/*
 * Copyright 2004-2018 H2 Group. Multiple-Licensed under the MPL 2.0,
 * and the EPL 1.0 (http://h2database.com/html/license.html).
 * Initial Developer: H2 Group
 */
package org.h2.util.geometry;

import static org.h2.util.geometry.GeometryUtils.DIMENSION_SYSTEM_XYM;
import static org.h2.util.geometry.GeometryUtils.DIMENSION_SYSTEM_XYZ;
import static org.h2.util.geometry.GeometryUtils.DIMENSION_SYSTEM_XYZM;
import static org.h2.util.geometry.GeometryUtils.GEOMETRY_COLLECTION;
import static org.h2.util.geometry.GeometryUtils.LINE_STRING;
import static org.h2.util.geometry.GeometryUtils.MAX_X;
import static org.h2.util.geometry.GeometryUtils.MAX_Y;
import static org.h2.util.geometry.GeometryUtils.MIN_X;
import static org.h2.util.geometry.GeometryUtils.MIN_Y;
import static org.h2.util.geometry.GeometryUtils.MULTI_LINE_STRING;
import static org.h2.util.geometry.GeometryUtils.MULTI_POINT;
import static org.h2.util.geometry.GeometryUtils.MULTI_POLYGON;
import static org.h2.util.geometry.GeometryUtils.POINT;
import static org.h2.util.geometry.GeometryUtils.POLYGON;
import static org.h2.util.geometry.GeometryUtils.checkFinite;
import static org.h2.util.geometry.GeometryUtils.toCanonicalDouble;

import java.io.ByteArrayOutputStream;

import org.h2.engine.SysProperties;
import org.h2.util.Bits;
import org.h2.util.StringUtils;
import org.h2.util.geometry.GeometryUtils.DimensionSystemTarget;
import org.h2.util.geometry.GeometryUtils.Target;

/**
 * EWKB format support for GEOMETRY data type.
 *
 * <p>
 * This class provides limited support of EWKB. EWKB is based on Well-known
 * Binary Representation (WKB) from OGC 06-103r4 and includes additional PostGIS
 * extensions. This class can read dimension system marks in both OGC WKB and
 * EWKB formats, but always writes them in EWKB format. SRID support from EWKB
 * is implemented. As an addition POINT EMPTY is stored with NaN values as
 * specified in <a href="http://www.geopackage.org/spec/">OGC 12-128r15</a>.
 * </p>
 */
public final class EWKBUtils {

    /**
     * Converter output target that writes a EWKB.
     */
    public static final class EWKBTarget extends Target {

        private final ByteArrayOutputStream output;

        private final int dimensionSystem;

        private final byte[] buf = new byte[8];

        private int type;

        private int srid;

        /**
         * Creates a new EWKB output target.
         *
         * @param output
         *            output stream
         * @param dimensionSystem
         *            dimension system to use
         */
        public EWKBTarget(ByteArrayOutputStream output, int dimensionSystem) {
            this.output = output;
            this.dimensionSystem = dimensionSystem;
        }

        @Override
        protected void init(int srid) {
            this.srid = srid;
        }

        @Override
        protected void startPoint() {
            writeHeader(POINT);
        }

        @Override
        protected void startLineString(int numPoints) {
            writeHeader(LINE_STRING);
            writeInt(numPoints);
        }

        @Override
        protected void startPolygon(int numInner, int numPoints) {
            writeHeader(POLYGON);
            writeInt(numInner + 1);
            writeInt(numPoints);
        }

        @Override
        protected void startPolygonInner(int numInner) {
            writeInt(numInner);
        }

        @Override
        protected void startCollection(int type, int numItems) {
            writeHeader(type);
            writeInt(numItems);
        }

        private void writeHeader(int type) {
            this.type = type;
            switch (dimensionSystem) {
            case DIMENSION_SYSTEM_XYZ:
                type |= EWKB_Z;
                break;
            case DIMENSION_SYSTEM_XYZM:
                type |= EWKB_Z;
                //$FALL-THROUGH$
            case DIMENSION_SYSTEM_XYM:
                type |= EWKB_M;
            }
            if (srid != 0) {
                type |= EWKB_SRID;
            }
            output.write(0);
            writeInt(type);
            if (srid != 0) {
                writeInt(srid);
                // Never write SRID in inner objects
                srid = 0;
            }
        }

        @Override
        protected Target startCollectionItem(int index, int total) {
            return this;
        }

        @Override
        protected void addCoordinate(double x, double y, double z, double m, int index, int total) {
            boolean check = type != POINT || !Double.isNaN(x) || !Double.isNaN(y) || !Double.isNaN(z)
                    || !Double.isNaN(m);
            if (check) {
                checkFinite(x);
                checkFinite(y);
            }
            writeDouble(x);
            writeDouble(y);
            if ((dimensionSystem & DIMENSION_SYSTEM_XYZ) != 0) {
                writeDouble(!SysProperties.MIXED_GEOMETRIES && check ? checkFinite(z) : z);
            }
            if ((dimensionSystem & DIMENSION_SYSTEM_XYM) != 0) {
                writeDouble(check ? checkFinite(m) : m);
            }
        }

        private void writeInt(int v) {
            Bits.writeInt(buf, 0, v);
            output.write(buf, 0, 4);
        }

        private void writeDouble(double v) {
            v = toCanonicalDouble(v);
            Bits.writeDouble(buf, 0, v);
            output.write(buf, 0, 8);
        }

    }

    /**
     * Helper source object for EWKB reading.
     */
    private static final class EWKBSource {
        private final byte[] ewkb;

        private int offset;

        /**
         * Whether current byte order is big-endian.
         */
        boolean bigEndian;

        /**
         * Creates new instance of EWKB source.
         *
         * @param ewkb
         *            EWKB
         */
        EWKBSource(byte[] ewkb) {
            this.ewkb = ewkb;
        }

        /**
         * Reads one byte.
         *
         * @return next byte
         */
        byte readByte() {
            return ewkb[offset++];
        }

        /**
         * Reads a 32-bit integer using current byte order.
         *
         * @return next 32-bit integer
         */
        int readInt() {
            int result = bigEndian ? Bits.readInt(ewkb, offset) : Bits.readIntLE(ewkb, offset);
            offset += 4;
            return result;
        }

        /**
         * Reads a 64-bit floating point using current byte order.
         *
         * @return next 64-bit floating point
         */
        double readCoordinate() {
            double v = bigEndian ? Bits.readDouble(ewkb, offset) : Bits.readDoubleLE(ewkb, offset);
            offset += 8;
            return toCanonicalDouble(v);
        }

        @Override
        public String toString() {
            String s = StringUtils.convertBytesToHex(ewkb);
            int idx = offset * 2;
            return new StringBuilder(s.length() + 3).append(s, 0, idx).append("<*>").append(s, idx, s.length())
                    .toString();
        }

    }

    /**
     * Geometry type mask that indicates presence of dimension Z.
     */
    public static final int EWKB_Z = 0x8000_0000;

    /**
     * Geometry type mask that indicates presence of dimension M.
     */
    public static final int EWKB_M = 0x4000_0000;

    /**
     * Geometry type mask that indicates presence of SRID.
     */
    public static final int EWKB_SRID = 0x2000_0000;

    /**
     * Converts any supported EWKB to EWKB representation that is used by this
     * class. Reduces dimension system to minimal possible and uses EWKB flags
     * for dimension system indication. May also perform other changes.
     *
     * @param ewkb
     *            source EWKB
     * @return canonical EWKB, may be the same as the source
     */
    public static byte[] ewkb2ewkb(byte[] ewkb) {
        // Determine dimension system first
        DimensionSystemTarget dimensionTarget = new DimensionSystemTarget();
        parseEWKB(ewkb, dimensionTarget);
        // Write an EWKB
        return ewkb2ewkb(ewkb, dimensionTarget.getDimensionSystem());
    }

    /**
     * Converts any supported EWKB to EWKB representation that is used by this
     * class. Reduces dimension system to minimal possible and uses EWKB flags
     * for dimension system indication. May also perform other changes.
     *
     * @param ewkb
     *            source EWKB
     * @param dimensionSystem
     *            dimension system
     * @return canonical EWKB, may be the same as the source
     */
    public static byte[] ewkb2ewkb(byte[] ewkb, int dimensionSystem) {
        ByteArrayOutputStream output = new ByteArrayOutputStream();
        EWKBTarget target = new EWKBTarget(output, dimensionSystem);
        parseEWKB(ewkb, target);
        return output.toByteArray();
    }

    /**
     * Parses a EWKB.
     *
     * @param ewkb
     *            EWKB representation
     * @param target
     *            output target
     */
    public static void parseEWKB(byte[] ewkb, Target target) {
        try {
            parseEWKB(new EWKBSource(ewkb), target, 0);
        } catch (ArrayIndexOutOfBoundsException e) {
            throw new IllegalArgumentException();
        }
    }

    /**
     * Converts geometry type with flags to a dimension system.
     *
     * @param type
     *            geometry type with flags
     * @return dimension system
     */
    public static int type2dimensionSystem(int type) {
        // PostGIS extensions
        boolean useZ = (type & EWKB_Z) != 0;
        boolean useM = (type & EWKB_M) != 0;
        // OGC 06-103r4
        type &= 0xffff;
        switch (type / 1_000) {
        case DIMENSION_SYSTEM_XYZ:
            useZ = true;
            break;
        case DIMENSION_SYSTEM_XYZM:
            useZ = true;
            //$FALL-THROUGH$
        case DIMENSION_SYSTEM_XYM:
            useM = true;
        }
        return (useZ ? DIMENSION_SYSTEM_XYZ : 0) | (useM ? DIMENSION_SYSTEM_XYM : 0);
    }

    /**
     * Parses a EWKB.
     *
     * @param source
     *            EWKB source
     * @param target
     *            output target
     * @param parentType
     *            type of parent geometry collection, or 0 for the root geometry
     */
    private static void parseEWKB(EWKBSource source, Target target, int parentType) {
        // Read byte order of a next geometry
        switch (source.readByte()) {
        case 0:
            source.bigEndian = true;
            break;
        case 1:
            source.bigEndian = false;
            break;
        default:
            throw new IllegalArgumentException();
        }
        // Type contains type of a geometry and additional flags
        int type = source.readInt();
        // PostGIS extensions
        boolean useZ = (type & EWKB_Z) != 0;
        boolean useM = (type & EWKB_M) != 0;
        int srid = (type & EWKB_SRID) != 0 ? source.readInt() : 0;
        // Use only top-level SRID
        if (parentType == 0) {
            target.init(srid);
        }
        // OGC 06-103r4
        type &= 0xffff;
        switch (type / 1_000) {
        case DIMENSION_SYSTEM_XYZ:
            useZ = true;
            break;
        case DIMENSION_SYSTEM_XYZM:
            useZ = true;
            //$FALL-THROUGH$
        case DIMENSION_SYSTEM_XYM:
            useM = true;
        }
        target.dimensionSystem((useZ ? DIMENSION_SYSTEM_XYZ : 0) | (useM ? DIMENSION_SYSTEM_XYM : 0));
        type %= 1_000;
        switch (type) {
        case POINT:
            if (parentType != 0 && parentType != MULTI_POINT && parentType != GEOMETRY_COLLECTION) {
                throw new IllegalArgumentException();
            }
            target.startPoint();
            addCoordinate(source, target, useZ, useM, 0, 1);
            break;
        case LINE_STRING: {
            if (parentType != 0 && parentType != MULTI_LINE_STRING && parentType != GEOMETRY_COLLECTION) {
                throw new IllegalArgumentException();
            }
            int numPoints = source.readInt();
            if (numPoints < 0 || numPoints == 1) {
                throw new IllegalArgumentException();
            }
            target.startLineString(numPoints);
            for (int i = 0; i < numPoints; i++) {
                addCoordinate(source, target, useZ, useM, i, numPoints);
            }
            break;
        }
        case POLYGON: {
            if (parentType != 0 && parentType != MULTI_POLYGON && parentType != GEOMETRY_COLLECTION) {
                throw new IllegalArgumentException();
            }
            int numInner = source.readInt() - 1;
            if (numInner < 0) {
                throw new IllegalArgumentException();
            }
            int size = source.readInt();
            // Size may be 0 (EMPTY) or 4+
            if (size < 0 || size >= 1 && size <= 3) {
                throw new IllegalArgumentException();
            }
            if (size == 0 && numInner > 0) {
                throw new IllegalArgumentException();
            }
            target.startPolygon(numInner, size);
            if (size > 0) {
                addRing(source, target, useZ, useM, size);
                for (int i = 0; i < numInner; i++) {
                    size = source.readInt();
                    // Size may be 0 (EMPTY) or 4+
                    if (size < 0 || size >= 1 && size <= 3) {
                        throw new IllegalArgumentException();
                    }
                    target.startPolygonInner(size);
                    addRing(source, target, useZ, useM, size);
                }
                target.endNonEmptyPolygon();
            }
            break;
        }
        case MULTI_POINT:
        case MULTI_LINE_STRING:
        case MULTI_POLYGON:
        case GEOMETRY_COLLECTION: {
            if (parentType != 0 && parentType != GEOMETRY_COLLECTION) {
                throw new IllegalArgumentException();
            }
            int numItems = source.readInt();
            if (numItems < 0) {
                throw new IllegalArgumentException();
            }
            target.startCollection(type, numItems);
            for (int i = 0; i < numItems; i++) {
                Target innerTarget = target.startCollectionItem(i, numItems);
                parseEWKB(source, innerTarget, type);
                target.endCollectionItem(innerTarget, i, numItems);
            }
            target.endCollection(type);
            break;
        }
        default:
            throw new IllegalArgumentException();
        }
    }

    private static void addRing(EWKBSource source, Target target, boolean useZ, boolean useM, int size) {
        // 0 or 4+ are valid
        if (size >= 4) {
            double startX = source.readCoordinate(), startY = source.readCoordinate();
            target.addCoordinate(startX, startY, //
                    useZ ? source.readCoordinate() : Double.NaN, useM ? source.readCoordinate() : Double.NaN, //
                    0, size);
            for (int i = 1; i < size - 1; i++) {
                addCoordinate(source, target, useZ, useM, i, size);
            }
            double endX = source.readCoordinate(), endY = source.readCoordinate();
            /*
             * TODO OGC 06-103r4 determines points as equal if they have the
             * same X and Y coordinates. Should we check Z and M here too?
             */
            if (startX != endX || startY != endY) {
                throw new IllegalArgumentException();
            }
            target.addCoordinate(endX, endY, //
                    useZ ? source.readCoordinate() : Double.NaN, useM ? source.readCoordinate() : Double.NaN, //
                    size - 1, size);
        }
    }

    private static void addCoordinate(EWKBSource source, Target target, boolean useZ, boolean useM, int index,
            int total) {
        target.addCoordinate(source.readCoordinate(), source.readCoordinate(),
                useZ ? source.readCoordinate() : Double.NaN, useM ? source.readCoordinate() : Double.NaN, //
                index, total);
    }

    /**
     * Converts an envelope to a WKB.
     *
     * @param envelope
     *            envelope, or null
     * @return WKB, or null
     */
    public static byte[] envelope2wkb(double[] envelope) {
        if (envelope == null) {
            return null;
        }
        byte[] result;
        double minX = envelope[MIN_X], maxX = envelope[MAX_X], minY = envelope[MIN_Y], maxY = envelope[MAX_Y];
        if (minX == maxX && minY == maxY) {
            result = new byte[21];
            result[4] = POINT;
            Bits.writeDouble(result, 5, minX);
            Bits.writeDouble(result, 13, minY);
        } else if (minX == maxX || minY == maxY) {
            result = new byte[41];
            result[4] = LINE_STRING;
            result[8] = 2;
            Bits.writeDouble(result, 9, minX);
            Bits.writeDouble(result, 17, minY);
            Bits.writeDouble(result, 25, maxX);
            Bits.writeDouble(result, 33, maxY);
        } else {
            result = new byte[93];
            result[4] = POLYGON;
            result[8] = 1;
            result[12] = 5;
            Bits.writeDouble(result, 13, minX);
            Bits.writeDouble(result, 21, minY);
            Bits.writeDouble(result, 29, minX);
            Bits.writeDouble(result, 37, maxY);
            Bits.writeDouble(result, 45, maxX);
            Bits.writeDouble(result, 53, maxY);
            Bits.writeDouble(result, 61, maxX);
            Bits.writeDouble(result, 69, minY);
            Bits.writeDouble(result, 77, minX);
            Bits.writeDouble(result, 85, minY);
        }
        return result;
    }

    private EWKBUtils() {
    }

}
