import { ref } from "vue";

export default function useDraw() {
  // 指向最外层容器
  const appRef = ref();
  // 定时函数
  const timer:any = ref(0);
  // 默认缩放值
  const scale = {
    width: "1",
    height: "1",
  };
  // 设计稿尺寸（px）
  const baseWidth = 1920;
  const baseHeight = 1080;

  // 需保持的比例
  const baseProportion = parseFloat((baseWidth / baseHeight).toFixed(5));
  const calcRate = () => {
    // 当前宽高比
    const currentRate = parseFloat(
      (window.innerWidth / window.innerHeight).toFixed(5)
    );
    if (appRef.value) {
      if (currentRate > baseProportion) {
        // 表示更宽
        scale.width = (
          (window.innerHeight * baseProportion) /
          baseWidth
        ).toFixed(5);
        scale.height = (window.innerHeight / baseHeight).toFixed(5);
        appRef.value.style.transform = `scale(${scale.width}, ${scale.height}) translate(-50%, -50%)`;
      } else {
        // 表示更高
        scale.height = (
          window.innerWidth /
          baseProportion /
          baseHeight
        ).toFixed(5);
        scale.width = (window.innerWidth / baseWidth).toFixed(5);
        appRef.value.style.transform = `scale(${scale.width}, ${scale.height}) translate(-50%, -50%)`;
      }
                window.sessionStorage.setItem("scaleWidth", scale.width);
            window.sessionStorage.setItem("scaleheight", scale.height);
    }
  };

  const resize = () => {
    clearTimeout(timer.value);
    timer.value = setTimeout(() => {
      calcRate();
    }, 200);
  };

  // 改变窗口大小重新绘制
  const windowDraw = () => {
    window.addEventListener("resize", resize);
  };

  // 改变窗口大小重新绘制
  const unWindowDraw = () => {
    window.removeEventListener("resize", resize);
  };

  return {
    appRef,
    calcRate,
    windowDraw,
    unWindowDraw,
  };
}
