/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */
package org.apache.sanselan.formats.tiff.write;

import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Map;

import org.apache.sanselan.FormatCompliance;
import org.apache.sanselan.ImageReadException;
import org.apache.sanselan.ImageWriteException;
import org.apache.sanselan.common.BinaryFileFunctions;
import org.apache.sanselan.common.BinaryOutputStream;
import org.apache.sanselan.common.byteSources.ByteSource;
import org.apache.sanselan.common.byteSources.ByteSourceArray;
import org.apache.sanselan.formats.tiff.JpegImageData;
import org.apache.sanselan.formats.tiff.TiffContents;
import org.apache.sanselan.formats.tiff.TiffDirectory;
import org.apache.sanselan.formats.tiff.TiffElement;
import org.apache.sanselan.formats.tiff.TiffField;
import org.apache.sanselan.formats.tiff.TiffImageData;
import org.apache.sanselan.formats.tiff.TiffReader;
import org.apache.sanselan.util.Debug;

public class TiffImageWriterLossless extends TiffImageWriterBase
{
	private final byte exifBytes[];

	public TiffImageWriterLossless(byte exifBytes[])
	{
		this.exifBytes = exifBytes;
	}

	public TiffImageWriterLossless(int byteOrder, byte exifBytes[])
	{
		super(byteOrder);
		this.exifBytes = exifBytes;
	}

	//	private static class TiffPiece
	//	{
	//		public final int offset;
	//		public final int length;
	//
	//		public TiffPiece(final int offset, final int length)
	//		{
	//			this.offset = offset;
	//			this.length = length;
	//		}
	//	}

	private void dumpElements(List elements) throws IOException
	{
		//		try
		//		{
		ByteSource byteSource = new ByteSourceArray(exifBytes);

		dumpElements(byteSource, elements);
		//		}
		//		catch (ImageReadException e)
		//		{
		//			throw new ImageWriteException(e.getMessage(), e);
		//		}
	}

	private void dumpElements(ByteSource byteSource, List elements)
			throws IOException
	{
		int last = TIFF_HEADER_SIZE;
		for (int i = 0; i < elements.size(); i++)
		{
			TiffElement element = (TiffElement) elements.get(i);
			if (element.offset > last)
			{
				final int SLICE_SIZE = 32;
				int gepLength = element.offset - last;
				Debug.debug("gap of " + gepLength + " bytes.");
				byte bytes[] = byteSource.getBlock(last, gepLength);
				if (bytes.length > 2 * SLICE_SIZE)
				{
					Debug.debug("\t" + "head", BinaryFileFunctions.head(bytes,
							SLICE_SIZE));
					Debug.debug("\t" + "tail", BinaryFileFunctions.tail(bytes,
							SLICE_SIZE));
				}
				else
					Debug.debug("\t" + "bytes", bytes);
			}

			Debug.debug("element[" + i + "]:" + element.getElementDescription()
					+ " (" + element.offset + " + " + element.length + " = "
					+ (element.offset + element.length) + ")");
			if (element instanceof TiffDirectory)
			{
				TiffDirectory dir = (TiffDirectory) element;
				Debug.debug("\t" + "next Directory Offset: "
						+ dir.nextDirectoryOffset);
			}
			last = element.offset + element.length;
		}
		Debug.debug();
	}

	private List analyzeOldTiff() throws ImageWriteException, IOException
	{
		try
		{
			ByteSource byteSource = new ByteSourceArray(exifBytes);
			Map params = null;
			FormatCompliance formatCompliance = FormatCompliance.getDefault();
			TiffContents contents = new TiffReader(false).readContents(byteSource,
					params, formatCompliance);

			ArrayList elements = new ArrayList();
			//			result.add(contents.header); // ?

			List directories = contents.directories;
			for (int d = 0; d < directories.size(); d++)
			{
				TiffDirectory directory = (TiffDirectory) directories.get(d);
				elements.add(directory);

				List fields = directory.getDirectoryEntrys();
				for (int f = 0; f < fields.size(); f++)
				{
					TiffField field = (TiffField) fields.get(f);
					TiffElement oversizeValue = field.getOversizeValueElement();
					if (oversizeValue != null)
						elements.add(oversizeValue);

				}

				JpegImageData jpegImageData = directory.getJpegImageData();
				if (jpegImageData != null)
					elements.add(jpegImageData);

				TiffImageData tiffImageData = directory.getTiffImageData();
				if (tiffImageData != null)
				{
					TiffElement.DataElement data[] = tiffImageData
							.getImageData();
					for (int i = 0; i < data.length; i++)
						elements.add(data[i]);
				}
			}

			Collections.sort(elements, TiffElement.COMPARATOR);

			//			dumpElements(byteSource, elements);

			List result = new ArrayList();
			{
				final int TOLERANCE = 3;
				//				int last = TIFF_HEADER_SIZE;
				TiffElement start = null;
				int index = -1;
				for (int i = 0; i < elements.size(); i++)
				{
					TiffElement element = (TiffElement) elements.get(i);
					int lastElementByte = element.offset + element.length;
					if (start == null)
					{
						start = element;
						index = lastElementByte;
					}
					else if (element.offset - index > TOLERANCE)
					{
						result.add(new TiffElement.Stub(start.offset, index
								- start.offset));
						start = element;
						index = lastElementByte;
					}
					else
					{
						index = lastElementByte;
					}
				}
				if (null != start)
					result.add(new TiffElement.Stub(start.offset, index
							- start.offset));
			}

			//			dumpElements(byteSource, result);

			return result;
		}
		catch (ImageReadException e)
		{
			throw new ImageWriteException(e.getMessage(), e);
		}
	}

	public void write(OutputStream os, TiffOutputSet outputSet)
			throws IOException, ImageWriteException
	{
		List analysis = analyzeOldTiff();
		int oldLength = exifBytes.length;
		if (analysis.size() < 1)
			throw new ImageWriteException("Couldn't analyze old tiff data.");
		else if (analysis.size() == 1)
		{
			TiffElement onlyElement = (TiffElement) analysis.get(0);
			//			Debug.debug("onlyElement", onlyElement.getElementDescription());
			if (onlyElement.offset == TIFF_HEADER_SIZE
					&& onlyElement.offset + onlyElement.length
							+ TIFF_HEADER_SIZE == oldLength)
			{
				// no gaps in old data, safe to complete overwrite.
				new TiffImageWriterLossy(byteOrder).write(os, outputSet);
				return;
			}
		}

		//		if (true)
		//			throw new ImageWriteException("hahah");

		//		List directories = outputSet.getDirectories();

		TiffOutputSummary outputSummary = validateDirectories(outputSet);

		List outputItems = outputSet.getOutputItems(outputSummary);

		int outputLength = updateOffsetsStep(analysis, outputItems);
		//		Debug.debug("outputLength", outputLength);

		outputSummary.updateOffsets(byteOrder);

		writeStep(os, outputSet, analysis, outputItems, outputLength);

	}

	private static final Comparator ELEMENT_SIZE_COMPARATOR = new Comparator()
	{
		public int compare(Object o1, Object o2)
		{
			TiffElement e1 = (TiffElement) o1;
			TiffElement e2 = (TiffElement) o2;
			return e1.length - e2.length;
		}
	};

	private static final Comparator ITEM_SIZE_COMPARATOR = new Comparator()
	{
		public int compare(Object o1, Object o2)
		{
			TiffOutputItem e1 = (TiffOutputItem) o1;
			TiffOutputItem e2 = (TiffOutputItem) o2;
			return e1.getItemLength() - e2.getItemLength();
		}
	};

	private int updateOffsetsStep(List analysis, List outputItems)
			throws IOException, ImageWriteException
	{
		// items we cannot fit into a gap, we shall append to tail.
		int overflowIndex = exifBytes.length;

		// make copy.
		List unusedElements = new ArrayList(analysis);

		// should already be in order of offset, but make sure.
		Collections.sort(unusedElements, TiffElement.COMPARATOR);
		Collections.reverse(unusedElements);
		// any items that represent a gap at the end of the exif segment, can be discarded.
		while (unusedElements.size() > 0)
		{
			TiffElement element = (TiffElement) unusedElements.get(0);
			int elementEnd = element.offset + element.length;
			if (elementEnd == overflowIndex)
			{
				// discarding a tail element.  should only happen once.
				overflowIndex -= element.length;
				unusedElements.remove(0);
			}
			else
				break;
		}

		Collections.sort(unusedElements, ELEMENT_SIZE_COMPARATOR);
		Collections.reverse(unusedElements);

		//		Debug.debug("unusedElements");
		//		dumpElements(unusedElements);

		// make copy.
		List unplacedItems = new ArrayList(outputItems);
		Collections.sort(unplacedItems, ITEM_SIZE_COMPARATOR);
		Collections.reverse(unplacedItems);

		while (unplacedItems.size() > 0)
		{
			// pop off largest unplaced item.
			TiffOutputItem outputItem = (TiffOutputItem) unplacedItems
					.remove(0);
			int outputItemLength = outputItem.getItemLength();
			//			Debug.debug("largest unplaced item: "
			//					+ outputItem.getItemDescription() + " (" + outputItemLength
			//					+ ")");

			// search for the smallest possible element large enough to hold the item.
			TiffElement bestFit = null;
			for (int i = 0; i < unusedElements.size(); i++)
			{
				TiffElement element = (TiffElement) unusedElements.get(i);
				if (element.length >= outputItemLength)
					bestFit = element;
				else
					break;
			}
			if (null == bestFit)
			{
				// we couldn't place this item.  overflow.
				outputItem.setOffset(overflowIndex);
				overflowIndex += outputItemLength;
			}
			else
			{
				outputItem.setOffset(bestFit.offset);
				unusedElements.remove(bestFit);

				if (bestFit.length > outputItemLength)
				{
					// not a perfect fit.
					int excessOffset = bestFit.offset + outputItemLength;
					int excessLength = bestFit.length - outputItemLength;
					unusedElements.add(new TiffElement.Stub(excessOffset,
							excessLength));
					// make sure the new element is in the correct order.
					Collections.sort(unusedElements, ELEMENT_SIZE_COMPARATOR);
					Collections.reverse(unusedElements);
				}
			}
		}

		return overflowIndex;
		//
		//		if (true)
		//			throw new IOException("mew");
		//
		//		//		int offset = TIFF_HEADER_SIZE;
		//		int offset = exifBytes.length;
		//
		//		for (int i = 0; i < outputItems.size(); i++)
		//		{
		//			TiffOutputItem outputItem = (TiffOutputItem) outputItems.get(i);
		//
		//			outputItem.setOffset(offset);
		//			int itemLength = outputItem.getItemLength();
		//			offset += itemLength;
		//
		//			int remainder = imageDataPaddingLength(itemLength);
		//			offset += remainder;
		//		}
	}
	private static class BufferOutputStream extends OutputStream
	{
		private final byte buffer[];
		private int index;

		public BufferOutputStream(final byte[] buffer, final int index)
		{
			this.buffer = buffer;
			this.index = index;
		}

		public void write(int b) throws IOException
		{
			if (index >= buffer.length)
				throw new IOException("Buffer overflow.");

			buffer[index++] = (byte) b;
		}

		public void write(byte b[], int off, int len) throws IOException
		{
			if (index + len > buffer.length)
				throw new IOException("Buffer overflow.");
			System.arraycopy(b, off, buffer, index, len);
			index += len;
		}
	}

	private void writeStep(OutputStream os, TiffOutputSet outputSet,
			List analysis, List outputItems, int outputLength)
			throws IOException, ImageWriteException
	{
		TiffOutputDirectory rootDirectory = outputSet.getRootDirectory();

		byte output[] = new byte[outputLength];

		// copy old data (including maker notes, etc.)
		System.arraycopy(exifBytes, 0, output, 0, Math.min(exifBytes.length,
				output.length));

		//		bos.write(exifBytes, TIFF_HEADER_SIZE, exifBytes.length
		//		- TIFF_HEADER_SIZE);

		{
			BufferOutputStream tos = new BufferOutputStream(output, 0);
			BinaryOutputStream bos = new BinaryOutputStream(tos, byteOrder);
			writeImageFileHeader(bos, rootDirectory.getOffset());
		}

		// zero out the parsed pieces of old exif segment, in case we don't overwrite them.
		for (int i = 0; i < analysis.size(); i++)
		{
			TiffElement element = (TiffElement) analysis.get(i);
			for (int j = 0; j < element.length; j++)
			{
				int index = element.offset + j;
				if (index < output.length)
					output[index] = 0;
			}
		}

		// write in the new items
		for (int i = 0; i < outputItems.size(); i++)
		{
			TiffOutputItem outputItem = (TiffOutputItem) outputItems.get(i);

			BufferOutputStream tos = new BufferOutputStream(output, outputItem
					.getOffset());
			BinaryOutputStream bos = new BinaryOutputStream(tos, byteOrder);
			outputItem.writeItem(bos);
		}

		os.write(output);
	}

}
