//
//  DeflateStream.cpp
//  OpenSpades
//
//  Created by yvt on 7/16/13.
//  Copyright (c) 2013 yvt.jp. All rights reserved.
//

#include "DeflateStream.h"
#include "Exception.h"
#include "Debug.h"
#include "../Core/Debug.h"
#include <string.h>

namespace spades {
	static const size_t chunkSize = 16384;
	static const size_t bufferSize = 65536;
	DeflateStream::DeflateStream(IStream *stream,
								 CompressMode mode,
								 bool ac) {
		SPADES_MARK_FUNCTION();
		
		this->baseStream = stream;
		this->mode = mode;
		autoClose = ac;
		
		zstream.zalloc = Z_NULL;
		zstream.zfree = Z_NULL;
		zstream.opaque = Z_NULL;
		
		position = 0;
		
		int ret;
		if(mode == CompressModeCompress) {
			ret = deflateInit(&zstream, 5);
		}else if(mode == CompressModeDecompress){
			ret = inflateInit(&zstream);
		}else{
			SPInvalidEnum("mode", mode);
		}
		
		if(ret != Z_OK){
			SPRaise("Failed to initialize zlib deflator/inflator: %s",
					zError(ret));
		}
		
		valid = true;
		reachedEOF = false;
		bufferPos = 0;
		
	}
	DeflateStream::~DeflateStream() {
		SPADES_MARK_FUNCTION();
		if(valid){
			if(mode == CompressModeCompress){
				deflateEnd(&zstream);
			}else if(mode == CompressModeDecompress){
				inflateEnd(&zstream);
			}else{
				SPAssert(false);
			}
		}
		if(autoClose){
			delete baseStream;
		}
	}
	
#pragma mark - Deflate
	
	void DeflateStream::CompressBuffer() {
		SPADES_MARK_FUNCTION();
		SPAssert(mode == CompressModeCompress);
		char outputBuffer[chunkSize];
		
		if(!valid){
			SPRaise("State is invalid");
		}
		
		zstream.avail_in = buffer.size();
		zstream.next_in = (Bytef*)buffer.data();
		
		do{
			zstream.avail_out = chunkSize;
			zstream.next_out = (Bytef*)outputBuffer;
			int ret = deflate(&zstream, Z_NO_FLUSH);
			if(ret == Z_STREAM_ERROR) {
				valid = false;
				deflateEnd(&zstream);
				SPRaise("Error while deflating: %s",
						zError(ret));
			}
			
			int got = chunkSize - zstream.avail_out;
			baseStream->Write(outputBuffer, got);
		}while(zstream.avail_out == 0);
		
		SPAssert(zstream.avail_in == 0);
		std::vector<char>().swap(buffer);
	}
	
	void DeflateStream::DeflateEnd() {
		SPADES_MARK_FUNCTION();
		if(mode != CompressModeCompress){
			SPRaise("DeflareEnd called when decompressing");
		}
		if(!valid){
			SPRaise("State is invalid");
		}
		
		char outputBuffer[chunkSize];
		
		zstream.avail_in = 0;
		do{
			zstream.avail_out = chunkSize;
			zstream.next_out = (Bytef*)outputBuffer;
			int ret = deflate(&zstream, Z_FINISH);
			if(ret == Z_STREAM_ERROR) {
				valid = false;
				deflateEnd(&zstream);
				SPRaise("Error while deflating: %s",
						zError(ret));
			}
			
			int got = chunkSize - zstream.avail_out;
			baseStream->Write(outputBuffer, got);
		}while(zstream.avail_out == 0);
		
		deflateEnd(&zstream);
		valid = false;
	}
	
	void DeflateStream::WriteByte(int byte){
		SPADES_MARK_FUNCTION();
		if(mode != CompressModeCompress){
			SPRaise("Attempted to write when decompressing");
		}
		if(!valid){
			SPRaise("State is invalid");
		}
		
		if(buffer.size() >= bufferSize){
			CompressBuffer();
		}
		
		buffer.push_back((char)byte);
	}
	
	void DeflateStream::Write(const void *data, size_t bytes) {
		SPADES_MARK_FUNCTION();
		if(mode != CompressModeCompress){
			SPRaise("Attempted to write when decompressing");
		}
		if(!valid){
			SPRaise("State is invalid");
		}
		
		if(buffer.size() >= bufferSize){
			CompressBuffer();
		}
		
		const char *dt = reinterpret_cast<const char *>(data);
		buffer.insert(buffer.end(),
					  dt, dt + bytes);
	}
	
#pragma mark - inflateEnd
	void DeflateStream::FillBuffer() {
		SPAssert(bufferPos >= buffer.size());
		buffer.clear();
		
		SPADES_MARK_FUNCTION();
		SPAssert(mode == CompressModeDecompress);
		char inputBuffer[chunkSize];
		char outputBuffer[chunkSize];
		uLong oval = zstream.total_out;
		
		if(reachedEOF)
			return;
		if(!valid){
			SPRaise("State is invalid");
		}
		
		while(buffer.size() < bufferSize){
		
			
			size_t readSize;
			readSize = chunkSize - nextbuffer.size();
			for(size_t i = 0; i < nextbuffer.size(); i++)
				inputBuffer[i] = nextbuffer[i];
			readSize = baseStream->Read(inputBuffer + nextbuffer.size(), readSize);
			readSize += nextbuffer.size();
			zstream.avail_in = readSize;
			zstream.next_in = (Bytef*)inputBuffer;
			
			do{
				zstream.avail_out = chunkSize;
				zstream.next_out = (Bytef*)outputBuffer;
				int ret = inflate(&zstream, Z_NO_FLUSH);
				if(ret == Z_STREAM_ERROR ||
				   ret == Z_NEED_DICT ||
				   ret == Z_DATA_ERROR ||
				   ret == Z_MEM_ERROR) {
					valid = false;
					inflateEnd(&zstream);
					SPRaise("Error while inflating: %s",
							zError(ret));
				}
				if(ret == Z_STREAM_END && zstream.avail_out != 0){
					reachedEOF = true;
				}
				int got = chunkSize - zstream.avail_out;
				buffer.insert(buffer.end(),
							  outputBuffer,
							  outputBuffer + got);
			}while(zstream.avail_out == 0 && !reachedEOF);
			
			if(reachedEOF)
				break;
			else{
				if(readSize == 0){
					valid = false;
					inflateEnd(&zstream);
					SPRaise("EOF reached while reading compressed data");
				}
				nextbuffer.resize(zstream.avail_in);
				for(size_t i = 0; i < zstream.avail_in; i++)
					nextbuffer[i] = zstream.next_in[i];
			}
		}
		
		SPAssert(buffer.size() == zstream.total_out - oval);
		bufferPos = 0;
		
	}
	
	int DeflateStream::ReadByte() {
		SPADES_MARK_FUNCTION();
		if(bufferPos >= buffer.size()){
			FillBuffer();
		}
		if(bufferPos >= buffer.size()){
			SPAssert(reachedEOF);
			return -1;
		}
		position++;
		return (unsigned char)buffer[bufferPos++];
	}
	
	size_t DeflateStream::Read(void *data, size_t bytes) {
		SPADES_MARK_FUNCTION();
		size_t readBytes = 0;
		while(bytes > 0){
			if(bufferPos >= buffer.size()){
				FillBuffer();
				if(reachedEOF)
					break;
			}
			
			size_t copySize = bytes;
			if(copySize > (buffer.size() - bufferPos))
				copySize = buffer.size() - bufferPos;
			
			memcpy(data, buffer.data() + bufferPos,
				   copySize);
			
			reinterpret_cast<char *&>(data) += copySize;
			SPAssert(bytes >= copySize);
			bytes -= copySize;
			readBytes += copySize;
			bufferPos += copySize;
			position += copySize;
		}
		return readBytes;
	}
	
#pragma mark - Seek
	
	uint64_t DeflateStream::GetPosition() {
		return position;
	}
	void DeflateStream::SetPosition(uint64_t pos){
		SPADES_MARK_FUNCTION();
		SPRaise("Invalid operation");
	}
	
	uint64_t DeflateStream::GetLength() {
		SPADES_MARK_FUNCTION();
		if(mode == CompressModeCompress){
			return position;
		}else{
			SPRaise("Cannot retreive uncompressed data length");
		}
	}
	
	void DeflateStream::SetLength(uint64_t){
		SPADES_MARK_FUNCTION();
		SPRaise("Invalid operation");
	}
	
	
}