package org.apache.poi.hpsf;

import org.apache.poi.util.Internal;
import org.apache.poi.util.LittleEndian;

@Internal
class Array
{
    static class ArrayDimension
    {
        static final int SIZE = 8;

        private int _indexOffset;
        private long _size;

        ArrayDimension( byte[] data, int offset )
        {
            _size = LittleEndian.getUInt( data, offset );
            _indexOffset = LittleEndian.getInt( data, offset
                    + LittleEndian.INT_SIZE );
        }
    }

    static class ArrayHeader
    {
        private ArrayDimension[] _dimensions;
        private int _type;

        ArrayHeader( byte[] data, int startOffset )
        {
            int offset = startOffset;

            _type = LittleEndian.getInt( data, offset );
            offset += LittleEndian.INT_SIZE;

            long numDimensionsUnsigned = LittleEndian.getUInt( data, offset );
            offset += LittleEndian.INT_SIZE;

            if ( !( 1 <= numDimensionsUnsigned && numDimensionsUnsigned <= 31 ) )
                throw new IllegalPropertySetDataException(
                        "Array dimension number " + numDimensionsUnsigned
                                + " is not in [1; 31] range" );
            int numDimensions = (int) numDimensionsUnsigned;

            _dimensions = new ArrayDimension[numDimensions];
            for ( int i = 0; i < numDimensions; i++ )
            {
                _dimensions[i] = new ArrayDimension( data, offset );
                offset += ArrayDimension.SIZE;
            }
        }

        long getNumberOfScalarValues()
        {
            long result = 1;
            for ( ArrayDimension dimension : _dimensions )
                result *= dimension._size;
            return result;
        }

        int getSize()
        {
            return LittleEndian.INT_SIZE * 2 + _dimensions.length
                    * ArrayDimension.SIZE;
        }

        int getType()
        {
            return _type;
        }
    }

    private ArrayHeader _header;
    private TypedPropertyValue[] _values;

    Array()
    {
    }

    Array( final byte[] data, final int offset )
    {
        read( data, offset );
    }

    int read( final byte[] data, final int startOffset )
    {
        int offset = startOffset;

        _header = new ArrayHeader( data, offset );
        offset += _header.getSize();

        long numberOfScalarsLong = _header.getNumberOfScalarValues();
        if ( numberOfScalarsLong > Integer.MAX_VALUE )
            throw new UnsupportedOperationException(
                    "Sorry, but POI can't store array of properties with size of "
                            + numberOfScalarsLong + " in memory" );
        int numberOfScalars = (int) numberOfScalarsLong;

        _values = new TypedPropertyValue[numberOfScalars];
        final int type = _header._type;
        if ( type == Variant.VT_VARIANT )
        {
            for ( int i = 0; i < numberOfScalars; i++ )
            {
                TypedPropertyValue typedPropertyValue = new TypedPropertyValue();
                offset += typedPropertyValue.read( data, offset );
            }
        }
        else
        {
            for ( int i = 0; i < numberOfScalars; i++ )
            {
                TypedPropertyValue typedPropertyValue = new TypedPropertyValue(
                        type, null );
                offset += typedPropertyValue.readValuePadded( data, offset );
            }
        }

        return offset - startOffset;
    }
}