/*
 * PacketLib.h
 *
 *  Created on: Nov 24, 2022
 *      Author: valerio
 */

#ifndef INCLUDE_BASEPACKET_H_
#define INCLUDE_BASEPACKET_H_

#include <vector>
#include <map>
#include <string>
#include <cstring>
#include <algorithm>
#include <numeric>
#include <iostream>
#include <cmath>
#include <functional>

namespace inaf::oasbo::PacketLib {

template<typename ValueType>
class bit_iterator: public std::iterator<std::random_access_iterator_tag,
		ValueType> {
public:
	bit_iterator(const uint8_t *data, int offset, std::vector<int> fieldSizes,
			std::function<ValueType(const uint8_t *,size_t,int)> func) :
			m_data(data), m_offset(offset), m_fieldSizes(fieldSizes), m_func(func) {
	}

	bit_iterator(const bit_iterator &other) :
			m_data(other.m_data), m_offset(other.m_offset), m_fieldSizes(
					other.m_fieldSizes), m_func(other.m_func) {
	}

	bit_iterator& operator++() {
		++m_offset;
		return *this;
	}

	bit_iterator operator++(int) {
		bit_iterator temp(*this);
		++m_offset;
		return temp;
	}

	bit_iterator& operator--() {
		--m_offset;
		return *this;
	}

	bit_iterator operator--(int) {
		bit_iterator temp(*this);
		--m_offset;
		return temp;
	}

	bit_iterator operator+(int n) const {
		return bit_iterator(m_data, m_offset + n);
	}

	bit_iterator operator-(int n) const {
		return bit_iterator(m_data, m_offset - n);
	}

	int operator-(const bit_iterator &other) const {
		return m_offset - other.m_offset;
	}

	bool operator==(const bit_iterator &other) const {
		return m_data == other.m_data && m_offset == other.m_offset;
	}

	bool operator!=(const bit_iterator &other) const {
		return !(*this == other);
	}

	ValueType operator*() const {
		size_t offset = std::accumulate(m_fieldSizes.begin(), m_fieldSizes.begin() + m_offset, 0); // offset from the beginning of the byte
		int num_bits = m_fieldSizes[m_offset];
		return m_func(m_data,offset, num_bits);
	}

private:
	const uint8_t *m_data;
	int m_offset;
	std::vector<int> m_fieldSizes;
	std::function<ValueType(const uint8_t *,size_t,int)> m_func;
};

class BasePacketStructure {

public:
	virtual ~BasePacketStructure() = default;
	virtual std::vector<std::tuple<int, std::string, int>> getPacketStructure() = 0;
};

template<typename ValueType>
class BasePacketTempl {
protected:
	uint8_t *binaryPointer;
	std::vector<int> fieldSizes;
	std::map<size_t, size_t> fieldNameToOffsetsMap;
	std::map<std::string, int> fieldNameToIndexMap;
	std::map<int, std::string> indexToFieldNameMap;

	void updateFieldSizes(
			const std::vector<std::tuple<int, std::string, int>> &paramsTuple) {
		std::for_each(paramsTuple.begin(), paramsTuple.end(),
				[&](const std::tuple<int, std::string, int> &tup) {
					this->fieldSizes.push_back(std::get < 2 > (tup));
				});
	}

	void updateFieldOffsets(
			const std::vector<std::tuple<int, std::string, int>> &paramsTuple) {
		size_t offset = 0;
		for (size_t i = 0; i < paramsTuple.size(); i++) {
			fieldNameToOffsetsMap[i] = offset;
			offset += std::get < 2 > (paramsTuple[i]);
		}
	}
	void updateFieldNameAndIndexMap(
			const std::vector<std::tuple<int, std::string, int>> &paramsTuple) {
		std::for_each(paramsTuple.begin(), paramsTuple.end(),
				[&](const std::tuple<int, std::string, int> &tup) {
					this->fieldNameToIndexMap[std::get < 1 > (tup)] = std::get
							< 0 > (tup);
					this->indexToFieldNameMap[std::get < 0 > (tup)] = std::get
							< 1 > (tup);
				});
	}

public:

	BasePacketTempl(std::vector<std::tuple<int, std::string, int>> paramsTuple) {
		this->updateFieldSizes(paramsTuple);
		this->updateFieldNameAndIndexMap(paramsTuple);
		this->updateFieldOffsets(paramsTuple);
		this->binaryPointer = new uint8_t[paramsTuple.size() * sizeof(ValueType)]; //tot number of field times the maximum bytesize of the value;
	}
	virtual ~BasePacketTempl() = default;

	void updateStructure(std::vector<std::tuple<int, std::string, int>> paramsTuple){
		this->updateFieldSizes(paramsTuple);
		this->updateFieldNameAndIndexMap(paramsTuple);
		this->updateFieldOffsets(paramsTuple);
	}

	static ValueType _readValueFromBinaryAt_(const uint8_t *binaryPointer, size_t offset,
			int num_bits) {
		int bit_offset = offset % 8;
		int byte_offset = offset / 8;
		ValueType value = 0;

		for (int i = 0; i < num_bits; i++) {
			int byte_index = byte_offset + (bit_offset + i) / 8;
			int bit_index = (bit_offset + i) % 8;
			uint8_t byte = binaryPointer[byte_index];
			uint8_t bit_mask = 1 << (7 - bit_index);
			value |= (byte & bit_mask) ? (1 << (num_bits - i - 1)) : 0;
		}
		return value;
	}

	ValueType readValueFromBinaryAt(int index) {
		size_t offset = fieldNameToOffsetsMap.at(index); // offset from the beginning of the byte
		int num_bits = this->fieldSizes[index]; //remaining bits to read
		ValueType value = _readValueFromBinaryAt_(binaryPointer, offset, num_bits);
		return value;
	}

	std::vector<int> const* getFieldSizes() const {
		return &fieldSizes;
	}
	uint8_t const* getBinaryPointer() const {
		return binaryPointer;
	}

	void copyToBinaryPointer(const uint8_t *from, uint size) {
		std::memcpy(binaryPointer, from, size);
	}
	void copyToBinaryPointer(const uint8_t *from, uint size, uint offset) {
		std::memcpy(&binaryPointer[offset], from, size);
	}

	size_t indexOfField(std::string fieldName) {
		return this->fieldNameToIndexMap.at(fieldName);
	}
	std::string fieldNameOfIndex(size_t index) {
		return this->indexToFieldNameMap.at(index);
	}

	ValueType operator[](int index) {
		return readValueFromBinaryAt(index);
	}

	ValueType operator[](std::string fieldName) {
		try{
		int index = this->fieldNameToIndexMap.at(fieldName);
		return readValueFromBinaryAt(index);
		}
		catch(const std::out_of_range& oor){
			std::cerr << "Error: no field with name '" << fieldName << "', returning 0" << std::endl;
			return 0;
		}
	}


	bit_iterator<ValueType> begin() const {
		return bit_iterator<ValueType>(binaryPointer, 0, fieldSizes,
				&_readValueFromBinaryAt_);
	}

	bit_iterator<ValueType> end() const {
		return bit_iterator<ValueType>(binaryPointer, fieldSizes.size(), fieldSizes,
				&_readValueFromBinaryAt_);
	}

	virtual size_t getHeaderSize()=0;
	virtual size_t getPayloadSize()=0;
	virtual size_t getTailSize()=0;
	virtual size_t getMaxPacketSize()=0;
};

using valueType = size_t;
class BasePacket : public BasePacketTempl<valueType> {

protected:

public:
	BasePacket(std::vector<std::tuple<int, std::string, int>> paramsTuple) :
		BasePacketTempl<valueType>(paramsTuple) {
	}
	virtual ~BasePacket() = default;

};
}
#endif