"use strict";

const modifiers = /^(Command|Cmd|Control|Ctrl|CommandOrControl|CmdOrCtrl|Alt|Option|AltGr|Shift|Super)$/;
const keyCodes = /^([0-9A-Z)!@#$%^&*(:+<_>?~{|}";=,\-./`[\\\]']|F1*[1-9]|F10|F2[0-4]|Plus|Space|Tab|Backspace|Delete|Insert|Return|Enter|Up|Down|Left|Right|Home|End|PageUp|PageDown|Escape|Esc|VolumeUp|VolumeDown|VolumeMute|MediaNextTrack|MediaPreviousTrack|MediaStop|MediaPlayPause|PrintScreen)$/;

module.exports = function (str) {
	let parts = str.split("+");
	let keyFound = false;
    return parts.every((val, index) => {
		const isKey = keyCodes.test(val);
		const isModifier = modifiers.test(val);
		if (isKey) {
			// Key must be unique
			if (keyFound) return false;
			keyFound = true;
		}
		// Key is required
		if (index === parts.length - 1 && !keyFound) return false;
        return isKey || isModifier;
    });
};