"use strict";

const atRuleParamIndex = require("../utils/atRuleParamIndex");
const report = require("../utils/report");
const styleSearch = require("style-search");

module.exports = function(opts) {
  opts.root.walkAtRules(/^media$/i, atRule => {
    const params = atRule.raws.params ? atRule.raws.params.raw : atRule.params;

    styleSearch({ source: params, target: "," }, match => {
      let index = match.startIndex;

      if (opts.allowTrailingComments) {
        // if there is a comment on the same line at after the comma, check the space after the comment.
        let execResult;

        while (
          (execResult = /^[^\S\r\n]*\/\*([\s\S]*?)\*\//.exec(
            params.slice(index + 1)
          ))
        ) {
          index += execResult[0].length;
        }

        if (
          (execResult = /^([^\S\r\n]*\/\/([\s\S]*?))\r?\n/.exec(
            params.slice(index + 1)
          ))
        ) {
          index += execResult[1].length;
        }
      }

      checkComma(params, index, atRule);
    });
  });

  function checkComma(source, index, node) {
    opts.locationChecker({
      source,
      index,
      err: m => {
        const commaIndex = index + atRuleParamIndex(node);

        if (opts.fix && opts.fix(node, commaIndex)) {
          return;
        }

        report({
          message: m,
          node,
          index: commaIndex,
          result: opts.result,
          ruleName: opts.checkedRuleName
        });
      }
    });
  }
};