text: /**
   * @fileoverview Rule to flag use of alert, confirm, prompt
   * @author Nicholas C. Zakas
   */
  "use strict";
  
  //------------------------------------------------------------------------------
  // Helpers
  //------------------------------------------------------------------------------
  
  /**
   * Checks if the given name is a prohibited identifier.
   * @param {string} name The name to check
   * @returns {boolean} Whether or not the name is prohibited.
   */
  function isProhibitedIdentifier(name) {
      return /^(alert|confirm|prompt)$/.test(name);
  }
  
  /**
   * Reports the given node and identifier name.
   * @param {RuleContext} context The ESLint rule context.
   * @param {ASTNode} node The node to report on.
   * @param {string} identifierName The name of the identifier.
   * @returns {void}
   */
  function report(context, node, identifierName) {
      context.report(node, "Unexpected {{name}}.", { name: identifierName });
  }
  
  /**
   * Returns the property name of a MemberExpression.
   * @param {ASTNode} memberExpressionNode The MemberExpression node.
   * @returns {string|null} Returns the property name if available, null else.
   */
  function getPropertyName(memberExpressionNode) {
      if (memberExpressionNode.computed) {
          if (memberExpressionNode.property.type === "Literal") {
              return memberExpressionNode.property.value;
          }
      } else {
          return memberExpressionNode.property.name;
      }
      return null;
  }
  
  /**
   * Finds the escope reference in the given scope.
   * @param {Object} scope The scope to search.
   * @param {ASTNode} node The identifier node.
   * @returns {Reference|null} Returns the found reference or null if none were found.
   */
  function findReference(scope, node) {
      var references = scope.references.filter(function(reference) {
          return reference.identifier.range[0] === node.range[0] &&
              reference.identifier.range[1] === node.range[1];
      });
  
      if (references.length === 1) {
          return references[0];
      }
      return null;
  }
  
  /**
   * Checks if the given identifier node is shadowed in the given scope.
   * @param {Object} scope The current scope.
   * @param {Object} globalScope The global scope.
   * @param {string} node The identifier node to check
   * @returns {boolean} Whether or not the name is shadowed.
   */
  function isShadowed(scope, globalScope, node) {
      var reference = findReference(scope, node);
  
      return reference && reference.resolved && reference.resolved.defs.length > 0;
  }
  
  /**
   * Checks if the given identifier node is a ThisExpression in the global scope or the global window property.
   * @param {Object} scope The current scope.
   * @param {Object} globalScope The global scope.
   * @param {string} node The identifier node to check
   * @returns {boolean} Whether or not the node is a reference to the global object.
   */
  function isGlobalThisReferenceOrGlobalWindow(scope, globalScope, node) {
      if (scope.type === "global" && node.type === "ThisExpression") {
          return true;
      } else if (node.name === "window") {
          return !isShadowed(scope, globalScope, node);
      }
  
      return false;
  }
  
  //------------------------------------------------------------------------------
  // Rule Definition
  //------------------------------------------------------------------------------
  
  module.exports = {
      meta: {
          docs: {
              description: "disallow the use of `alert`, `confirm`, and `prompt`",
              category: "Best Practices",
              recommended: false
          },
  
          schema: []
      },
  
      create: function(context) {
          var globalScope;
  
          return {
  
              Program: function() {
                  globalScope = context.getScope();
              },
  
              CallExpression: function(node) {
                  var callee = node.callee,
                      identifierName,
                      currentScope = context.getScope();
  
                  // without window.
                  if (callee.type === "Identifier") {
                      identifierName = callee.name;
  
                      if (!isShadowed(currentScope, globalScope, callee) && isProhibitedIdentifier(callee.name)) {
                          report(context, node, identifierName);
                      }
  
                  } else if (callee.type === "MemberExpression" && isGlobalThisReferenceOrGlobalWindow(currentScope, globalScope, callee.object)) {
                      identifierName = getPropertyName(callee);
  
                      if (isProhibitedIdentifier(identifierName)) {
                          report(context, node, identifierName);
                      }
                  }
  
              }
          };
  
      }
  };
  