import { fromUrl } from 'geotiff'; // 假设你用的是这个包
import { transform } from 'ol/proj';
import { fromLonLat } from 'ol/proj';
import ImageLayer from 'ol/layer/Image';
import Static from 'ol/source/ImageStatic';
import gcoord from 'gcoord';

export class GeoTiffLoader {
  imageExtent: number[] = [];
  imageLayer: ImageLayer<Static> | null = null;
  tiffUrl: string;

  constructor(tiffUrl: string) {
    this.tiffUrl = tiffUrl;
  }

  async init() {
    const tiff = await fromUrl(this.tiffUrl);
    const image = await tiff.getImage();

    const width = image.getWidth();
    const height = image.getHeight();
    const bbox = image.getBoundingBox(); // [minX, minY, maxX, maxY]
    console.log('bbox', bbox);

    const rasters = (await image.readRasters({ interleave: true })) as Uint8Array;

    // 创建 Canvas
    const canvas = document.createElement('canvas');
    canvas.width = width;
    canvas.height = height;
    const ctx = canvas.getContext('2d')!;
    const imageData = ctx.createImageData(width, height);

    // 设置 RGBA 数据
    imageData.data.set(rasters);
    ctx.putImageData(imageData, 0, 0);

    // 转成 Data URL
    const imageUrl = canvas.toDataURL();

    // 坐标转换
    const minLonLat = transform([bbox[0], bbox[1]], 'EPSG:32648', 'EPSG:4326');
    const maxLonLat = transform([bbox[2], bbox[3]], 'EPSG:32648', 'EPSG:4326');

    // 转为 GCJ02 坐标系
    // 这里断言为[number, number, number]，补0做三维坐标
    const gcjMin = gcoord.transform([minLonLat[0], minLonLat[1], 0], gcoord.WGS84, gcoord.GCJ02);
    const gcjMax = gcoord.transform([maxLonLat[0], maxLonLat[1], 0], gcoord.WGS84, gcoord.GCJ02);

    // 再转为 EPSG:3857
    const minXY = fromLonLat(gcjMin);
    const maxXY = fromLonLat(gcjMax);

    this.imageExtent = [...minXY, ...maxXY];

    this.imageLayer = new ImageLayer({
      source: new Static({
        url: imageUrl,
        imageExtent: this.imageExtent,
        projection: 'EPSG:3857'
      })
    });

    console.log('imageExtent', this.imageExtent);
  }
}