'use strict';

const _ = require('lodash');
const declarationValueIndex = require('../../utils/declarationValueIndex');
const isStandardSyntaxFunction = require('../../utils/isStandardSyntaxFunction');
const matchesStringOrRegExp = require('../../utils/matchesStringOrRegExp');
const postcss = require('postcss');
const report = require('../../utils/report');
const ruleMessages = require('../../utils/ruleMessages');
const validateOptions = require('../../utils/validateOptions');
const valueParser = require('postcss-value-parser');

const ruleName = 'function-whitelist';

const messages = ruleMessages(ruleName, {
	rejected: (name) => `Unexpected function "${name}"`,
});

function rule(whitelistInput) {
	const whitelist = [].concat(whitelistInput);

	return (root, result) => {
		const validOptions = validateOptions(result, ruleName, {
			actual: whitelist,
			possible: [_.isString, _.isRegExp],
		});

		if (!validOptions) {
			return;
		}

		root.walkDecls((decl) => {
			const value = decl.value;

			valueParser(value).walk((node) => {
				if (node.type !== 'function') {
					return;
				}

				if (!isStandardSyntaxFunction(node)) {
					return;
				}

				if (matchesStringOrRegExp(postcss.vendor.unprefixed(node.value), whitelist)) {
					return;
				}

				report({
					message: messages.rejected(node.value),
					node: decl,
					index: declarationValueIndex(decl) + node.sourceIndex,
					result,
					ruleName,
				});
			});
		});
	};
}

rule.primaryOptionArray = true;

rule.ruleName = ruleName;
rule.messages = messages;
module.exports = rule;
