/*
 * Copyright (c) 2020 NAVER Corp.
 * egjs projects are licensed under the MIT license
 */

import * as THREE from "three";
import type { XRSystem } from "webxr";

import View3D from "../View3D";
import Animation from "../core/Animation";
import WebARControl, { WebARControlOptions } from "../control/ar/WebARControl";
import * as DEFAULT from "../const/default";
import * as XR from "../const/xr";
import * as BROWSER from "../const/browser";
import { AR_SESSION_TYPE, AUTO, EVENTS } from "../const/external";
import { getNullableElement, merge } from "../utils";
import { XRRenderContext } from "../type/xr";

import ARSession from "./ARSession";
import ARScene from "./ARScene";
import DOMOverlay from "./features/DOMOverlay";
import HitTest from "./features/HitTest";
import LightEstimation from "./features/LightEstimation";

declare global {
  interface Navigator { xr: XRSystem }
}

/**
 * Options for WebARSession
 * @interface
 * @extends WebARControlOptions
 * @param {object} [features={}] Additional features(see {@link https://developer.mozilla.org/en-US/docs/Web/API/XRSessionInit XRSessionInit}) of the WebXR session.
 * @param {boolean} [vertical=false] Whether to place 3D model vertically on the wall.
 * @param {HTMLElement|string|null} [overlayRoot=null] `dom-overlay`'s root element. You can set either HTMLElement or query selector for that element.
 * @param {boolean} [useLightEstimation=true] Whether to use `light-estimation` feature.
 * @param {boolean|ARSwirlControlOptions} [rotate=true] Options for the rotate control inside the AR session. You can disable rotate control by giving `false`.
 * @param {boolean|ARTranslateControlOptions} [translate=true] Options for the translate control inside the AR session. You can disable translate control by giving `false`.
 * @param {boolean|ARScaleControlOptions} [scale=true] Options for the scale control inside the AR session. You can disable scale control by giving `false`.
 * @param {FloorIndicatorOptions} [ring={}] Options for the floor ring.
 * @param {DeadzoneCheckerOptions} [deadzone={}] Control's deadzone options.
 * @param {"auto"|number} [initialScale="auto"] Initial scale of the model. If set to "auto", it will modify big overflowing 3D model's scale to fit the screen when it's initially displayed. This won't increase the 3D model's scale more than 1.
 */
export interface WebARSessionOptions extends WebARControlOptions {
  features: typeof XR.EMPTY_FEATURES;
  useLightEstimation: boolean;
  vertical: boolean;
  overlayRoot: HTMLElement | string | null;
}

/**
 * WebXR based abstract AR session class
 */
class WebARSession implements ARSession {
  /**
   * Return availability of this session
   * @returns {Promise<boolean>} A Promise that resolves availability of this session(boolean).
   */
  public static isAvailable() {
    if (
      !XR.WEBXR_SUPPORTED()
      || !HitTest.isAvailable()
      || !DOMOverlay.isAvailable()
    ) return Promise.resolve(false);

    return navigator.xr.isSessionSupported(XR.SESSION.AR);
  }

  public static readonly type = AR_SESSION_TYPE.WEBXR;

  // Options
  // As those values are referenced only while entering the session, so I'm leaving this values public
  public features: WebARSessionOptions["features"];
  public vertical: WebARSessionOptions["vertical"];
  public overlayRoot: WebARSessionOptions["overlayRoot"];
  public useLightEstimation: WebARSessionOptions["useLightEstimation"];

  // Internal Components
  private _view3D: View3D;
  private _arScene: ARScene;
  private _control: WebARControl;
  private _hitTest: HitTest;
  private _domOverlay: DOMOverlay;
  private _lightEstimation: LightEstimation;

  // Internal States
  private _modelPlaced: boolean;

  /**
   * {@link ARControl} instance of this session
   * @type ARFloorControl
   */
  public get control() { return this._control; }

  public get arScene() { return this._arScene; }
  public get hitTest() { return this._hitTest; }
  public get domOverlay() { return this._domOverlay; }
  public get lightEstimation() { return this._lightEstimation; }

  /**
   * Create new instance of WebARSession
   * @param {View3D} view3D Instance of the View3D
   * @param {object} [options={}] Options
   * @param {object} [options.features={}] Additional features(see {@link https://developer.mozilla.org/en-US/docs/Web/API/XRSessionInit XRSessionInit}) of the WebXR session.
   * @param {boolean} [options.vertical=false] Whether to place 3D model vertically on the wall.
   * @param {HTMLElement|string|null} [options.overlayRoot=null] `dom-overlay`'s root element. You can set either HTMLElement or query selector for that element.
   * @param {boolean} [options.useLightEstimation=true] Whether to use `light-estimation` feature.
   * @param {boolean|ARSwirlControlOptions} [options.rotate=true] Options for the rotate control inside the AR session. You can disable rotate control by giving `false`.
   * @param {boolean|ARTranslateControlOptions} [options.translate=true] Options for the translate control inside the AR session. You can disable translate control by giving `false`.
   * @param {boolean|ARScaleControlOptions} [options.scale=true] Options for the scale control inside the AR session. You can disable scale control by giving `false`.
   * @param {FloorIndicatorOptions} [options.ring={}] Options for the floor ring.
   * @param {DeadzoneCheckerOptions} [options.deadzone={}] Control's deadzone options.
   * @param {"auto"|number} [options.initialScale="auto"] Initial scale of the model. If set to "auto", it will modify big overflowing 3D model's scale to fit the screen when it's initially displayed. This won't increase the 3D model's scale more than 1.
   */
  public constructor(view3D: View3D, {
    features = XR.EMPTY_FEATURES,
    vertical = false,
    overlayRoot = null,
    useLightEstimation = true,
    rotate = true,
    translate = true,
    scale = true,
    ring = {},
    deadzone = {},
    initialScale = AUTO
  }: Partial<WebARSessionOptions> = {}) {
    this._view3D = view3D;

    // Init internal states
    this._modelPlaced = false;

    // Bind options
    this.features = features;
    this.vertical = vertical;
    this.overlayRoot = overlayRoot;
    this.useLightEstimation = useLightEstimation;

    // Create internal components
    this._arScene = new ARScene();
    this._control = new WebARControl(view3D, this._arScene, {
      rotate,
      translate,
      scale,
      ring,
      deadzone,
      initialScale
    });
    this._hitTest = new HitTest();
    this._domOverlay = new DOMOverlay();
    this._lightEstimation = new LightEstimation(view3D, this._arScene);
  }

  /**
   * Enter session
   * @param view3D Instance of the View3D
   * @returns {Promise}
   */
  public async enter() {
    const view3D = this._view3D;
    const scene = view3D.scene;
    const arScene = this._arScene;
    const renderer = view3D.renderer;
    const threeRenderer = renderer.threeRenderer;
    const control = this._control;
    const hitTest = this._hitTest;
    const domOverlay = this._domOverlay;
    const useLightEstimation = this.useLightEstimation;
    const lightEstimation = this._lightEstimation;
    const vertical = this.vertical;
    const features = this._getAllXRFeatures();

    // Enable xr
    threeRenderer.xr.enabled = true;

    if (useLightEstimation) {
      // Estimation requires "sessionstart" event of the renderer
      // So it should be initialized before requesting session
      lightEstimation.init();
    }

    const session = await navigator.xr.requestSession(XR.SESSION.AR, features) as unknown as THREE.XRSession;

    // Cache original values
    const originalPixelRatio = threeRenderer.getPixelRatio();

    threeRenderer.setPixelRatio(1);
    threeRenderer.xr.setReferenceSpaceType(XR.REFERENCE_SPACE.LOCAL);
    await threeRenderer.xr.setSession(session);

    arScene.init(view3D);
    hitTest.init(session);

    const onSessionEnd = async () => {
      control.destroy(session);
      arScene.destroy(view3D);
      lightEstimation.destroy();

      domOverlay.destroy();

      // Restore original values
      threeRenderer.setPixelRatio(originalPixelRatio);

      // Restore render loop
      renderer.stopAnimationLoop();
      renderer.setAnimationLoop(renderer.defaultRenderLoop);

      view3D.trigger(EVENTS.AR_END, { target: view3D, type: EVENTS.AR_END, session: this });
    };

    session.addEventListener("end", onSessionEnd, { once: true });

    // Set XR session render loop
    const screenSize = new THREE.Vector2(window.outerWidth, window.outerHeight);
    const arClock = new THREE.Clock();
    arClock.start();

    renderer.stopAnimationLoop();
    threeRenderer.xr.setAnimationLoop((_, frame?: THREE.XRFrame) => {
      const xrCamArray = (threeRenderer.xr.getCamera(new THREE.PerspectiveCamera()) as THREE.ArrayCamera);
      const delta = arClock.getDelta();

      if (xrCamArray.cameras.length <= 0) return;

      const xrCam = xrCamArray.cameras[0];

      const referenceSpace = threeRenderer.xr.getReferenceSpace()!;
      const glLayer = session.renderState.baseLayer;

      const size = {
        width: glLayer?.framebufferWidth ?? 1,
        height: glLayer?.framebufferHeight ?? 1
      };

      const ctx: XRRenderContext = {
        view3D,
        scene: arScene,
        session,
        delta,
        frame,
        vertical,
        referenceSpace,
        xrCam,
        size
      };

      const deltaMiliSec = delta * 1000;

      view3D.trigger(EVENTS.BEFORE_RENDER, {
        type: EVENTS.BEFORE_RENDER,
        target: view3D,
        delta: deltaMiliSec
      });

      if (!this._modelPlaced) {
        this._initModelPosition(ctx);
      } else {
        view3D.animator.update(delta);
        control.update(ctx);
        scene.shadowPlane.render();
        threeRenderer.render(arScene.root, xrCam);
        view3D.annotation.render(xrCam, screenSize);
      }

      view3D.trigger(EVENTS.RENDER, {
        type: EVENTS.RENDER,
        target: view3D,
        delta: deltaMiliSec
      });
    });

    view3D.trigger(EVENTS.AR_START, {
      type: EVENTS.AR_START,
      target: view3D,
      session: this
    });
  }

  /**
   * Exit this session
   */
  public async exit() {
    const session = this._view3D.renderer.threeRenderer.xr.getSession();

    return session?.end();
  }

  private _getAllXRFeatures() {
    const userFeatures = this.features;
    const overlayRoot = getNullableElement(this.overlayRoot) ?? this._createARRootElement();

    return merge(
      {},
      this._domOverlay.getFeatures(overlayRoot),
      this._hitTest.getFeatures(),
      this._lightEstimation.getFeatures(),
      userFeatures
    );
  }

  private _initModelPosition(ctx: XRRenderContext) {
    const {
      frame,
      session,
      size,
      vertical,
      referenceSpace
    } = ctx;
    const view3D = this._view3D;
    const model = view3D.model;
    const arScene = this._arScene;
    const hitTest = this._hitTest;

    // Make sure the model is loaded
    if (!hitTest.ready || !model) return;

    const control = this._control;
    const hitTestResults = hitTest.getResults(frame);

    if (hitTestResults.length <= 0) return;

    const hit = hitTestResults[0];
    const hitPose = hit.getPose(referenceSpace);

    if (!hitPose) return;

    const hitMatrix = new THREE.Matrix4().fromArray(hitPose.transform.matrix);

    // If transformed coords space's y axis is not facing the correct direction, don't use it.
    if (
      (!vertical && hitMatrix.elements[5] < 0.75)
      || (vertical && (hitMatrix.elements[5] >= 0.25 || hitMatrix.elements[5] <= -0.25))
    ) return;

    const hitPosition = new THREE.Vector3().setFromMatrixPosition(hitMatrix);
    const hitRotation = new THREE.Quaternion();

    if (vertical) {
      const globalUp = new THREE.Vector3(0, 1, 0);
      const hitOrientation = hitPose.transform.orientation;
      const wallNormal = globalUp.clone()
        .applyQuaternion(new THREE.Quaternion(hitOrientation.x, hitOrientation.y, hitOrientation.z, hitOrientation.w))
        .normalize();
      const wallX = new THREE.Vector3().crossVectors(new THREE.Vector3(0, 1, 0), wallNormal);

      const wallMatrix = new THREE.Matrix4().makeBasis(wallX, globalUp, wallNormal);
      const wallEuler = new THREE.Euler(0, 0, 0, "YXZ").setFromRotationMatrix(wallMatrix);

      wallEuler.z = 0;
      wallEuler.x = Math.PI / 2;

      hitRotation.setFromEuler(wallEuler);
      arScene.setWallRotation(hitRotation);
    }

    // Reset rotation & update position
    arScene.updateModelRootPosition(model, vertical);
    arScene.setRootPosition(hitPosition);
    arScene.showModel();

    // Don't need hit-test anymore, as we're having new one in WebARControl
    hitTest.destroy();

    this._modelPlaced = true;
    view3D.trigger(EVENTS.AR_MODEL_PLACED, { type: EVENTS.AR_MODEL_PLACED, target: view3D, session: this, model });

    void control.init({
      model,
      vertical,
      session,
      size,
      hitPosition,
      hitRotation
    });

    const initialScale = control.scale.scale;

    // Show scale up animation
    const scaleUpAnimation = new Animation({
      context: session,
      duration: 1000
    });

    scaleUpAnimation.on("progress", evt => {
      arScene.setModelScale(evt.easedProgress * initialScale);
    });

    scaleUpAnimation.on("finish", () => {
      arScene.setModelScale(initialScale);
      control.enable(session);
    });

    scaleUpAnimation.start();
  }

  private _createARRootElement(): HTMLElement {
    const view3D = this._view3D;
    const root = document.createElement(BROWSER.EL_DIV);

    root.classList.add(DEFAULT.AR_OVERLAY_CLASS);
    view3D.rootEl.appendChild(root);
    view3D.once(EVENTS.AR_END, () => {
      view3D.rootEl.removeChild(root);
    });

    return root;
  }
}

export default WebARSession;