/*
 * Copyright 2007 ZXing authors
 *
 * 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.
 */

/*namespace com.google.zxing.qrcode.decoder {*/

import DecodeHintType from './../../DecodeHintType';
import BitMatrix from './../../common/BitMatrix';
import DecoderResult from './../../common/DecoderResult';
import GenericGF from './../../common/reedsolomon/GenericGF';
import ReedSolomonDecoder from './../../common/reedsolomon/ReedSolomonDecoder';
import BitMatrixParser from './BitMatrixParser';
import QRCodeDecoderMetaData from './QRCodeDecoderMetaData';
import DataBlock from './DataBlock';
import DecodedBitStreamParser from './DecodedBitStreamParser';
import Exception from './../../Exception';

/*import java.util.Map;*/

/**
 * <p>The main class which implements QR Code decoding -- as opposed to locating and extracting
 * the QR Code from an image.</p>
 *
 * @author Sean Owen
 */
export default class Decoder {

    private rsDecoder: ReedSolomonDecoder;

    public constructor() {
        this.rsDecoder = new ReedSolomonDecoder(GenericGF.QR_CODE_FIELD_256);
    }

    // public decode(image: boolean[][]): DecoderResult /*throws ChecksumException, FormatException*/ {
    //   return decode(image, null)
    // }

    /**
     * <p>Convenience method that can decode a QR Code represented as a 2D array of booleans.
     * "true" is taken to mean a black module.</p>
     *
     * @param image booleans representing white/black QR Code modules
     * @param hints decoding hints that should be used to influence decoding
     * @return text and bytes encoded within the QR Code
     * @throws FormatException if the QR Code cannot be decoded
     * @throws ChecksumException if error correction fails
     */
    public decodeBooleanArray(image: boolean[][], hints?: Map<DecodeHintType, any>): DecoderResult {
        return this.decodeBitMatrix(BitMatrix.parseFromBooleanArray(image), hints);
    }

    // public decodeBitMatrix(bits: BitMatrix): DecoderResult /*throws ChecksumException, FormatException*/ {
    //   return decode(bits, null)
    // }

    /**
     * <p>Decodes a QR Code represented as a {@link BitMatrix}. A 1 or "true" is taken to mean a black module.</p>
     *
     * @param bits booleans representing white/black QR Code modules
     * @param hints decoding hints that should be used to influence decoding
     * @return text and bytes encoded within the QR Code
     * @throws FormatException if the QR Code cannot be decoded
     * @throws ChecksumException if error correction fails
     */
    public decodeBitMatrix(bits: BitMatrix, hints?: Map<DecodeHintType, any>): DecoderResult {

        // Construct a parser and read version, error-correction level
        const parser = new BitMatrixParser(bits);
        let ex = null;
        try {
            return this.decodeBitMatrixParser(parser, hints);
        } catch (e/*: FormatException, ChecksumException*/) {
            ex = e;
        }

        try {

            // Revert the bit matrix
            parser.remask();

            // Will be attempting a mirrored reading of the version and format info.
            parser.setMirror(true);

            // Preemptively read the version.
            parser.readVersion();

            // Preemptively read the format information.
            parser.readFormatInformation();

            /*
             * Since we're here, this means we have successfully detected some kind
             * of version and format information when mirrored. This is a good sign,
             * that the QR code may be mirrored, and we should try once more with a
             * mirrored content.
             */
            // Prepare for a mirrored reading.
            parser.mirror();

            const result = this.decodeBitMatrixParser(parser, hints);

            // Success! Notify the caller that the code was mirrored.
            result.setOther(new QRCodeDecoderMetaData(true));

            return result;

        } catch (e/*FormatException | ChecksumException*/) {
            // Throw the exception from the original reading
            if (ex !== null) {
                throw ex;
            }
            throw e;

        }
    }

    private decodeBitMatrixParser(parser: BitMatrixParser, hints: Map<DecodeHintType, any>): DecoderResult {
        const version = parser.readVersion();
        const ecLevel = parser.readFormatInformation().getErrorCorrectionLevel();

        // Read codewords
        const codewords = parser.readCodewords();
        // Separate into data blocks
        const dataBlocks = DataBlock.getDataBlocks(codewords, version, ecLevel);

        // Count total number of data bytes
        let totalBytes = 0;
        for (const dataBlock of dataBlocks) {
            totalBytes += dataBlock.getNumDataCodewords();
        }
        const resultBytes = new Uint8Array(totalBytes);
        let resultOffset = 0;

        // Error-correct and copy data blocks together into a stream of bytes
        for (const dataBlock of dataBlocks) {
            const codewordBytes = dataBlock.getCodewords();
            const numDataCodewords = dataBlock.getNumDataCodewords();
            this.correctErrors(codewordBytes, numDataCodewords);
            for (let i = 0; i < numDataCodewords; i++) {
                resultBytes[resultOffset++] = codewordBytes[i];
            }
        }

        // Decode the contents of that stream of bytes
        return DecodedBitStreamParser.decode(resultBytes, version, ecLevel, hints);
    }

    /**
     * <p>Given data and error-correction codewords received, possibly corrupted by errors, attempts to
     * correct the errors in-place using Reed-Solomon error correction.</p>
     *
     * @param codewordBytes data and error correction codewords
     * @param numDataCodewords number of codewords that are data bytes
     * @throws ChecksumException if error correction fails
     */
    private correctErrors(codewordBytes: Uint8Array, numDataCodewords: number /*int*/): void /*throws ChecksumException*/ {
        const numCodewords = codewordBytes.length;
        // First read into an array of ints
        const codewordsInts = new Int32Array(codewordBytes);
        // TYPESCRIPTPORT: not realy necessary to transform to ints? could redesign everything to work with unsigned bytes?
        // const codewordsInts = new Int32Array(numCodewords)
        // for (let i = 0; i < numCodewords; i++) {
        //   codewordsInts[i] = codewordBytes[i] & 0xFF
        // }
        try {
            this.rsDecoder.decode(codewordsInts, codewordBytes.length - numDataCodewords);
        } catch (ignored/*: ReedSolomonException*/) {
            throw new Exception(Exception.ChecksumException);
        }
        // Copy back into array of bytes -- only need to worry about the bytes that were data
        // We don't care about errors in the error-correction codewords
        for (let i = 0; i < numDataCodewords; i++) {
            codewordBytes[i] = /*(byte) */codewordsInts[i];
        }
    }

}