import {
  Material,
  Matrix,
  MeshRenderer,
  MeshTopology,
  ModelMesh,
  Script,
  Texture2D,
  Vector2,
  Vector3
} from "oasis-engine";
import { PaladinAdapter } from "../adapter/PaladinAdapter";
import { BgMaterialAndroid } from "./Android/BgMaterialAndroid";
import { ARManager } from "./ARManager";
import { BgMaterialIos } from "./IOS/BgMaterialIos";

/**
 * 使用时再重写，性能可以得到提升
 */
export class ARBackground extends Script {
  private _material: Material;
  private _textureY: Texture2D;
  private _textureUV: Texture2D;
  private _textureProject: Matrix;
  onAwake() {
    const { entity, engine } = this;
    // MeshRenderer
    const renderer = entity.addComponent(MeshRenderer);
    renderer.mesh = this._createPlane();
    const material = PaladinAdapter.isIOS ? new BgMaterialIos(engine) : new BgMaterialAndroid(engine);
    renderer.setMaterial(material);
    this._material = material;
  }

  /**
   * 更新相机背景
   * @param curARFrame - AR 帧数据
   */
  onUpdate(deltaTime: number): void {
    const { textureY, textureUV, textureProject } = ARManager.ins;
    if (textureY && textureY != this._textureY) {
      this._material.shaderData.setTexture("u_frameY", textureY);
      this._textureY = textureY;
      if (PaladinAdapter.isIOS) {
        const scaleMatrix = this._material.shaderData.getMatrix("u_scaleMatrix");
        const screenWidth = this.engine.canvas.width;
        const screenHeight = this.engine.canvas.height;
        const frameWidth = textureY.height;
        const frameHeight = textureY.width;
        const screenRatio = screenWidth / screenHeight;
        const frameRatio = frameWidth / frameHeight;
        const ratio = screenRatio / frameRatio;
        if (ratio > 1) {
          scaleMatrix.elements[0] = 1;
          scaleMatrix.elements[5] = ratio;
        } else {
          scaleMatrix.elements[0] = 1 / ratio;
          scaleMatrix.elements[5] = 1;
        }
      }
    }
    if (textureUV && textureUV != this._textureUV) {
      this._material.shaderData.setTexture("u_frameUV", textureUV);
      this._textureUV = textureUV;
    }
    if (textureProject != this._textureProject) {
      this._material.shaderData.setMatrix("u_proMatrix", textureProject);
      this._textureProject = textureProject;
    }
  }

  /**
   * 创建相机背景平面
   * @returns
   */
  private _createPlane(): ModelMesh {
    const mesh = new ModelMesh(this.engine);
    mesh.setPositions([new Vector3(-1, -1, 1), new Vector3(1, -1, 1), new Vector3(1, 1, 1), new Vector3(-1, 1, 1)]);
    mesh.setUVs([new Vector2(0, 1), new Vector2(1, 1), new Vector2(1, 0), new Vector2(0, 0)]);
    mesh.uploadData(true);
    mesh.addSubMesh(0, 4, MeshTopology.TriangleFan);
    return mesh;
  }
}