/*******************************************************************************

 Copyright (c) 2009, Charles McGarvey
 All rights reserved.
 
 Redistribution   and   use  in  source  and  binary  forms,  with  or  without
 modification, are permitted provided that the following conditions are met:
 
   * Redistributions  of  source  code  must retain the above copyright notice,
     this list of conditions and the following disclaimer.
   * Redistributions  in binary form must reproduce the above copyright notice,
     this  list of conditions and the following disclaimer in the documentation
     and/or other materials provided with the distribution.
 
 THIS  SOFTWARE  IS  PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 AND  ANY  EXPRESS  OR  IMPLIED  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 DISCLAIMED.  IN  NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 FOR  ANY  DIRECT,  INDIRECT,  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 DAMAGES  (INCLUDING,  BUT  NOT  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 SERVICES;  LOSS  OF  USE,  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 CAUSED  AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 OR  TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

*******************************************************************************/

#include <fstream>
#include <queue>

#include <yajl/yajl_parse.h>

#include "Deserializer.hh"
#include "Log.hh"
#include "Serializable.hh"


namespace Mf {


class Deserializer::Impl
{
public:
	Impl(const std::string& filePath, bool comments = false,
			bool check = false)
	{
		std::ifstream* input = new std::ifstream(filePath.c_str());
		init(*input, true, comments, check);
	}

	Impl(std::istream& input, bool comments = false,
			bool check = false)
	{
		init(input, false, comments, check);
	}

	~Impl()
	{
		while (!parsed.empty())
		{
			delete parsed.front();
			parsed.pop();
		}

		if (deleteWhenDone)
		{
			delete in;
		}
		yajl_free(hand);
	}

	void raise()
	{
		unsigned char* errorStr = yajl_get_error(hand, 0, 0, 0);
		logError("parser error: %s", errorStr);
		yajl_free_error(hand, errorStr);

		throw Exception(Exception::PARSING_FAILED);
	}


	static int parsedNull(void* ctx)
	{
		((Impl*)ctx)->parsed.push(new SerializableNull);
		return 1;
	}

	static int parsedBoolean(void* ctx, int value)
	{
		((Impl*)ctx)->parsed.push(new SerializableBasic<Serializable::Boolean>(value));
		return 1;
	}

	static int parsedInteger(void* ctx, long value)
	{
		((Impl*)ctx)->parsed.push(new SerializableBasic<Serializable::Integer>(value));
		return 1;
	}

	static int parsedFloat(void* ctx, double value)
	{
		((Impl*)ctx)->parsed.push(new SerializableBasic<Serializable::Float>(value));
		return 1;
	}

	static int parsedString(void* ctx, const unsigned char* value,
			unsigned length)
	{
		((Impl*)ctx)->parsed.push(new SerializableBasic<Serializable::String>(std::string((char*)value, length)));
		return 1;
	}

	static int parsedBeginMap(void* ctx)
	{
		((Impl*)ctx)->parsed.push(new SerializableBasic<Serializable::Map>);
		return 1;
	}

	static int parsedMapKey(void* ctx, const unsigned char* value,
			unsigned length)
	{
		// same thing as a string
		return parsedString(ctx, value, length);
	}

	static int parsedEndMap(void* ctx)
	{
		// null means the end of a structure
		((Impl*)ctx)->parsed.push(0);
		return 1;
	}

	static int parsedBeginArray(void* ctx)
	{
		((Impl*)ctx)->parsed.push(new SerializableBasic<Serializable::Array>);
		return 1;
	}

	static int parsedEndArray(void* ctx)
	{
		// null means the end of a structure
		((Impl*)ctx)->parsed.push(0);
		return 1;
	}


	void parse()
	{
		unsigned char buffer[4096];

		yajl_status stat;

		while (parsed.empty() && in->good())
		{
			in->read((char*)buffer, sizeof(buffer));
			unsigned readIn = in->gcount();

			if (readIn > 0)
			{
				stat = yajl_parse(hand, buffer, readIn);
			}
			else
			{
				stat = yajl_parse_complete(hand);
			}

			if (stat != yajl_status_ok &&
					stat != yajl_status_insufficient_data)
			{
				raise();
			}
		}
	}


	yajl_handle hand;

	std::istream* in;
	bool deleteWhenDone;

	std::queue<Serializable*> parsed;

private:
	void init(std::istream& input, bool deleteIn, bool comments, bool check)
	{
		// this has to be static because yajl actually does not copy it into its
		// internal data structures but rather keeps a pointer to this
		static const yajl_callbacks callbacks =
		{
			Impl::parsedNull,
			Impl::parsedBoolean,
			Impl::parsedInteger,
			Impl::parsedFloat,
			0,
			Impl::parsedString,
			Impl::parsedBeginMap,
			Impl::parsedMapKey,
			Impl::parsedEndMap,
			Impl::parsedBeginArray,
			Impl::parsedEndArray
		};

		in = &input;
		deleteWhenDone = deleteIn;

		yajl_parser_config config = {comments, check};
		hand = yajl_alloc(&callbacks, &config, NULL, this);
	}
};


Deserializer::Deserializer(const std::string& filePath, bool comments,
		bool check) :
	// pass through
	impl_(new Deserializer::Impl(filePath, comments, check)) {}

Deserializer::Deserializer(std::istream& input, bool comments, bool check) :
	// pass through
	impl_(new Deserializer::Impl(input, comments, check)) {}


SerializableP Deserializer::deserialize()
{
	Serializable* ptr = pullNext();
	if (ptr)
	{
		ptr->deserialize(*this);
	}
	return SerializableP(ptr);
}


Serializable* Deserializer::pullNext()
{
	impl_->parse();
	if (!impl_->parsed.empty())
	{
		Serializable* ptr = impl_->parsed.front();
		return ptr;
	}
	return 0;
}

void Deserializer::pop()
{
	// pass through
	impl_->parsed.pop();
}


} // namespace Mf

/** vim: set ts=4 sw=4 tw=80: *************************************************/