import { materialContentUrl } from "@/lib/client/asset-urls";
import type { PromptMaterial } from "@/lib/prompt/assembler";
import type { SeedreamAnnotation } from "@/lib/seedream/creation";

const markerColor = "#2563eb";

export async function createSeedreamMarkedFile(
  source: PromptMaterial,
  annotations: SeedreamAnnotation[],
  imageIndex: number
) {
  const strokes = annotations.filter((annotation) => annotation.kind === "stroke" && annotation.points && annotation.points.length > 1);
  if (!strokes.length) return null;

  const response = await fetch(materialContentUrl(source), { credentials: "same-origin" });
  if (!response.ok) throw new Error(`读取图${imageIndex}失败，无法合成蓝色标记`);
  const bitmap = await createImageBitmap(await response.blob());
  try {
    const canvas = document.createElement("canvas");
    canvas.width = bitmap.width;
    canvas.height = bitmap.height;
    const context = canvas.getContext("2d");
    if (!context) throw new Error("当前浏览器无法创建标记画布");
    context.drawImage(bitmap, 0, 0);
    context.strokeStyle = markerColor;
    context.fillStyle = markerColor;
    context.lineCap = "round";
    context.lineJoin = "round";
    context.lineWidth = Math.max(5, Math.round(Math.min(bitmap.width, bitmap.height) * 0.012));

    for (const stroke of strokes) {
      const points = stroke.points || [];
      if (!points.length) continue;
      context.beginPath();
      context.moveTo(points[0].x / 1000 * bitmap.width, points[0].y / 1000 * bitmap.height);
      for (const point of points.slice(1)) {
        context.lineTo(point.x / 1000 * bitmap.width, point.y / 1000 * bitmap.height);
      }
      context.stroke();
    }

    const blob = await canvasBlob(canvas, "image/png");
    return new File([blob], `seedream-marked-image-${imageIndex}.png`, { type: "image/png" });
  } finally {
    bitmap.close();
  }
}

function canvasBlob(canvas: HTMLCanvasElement, type: string) {
  return new Promise<Blob>((resolve, reject) => {
    canvas.toBlob((blob) => {
      if (blob) resolve(blob);
      else reject(new Error("生成标记图片失败"));
    }, type);
  });
}