it.auties.whatsapp.api.QrHandler Maven / Gradle / Ivy

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package it.auties.whatsapp.api;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
import it.auties.qr.QrTerminal;

import java.awt.*;
import java.io.IOException;
import java.io.UncheckedIOException;
import java.nio.file.Path;
import java.util.Map;
import java.util.function.Consumer;

import static com.google.zxing.client.j2se.MatrixToImageWriter.writeToPath;
import static java.lang.System.Logger.Level.INFO;
import static java.nio.file.Files.createTempFile;

/**
 * This interface allows to consume a qr code and provides default common implementations to do so
 */
@SuppressWarnings("unused")
public non-sealed interface QrHandler extends Consumer, WebVerificationHandler {
    /**
     * Prints the QR code to the terminal. If your terminal doesn't support utf, you may see random
     * characters.
     */
    static QrHandler toTerminal() {
        return toString(System.out::println);
    }

    /**
     * Transforms the qr code in a UTF-8 string and accepts a consumer for the latter
     *
     * @param smallQrConsumer the non-null consumer
     */
    static QrHandler toString(Consumer smallQrConsumer) {
        return qr -> {
            var matrix = createMatrix(qr, 10, 0);
            smallQrConsumer.accept(QrTerminal.toString(matrix, true));
        };
    }

    /**
     * Transforms the qr code in a UTF-8 plain string and accepts a consumer for the latter
     *
     * @param qrConsumer the non-null consumer
     */
    static QrHandler toPlainString(Consumer qrConsumer) {
        return qrConsumer::accept;
    }

    /**
     * Utility method to create a matrix from a qr countryCode
     *
     * @param qr     the non-null source
     * @param size   the size of the qr countryCode
     * @param margin the margin for the qr countryCode
     * @return a non-null matrix
     */
    static BitMatrix createMatrix(String qr, int size, int margin) {
        try {
            var writer = new MultiFormatWriter();
            return writer.encode(qr, BarcodeFormat.QR_CODE, size, size, Map.of(EncodeHintType.MARGIN, margin, EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L));
        } catch (WriterException exception) {
            throw new UnsupportedOperationException("Cannot create qr countryCode", exception);
        }
    }

    /**
     * Saves the QR code to a temp file
     *
     * @param fileConsumer the consumer to digest the created file
     */
    static QrHandler toFile(ToFileConsumer fileConsumer) {
        try {
            var file = createTempFile("qr", ".jpg");
            return toFile(file, fileConsumer);
        } catch (IOException exception) {
            throw new UncheckedIOException("Cannot create temp file for qr handler", exception);
        }
    }

    /**
     * Saves the QR code to a specified file
     *
     * @param path         the location where the qr will be written
     * @param fileConsumer the consumer to digest the created file
     */
    static QrHandler toFile(Path path, ToFileConsumer fileConsumer) {
        return qr -> {
            try {
                var matrix = createMatrix(qr, 500, 5);
                writeToPath(matrix, "jpg", path);
                fileConsumer.accept(path);
            } catch (IOException exception) {
                throw new UncheckedIOException("Cannot save qr to file", exception);
            }
        };
    }

    /**
     * This interface allows to consume a file created by
     * {@link QrHandler#toFile(Path, ToFileConsumer)} easily
     */
    interface ToFileConsumer extends Consumer {
        /**
         * Discard the newly created file
         */
        static ToFileConsumer discarding() {
            return ignored -> {
            };
        }

        /**
         * Prints the location of the file on the terminal using the system logger
         */
        static ToFileConsumer toTerminal() {
            return path -> System.getLogger(QrHandler.class.getName())
                    .log(INFO, "Saved qr code at %s".formatted(path));
        }

        /**
         * Opens the file if a Desktop environment is available
         */
        static ToFileConsumer toDesktop() {
            return path -> {
                try {
                    if (!Desktop.isDesktopSupported()) {
                        return;
                    }
                    Desktop.getDesktop().open(path.toFile());
                } catch (Throwable throwable) {
                    throw new RuntimeException("Cannot open file with desktop", throwable);
                }
            };
        }
    }
}