
+     *   Valid values are: ctrl, alt, shift, meta, or mouseN, where N is an integer.
+     * @returns A user-friendly string for the combination of key and modifiers.
+     */
+    getInputDisplayValue(key, modifiers) {
+        const separator = this._inputSeparator;
+        let displayValue = '';
+        let first = true;
+        for (const modifier of modifiers) {
+            if (first) {
+                first = false;
+            } else {
+                displayValue += separator;
+            }
+            displayValue += this.getModifierDisplayValue(modifier);
+        }
+        if (typeof key === 'string') {
+            if (!first) { displayValue += separator; }
+            displayValue += this.getKeyDisplayValue(key);
+        }
+        return displayValue;
+    }
+
+    /**
+     * Gets a display string for a single modifier.
+     * @param modifier A string representing a modifier.
+     *   Valid values are: ctrl, alt, shift, meta, or mouseN, where N is an integer.
+     * @returns A user-friendly string for the modifier.
+     */
+    getModifierDisplayValue(modifier) {
+        const match = this._mouseInputNamePattern.exec(modifier);
+        if (match !== null) {
+            return `Mouse ${match[1]}`;
+        }
+
+        const name = this._modifierKeyNames.get(modifier);
+        return (typeof name !== 'undefined' ? name : modifier);
+    }
+
+    /**
+     * Gets a display string for a key.
+     * @param key The key code string, or `null` for no key.
+     * @returns A user-friendly string for the combination of key and modifiers, or `null` if key was already `null`.
+     */
+    getKeyDisplayValue(key) {
+        if (typeof key === 'string' && key.length === 4 && key.startsWith('Key')) {
+            key = key.substring(3);
+        }
+        return key;
+    }
+
+    /**
+     * Gets a display string for a single modifier.
+     * @param modifier A string representing a modifier.
+     *   Valid values are: ctrl, alt, shift, meta, or mouseN, where N is an integer.
+     * @returns `'mouse'` if the modifier represents a mouse button, `'key'` otherwise.
+     */
+    getModifierType(modifier) {
+        return (this._mouseInputNamePattern.test(modifier) ? 'mouse' : 'key');
+    }
+
+    /**
+     * Converts an extension command string into a standard input.
+     * @param command An extension command string.
+     * @returns An object `{key, modifiers}`, where key is a string (or `null`) representing the key, and modifiers is an array of modifier keys.
+     */
+    convertCommandToInput(command) {
+        let key = null;
+        const modifiers = new Set();
+        if (typeof command === 'string' && command.length > 0) {
+            const parts = command.split('+');
+            const ii = parts.length - 1;
+            key = this._convertCommandKeyToInputKey(parts[ii]);
+            for (let i = 0; i < ii; ++i) {
+                modifiers.add(this._convertCommandModifierToInputModifier(parts[i]));
+            }
+        }
+        return {key, modifiers: this.sortModifiers([...modifiers])};
+    }
+
+    /**
+     * Gets a command string for a specified input.
+     * @param key The key code string, or `null` for no key.
+     * @param modifiers An array of modifier keys.
+     *   Valid values are: ctrl, alt, shift, meta.
+     * @returns An extension command string representing the input.
+     */
+    convertInputToCommand(key, modifiers) {
+        const separator = '+';
+        let command = '';
+        let first = true;
+        for (const modifier of modifiers) {
+            if (first) {
+                first = false;
+            } else {
+                command += separator;
+            }
+            command += this._convertInputModifierToCommandModifier(modifier);
+        }
+        if (typeof key === 'string') {
+            if (!first) { command += separator; }
+            command += this._convertInputKeyToCommandKey(key);
+        }
+        return command;
+    }
+
+    /**
+     * Sorts an array of modifiers.
+     * @param modifiers An array of modifiers.
+     *   Valid values are: ctrl, alt, shift, meta.
+     * @returns A sorted array of modifiers. The array instance is the same as the input array.
+     */
+    sortModifiers(modifiers) {
+        const pattern = this._mouseInputNamePattern;
+        const keyPriorities = this._modifierPriorities;
+        const stringComparer = this._stringComparer;
+
+        const count = modifiers.length;
+        const modifierInfos = [];
+        for (let i = 0; i < count; ++i) {
+            const modifier = modifiers[i];
+            const match = pattern.exec(modifier);
+            let info;
+            if (match !== null) {
+                info = [modifier, 1, Number.parseInt(match[1], 10), i];
+            } else {
+                let priority = keyPriorities.get(modifier);
+                if (typeof priority === 'undefined') { priority = 0; }
+                info = [modifier, 0, priority, i];
+            }
+            modifierInfos.push(info);
+        }
+
+        modifierInfos.sort((a, b) => {
+            let i = a[1] - b[1];
+            if (i !== 0) { return i; }
+
+            i = a[2] - b[2];
+            if (i !== 0) { return i; }
+
+            i = stringComparer.compare(a[0], b[0]);
+            if (i !== 0) { return i; }
+
+            i = a[3] - b[3];
+            return i;
+        });
+
+        for (let i = 0; i < count; ++i) {
+            modifiers[i] = modifierInfos[i][0];
+        }
+
+        return modifiers;
+    }
+
+    // Private
+
+    _getModifierKeyNames(os) {
+        switch (os) {
+            case 'win':
+                return [
+                    ['alt', 'Alt'],
+                    ['ctrl', 'Ctrl'],
+                    ['shift', 'Shift'],
+                    ['meta', 'Windows']
+                ];
+            case 'mac':
+                return [
+                    ['alt', 'Opt'],
+                    ['ctrl', 'Ctrl'],
+                    ['shift', 'Shift'],
+                    ['meta', 'Cmd']
+                ];
+            case 'linux':
+            case 'openbsd':
+            case 'cros':
+            case 'android':
+                return [
+                    ['alt', 'Alt'],
+                    ['ctrl', 'Ctrl'],
+                    ['shift', 'Shift'],
+                    ['meta', 'Super']
+                ];
+            default: // 'unknown', etc
+                return [
+                    ['alt', 'Alt'],
+                    ['ctrl', 'Ctrl'],
+                    ['shift', 'Shift'],
+                    ['meta', 'Meta']
+                ];
+        }
+    }
+
+    _updateModifierKeyNames() {
+        const map = this._modifierKeyNames;
+        map.clear();
+        for (const [key, value] of this._getModifierKeyNames(this._os)) {
+            map.set(key, value);
+        }
+    }
+
+    _convertCommandKeyToInputKey(key) {
+        if (key.length === 1) {
+            key = `Key${key}`;
+        }
+        return key;
+    }
+
+    _convertCommandModifierToInputModifier(modifier) {
+        switch (modifier) {
+            case 'Ctrl': return (this._os === 'mac' ? 'meta' : 'ctrl');
+            case 'Alt': return 'alt';
+            case 'Shift': return 'shift';
+            case 'MacCtrl': return 'ctrl';
+            case 'Command': return 'meta';
+            default: return modifier;
+        }
+    }
+
+    _convertInputKeyToCommandKey(key) {
+        if (key.length === 4 && key.startsWith('Key')) {
+            key = key.substring(3);
+        }
+        return key;
+    }
+
+    _convertInputModifierToCommandModifier(modifier) {
+        switch (modifier) {
+            case 'ctrl': return (this._os === 'mac' ? 'MacCtrl' : 'Ctrl');
+            case 'alt': return 'Alt';
+            case 'shift': return 'Shift';
+            case 'meta': return 'Command';
+            default: return modifier;
+        }
+    }
+}