'use strict';

const _ = require('lodash');
const beforeBlockString = require('../../utils/beforeBlockString');
const blockString = require('../../utils/blockString');
const hasBlock = require('../../utils/hasBlock');
const hasEmptyBlock = require('../../utils/hasEmptyBlock');
const optionsMatches = require('../../utils/optionsMatches');
const report = require('../../utils/report');
const ruleMessages = require('../../utils/ruleMessages');
const validateOptions = require('../../utils/validateOptions');
const whitespaceChecker = require('../../utils/whitespaceChecker');

const ruleName = 'block-opening-brace-space-before';

const messages = ruleMessages(ruleName, {
	expectedBefore: () => 'Expected single space before "{"',
	rejectedBefore: () => 'Unexpected whitespace before "{"',
	expectedBeforeSingleLine: () => 'Expected single space before "{" of a single-line block',
	rejectedBeforeSingleLine: () => 'Unexpected whitespace before "{" of a single-line block',
	expectedBeforeMultiLine: () => 'Expected single space before "{" of a multi-line block',
	rejectedBeforeMultiLine: () => 'Unexpected whitespace before "{" of a multi-line block',
});

function rule(expectation, options, context) {
	const checker = whitespaceChecker('space', expectation, messages);

	return (root, result) => {
		const validOptions = validateOptions(
			result,
			ruleName,
			{
				actual: expectation,
				possible: [
					'always',
					'never',
					'always-single-line',
					'never-single-line',
					'always-multi-line',
					'never-multi-line',
				],
			},
			{
				actual: options,
				possible: {
					ignoreAtRules: [_.isString, _.isRegExp],
				},
				optional: true,
			},
		);

		if (!validOptions) {
			return;
		}

		// Check both kinds of statements: rules and at-rules
		root.walkRules(check);
		root.walkAtRules(check);

		function check(statement) {
			// Return early if blockless or has an empty block
			if (!hasBlock(statement) || hasEmptyBlock(statement)) {
				return;
			}

			// Return early if at-rule is to be ignored
			if (optionsMatches(options, 'ignoreAtRules', statement.name)) {
				return;
			}

			const source = beforeBlockString(statement);
			const beforeBraceNoRaw = beforeBlockString(statement, {
				noRawBefore: true,
			});

			let index = beforeBraceNoRaw.length - 1;

			if (beforeBraceNoRaw[index - 1] === '\r') {
				index -= 1;
			}

			checker.before({
				source,
				index: source.length,
				lineCheckStr: blockString(statement),
				err: (m) => {
					if (context.fix) {
						if (expectation.startsWith('always')) {
							statement.raws.between = ' ';

							return;
						}

						if (expectation.startsWith('never')) {
							statement.raws.between = '';

							return;
						}
					}

					report({
						message: m,
						node: statement,
						index,
						result,
						ruleName,
					});
				},
			});
		}
	};
}

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