"use strict";
  
  const conversions = require("webidl-conversions");
  const utils = require("./utils.js");
  
  const convertNode = require("./Node.js").convert;
  const impl = utils.implSymbol;
  const ctorRegistry = utils.ctorRegistrySymbol;
  
  const interfaceName = "TreeWalker";
  
  /**
   * When an interface-module that implements this interface as a mixin is loaded, it will append its own `.is()`
   * method into this array. It allows objects that directly implements *those* interfaces to be recognized as
   * implementing this mixin interface.
   */
  exports._mixedIntoPredicates = [];
  exports.is = function is(obj) {
    if (obj) {
      if (utils.hasOwn(obj, impl) && obj[impl] instanceof Impl.implementation) {
        return true;
      }
      for (const isMixedInto of exports._mixedIntoPredicates) {
        if (isMixedInto(obj)) {
          return true;
        }
      }
    }
    return false;
  };
  exports.isImpl = function isImpl(obj) {
    if (obj) {
      if (obj instanceof Impl.implementation) {
        return true;
      }
  
      const wrapper = utils.wrapperForImpl(obj);
      for (const isMixedInto of exports._mixedIntoPredicates) {
        if (isMixedInto(wrapper)) {
          return true;
        }
      }
    }
    return false;
  };
  exports.convert = function convert(obj, { context = "The provided value" } = {}) {
    if (exports.is(obj)) {
      return utils.implForWrapper(obj);
    }
    throw new TypeError(`${context} is not of type 'TreeWalker'.`);
  };
  
  exports.create = function create(globalObject, constructorArgs, privateData) {
    if (globalObject[ctorRegistry] === undefined) {
      throw new Error("Internal error: invalid global object");
    }
  
    const ctor = globalObject[ctorRegistry]["TreeWalker"];
    if (ctor === undefined) {
      throw new Error("Internal error: constructor TreeWalker is not installed on the passed global object");
    }
  
    let obj = Object.create(ctor.prototype);
    obj = exports.setup(obj, globalObject, constructorArgs, privateData);
    return obj;
  };
  exports.createImpl = function createImpl(globalObject, constructorArgs, privateData) {
    const obj = exports.create(globalObject, constructorArgs, privateData);
    return utils.implForWrapper(obj);
  };
  exports._internalSetup = function _internalSetup(obj) {};
  exports.setup = function setup(obj, globalObject, constructorArgs = [], privateData = {}) {
    privateData.wrapper = obj;
  
    exports._internalSetup(obj);
    Object.defineProperty(obj, impl, {
      value: new Impl.implementation(globalObject, constructorArgs, privateData),
      configurable: true
    });
  
    obj[impl][utils.wrapperSymbol] = obj;
    if (Impl.init) {
      Impl.init(obj[impl], privateData);
    }
    return obj;
  };
  
  exports.install = function install(globalObject) {
    class TreeWalker {
      constructor() {
        throw new TypeError("Illegal constructor");
      }
  
      parentNode() {
        if (!this || !exports.is(this)) {
          throw new TypeError("Illegal invocation");
        }
  
        return utils.tryWrapperForImpl(this[impl].parentNode());
      }
  
      firstChild() {
        if (!this || !exports.is(this)) {
          throw new TypeError("Illegal invocation");
        }
  
        return utils.tryWrapperForImpl(this[impl].firstChild());
      }
  
      lastChild() {
        if (!this || !exports.is(this)) {
          throw new TypeError("Illegal invocation");
        }
  
        return utils.tryWrapperForImpl(this[impl].lastChild());
      }
  
      previousSibling() {
        if (!this || !exports.is(this)) {
          throw new TypeError("Illegal invocation");
        }
  
        return utils.tryWrapperForImpl(this[impl].previousSibling());
      }
  
      nextSibling() {
        if (!this || !exports.is(this)) {
          throw new TypeError("Illegal invocation");
        }
  
        return utils.tryWrapperForImpl(this[impl].nextSibling());
      }
  
      previousNode() {
        if (!this || !exports.is(this)) {
          throw new TypeError("Illegal invocation");
        }
  
        return utils.tryWrapperForImpl(this[impl].previousNode());
      }
  
      nextNode() {
        if (!this || !exports.is(this)) {
          throw new TypeError("Illegal invocation");
        }
  
        return utils.tryWrapperForImpl(this[impl].nextNode());
      }
  
      get root() {
        if (!this || !exports.is(this)) {
          throw new TypeError("Illegal invocation");
        }
  
        return utils.getSameObject(this, "root", () => {
          return utils.tryWrapperForImpl(this[impl]["root"]);
        });
      }
  
      get whatToShow() {
        if (!this || !exports.is(this)) {
          throw new TypeError("Illegal invocation");
        }
  
        return this[impl]["whatToShow"];
      }
  
      get filter() {
        if (!this || !exports.is(this)) {
          throw new TypeError("Illegal invocation");
        }
  
        return utils.tryWrapperForImpl(this[impl]["filter"]);
      }
  
      get currentNode() {
        if (!this || !exports.is(this)) {
          throw new TypeError("Illegal invocation");
        }
  
        return utils.tryWrapperForImpl(this[impl]["currentNode"]);
      }
  
      set currentNode(V) {
        if (!this || !exports.is(this)) {
          throw new TypeError("Illegal invocation");
        }
  
        V = convertNode(V, { context: "Failed to set the 'currentNode' property on 'TreeWalker': The provided value" });
  
        this[impl]["currentNode"] = V;
      }
    }
    Object.defineProperties(TreeWalker.prototype, {
      parentNode: { enumerable: true },
      firstChild: { enumerable: true },
      lastChild: { enumerable: true },
      previousSibling: { enumerable: true },
      nextSibling: { enumerable: true },
      previousNode: { enumerable: true },
      nextNode: { enumerable: true },
      root: { enumerable: true },
      whatToShow: { enumerable: true },
      filter: { enumerable: true },
      currentNode: { enumerable: true },
      [Symbol.toStringTag]: { value: "TreeWalker", configurable: true }
    });
    if (globalObject[ctorRegistry] === undefined) {
      globalObject[ctorRegistry] = Object.create(null);
    }
    globalObject[ctorRegistry][interfaceName] = TreeWalker;
  
    Object.defineProperty(globalObject, interfaceName, {
      configurable: true,
      writable: true,
      value: TreeWalker
    });
  };
  
  const Impl = require("../traversal/TreeWalker-impl.js");