source: imaps-frontend/node_modules/clean-css/lib/optimizer/level-2/merge-adjacent.js

var isMergeable = require('./is-mergeable');

var optimizeProperties = require('./properties/optimize');

var sortSelectors = require('../level-1/sort-selectors');
var tidyRules = require('../level-1/tidy-rules');

var OptimizationLevel = require('../../options/optimization-level').OptimizationLevel;

var serializeBody = require('../../writer/one-time').body;
var serializeRules = require('../../writer/one-time').rules;

var Token = require('../../tokenizer/token');

function mergeAdjacent(tokens, context) {
  var lastToken = [null, [], []];
  var options = context.options;
  var adjacentSpace = options.compatibility.selectors.adjacentSpace;
  var selectorsSortingMethod = options.level[OptimizationLevel.One].selectorsSortingMethod;
  var mergeablePseudoClasses = options.compatibility.selectors.mergeablePseudoClasses;
  var mergeablePseudoElements = options.compatibility.selectors.mergeablePseudoElements;
  var mergeLimit = options.compatibility.selectors.mergeLimit;
  var multiplePseudoMerging = options.compatibility.selectors.multiplePseudoMerging;

  for (var i = 0, l = tokens.length; i < l; i++) {
    var token = tokens[i];

    if (token[0] != Token.RULE) {
      lastToken = [null, [], []];
      continue;
    }

    if (lastToken[0] == Token.RULE && serializeRules(token[1]) == serializeRules(lastToken[1])) {
      Array.prototype.push.apply(lastToken[2], token[2]);
      optimizeProperties(lastToken[2], true, true, context);
      token[2] = [];
    } else if (lastToken[0] == Token.RULE && serializeBody(token[2]) == serializeBody(lastToken[2])
        && isMergeable(serializeRules(token[1]), mergeablePseudoClasses, mergeablePseudoElements, multiplePseudoMerging)
        && isMergeable(
          serializeRules(lastToken[1]),
          mergeablePseudoClasses,
          mergeablePseudoElements,
          multiplePseudoMerging
        )
        && lastToken[1].length < mergeLimit) {
      lastToken[1] = tidyRules(lastToken[1].concat(token[1]), false, adjacentSpace, false, context.warnings);
      lastToken[1] = lastToken.length > 1 ? sortSelectors(lastToken[1], selectorsSortingMethod) : lastToken[1];
      token[2] = [];
    } else {
      lastToken = token;
    }
  }
}

module.exports = mergeAdjacent;