"use strict";
  const DOMException = require("domexception/webidl2js-wrapper");
  
  const reportException = require("../helpers/runtime-script-errors");
  const idlUtils = require("../generated/utils");
  const { nodeRoot } = require("../helpers/node");
  const {
    isNode, isShadowRoot, isSlotable, getEventTargetParent,
    isShadowInclusiveAncestor, retarget
  } = require("../helpers/shadow-dom");
  
  const MouseEvent = require("../generated/MouseEvent");
  
  const EVENT_PHASE = {
    NONE: 0,
    CAPTURING_PHASE: 1,
    AT_TARGET: 2,
    BUBBLING_PHASE: 3
  };
  
  class EventTargetImpl {
    constructor(globalObject) {
      this._globalObject = globalObject;
      this._eventListeners = Object.create(null);
    }
  
    addEventListener(type, callback, options) {
      // webidl2js currently can't handle neither optional arguments nor callback interfaces
      if (callback === undefined || callback === null) {
        callback = null;
      } else if (typeof callback !== "object" && typeof callback !== "function") {
        throw new TypeError("Only undefined, null, an object, or a function are allowed for the callback parameter");
      }
  
      options = normalizeEventHandlerOptions(options, ["capture", "once", "passive"]);
  
      if (callback === null) {
        return;
      }
  
      if (!this._eventListeners[type]) {
        this._eventListeners[type] = [];
      }
  
      for (let i = 0; i < this._eventListeners[type].length; ++i) {
        const listener = this._eventListeners[type][i];
        if (listener.options.capture === options.capture && listener.callback === callback) {
          return;
        }
      }
  
      this._eventListeners[type].push({
        callback,
        options
      });
    }
  
    removeEventListener(type, callback, options) {
      if (callback === undefined || callback === null) {
        callback = null;
      } else if (typeof callback !== "object" && typeof callback !== "function") {
        throw new TypeError("Only undefined, null, an object, or a function are allowed for the callback parameter");
      }
  
      options = normalizeEventHandlerOptions(options, ["capture"]);
  
      if (callback === null) {
        // Optimization, not in the spec.
        return;
      }
  
      if (!this._eventListeners[type]) {
        return;
      }
  
      for (let i = 0; i < this._eventListeners[type].length; ++i) {
        const listener = this._eventListeners[type][i];
        if (listener.callback === callback && listener.options.capture === options.capture) {
          this._eventListeners[type].splice(i, 1);
          break;
        }
      }
    }
  
    dispatchEvent(eventImpl) {
      if (eventImpl._dispatchFlag || !eventImpl._initializedFlag) {
        throw DOMException.create(this._globalObject, [
          "Tried to dispatch an uninitialized event",
          "InvalidStateError"
        ]);
      }
      if (eventImpl.eventPhase !== EVENT_PHASE.NONE) {
        throw DOMException.create(this._globalObject, [
          "Tried to dispatch a dispatching event",
          "InvalidStateError"
        ]);
      }
  
      eventImpl.isTrusted = false;
  
      return this._dispatch(eventImpl);
    }
  
    // https://dom.spec.whatwg.org/#get-the-parent
    _getTheParent() {
      return null;
    }
  
    // https://dom.spec.whatwg.org/#concept-event-dispatch
    // legacyOutputDidListenersThrowFlag optional parameter is not necessary here since it is only used by indexDB.
    _dispatch(eventImpl, targetOverride /* , legacyOutputDidListenersThrowFlag */) {
      let targetImpl = this;
      let clearTargets = false;
      let activationTarget = null;
  
      eventImpl._dispatchFlag = true;
  
      targetOverride = targetOverride || targetImpl;
      let relatedTarget = retarget(eventImpl.relatedTarget, targetImpl);
  
      if (targetImpl !== relatedTarget || targetImpl === eventImpl.relatedTarget) {
        const touchTargets = [];
  
        appendToEventPath(eventImpl, targetImpl, targetOverride, relatedTarget, touchTargets, false);
  
        const isActivationEvent = MouseEvent.isImpl(eventImpl) && eventImpl.type === "click";
  
        if (isActivationEvent && targetImpl._hasActivationBehavior) {
          activationTarget = targetImpl;
        }
  
        let slotInClosedTree = false;
        let slotable = isSlotable(targetImpl) && targetImpl._assignedSlot ? targetImpl : null;
        let parent = getEventTargetParent(targetImpl, eventImpl);
  
        // Populate event path
        // https://dom.spec.whatwg.org/#event-path
        while (parent !== null) {
          if (slotable !== null) {
            if (parent.localName !== "slot") {
              throw new Error(`JSDOM Internal Error: Expected parent to be a Slot`);
            }
  
            slotable = null;
  
            const parentRoot = nodeRoot(parent);
            if (isShadowRoot(parentRoot) && parentRoot.mode === "closed") {
              slotInClosedTree = true;
            }
          }
  
          if (isSlotable(parent) && parent._assignedSlot) {
            slotable = parent;
          }
  
          relatedTarget = retarget(eventImpl.relatedTarget, parent);
  
          if (
            (isNode(parent) && isShadowInclusiveAncestor(nodeRoot(targetImpl), parent)) ||
            idlUtils.wrapperForImpl(parent).constructor.name === "Window"
          ) {
            if (isActivationEvent && eventImpl.bubbles && activationTarget === null &&
                parent._hasActivationBehavior) {
              activationTarget = parent;
            }
  
            appendToEventPath(eventImpl, parent, null, relatedTarget, touchTargets, slotInClosedTree);
          } else if (parent === relatedTarget) {
            parent = null;
          } else {
            targetImpl = parent;
  
            if (isActivationEvent && activationTarget === null && targetImpl._hasActivationBehavior) {
              activationTarget = targetImpl;
            }
  
            appendToEventPath(eventImpl, parent, targetImpl, relatedTarget, touchTargets, slotInClosedTree);
          }
  
          if (parent !== null) {
            parent = getEventTargetParent(parent, eventImpl);
          }
  
          slotInClosedTree = false;
        }
  
        let clearTargetsStructIndex = -1;
        for (let i = eventImpl._path.length - 1; i >= 0 && clearTargetsStructIndex === -1; i--) {
          if (eventImpl._path[i].target !== null) {
            clearTargetsStructIndex = i;
          }
        }
        const clearTargetsStruct = eventImpl._path[clearTargetsStructIndex];
  
        clearTargets =
            (isNode(clearTargetsStruct.target) && isShadowRoot(nodeRoot(clearTargetsStruct.target))) ||
            (isNode(clearTargetsStruct.relatedTarget) && isShadowRoot(nodeRoot(clearTargetsStruct.relatedTarget)));
  
        if (activationTarget !== null && activationTarget._legacyPreActivationBehavior) {
          activationTarget._legacyPreActivationBehavior();
        }
  
        for (let i = eventImpl._path.length - 1; i >= 0; --i) {
          const struct = eventImpl._path[i];
  
          if (struct.target !== null) {
            eventImpl.eventPhase = EVENT_PHASE.AT_TARGET;
          } else {
            eventImpl.eventPhase = EVENT_PHASE.CAPTURING_PHASE;
          }
  
          invokeEventListeners(struct, eventImpl, "capturing");
        }
  
        for (let i = 0; i < eventImpl._path.length; i++) {
          const struct = eventImpl._path[i];
  
          if (struct.target !== null) {
            eventImpl.eventPhase = EVENT_PHASE.AT_TARGET;
          } else {
            if (!eventImpl.bubbles) {
              continue;
            }
  
            eventImpl.eventPhase = EVENT_PHASE.BUBBLING_PHASE;
          }
  
          invokeEventListeners(struct, eventImpl, "bubbling");
        }
      }
  
      eventImpl.eventPhase = EVENT_PHASE.NONE;
  
      eventImpl.currentTarget = null;
      eventImpl._path = [];
      eventImpl._dispatchFlag = false;
      eventImpl._stopPropagationFlag = false;
      eventImpl._stopImmediatePropagationFlag = false;
  
      if (clearTargets) {
        eventImpl.target = null;
        eventImpl.relatedTarget = null;
      }
  
      if (activationTarget !== null) {
        if (!eventImpl._canceledFlag) {
          activationTarget._activationBehavior();
        } else if (activationTarget._legacyCanceledActivationBehavior) {
          activationTarget._legacyCanceledActivationBehavior();
        }
      }
  
      return !eventImpl._canceledFlag;
    }
  }
  
  module.exports = {
    implementation: EventTargetImpl
  };
  
  // https://dom.spec.whatwg.org/#concept-event-listener-invoke
  function invokeEventListeners(struct, eventImpl, phase) {
    const structIndex = eventImpl._path.indexOf(struct);
    for (let i = structIndex; i >= 0; i--) {
      const t = eventImpl._path[i];
      if (t.target) {
        eventImpl.target = t.target;
        break;
      }
    }
  
    eventImpl.relatedTarget = idlUtils.wrapperForImpl(struct.relatedTarget);
  
    if (eventImpl._stopPropagationFlag) {
      return;
    }
  
    eventImpl.currentTarget = idlUtils.wrapperForImpl(struct.item);
  
    const listeners = struct.item._eventListeners;
    innerInvokeEventListeners(eventImpl, listeners, phase, struct);
  }
  
  // https://dom.spec.whatwg.org/#concept-event-listener-inner-invoke
  function innerInvokeEventListeners(eventImpl, listeners, phase) {
    let found = false;
  
    const { type, target } = eventImpl;
    const wrapper = idlUtils.wrapperForImpl(target);
  
    if (!listeners || !listeners[type]) {
      return found;
    }
  
    // Copy event listeners before iterating since the list can be modified during the iteration.
    const handlers = listeners[type].slice();
  
    for (let i = 0; i < handlers.length; i++) {
      const listener = handlers[i];
      const { capture, once, passive } = listener.options;
  
      // Check if the event listener has been removed since the listeners has been cloned.
      if (!listeners[type].includes(listener)) {
        continue;
      }
  
      found = true;
  
      if (
        (phase === "capturing" && !capture) ||
        (phase === "bubbling" && capture)
      ) {
        continue;
      }
  
      if (once) {
        listeners[type].splice(listeners[type].indexOf(listener), 1);
      }
  
      if (passive) {
        eventImpl._inPassiveListenerFlag = true;
      }
  
      try {
        if (typeof listener.callback === "object") {
          if (typeof listener.callback.handleEvent === "function") {
            listener.callback.handleEvent(idlUtils.wrapperForImpl(eventImpl));
          }
        } else {
          listener.callback.call(eventImpl.currentTarget, idlUtils.wrapperForImpl(eventImpl));
        }
      } catch (e) {
        let window = null;
        if (wrapper && wrapper._document) {
          // Triggered by Window
          window = wrapper;
        } else if (target._ownerDocument) {
          // Triggered by most webidl2js'ed instances
          window = target._ownerDocument._defaultView;
        } else if (wrapper._ownerDocument) {
          // Currently triggered by some non-webidl2js things
          window = wrapper._ownerDocument._defaultView;
        }
  
        if (window) {
          reportException(window, e);
        }
        // Errors in window-less documents just get swallowed... can you think of anything better?
      }
  
      eventImpl._inPassiveListenerFlag = false;
  
      if (eventImpl._stopImmediatePropagationFlag) {
        return found;
      }
    }
  
    return found;
  }
  
  /**
   * Normalize the event listeners options argument in order to get always a valid options object
   * @param   {Object} options         - user defined options
   * @param   {Array} defaultBoolKeys  - boolean properties that should belong to the options object
   * @returns {Object} object containing at least the "defaultBoolKeys"
   */
  function normalizeEventHandlerOptions(options, defaultBoolKeys) {
    const returnValue = {};
  
    // no need to go further here
    if (typeof options === "boolean" || options === null || typeof options === "undefined") {
      returnValue.capture = Boolean(options);
      return returnValue;
    }
  
    // non objects options so we typecast its value as "capture" value
    if (typeof options !== "object") {
      returnValue.capture = Boolean(options);
      // at this point we don't need to loop the "capture" key anymore
      defaultBoolKeys = defaultBoolKeys.filter(k => k !== "capture");
    }
  
    for (const key of defaultBoolKeys) {
      returnValue[key] = Boolean(options[key]);
    }
  
    return returnValue;
  }
  
  // https://dom.spec.whatwg.org/#concept-event-path-append
  function appendToEventPath(eventImpl, target, targetOverride, relatedTarget, touchTargets, slotInClosedTree) {
    const itemInShadowTree = isNode(target) && isShadowRoot(nodeRoot(target));
    const rootOfClosedTree = isShadowRoot(target) && target.mode === "closed";
  
    eventImpl._path.push({
      item: target,
      itemInShadowTree,
      target: targetOverride,
      relatedTarget,
      touchTargets,
      rootOfClosedTree,
      slotInClosedTree
    });
  }