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

const ContextDependencyHelpers = exports;

/**
 * Escapes regular expression metacharacters
 * @param {string} str String to quote
 * @returns {string} Escaped string
 */
const quotemeta = str => {
	return str.replace(/[-[\]\\/{}()*+?.^$|]/g, "\\$&");
};

const splitContextFromPrefix = prefix => {
	const idx = prefix.lastIndexOf("/");
	let context = ".";
	if (idx >= 0) {
		context = prefix.substr(0, idx);
		prefix = `.${prefix.substr(idx)}`;
	}
	return {
		context,
		prefix
	};
};

const splitQueryFromPostfix = postfix => {
	const idx = postfix.indexOf("?");
	let query = "";
	if (idx >= 0) {
		query = postfix.substr(idx);
		postfix = postfix.substr(0, idx);
	}
	return {
		postfix,
		query
	};
};

ContextDependencyHelpers.create = (
	Dep,
	range,
	param,
	expr,
	options,
	contextOptions,
	// when parser is not passed in, expressions won't be walked
	parser = null
) => {
	if (param.isTemplateString()) {
		let prefixRaw = param.quasis[0].string;
		let postfixRaw =
			param.quasis.length > 1
				? param.quasis[param.quasis.length - 1].string
				: "";

		const valueRange = param.range;
		const { context, prefix } = splitContextFromPrefix(prefixRaw);
		const { postfix, query } = splitQueryFromPostfix(postfixRaw);

		// When there are more than two quasis, the generated RegExp can be more precise
		// We join the quasis with the expression regexp
		const innerQuasis = param.quasis.slice(1, param.quasis.length - 1);
		const innerRegExp =
			options.wrappedContextRegExp.source +
			innerQuasis
				.map(q => quotemeta(q.string) + options.wrappedContextRegExp.source)
				.join("");

		// Example: `./context/pre${e}inner${e}inner2${e}post?query`
		// context: "./context"
		// prefix: "./pre"
		// innerQuasis: [BEE("inner"), BEE("inner2")]
		// (BEE = BasicEvaluatedExpression)
		// postfix: "post"
		// query: "?query"
		// regExp: /^\.\/pre.*inner.*inner2.*post$/
		const regExp = new RegExp(
			`^${quotemeta(prefix)}${innerRegExp}${quotemeta(postfix)}$`
		);
		const dep = new Dep(
			Object.assign(
				{
					request: context + query,
					recursive: options.wrappedContextRecursive,
					regExp,
					mode: "sync"
				},
				contextOptions
			),
			range,
			valueRange
		);
		dep.loc = expr.loc;
		const replaces = [];

		param.parts.forEach((part, i) => {
			if (i % 2 === 0) {
				// Quasis or merged quasi
				let range = part.range;
				let value = part.string;
				if (param.templateStringKind === "cooked") {
					value = JSON.stringify(value);
					value = value.slice(1, value.length - 1);
				}
				if (i === 0) {
					// prefix
					value = prefix;
					range = [param.range[0], part.range[1]];
					value =
						(param.templateStringKind === "cooked" ? "`" : "String.raw`") +
						value;
				} else if (i === param.parts.length - 1) {
					// postfix
					value = postfix;
					range = [part.range[0], param.range[1]];
					value = value + "`";
				} else if (
					part.expression &&
					part.expression.type === "TemplateElement" &&
					part.expression.value.raw === value
				) {
					// Shortcut when it's a single quasi and doesn't need to be replaced
					return;
				}
				replaces.push({
					range,
					value
				});
			} else {
				// Expression
				if (parser) {
					parser.walkExpression(part.expression);
				}
			}
		});

		dep.replaces = replaces;
		dep.critical =
			options.wrappedContextCritical &&
			"a part of the request of a dependency is an expression";
		return dep;
	} else if (
		param.isWrapped() &&
		((param.prefix && param.prefix.isString()) ||
			(param.postfix && param.postfix.isString()))
	) {
		let prefixRaw =
			param.prefix && param.prefix.isString() ? param.prefix.string : "";
		let postfixRaw =
			param.postfix && param.postfix.isString() ? param.postfix.string : "";
		const prefixRange =
			param.prefix && param.prefix.isString() ? param.prefix.range : null;
		const postfixRange =
			param.postfix && param.postfix.isString() ? param.postfix.range : null;
		const valueRange = param.range;
		const { context, prefix } = splitContextFromPrefix(prefixRaw);
		const { postfix, query } = splitQueryFromPostfix(postfixRaw);
		const regExp = new RegExp(
			`^${quotemeta(prefix)}${options.wrappedContextRegExp.source}${quotemeta(
				postfix
			)}$`
		);
		const dep = new Dep(
			Object.assign(
				{
					request: context + query,
					recursive: options.wrappedContextRecursive,
					regExp,
					mode: "sync"
				},
				contextOptions
			),
			range,
			valueRange
		);
		dep.loc = expr.loc;
		const replaces = [];
		if (prefixRange) {
			replaces.push({
				range: prefixRange,
				value: JSON.stringify(prefix)
			});
		}
		if (postfixRange) {
			replaces.push({
				range: postfixRange,
				value: JSON.stringify(postfix)
			});
		}
		dep.replaces = replaces;
		dep.critical =
			options.wrappedContextCritical &&
			"a part of the request of a dependency is an expression";

		if (parser && param.wrappedInnerExpressions) {
			for (const part of param.wrappedInnerExpressions) {
				if (part.expression) parser.walkExpression(part.expression);
			}
		}

		return dep;
	} else {
		const dep = new Dep(
			Object.assign(
				{
					request: options.exprContextRequest,
					recursive: options.exprContextRecursive,
					regExp: options.exprContextRegExp,
					mode: "sync"
				},
				contextOptions
			),
			range,
			param.range
		);
		dep.loc = expr.loc;
		dep.critical =
			options.exprContextCritical &&
			"the request of a dependency is an expression";

		if (parser) {
			parser.walkExpression(param.expression);
		}

		return dep;
	}
};