import type { WebContents } from "electron";
import type {
  DocxMediaCaptureAdapter,
  DocxMediaCaptureRequest
} from "@md-to-pdf/application";
import type { DocxMediaCapturePlan } from "@md-to-pdf/core";

interface CaptureScreenshotResult {
  data: string;
}

function createRenderScript(request: DocxMediaCaptureRequest) {
  const serialized = JSON.stringify(request);
  return `(async () => {
    const request = ${serialized};
    const renderer = window.__mdToPdfRenderDocxMedia;
    if (!renderer) {
      throw new Error("DOCX 媒体渲染运行时不可用");
    }
    return renderer(request.payload, request.dimensions);
  })()`;
}

export async function captureDocxMediaWithElectronWebContents(
  webContents: WebContents,
  request: DocxMediaCaptureRequest,
  signal?: AbortSignal
) {
  signal?.throwIfAborted();
  const plan = (await webContents.executeJavaScript(
    createRenderScript(request),
    true
  )) as DocxMediaCapturePlan;
  signal?.throwIfAborted();
  const ownsDebugger = !webContents.debugger.isAttached();
  if (ownsDebugger) {
    webContents.debugger.attach("1.3");
  }

  try {
    const captures = [];
    for (const target of plan.targets) {
      signal?.throwIfAborted();
      const result = (await webContents.debugger.sendCommand(
        "Page.captureScreenshot",
        {
          format: "png",
          fromSurface: true,
          captureBeyondViewport: true,
          clip: {
            x: target.captureX,
            y: target.captureY,
            width: target.captureWidthPx,
            height: target.captureHeightPx,
            scale: target.rasterScale
          }
        }
      )) as CaptureScreenshotResult;
      captures.push({
        id: target.id,
        png: Buffer.from(result.data, "base64")
      });
    }
    signal?.throwIfAborted();
    return { plan, captures };
  } finally {
    if (ownsDebugger && webContents.debugger.isAttached()) {
      webContents.debugger.detach();
    }
  }
}

export class ElectronDocxMediaCaptureAdapter
  implements DocxMediaCaptureAdapter
{
  constructor(private readonly webContents: WebContents) {}

  capture(request: DocxMediaCaptureRequest, signal?: AbortSignal) {
    return captureDocxMediaWithElectronWebContents(
      this.webContents,
      request,
      signal
    );
  }
}