/**

  * djm-fix

  * Copyright © 2025 František Kučera (Frantovo.cz, GlobalCode.info)

  *

  * This program is free software: you can redistribute it and/or modify

  * it under the terms of the GNU General Public License as published by

  * the Free Software Foundation, version 3 of the License.

  *

  * This program is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

  * GNU General Public License for more details.

  *

  * You should have received a copy of the GNU General Public License

  * along with this program. If not, see <http://www.gnu.org/licenses/>.

  */

 #include <iostream>

 #include <iomanip>

 #include "MessageCodec.h"

 Message MessageCodec::decode(std::vector<uint8_t> data) {

 	using ERR = std::invalid_argument;

 	if (data.empty() || data.front() != 0xf0 || data.back() != 0xf7)

 		throw ERR("not a MIDI SysEx message");

 	// Manufacturer MIDI SysEx ID Numbers:

 	//   00H 40H 05H = AlphaTheta Corporation

 	//   00H 40H 06H = Pioneer Corporation

 	if (data.size() < 4

 			|| data[1] != 0x00

 			|| data[2] != 0x40

 			|| data[3] != 0x05)

 		throw ERR("wrong message Manufacturer MIDI SysEx ID");

 	if (data.size() < 8) throw ERR("missing model");

 	uint8_t model = data[7];

 	if (data.size() < 10) throw ERR("missing message type");

 	MessageType msgType;

 	if /**/ (data[9] == 0x11) msgType = MessageType::D11_GREETING;

 	else if (data[9] == 0x12) msgType = MessageType::H12_SEED1;

 	else if (data[9] == 0x13) msgType = MessageType::D13_HASH1_SEED2;

 	else if (data[9] == 0x14) msgType = MessageType::H14_HASH2;

 	else if (data[9] == 0x15) msgType = MessageType::D15_CONFIRMATION;

 	else throw ERR("unsupported message type");

 	if (data.size() < 11) throw ERR("missing message length");

 	if (data[10] != data.size() - 10) throw ERR("wrong message length");

 	std::vector<Field> fields;

 	for (size_t start = 11; data.size() > start + 1;) {

 		FieldType fieldType;

 		if /**/ (data[start] == 0x01) fieldType = FieldType::F01;

 		else if (data[start] == 0x02) fieldType = FieldType::F02;

 		else if (data[start] == 0x03) fieldType = FieldType::F03;

 		else if (data[start] == 0x04) fieldType = FieldType::F04;

 		else if (data[start] == 0x05) fieldType = FieldType::F05;

 		else throw ERR("unsupported field type");

 		size_t fieldSize = data[start + 1];

 		if (data.size() < start + fieldSize + 1) throw ERR("field overflow");

 		//                                    ^ 0xf7 messsage end

 		std::vector<uint8_t> fieldData(

 				data.begin() + start + 2,

 				data.begin() + start + fieldSize);

 		fields.push_back({fieldType, fieldData});

 		start += fieldSize;

 	}

 	return Message(msgType, model, fields);

 }

 std::vector<uint8_t> MessageCodec::encode(Message msg) {

 	using ERR = std::invalid_argument;

 	std::vector<uint8_t> data;

 	data.push_back(0xf0);

 	data.push_back(0x00);

 	data.push_back(0x40);

 	data.push_back(0x05);

 	data.push_back(0x00);

 	data.push_back(0x00);

 	data.push_back(0x00);

 	data.push_back(msg.model);

 	data.push_back(0x00);

 	data.push_back((uint8_t) msg.type);

 	uint8_t msgLength = 2; // 2 = type + lenght

 	for (const auto& field : msg.fields) msgLength += field.data.size() + 2;

 	data.push_back(msgLength);

 	for (const auto& field : msg.fields) {

 		size_t fieldSize = field.data.size() + 2;

 		if (fieldSize > 256) throw ERR("message field too long");

 		data.push_back((uint8_t) field.type);

 		data.push_back((uint8_t) (fieldSize));

 		data.insert(data.end(), field.data.begin(), field.data.end());

 	}

 	data.push_back(0xf7);

 	return data;

 }