/*
 * Copyright 2008 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.oned {*/

import BarcodeFormat from '../BarcodeFormat';
import BitArray from '../common/BitArray';
import DecodeHintType from '../DecodeHintType';
import Exception from '../Exception';
import Result from '../Result';
import ResultPoint from '../ResultPoint';
import OneDReader from './OneDReader';
import StringBuilder from "../util/StringBuilder";
import System from "../util/System";

/**
 * <p>Decodes ITF barcodes.</p>
 *
 * @author Tjieco
 */
export default class ITFReader extends OneDReader {

    private static W = 3; // Pixel width of a 3x wide line
    private static w = 2; // Pixel width of a 2x wide line
    private static N = 1; // Pixed width of a narrow line

    private static PATTERNS: number[][] = [
        [1, 1, 2, 2, 1], // 0
        [2, 1, 1, 1, 2], // 1
        [1, 2, 1, 1, 2], // 2
        [2, 2, 1, 1, 1], // 3
        [1, 1, 2, 1, 2], // 4
        [2, 1, 2, 1, 1], // 5
        [1, 2, 2, 1, 1], // 6
        [1, 1, 1, 2, 2], // 7
        [2, 1, 1, 2, 1], // 8
        [1, 2, 1, 2, 1], // 9
        [1, 1, 3, 3, 1], // 0
        [3, 1, 1, 1, 3], // 1
        [1, 3, 1, 1, 3], // 2
        [3, 3, 1, 1, 1], // 3
        [1, 1, 3, 1, 3], // 4
        [3, 1, 3, 1, 1], // 5
        [1, 3, 3, 1, 1], // 6
        [1, 1, 1, 3, 3], // 7
        [3, 1, 1, 3, 1], // 8
        [1, 3, 1, 3, 1]  // 9
    ];

    private static  MAX_AVG_VARIANCE = 0.38;
    private static  MAX_INDIVIDUAL_VARIANCE = 0.5;



    /* /!** Valid ITF lengths. Anything longer than the largest value is also allowed. *!/*/
    private static DEFAULT_ALLOWED_LENGTHS:number[] = [6, 8, 10, 12, 14];

    // Stores the actual narrow line width of the image being decoded.
    private narrowLineWidth = -1;

    /*/!**
     * Start/end guard pattern.
     *
     * Note: The end pattern is reversed because the row is reversed before
     * searching for the END_PATTERN
     *!/*/
    private static START_PATTERN = [1, 1, 1, 1];
    private static END_PATTERN_REVERSED: number[][] = [
        [1, 1, 2], // 2x
        [1, 1, 3]  // 3x
    ];

    // See ITFWriter.PATTERNS
    /*

    /!**
     * Patterns of Wide / Narrow lines to indicate each digit
     *!/
    */

    public decodeRow(rowNumber: number, row: BitArray, hints?: Map<DecodeHintType, any>): Result {

        // Find out where the Middle section (payload) starts & ends
        let startRange: number[] = this.decodeStart(row);
        let endRange: number[] = this.decodeEnd(row);

        let result: StringBuilder = new StringBuilder();
        ITFReader.decodeMiddle(row, startRange[1], endRange[0], result);
        let resultString: string = result.toString();

        let allowedLengths: number[] = null;
        if (hints != null) {
            allowedLengths = hints.get(DecodeHintType.ALLOWED_LENGTHS);

        }
        if (allowedLengths == null) {
            allowedLengths = ITFReader.DEFAULT_ALLOWED_LENGTHS;
        }

        // To avoid false positives with 2D barcodes (and other patterns), make
        // an assumption that the decoded string must be a 'standard' length if it's short
        let length: number = resultString.length;
        let lengthOK: boolean = false;
        let maxAllowedLength: number = 0;
        for(let value of allowedLengths) {
            if (length == value) {
                lengthOK = true;
                break;
            }
            if (value > maxAllowedLength) {
                maxAllowedLength = value;
            }
        }
        if (!lengthOK && length > maxAllowedLength) {
            lengthOK = true;
        }
        if (!lengthOK) {
            throw new Exception(Exception.FormatException)
        }

        const points: ResultPoint[] = [new ResultPoint(startRange[1], rowNumber), new ResultPoint(endRange[0], rowNumber)];


        let resultReturn: Result = new Result(
            resultString,
            null, // no natural byte representation for these barcodes
            0,
            points,
            BarcodeFormat.ITF,
            new Date().getTime()
        );

        return resultReturn
    }
    /*
    /!**
     * @param row          row of black/white values to search
     * @param payloadStart offset of start pattern
     * @param resultString {@link StringBuilder} to append decoded chars to
     * @throws NotFoundException if decoding could not complete successfully
     *!/*/
    private static decodeMiddle(row: BitArray,
                                payloadStart: number,
                                payloadEnd: number,
                                resultString: StringBuilder) {

        // Digits are interleaved in pairs - 5 black lines for one digit, and the
        // 5
        // interleaved white lines for the second digit.
        // Therefore, need to scan 10 lines and then
        // split these into two arrays

        let counterDigitPair: number[] = new Array(10); //10
        let counterBlack: number[]= new Array(5); //5
        let counterWhite: number[]= new Array(5); //5

        counterDigitPair.fill(0);
        counterBlack.fill(0);
        counterWhite.fill(0);

        while (payloadStart < payloadEnd) {

            // Get 10 runs of black/white.
            OneDReader.recordPattern(row, payloadStart, counterDigitPair);
            // Split them into each array
            for (let k = 0; k < 5; k++) {
                let twoK: number = 2 * k;
                counterBlack[k] = counterDigitPair[twoK];
                counterWhite[k] = counterDigitPair[twoK + 1];
            }

            let bestMatch: number = ITFReader.decodeDigit(counterBlack);
            resultString.append(bestMatch.toString());
            bestMatch = this.decodeDigit(counterWhite);
            resultString.append(bestMatch.toString());

            counterDigitPair.forEach(function(counterDigit) {
                payloadStart += counterDigit;
            });
        }
    }

    /*/!**
     * Identify where the start of the middle / payload section starts.
     *
     * @param row row of black/white values to search
     * @return Array, containing index of start of 'start block' and end of
     *         'start block'
     *!/*/
    private decodeStart(row: BitArray): number[] {


        let endStart = ITFReader.skipWhiteSpace(row);
        let startPattern: number[] = ITFReader.findGuardPattern(row, endStart, ITFReader.START_PATTERN);

        // Determine the width of a narrow line in pixels. We can do this by
        // getting the width of the start pattern and dividing by 4 because its
        // made up of 4 narrow lines.
        this.narrowLineWidth = (startPattern[1] - startPattern[0]) / 4;

        this.validateQuietZone(row, startPattern[0]);

        return startPattern;
    }

    /*/!**
     * The start & end patterns must be pre/post fixed by a quiet zone. This
     * zone must be at least 10 times the width of a narrow line.  Scan back until
     * we either get to the start of the barcode or match the necessary number of
     * quiet zone pixels.
     *
     * Note: Its assumed the row is reversed when using this method to find
     * quiet zone after the end pattern.
     *
     * ref: http://www.barcode-1.net/i25code.html
     *
     * @param row bit array representing the scanned barcode.
     * @param startPattern index into row of the start or end pattern.
     * @throws NotFoundException if the quiet zone cannot be found
     *!/*/
    private validateQuietZone(row:BitArray, startPattern: number): void {

        let quietCount: number = this.narrowLineWidth * 10;  // expect to find this many pixels of quiet zone

        // if there are not so many pixel at all let's try as many as possible
        quietCount = quietCount < startPattern ? quietCount : startPattern;

        for (let i = startPattern - 1; quietCount > 0 && i >= 0; i--) {
            if (row.get(i)) {
                break;
            }
            quietCount--;
        }
        if (quietCount != 0) {
            // Unable to find the necessary number of quiet zone pixels.
            throw new Exception(Exception.NotFoundException)
        }
    }
    /*
    /!**
     * Skip all whitespace until we get to the first black line.
     *
     * @param row row of black/white values to search
     * @return index of the first black line.
     * @throws NotFoundException Throws exception if no black lines are found in the row
     *!/*/
    private static skipWhiteSpace(row: BitArray): number {
        let width: number = row.getSize();
        let endStart: number = row.getNextSet(0);
        if (endStart == width) {
            throw new Exception(Exception.NotFoundException)
        }

        return endStart;
    }

    /*/!**
     * Identify where the end of the middle / payload section ends.
     *
     * @param row row of black/white values to search
     * @return Array, containing index of start of 'end block' and end of 'end
     *         block'
     *!/*/
    private decodeEnd(row: BitArray): number[] {

        // For convenience, reverse the row and then
        // search from 'the start' for the end block
        row.reverse();
        try {
            let endStart: number = ITFReader.skipWhiteSpace(row);
            let endPattern: number[];
            try {
                endPattern = ITFReader.findGuardPattern(row, endStart, ITFReader.END_PATTERN_REVERSED[0]);
            } catch (NotFoundException) {
                endPattern = ITFReader.findGuardPattern(row, endStart, ITFReader.END_PATTERN_REVERSED[1]);
            }

            // The start & end patterns must be pre/post fixed by a quiet zone. This
            // zone must be at least 10 times the width of a narrow line.
            // ref: http://www.barcode-1.net/i25code.html
            this.validateQuietZone(row, endPattern[0]);

            // Now recalculate the indices of where the 'endblock' starts & stops to
            // accommodate
            // the reversed nature of the search
            let temp = endPattern[0];
            endPattern[0] = row.getSize() - endPattern[1];
            endPattern[1] = row.getSize() - temp;

            return endPattern;
        } finally {
            // Put the row back the right way.
            row.reverse();
        }
    }
    /*
    /!**
     * @param row       row of black/white values to search
     * @param rowOffset position to start search
     * @param pattern   pattern of counts of number of black and white pixels that are
     *                  being searched for as a pattern
     * @return start/end horizontal offset of guard pattern, as an array of two
     *         ints
     * @throws NotFoundException if pattern is not found
     *!/*/
    private static findGuardPattern(row: BitArray,
                                    rowOffset: number,
                                    pattern: number[]): number[] {

        let patternLength: number = pattern.length;
        let counters: number[] = new Array(patternLength);
        let width: number = row.getSize();
        let isWhite: boolean = false;

        let counterPosition: number = 0;
        let patternStart: number = rowOffset;

        counters.fill(0);

        for (let x = rowOffset; x < width; x++) {
            if (row.get(x) != isWhite) {
                counters[counterPosition]++;
            } else {
                if (counterPosition == patternLength - 1) {
                    if (OneDReader.patternMatchVariance(counters, pattern, ITFReader.MAX_INDIVIDUAL_VARIANCE) < ITFReader.MAX_AVG_VARIANCE) {
                        return [patternStart, x];
                    }
                    patternStart += counters[0] + counters[1];
                    System.arraycopy(counters, 2, counters, 0, counterPosition - 1);
                    counters[counterPosition - 1] = 0;
                    counters[counterPosition] = 0;
                    counterPosition--;
                } else {
                    counterPosition++;
                }
                counters[counterPosition] = 1;
                isWhite = !isWhite;
            }
        }
        throw new Exception (Exception.NotFoundException)
    }

    /*/!**
     * Attempts to decode a sequence of ITF black/white lines into single
     * digit.
     *
     * @param counters the counts of runs of observed black/white/black/... values
     * @return The decoded digit
     * @throws NotFoundException if digit cannot be decoded
     *!/*/
    private static decodeDigit(counters: number[]): number {
        let bestVariance: number = ITFReader.MAX_AVG_VARIANCE; // worst variance we'll accept
        let bestMatch: number = -1;
        let max: number = ITFReader.PATTERNS.length;
        for (let i = 0; i < max; i++) {
            let pattern = ITFReader.PATTERNS[i];
            let variance: number = OneDReader.patternMatchVariance(counters, pattern, ITFReader.MAX_INDIVIDUAL_VARIANCE);
            if (variance < bestVariance) {
                bestVariance = variance;
                bestMatch = i;
            } else if (variance == bestVariance) {
                // if we find a second 'best match' with the same variance, we can not reliably report to have a suitable match
                bestMatch = -1;
            }
        }
        if (bestMatch >= 0) {
            return bestMatch % 10;
        } else {
            throw new Exception(Exception.NotFoundException)
        }
    }

}