/****************************************************************************
 * Copyright 2017 EPAM Systems
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ***************************************************************************/

import keyName from "w3c-keyname";

const mac = typeof navigator !== "undefined" ? /Mac/.test(navigator.platform) : false;

function normalizeKeyName(name) {
	let parts = name.split(/\+(?!$)/), result = parts[parts.length - 1];
	if (result === "Space") result = " ";
	let alt, ctrl, shift, meta;

	for (let i = 0; i < parts.length - 1; i++) {
		let mod = parts[i];
		if (/^(cmd|meta|m)$/i.test(mod)) meta = true;
		else if (/^a(lt)?$/i.test(mod)) alt = true;
		else if (/^(c|ctrl|control)$/i.test(mod)) ctrl = true;
		else if (/^s(hift)?$/i.test(mod)) shift = true;
		else if (/^mod$/i.test(mod)) { if (mac) meta = true; else ctrl = true; }
		else throw new Error("Unrecognized modifier name: " + mod);
	}

	if (alt) result = "Alt+" + result;
	if (ctrl) result = "Ctrl+" + result;
	if (meta) result = "Meta+" + result;
	if (shift) result = "Shift+" + result;

	return result;
}

function normalizeKeyMap(map) {
	const copy = Object.create(null);

	for (let prop in map) {
		if (map.hasOwnProperty(prop))
			copy[normalizeKeyName(prop)] = map[prop];
	}

	return copy;
}

function modifiers(name, event, shift) {
	if (event.altKey) name = "Alt+" + name;
	if (event.ctrlKey) name = "Ctrl+" + name;
	if (event.metaKey) name = "Meta+" + name;
	if (shift !== false && event.shiftKey) name = "Shift+" + name;

	return name;
}

function normalizeKeyEvent(event, base=false) {
	const name = keyName(event);
	const isChar = name.length === 1 && name !== " ";

	return isChar && !base ? modifiers(name, event, !isChar) :
	    modifiers(keyName.base[event.keyCode], event, true);
}

function keyNorm(obj) {
	if (obj instanceof KeyboardEvent)
		return normalizeKeyEvent(...arguments);

	return typeof obj === 'object' ? normalizeKeyMap(obj) :
		normalizeKeyName(obj);
}

function lookup(map, event) {
	const name = keyName(event);
	const isChar = name.length === 1 && name !== " ";
	let res = map[modifiers(name, event, !isChar)];
	let baseName;

	if (event.shiftKey && isChar && (baseName = keyName.base[event.keyCode])) {
		res = map[modifiers(baseName, event, true)] || res;
	}

	return res;
}

keyNorm.lookup = lookup;

export default keyNorm;