/**
   * @fileoverview Rule to enforce a maximum number of nested callbacks.
   * @author Ian Christian Myers
   * @copyright 2013 Ian Christian Myers. All rights reserved.
   */
  
  "use strict";
  
  //------------------------------------------------------------------------------
  // Rule Definition
  //------------------------------------------------------------------------------
  
  module.exports = function(context) {
  
      //--------------------------------------------------------------------------
      // Constants
      //--------------------------------------------------------------------------
  
      var THRESHOLD = context.options[0] || 10;
  
      //--------------------------------------------------------------------------
      // Helpers
      //--------------------------------------------------------------------------
  
      var callbackStack = [];
  
      /**
       * Checks a given function node for too many callbacks.
       * @param {ASTNode} node The node to check.
       * @returns {void}
       * @private
       */
      function checkFunction(node) {
          var parent = node.parent;
  
          if (parent.type === "CallExpression") {
              callbackStack.push(node);
          }
  
          if (callbackStack.length > THRESHOLD) {
              var opts = {num: callbackStack.length, max: THRESHOLD};
              context.report(node, "Too many nested callbacks ({{num}}). Maximum allowed is {{max}}.", opts);
          }
      }
  
      /**
       * Pops the call stack.
       * @returns {void}
       * @private
       */
      function popStack() {
          callbackStack.pop();
      }
  
      //--------------------------------------------------------------------------
      // Public API
      //--------------------------------------------------------------------------
  
      return {
          "ArrowFunctionExpression": checkFunction,
          "ArrowFunctionExpression:exit": popStack,
  
          "FunctionExpression": checkFunction,
          "FunctionExpression:exit": popStack
      };
  
  };
  
  module.exports.schema = [
      {
          "type": "integer"
      }
  ];