/*
 * Copyright (c) 2018-2019. Developed by Hedgecode.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.hedgecode.chess.qrcode;

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.util.EnumMap;
import java.util.Map;

import javax.imageio.ImageIO;

import com.google.zxing.BinaryBitmap;
import com.google.zxing.DecodeHintType;
import com.google.zxing.ReaderException;
import com.google.zxing.client.j2se.BufferedImageLuminanceSource;
import com.google.zxing.common.DecoderResult;
import com.google.zxing.common.DetectorResult;
import com.google.zxing.common.HybridBinarizer;
import com.google.zxing.qrcode.decoder.Decoder;
import com.google.zxing.qrcode.detector.Detector;

/**
 * Chess-specific QR Codes reader (image decoder).
 *
 * @author Dmitry Samoshin aka gotty
 */
public class ChessQRCodeReader {

    private final Decoder decoder;

    private static ChessQRCodeReader _instance = new ChessQRCodeReader();

    protected ChessQRCodeReader() {
        decoder = new Decoder();
    }

    public ChessQRResult read(File qrCodeImageFile) throws ChessQRCodeException {
        BufferedImage qrCodeImage;
        try {
            qrCodeImage = ImageIO.read(qrCodeImageFile);
        } catch (IOException e) {
            throw new ChessQRCodeException(
                    ChessQRCodeException.Type.READ, "read.input.qrcode.file", qrCodeImageFile.getName()
            );
        }
        return read(qrCodeImage);
    }

    public ChessQRResult read(InputStream qrCodeInputStream) throws ChessQRCodeException {
        BufferedImage qrCodeImage;
        try {
            qrCodeImage = ImageIO.read(qrCodeInputStream);
        } catch (IOException e) {
            throw new ChessQRCodeException(
                    ChessQRCodeException.Type.READ, "read.input.qrcode.stream", e.getMessage()
            );
        }
        return read(qrCodeImage);
    }

    public ChessQRResult read(URI qrCodeUri) throws ChessQRCodeException {
        BufferedImage qrCodeImage;
        try {
            qrCodeImage = ImageIO.read(qrCodeUri.toURL());
        } catch (IOException e) {
            throw new ChessQRCodeException(
                    ChessQRCodeException.Type.READ, "read.input.qrcode.url", qrCodeUri.toASCIIString()
            );
        }
        return read(qrCodeImage);
    }

    public ChessQRResult read(BufferedImage qrCodeImage) throws ChessQRCodeException {
        BinaryBitmap bitmap = new BinaryBitmap(
                new HybridBinarizer(
                        new BufferedImageLuminanceSource(qrCodeImage)
                )
        );
        return decode(bitmap, null);
    }

    private ChessQRResult decode(BinaryBitmap image, Map<DecodeHintType,?> hints)
            throws ChessQRCodeException
    {
        Map<DecodeHintType,Object> newHints = new EnumMap<>(DecodeHintType.class);
        if (hints != null) {
            newHints.putAll(hints);
            if (!hints.containsKey(DecodeHintType.CHARACTER_SET))
                newHints.put(DecodeHintType.CHARACTER_SET, ChessQRCodeConstants.CHARSET.name());
        } else {
            newHints.put(DecodeHintType.CHARACTER_SET, ChessQRCodeConstants.CHARSET.name());
        }
        hints = newHints;

        DecoderResult decoderResult;
        try {
            DetectorResult detectorResult = new Detector(
                    image.getBlackMatrix()
            ).detect(hints);

            decoderResult = decoder.decode(
                    detectorResult.getBits(), hints
            );
        } catch (ReaderException e) {
            throw new ChessQRCodeException(
                    ChessQRCodeException.Type.READ, "read.zxing.qrcode.error", e.getMessage()
            );
        }

        return createResult(decoderResult);
/*
        ResultPoint[] points = detectorResult.getPoints();

        if (decoderResult.getOther() instanceof QRCodeDecoderMetaData) {
            ((QRCodeDecoderMetaData) decoderResult.getOther()).applyMirroredCorrection(points);
        }

        Result result = new Result(
                decoderResult.getText(),
                decoderResult.getRawBytes(),
                points,
                BarcodeFormat.QR_CODE
        );

        List<byte[]> byteSegments = decoderResult.getByteSegments();
        if (byteSegments != null) {
            result.putMetadata(ResultMetadataType.BYTE_SEGMENTS, byteSegments);
        }
        String ecLevel = decoderResult.getECLevel();
        if (ecLevel != null) {
            result.putMetadata(ResultMetadataType.ERROR_CORRECTION_LEVEL, ecLevel);
        }
        if (decoderResult.hasStructuredAppend()) {
            result.putMetadata(
                    ResultMetadataType.STRUCTURED_APPEND_SEQUENCE,
                    decoderResult.getStructuredAppendSequenceNumber()
            );
            result.putMetadata(
                    ResultMetadataType.STRUCTURED_APPEND_PARITY,
                    decoderResult.getStructuredAppendParity()
            );
        }
        return result;
*/
    }

    protected ChessQRResult createResult(DecoderResult decoderResult) throws ChessQRCodeException {
        String result = decoderResult.getText();

        ChessQRCodeMode mode = ChessQRResult.getMode(result);
        if (mode == null) {
            throw new ChessQRCodeException(
                    ChessQRCodeException.Type.READ, "read.unknown.chess.mode"
            );
        }

        return new ChessQRResult(
                mode,
                ChessQRResult.getContents(result)
        );
    }

    public static ChessQRCodeReader getInstance() {
        return _instance;
    }


    public static void main(String[] args) {
        try {
            ChessQRResult qrCodeResult = ChessQRCodeReader.getInstance().read(
                    new File("qrcode.png")
            );
            System.out.println("Decoded format = " + qrCodeResult.getMode());
            System.out.println("Decoded text = " + qrCodeResult.getContents());
        } catch (ChessQRCodeException e) {
            System.out.println("Could not decode QR Code. Exception: " + e.getMessage());
        }
    }

}