/*
 * 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.detector {*/

import DecodeHintType from './../../DecodeHintType';
import ResultPoint from './../../ResultPoint';
import ResultPointCallback from './../../ResultPointCallback';
import BitMatrix from './../../common/BitMatrix';
import DetectorResult from './../../common/DetectorResult';
import GridSampler from './../../common/GridSampler';
import GridSamplerInstance from './../../common/GridSamplerInstance';
import PerspectiveTransform from './../../common/PerspectiveTransform';
import MathUtils from './../../common/detector/MathUtils';
import Version from './../decoder/Version';
import FinderPatternFinder from './FinderPatternFinder';
import FinderPatternInfo from './FinderPatternInfo';
import FinderPattern from './FinderPattern';
import Exception from './../../Exception';
import AlignmentPattern from './AlignmentPattern';
import AlignmentPatternFinder from './AlignmentPatternFinder';

/*import java.util.Map;*/

/**
 * <p>Encapsulates logic that can detect a QR Code in an image, even if the QR Code
 * is rotated or skewed, or partially obscured.</p>
 *
 * @author Sean Owen
 */
export default class Detector {

    private resultPointCallback: ResultPointCallback;

    public constructor(private image: BitMatrix) { }

    protected getImage(): BitMatrix {
        return this.image;
    }

    protected getResultPointCallback(): ResultPointCallback {
        return this.resultPointCallback;
    }

    /**
     * <p>Detects a QR Code in an image.</p>
     *
     * @return {@link DetectorResult} encapsulating results of detecting a QR Code
     * @throws NotFoundException if QR Code cannot be found
     * @throws FormatException if a QR Code cannot be decoded
     */
    // public detect(): DetectorResult /*throws NotFoundException, FormatException*/ {
    //   return detect(null)
    // }

    /**
     * <p>Detects a QR Code in an image.</p>
     *
     * @param hints optional hints to detector
     * @return {@link DetectorResult} encapsulating results of detecting a QR Code
     * @throws NotFoundException if QR Code cannot be found
     * @throws FormatException if a QR Code cannot be decoded
     */
    public detect(hints: Map<DecodeHintType, any>): DetectorResult /*throws NotFoundException, FormatException*/ {

        this.resultPointCallback = (hints === null || hints === undefined) ? null :
        /*(ResultPointCallback) */hints.get(DecodeHintType.NEED_RESULT_POINT_CALLBACK);

        const finder = new FinderPatternFinder(this.image, this.resultPointCallback);
        const info = finder.find(hints);

        return this.processFinderPatternInfo(info);
    }

    protected processFinderPatternInfo(info: FinderPatternInfo): DetectorResult {

        const topLeft: FinderPattern = info.getTopLeft();
        const topRight: FinderPattern = info.getTopRight();
        const bottomLeft: FinderPattern = info.getBottomLeft();

        const moduleSize: number /*float*/ = this.calculateModuleSize(topLeft, topRight, bottomLeft);
        if (moduleSize < 1.0) {
            throw new Exception(Exception.NotFoundException);
        }
        const dimension = Detector.computeDimension(topLeft, topRight, bottomLeft, moduleSize);
        const provisionalVersion: Version = Version.getProvisionalVersionForDimension(dimension);
        const modulesBetweenFPCenters = provisionalVersion.getDimensionForVersion() - 7;

        let alignmentPattern: AlignmentPattern = null;
        // Anything above version 1 has an alignment pattern
        if (provisionalVersion.getAlignmentPatternCenters().length > 0) {

            // Guess where a "bottom right" finder pattern would have been
            const bottomRightX: number /*float*/ = topRight.getX() - topLeft.getX() + bottomLeft.getX();
            const bottomRightY: number /*float*/ = topRight.getY() - topLeft.getY() + bottomLeft.getY();

            // Estimate that alignment pattern is closer by 3 modules
            // from "bottom right" to known top left location
            const correctionToTopLeft: number /*float*/ = 1.0 - 3.0 / modulesBetweenFPCenters;
            const estAlignmentX = /*(int) */Math.floor(topLeft.getX() + correctionToTopLeft * (bottomRightX - topLeft.getX()));
            const estAlignmentY = /*(int) */Math.floor(topLeft.getY() + correctionToTopLeft * (bottomRightY - topLeft.getY()));

            // Kind of arbitrary -- expand search radius before giving up
            for (let i = 4; i <= 16; i <<= 1) {
                try {
                    alignmentPattern = this.findAlignmentInRegion(moduleSize,
                        estAlignmentX,
                        estAlignmentY,
                        i);
                    break;
                } catch (re/*NotFoundException*/) {
                    if (!Exception.isOfType(re, Exception.NotFoundException)) {
                        throw re;
                    }
                    // try next round
                }
            }
            // If we didn't find alignment pattern... well try anyway without it
        }

        const transform: PerspectiveTransform =
            Detector.createTransform(topLeft, topRight, bottomLeft, alignmentPattern, dimension);

        const bits: BitMatrix = Detector.sampleGrid(this.image, transform, dimension);

        let points: ResultPoint[];
        if (alignmentPattern === null) {
            points = [bottomLeft, topLeft, topRight];
        } else {
            points = [bottomLeft, topLeft, topRight, alignmentPattern];
        }
        return new DetectorResult(bits, points);
    }

    private static createTransform(topLeft: ResultPoint,
        topRight: ResultPoint,
        bottomLeft: ResultPoint,
        alignmentPattern: ResultPoint,
        dimension: number /*int*/): PerspectiveTransform {
        const dimMinusThree: number /*float*/ = dimension - 3.5;
        let bottomRightX: number; /*float*/
        let bottomRightY: number; /*float*/
        let sourceBottomRightX: number; /*float*/
        let sourceBottomRightY: number; /*float*/
        if (alignmentPattern !== null) {
            bottomRightX = alignmentPattern.getX();
            bottomRightY = alignmentPattern.getY();
            sourceBottomRightX = dimMinusThree - 3.0;
            sourceBottomRightY = sourceBottomRightX;
        } else {
            // Don't have an alignment pattern, just make up the bottom-right point
            bottomRightX = (topRight.getX() - topLeft.getX()) + bottomLeft.getX();
            bottomRightY = (topRight.getY() - topLeft.getY()) + bottomLeft.getY();
            sourceBottomRightX = dimMinusThree;
            sourceBottomRightY = dimMinusThree;
        }

        return PerspectiveTransform.quadrilateralToQuadrilateral(
            3.5,
            3.5,
            dimMinusThree,
            3.5,
            sourceBottomRightX,
            sourceBottomRightY,
            3.5,
            dimMinusThree,
            topLeft.getX(),
            topLeft.getY(),
            topRight.getX(),
            topRight.getY(),
            bottomRightX,
            bottomRightY,
            bottomLeft.getX(),
            bottomLeft.getY());
    }

    private static sampleGrid(image: BitMatrix,
        transform: PerspectiveTransform,
        dimension: number /*int*/): BitMatrix /*throws NotFoundException*/ {

        const sampler = GridSamplerInstance.getInstance();
        return sampler.sampleGridWithTransform(image, dimension, dimension, transform);
    }

    /**
     * <p>Computes the dimension (number of modules on a size) of the QR Code based on the position
     * of the finder patterns and estimated module size.</p>
     */
    private static computeDimension(topLeft: ResultPoint,
        topRight: ResultPoint,
        bottomLeft: ResultPoint,
        moduleSize: number/*float*/): number /*int*/ /*throws NotFoundException*/ {
        const tltrCentersDimension = MathUtils.round(ResultPoint.distance(topLeft, topRight) / moduleSize);
        const tlblCentersDimension = MathUtils.round(ResultPoint.distance(topLeft, bottomLeft) / moduleSize);
        let dimension = Math.floor((tltrCentersDimension + tlblCentersDimension) / 2) + 7;
        switch (dimension & 0x03) { // mod 4
            case 0:
                dimension++;
                break;
            // 1? do nothing
            case 2:
                dimension--;
                break;
            case 3:
                throw new Exception(Exception.NotFoundException);
        }
        return dimension;
    }

    /**
     * <p>Computes an average estimated module size based on estimated derived from the positions
     * of the three finder patterns.</p>
     *
     * @param topLeft detected top-left finder pattern center
     * @param topRight detected top-right finder pattern center
     * @param bottomLeft detected bottom-left finder pattern center
     * @return estimated module size
     */
    protected calculateModuleSize(topLeft: ResultPoint,
        topRight: ResultPoint,
        bottomLeft: ResultPoint): number/*float*/ {
        // Take the average
        return (this.calculateModuleSizeOneWay(topLeft, topRight) +
            this.calculateModuleSizeOneWay(topLeft, bottomLeft)) / 2.0;
    }

    /**
     * <p>Estimates module size based on two finder patterns -- it uses
     * {@link #sizeOfBlackWhiteBlackRunBothWays(int, int, int, int)} to figure the
     * width of each, measuring along the axis between their centers.</p>
     */
    private calculateModuleSizeOneWay(pattern: ResultPoint, otherPattern: ResultPoint): number/*float*/ {
        const moduleSizeEst1: number /*float*/ = this.sizeOfBlackWhiteBlackRunBothWays(/*(int) */Math.floor(pattern.getX()),
        /*(int) */Math.floor(pattern.getY()),
        /*(int) */Math.floor(otherPattern.getX()),
        /*(int) */Math.floor(otherPattern.getY()));
        const moduleSizeEst2: number /*float*/ = this.sizeOfBlackWhiteBlackRunBothWays(/*(int) */Math.floor(otherPattern.getX()),
        /*(int) */Math.floor(otherPattern.getY()),
        /*(int) */Math.floor(pattern.getX()),
        /*(int) */Math.floor(pattern.getY()));
        if (isNaN(moduleSizeEst1)) {
            return moduleSizeEst2 / 7.0;
        }
        if (isNaN(moduleSizeEst2)) {
            return moduleSizeEst1 / 7.0;
        }
        // Average them, and divide by 7 since we've counted the width of 3 black modules,
        // and 1 white and 1 black module on either side. Ergo, divide sum by 14.
        return (moduleSizeEst1 + moduleSizeEst2) / 14.0;
    }

    /**
     * See {@link #sizeOfBlackWhiteBlackRun(int, int, int, int)}; computes the total width of
     * a finder pattern by looking for a black-white-black run from the center in the direction
     * of another point (another finder pattern center), and in the opposite direction too.
     */
    private sizeOfBlackWhiteBlackRunBothWays(fromX: number /*int*/, fromY: number /*int*/, toX: number /*int*/, toY: number /*int*/): number/*float*/ {

        let result: number /*float*/ = this.sizeOfBlackWhiteBlackRun(fromX, fromY, toX, toY);

        // Now count other way -- don't run off image though of course
        let scale: number /*float*/ = 1.0;
        let otherToX = fromX - (toX - fromX);
        if (otherToX < 0) {
            scale = fromX / /*(float) */(fromX - otherToX);
            otherToX = 0;
        } else if (otherToX >= this.image.getWidth()) {
            scale = (this.image.getWidth() - 1 - fromX) / /*(float) */(otherToX - fromX);
            otherToX = this.image.getWidth() - 1;
        }
        let otherToY = /*(int) */Math.floor(fromY - (toY - fromY) * scale);

        scale = 1.0;
        if (otherToY < 0) {
            scale = fromY / /*(float) */(fromY - otherToY);
            otherToY = 0;
        } else if (otherToY >= this.image.getHeight()) {
            scale = (this.image.getHeight() - 1 - fromY) / /*(float) */(otherToY - fromY);
            otherToY = this.image.getHeight() - 1;
        }
        otherToX = /*(int) */Math.floor(fromX + (otherToX - fromX) * scale);

        result += this.sizeOfBlackWhiteBlackRun(fromX, fromY, otherToX, otherToY);

        // Middle pixel is double-counted this way; subtract 1
        return result - 1.0;
    }

    /**
     * <p>This method traces a line from a point in the image, in the direction towards another point.
     * It begins in a black region, and keeps going until it finds white, then black, then white again.
     * It reports the distance from the start to this point.</p>
     *
     * <p>This is used when figuring out how wide a finder pattern is, when the finder pattern
     * may be skewed or rotated.</p>
     */
    private sizeOfBlackWhiteBlackRun(fromX: number /*int*/, fromY: number /*int*/, toX: number /*int*/, toY: number /*int*/): number/*float*/ {
        // Mild variant of Bresenham's algorithm
        // see http://en.wikipedia.org/wiki/Bresenham's_line_algorithm
        const steep: boolean = Math.abs(toY - fromY) > Math.abs(toX - fromX);
        if (steep) {
            let temp = fromX;
            fromX = fromY;
            fromY = temp;
            temp = toX;
            toX = toY;
            toY = temp;
        }

        const dx = Math.abs(toX - fromX);
        const dy = Math.abs(toY - fromY);
        let error = -dx / 2;
        const xstep = fromX < toX ? 1 : -1;
        const ystep = fromY < toY ? 1 : -1;

        // In black pixels, looking for white, first or second time.
        let state = 0;
        // Loop up until x == toX, but not beyond
        const xLimit = toX + xstep;
        for (let x = fromX, y = fromY; x !== xLimit; x += xstep) {
            const realX = steep ? y : x;
            const realY = steep ? x : y;

            // Does current pixel mean we have moved white to black or vice versa?
            // Scanning black in state 0,2 and white in state 1, so if we find the wrong
            // color, advance to next state or end if we are in state 2 already
            if ((state === 1) === this.image.get(realX, realY)) {
                if (state === 2) {
                    return MathUtils.distance(x, y, fromX, fromY);
                }
                state++;
            }

            error += dy;
            if (error > 0) {
                if (y === toY) {
                    break;
                }
                y += ystep;
                error -= dx;
            }
        }
        // Found black-white-black; give the benefit of the doubt that the next pixel outside the image
        // is "white" so this last point at (toX+xStep,toY) is the right ending. This is really a
        // small approximation; (toX+xStep,toY+yStep) might be really correct. Ignore this.
        if (state === 2) {
            return MathUtils.distance(toX + xstep, toY, fromX, fromY);
        }
        // else we didn't find even black-white-black; no estimate is really possible
        return NaN;
    }

    /**
     * <p>Attempts to locate an alignment pattern in a limited region of the image, which is
     * guessed to contain it. This method uses {@link AlignmentPattern}.</p>
     *
     * @param overallEstModuleSize estimated module size so far
     * @param estAlignmentX x coordinate of center of area probably containing alignment pattern
     * @param estAlignmentY y coordinate of above
     * @param allowanceFactor number of pixels in all directions to search from the center
     * @return {@link AlignmentPattern} if found, or null otherwise
     * @throws NotFoundException if an unexpected error occurs during detection
     */
    protected findAlignmentInRegion(overallEstModuleSize: number/*float*/,
        estAlignmentX: number /*int*/,
        estAlignmentY: number /*int*/,
        allowanceFactor: number/*float*/): AlignmentPattern {
        // Look for an alignment pattern (3 modules in size) around where it
        // should be
        const allowance = /*(int) */Math.floor(allowanceFactor * overallEstModuleSize);
        const alignmentAreaLeftX = Math.max(0, estAlignmentX - allowance);
        const alignmentAreaRightX = Math.min(this.image.getWidth() - 1, estAlignmentX + allowance);
        if (alignmentAreaRightX - alignmentAreaLeftX < overallEstModuleSize * 3) {
            throw new Exception(Exception.NotFoundException);
        }

        const alignmentAreaTopY = Math.max(0, estAlignmentY - allowance);
        const alignmentAreaBottomY = Math.min(this.image.getHeight() - 1, estAlignmentY + allowance);
        if (alignmentAreaBottomY - alignmentAreaTopY < overallEstModuleSize * 3) {
            throw new Exception(Exception.NotFoundException);
        }

        const alignmentFinder =
            new AlignmentPatternFinder(
                this.image,
                alignmentAreaLeftX,
                alignmentAreaTopY,
                alignmentAreaRightX - alignmentAreaLeftX,
                alignmentAreaBottomY - alignmentAreaTopY,
                overallEstModuleSize,
                this.resultPointCallback);
        return alignmentFinder.find();
    }

}