"use strict";

const ruleMessages = require("../../utils/ruleMessages");
const selectorListCommaWhitespaceChecker = require("../selectorListCommaWhitespaceChecker");
const validateOptions = require("../../utils/validateOptions");
const whitespaceChecker = require("../../utils/whitespaceChecker");

const ruleName = "selector-list-comma-space-before";

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

const rule = function(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"]
    });

    if (!validOptions) {
      return;
    }

    let fixData;

    selectorListCommaWhitespaceChecker({
      root,
      result,
      locationChecker: checker.before,
      checkedRuleName: ruleName,
      fix: context.fix
        ? (ruleNode, index) => {
            fixData = fixData || new Map();
            const commaIndices = fixData.get(ruleNode) || [];

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

            return true;
          }
        : null
    });

    if (fixData) {
      fixData.forEach((commaIndices, ruleNode) => {
        let selector = ruleNode.raws.selector
          ? ruleNode.raws.selector.raw
          : ruleNode.selector;

        commaIndices
          .sort((a, b) => b - a)
          .forEach(index => {
            let beforeSelector = selector.slice(0, index);
            const afterSelector = selector.slice(index);

            if (expectation.indexOf("always") >= 0) {
              beforeSelector = beforeSelector.replace(/\s*$/, " ");
            } else if (expectation.indexOf("never") >= 0) {
              beforeSelector = beforeSelector.replace(/\s*$/, "");
            }

            selector = beforeSelector + afterSelector;
          });

        if (ruleNode.raws.selector) {
          ruleNode.raws.selector.raw = selector;
        } else {
          ruleNode.selector = selector;
        }
      });
    }
  };
};

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