/**
   * @fileoverview RuleContext utility for rules
   * @author Nicholas C. Zakas
   * @copyright 2013 Nicholas C. Zakas. All rights reserved.
   * See LICENSE file in root directory for full license.
   */
  "use strict";
  
  //------------------------------------------------------------------------------
  // Requirements
  //------------------------------------------------------------------------------
  
  var RuleFixer = require("./util/rule-fixer");
  
  //------------------------------------------------------------------------------
  // Constants
  //------------------------------------------------------------------------------
  
  var PASSTHROUGHS = [
      "getAllComments",
      "getAncestors",
      "getComments",
      "getDeclaredVariables",
      "getFilename",
      "getFirstToken",
      "getFirstTokens",
      "getJSDocComment",
      "getLastToken",
      "getLastTokens",
      "getNodeByRangeIndex",
      "getScope",
      "getSource",
      "getSourceLines",
      "getTokenAfter",
      "getTokenBefore",
      "getTokenByRangeStart",
      "getTokens",
      "getTokensAfter",
      "getTokensBefore",
      "getTokensBetween",
      "markVariableAsUsed",
      "isMarkedAsUsed"
  ];
  
  //------------------------------------------------------------------------------
  // Typedefs
  //------------------------------------------------------------------------------
  
  /**
   * An error message description
   * @typedef {Object} MessageDescriptor
   * @property {string} nodeType The type of node.
   * @property {Location} loc The location of the problem.
   * @property {string} message The problem message.
   * @property {Object} [data] Optional data to use to fill in placeholders in the
   *      message.
   * @property {Function} fix The function to call that creates a fix command.
   */
  
  //------------------------------------------------------------------------------
  // Rule Definition
  //------------------------------------------------------------------------------
  
  /**
   * Acts as an abstraction layer between rules and the main eslint object.
   * @constructor
   * @param {string} ruleId The ID of the rule using this object.
   * @param {eslint} eslint The eslint object.
   * @param {number} severity The configured severity level of the rule.
   * @param {array} options The configuration information to be added to the rule.
   * @param {object} settings The configuration settings passed from the config file.
   * @param {object} ecmaFeatures The ecmaFeatures settings passed from the config file.
   */
  function RuleContext(ruleId, eslint, severity, options, settings, ecmaFeatures) {
  
      /**
       * The read-only ID of the rule.
       */
      Object.defineProperty(this, "id", {
          value: ruleId
      });
  
      /**
       * The read-only options of the rule
       */
      Object.defineProperty(this, "options", {
          value: options
      });
  
      /**
       * The read-only settings shared between all rules
       */
      Object.defineProperty(this, "settings", {
          value: settings
      });
  
      /**
       * The read-only ecmaFeatures shared across all rules
       */
      Object.defineProperty(this, "ecmaFeatures", {
          value: Object.create(ecmaFeatures)
      });
      Object.freeze(this.ecmaFeatures);
  
      // copy over passthrough methods
      PASSTHROUGHS.forEach(function(name) {
          this[name] = function() {
              return eslint[name].apply(eslint, arguments);
          };
      }, this);
  
      /**
       * Passthrough to eslint.report() that automatically assigns the rule ID and severity.
       * @param {ASTNode|MessageDescriptor} nodeOrDescriptor The AST node related to the message or a message
       *      descriptor.
       * @param {Object=} location The location of the error.
       * @param {string} message The message to display to the user.
       * @param {Object} opts Optional template data which produces a formatted message
       *     with symbols being replaced by this object's values.
       * @returns {void}
       */
      this.report = function(nodeOrDescriptor, location, message, opts) {
  
          var descriptor,
              fix = null;
  
          // check to see if it's a new style call
          if (arguments.length === 1) {
              descriptor = nodeOrDescriptor;
  
              // if there's a fix specified, get it
              if (typeof descriptor.fix === "function") {
                  fix = descriptor.fix(new RuleFixer());
              }
  
              eslint.report(
                  ruleId, severity, descriptor.node,
                  descriptor.loc || descriptor.node.loc.start,
                  descriptor.message, descriptor.data, fix
              );
  
              return;
          }
  
          // old style call
          eslint.report(ruleId, severity, nodeOrDescriptor, location, message, opts);
      };
  
      /**
       * Passthrough to eslint.getSourceCode().
       * @returns {SourceCode} The SourceCode object for the code.
       */
      this.getSourceCode = function() {
          return eslint.getSourceCode();
      };
  
  }
  
  RuleContext.prototype = {
      constructor: RuleContext
  };
  
  module.exports = RuleContext;