'use strict';

const declarationValueIndex = require('../../utils/declarationValueIndex');
const getDeclarationValue = require('../../utils/getDeclarationValue');
const ruleMessages = require('../../utils/ruleMessages');
const setDeclarationValue = require('../../utils/setDeclarationValue');
const validateOptions = require('../../utils/validateOptions');
const valueListCommaWhitespaceChecker = require('../valueListCommaWhitespaceChecker');
const whitespaceChecker = require('../../utils/whitespaceChecker');

const ruleName = 'value-list-comma-space-before';

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

const meta = {
	url: 'https://stylelint.io/user-guide/rules/list/value-list-comma-space-before',
};

/** @type {import('stylelint').Rule} */
const rule = (primary, _secondaryOptions, context) => {
	const checker = whitespaceChecker('space', primary, messages);

	return (root, result) => {
		const validOptions = validateOptions(result, ruleName, {
			actual: primary,
			possible: ['always', 'never', 'always-single-line', 'never-single-line'],
		});

		if (!validOptions) {
			return;
		}

		/** @type {Map<import('postcss').Declaration, number[]> | undefined} */
		let fixData;

		valueListCommaWhitespaceChecker({
			root,
			result,
			locationChecker: checker.before,
			checkedRuleName: ruleName,
			fix: context.fix
				? (declNode, index) => {
						const valueIndex = declarationValueIndex(declNode);

						if (index <= valueIndex) {
							return false;
						}

						fixData = fixData || new Map();
						const commaIndices = fixData.get(declNode) || [];

						commaIndices.push(index);
						fixData.set(declNode, commaIndices);

						return true;
				  }
				: null,
		});

		if (fixData) {
			for (const [decl, commaIndices] of fixData.entries()) {
				for (const index of commaIndices.sort((a, b) => b - a)) {
					const value = getDeclarationValue(decl);
					const valueIndex = index - declarationValueIndex(decl);
					let beforeValue = value.slice(0, valueIndex);
					const afterValue = value.slice(valueIndex);

					if (primary.startsWith('always')) {
						beforeValue = beforeValue.replace(/\s*$/, ' ');
					} else if (primary.startsWith('never')) {
						beforeValue = beforeValue.replace(/\s*$/, '');
					}

					setDeclarationValue(decl, beforeValue + afterValue);
				}
			}
		}
	};
};

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