"use strict";

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

const ruleName = "media-query-list-comma-newline-after";

const messages = ruleMessages(ruleName, {
  expectedAfter: () => 'Expected newline after ","',
  expectedAfterMultiLine: () =>
    'Expected newline after "," in a multi-line list',
  rejectedAfterMultiLine: () =>
    'Unexpected whitespace after "," in a multi-line list'
});

const rule = function(expectation, options, context) {
  const checker = whitespaceChecker("newline", expectation, messages);

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

    if (!validOptions) {
      return;
    }

    // Only check for the newline after the comma, while allowing
    // arbitrary indentation after the newline
    let fixData;

    mediaQueryListCommaWhitespaceChecker({
      root,
      result,
      locationChecker: checker.afterOneOnly,
      checkedRuleName: ruleName,
      allowTrailingComments: expectation.indexOf("always") === 0,
      fix: context.fix
        ? (atRule, index) => {
            const paramCommaIndex = index - atRuleParamIndex(atRule);

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

            commaIndices.push(paramCommaIndex);
            fixData.set(atRule, commaIndices);

            return true;
          }
        : null
    });

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

        commaIndices
          .sort((a, b) => b - a)
          .forEach(index => {
            const beforeComma = params.slice(0, index + 1);
            const afterComma = params.slice(index + 1);

            if (expectation.indexOf("always") === 0) {
              if (/^\s*\r?\n/.test(afterComma)) {
                params = beforeComma + afterComma.replace(/^[^\S\r\n]*/, "");
              } else {
                params = beforeComma + context.newline + afterComma;
              }
            } else if (expectation.indexOf("never") === 0) {
              params = beforeComma + afterComma.replace(/^\s*/, "");
            }
          });

        if (atRule.raws.params) {
          atRule.raws.params.raw = params;
        } else {
          atRule.params = params;
        }
      });
    }
  };
};

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