cheogram/src/main/java/eu/siacs/conversations/services/BarcodeProvider.java

package eu.siacs.conversations.services;

import android.content.ComponentName;
import android.content.ContentProvider;
import android.content.ContentValues;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.Color;
import android.net.Uri;
import android.os.CancellationSignal;
import android.os.IBinder;
import android.os.ParcelFileDescriptor;
import androidx.annotation.Nullable;
import android.util.Log;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.QRCodeWriter;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.OutputStream;
import java.util.Hashtable;

import eu.siacs.conversations.Config;
import eu.siacs.conversations.entities.Account;
import eu.siacs.conversations.utils.CryptoHelper;
import eu.siacs.conversations.xmpp.Jid;

public class BarcodeProvider extends ContentProvider implements ServiceConnection {

	private static final String AUTHORITY = ".barcodes";

	private final Object lock = new Object();

	private XmppConnectionService mXmppConnectionService;
	private boolean mBindingInProcess = false;

	public static Uri getUriForAccount(Context context, Account account) {
		final String packageId = context.getPackageName();
		return Uri.parse("content://" + packageId + AUTHORITY + "/" + account.getJid().asBareJid() + ".png");
	}

	public static Bitmap create2dBarcodeBitmap(String input, int size) {
		try {
			final QRCodeWriter barcodeWriter = new QRCodeWriter();
			final Hashtable<EncodeHintType, Object> hints = new Hashtable<>();
			hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.M);
			hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
			final BitMatrix result = barcodeWriter.encode(input, BarcodeFormat.QR_CODE, size, size, hints);
			final int width = result.getWidth();
			final int height = result.getHeight();
			final int[] pixels = new int[width * height];
			for (int y = 0; y < height; y++) {
				final int offset = y * width;
				for (int x = 0; x < width; x++) {
					pixels[offset + x] = result.get(x, y) ? Color.BLACK : Color.WHITE;
				}
			}
			final Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
			bitmap.setPixels(pixels, 0, width, 0, 0, width, height);
			return bitmap;
		} catch (final Exception e) {
			e.printStackTrace();
			return null;
		}
	}

	@Override
	public boolean onCreate() {
		File barcodeDirectory = new File(getContext().getCacheDir().getAbsolutePath() + "/barcodes/");
		if (barcodeDirectory.exists() && barcodeDirectory.isDirectory()) {
			for (File file : barcodeDirectory.listFiles()) {
				if (file.isFile() && !file.isHidden()) {
					if (file.delete()) {
						Log.d(Config.LOGTAG, "deleted old barcode file " + file.getAbsolutePath());
					}
				}
			}
		}
		return true;
	}

	@Nullable
	@Override
	public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
		return null;
	}

	@Nullable
	@Override
	public String getType(Uri uri) {
		return "image/png";
	}

	@Nullable
	@Override
	public Uri insert(Uri uri, ContentValues values) {
		return null;
	}

	@Override
	public int delete(Uri uri, String selection, String[] selectionArgs) {
		return 0;
	}

	@Override
	public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
		return 0;
	}

	@Override
	public ParcelFileDescriptor openFile(Uri uri, String mode) throws FileNotFoundException {
		return openFile(uri, mode, null);
	}

	@Override
	public ParcelFileDescriptor openFile(Uri uri, String mode, CancellationSignal signal) throws FileNotFoundException {
		Log.d(Config.LOGTAG, "opening file with uri (normal): " + uri.toString());
		String path = uri.getPath();
		if (path != null && path.endsWith(".png") && path.length() >= 5) {
			String jid = path.substring(1).substring(0, path.length() - 4);
			Log.d(Config.LOGTAG, "account:" + jid);
			if (connectAndWait()) {
				Log.d(Config.LOGTAG, "connected to background service");
				try {
					Account account = mXmppConnectionService.findAccountByJid(Jid.of(jid));
					if (account != null) {
						String shareableUri = account.getShareableUri();
						String hash = CryptoHelper.getFingerprint(shareableUri);
						File file = new File(getContext().getCacheDir().getAbsolutePath() + "/barcodes/" + hash);
						if (!file.exists()) {
							file.getParentFile().mkdirs();
							file.createNewFile();
							Bitmap bitmap = create2dBarcodeBitmap(account.getShareableUri(), 1024);
							OutputStream outputStream = new FileOutputStream(file);
							bitmap.compress(Bitmap.CompressFormat.PNG, 100, outputStream);
							outputStream.close();
							outputStream.flush();
						}
						return ParcelFileDescriptor.open(file, ParcelFileDescriptor.MODE_READ_ONLY);
					}
				} catch (Exception e) {
					throw new FileNotFoundException();
				}
			}
		}
		throw new FileNotFoundException();
	}

	private boolean connectAndWait() {
		Intent intent = new Intent(getContext(), XmppConnectionService.class);
		intent.setAction(this.getClass().getSimpleName());
		Context context = getContext();
		if (context != null) {
			synchronized (this) {
				if (mXmppConnectionService == null && !mBindingInProcess) {
					Log.d(Config.LOGTAG, "calling to bind service");
					context.bindService(intent, this, Context.BIND_AUTO_CREATE);
					this.mBindingInProcess = true;
				}
			}
			try {
				waitForService();
				return true;
			} catch (InterruptedException e) {
				return false;
			}
		} else {
			Log.d(Config.LOGTAG, "context was null");
			return false;
		}
	}

	@Override
	public void onServiceConnected(ComponentName name, IBinder service) {
		synchronized (this) {
			XmppConnectionService.XmppConnectionBinder binder = (XmppConnectionService.XmppConnectionBinder) service;
			mXmppConnectionService = binder.getService();
			mBindingInProcess = false;
			synchronized (this.lock) {
				lock.notifyAll();
			}
		}
	}

	@Override
	public void onServiceDisconnected(ComponentName name) {
		synchronized (this) {
			mXmppConnectionService = null;
		}
	}

	private void waitForService() throws InterruptedException {
		if (mXmppConnectionService == null) {
			synchronized (this.lock) {
				lock.wait();
			}
		} else {
			Log.d(Config.LOGTAG, "not waiting for service because already initialized");
		}
	}
}