"use strict";

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

const ruleName = "media-feature-range-operator-space-after";

const messages = ruleMessages(ruleName, {
  expectedAfter: () => "Expected single space after range operator",
  rejectedAfter: () => "Unexpected whitespace after range operator"
});

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"]
    });

    if (!validOptions) {
      return;
    }

    root.walkAtRules(/^media$/i, atRule => {
      const fixOperatorIndices = [];
      const fix = context.fix ? index => fixOperatorIndices.push(index) : null;

      findMediaOperator(atRule, (match, params, node) => {
        checkAfterOperator(match, params, node, fix);
      });

      if (fixOperatorIndices.length) {
        let params = atRule.raws.params
          ? atRule.raws.params.raw
          : atRule.params;

        fixOperatorIndices
          .sort((a, b) => b - a)
          .forEach(index => {
            const beforeOperator = params.slice(0, index + 1);
            const afterOperator = params.slice(index + 1);

            if (expectation === "always") {
              params = beforeOperator + afterOperator.replace(/^\s*/, " ");
            } else if (expectation === "never") {
              params = beforeOperator + afterOperator.replace(/^\s*/, "");
            }
          });

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

    function checkAfterOperator(match, params, node, fix) {
      const endIndex = match.startIndex + match.target.length - 1;

      checker.after({
        source: params,
        index: endIndex,
        err: m => {
          if (fix) {
            fix(endIndex);

            return;
          }

          report({
            message: m,
            node,
            index: endIndex + atRuleParamIndex(node) + 1,
            result,
            ruleName
          });
        }
      });
    }
  };
};

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