package com.rn_pdfToImageConverter;

import android.widget.Toast;
import android.net.Uri;

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.pdf.PdfRenderer;
import android.os.ParcelFileDescriptor;

import com.facebook.react.bridge.Arguments;
import com.facebook.react.bridge.Promise;
import com.facebook.react.bridge.ReactApplicationContext;
import com.facebook.react.bridge.ReactContextBaseJavaModule;
import com.facebook.react.bridge.ReactMethod;
import com.facebook.react.bridge.WritableMap;

import java.io.File;
import java.io.FileOutputStream;

public class RNPdfToImageConverterModule extends ReactContextBaseJavaModule {

  private static final String E_CONVERT_ERROR = "E_CONVERT_ERROR";

  private final ReactApplicationContext reactContext;

  public RNPdfToImageConverterModule(ReactApplicationContext reactContext) {
    super(reactContext);
    this.reactContext = reactContext;
  }

  @Override
  public String getName() {
    return "RNPdfToImageConverter";
  }

  @ReactMethod
  public void convert(String pdfUriString, Promise promise) {
    try {
      Uri path = Uri.parse(pdfUriString);

      ParcelFileDescriptor parcelFileDescriptor = reactContext.getContentResolver().openFileDescriptor(path, "r");

      PdfRenderer renderer = new PdfRenderer(parcelFileDescriptor);
      PdfRenderer.Page page = renderer.openPage(0);

      Bitmap bitmap = Bitmap.createBitmap(page.getWidth(), page.getHeight(), Bitmap.Config.ARGB_8888);
      Canvas canvas = new Canvas(bitmap);
      canvas.drawColor(Color.WHITE);

      page.render(bitmap, null, null, PdfRenderer.Page.RENDER_MODE_FOR_DISPLAY);
      File output = this.saveImage(bitmap, reactContext.getCacheDir());
      page.close();

      WritableMap map = Arguments.createMap();
      map.putString("outputFile", output.getAbsolutePath());
      promise.resolve(map);

    } catch(Exception e) {
      promise.reject(E_CONVERT_ERROR, e);
    }
  }

  private File saveImage(Bitmap finalBitmap, File cacheDir) {
    File file = new File(cacheDir.getAbsolutePath() + File.separator + System.currentTimeMillis() + "_pdf.png");
    if (file.exists()) file.delete ();
    try {
      FileOutputStream out = new FileOutputStream(file);
      finalBitmap.compress(Bitmap.CompressFormat.PNG, 100, out);
      out.flush();
      out.close();
    } catch (Exception e) {
      e.printStackTrace();
      return null;
    }
    return file;
  }
}