/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/

"use strict";

const loaderFlag = "LOADER_EXECUTION";

const webpackOptionsFlag = "WEBPACK_OPTIONS";

/**
 * @param {string} stack stack trace
 * @param {string} flag flag to cut off
 * @returns {string} stack trace without the specified flag included
 */
const cutOffByFlag = (stack, flag) => {
	const errorStack = stack.split("\n");
	for (let i = 0; i < errorStack.length; i++) {
		if (errorStack[i].includes(flag)) {
			errorStack.length = i;
		}
	}
	return errorStack.join("\n");
};

/**
 * @param {string} stack stack trace
 * @returns {string} stack trace without the loader execution flag included
 */
const cutOffLoaderExecution = stack => cutOffByFlag(stack, loaderFlag);

/**
 * @param {string} stack stack trace
 * @returns {string} stack trace without the webpack options flag included
 */
const cutOffWebpackOptions = stack => cutOffByFlag(stack, webpackOptionsFlag);

/**
 * @param {string} stack stack trace
 * @param {string} message error message
 * @returns {string} stack trace without the message included
 */
const cutOffMultilineMessage = (stack, message) => {
	const stackSplitByLines = stack.split("\n");
	const messageSplitByLines = message.split("\n");

	const result = [];

	stackSplitByLines.forEach((line, idx) => {
		if (!line.includes(messageSplitByLines[idx])) result.push(line);
	});

	return result.join("\n");
};

/**
 * @param {string} stack stack trace
 * @param {string} message error message
 * @returns {string} stack trace without the message included
 */
const cutOffMessage = (stack, message) => {
	const nextLine = stack.indexOf("\n");
	if (nextLine === -1) {
		return stack === message ? "" : stack;
	} else {
		const firstLine = stack.slice(0, nextLine);
		return firstLine === message ? stack.slice(nextLine + 1) : stack;
	}
};

/**
 * @param {string} stack stack trace
 * @param {string} message error message
 * @returns {string} stack trace without the loader execution flag and message included
 */
const cleanUp = (stack, message) => {
	stack = cutOffLoaderExecution(stack);
	stack = cutOffMessage(stack, message);
	return stack;
};

/**
 * @param {string} stack stack trace
 * @param {string} message error message
 * @returns {string} stack trace without the webpack options flag and message included
 */
const cleanUpWebpackOptions = (stack, message) => {
	stack = cutOffWebpackOptions(stack);
	stack = cutOffMultilineMessage(stack, message);
	return stack;
};

exports.cutOffByFlag = cutOffByFlag;
exports.cutOffLoaderExecution = cutOffLoaderExecution;
exports.cutOffWebpackOptions = cutOffWebpackOptions;
exports.cutOffMultilineMessage = cutOffMultilineMessage;
exports.cutOffMessage = cutOffMessage;
exports.cleanUp = cleanUp;
exports.cleanUpWebpackOptions = cleanUpWebpackOptions;