using System;
using System.IO;

namespace V2GProtocol
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("=== V2G Transfer Protocol Decoder/Encoder ===");
            Console.WriteLine("ISO 15118-2 / DIN SPEC 70121 / SAP Protocol");
            Console.WriteLine();

            try
            {
                // 기본 데이터 파일 경로
                string dataFilePath = @"data\632 raw data.txt";
                
                if (args.Length > 0)
                {
                    dataFilePath = args[0];
                }

                if (!File.Exists(dataFilePath))
                {
                    Console.WriteLine($"Error: Data file not found: {dataFilePath}");
                    Console.WriteLine("Usage: V2GDecoder.exe [data_file_path]");
                    return;
                }

                Console.WriteLine($"Loading data from: {dataFilePath}");
                
                // 헥스 파일에서 바이너리 데이터 파싱
                byte[] rawData = V2GDecoder.ParseHexFile(dataFilePath);
                
                Console.WriteLine($"Parsed {rawData.Length} bytes from hex file");
                Console.WriteLine();
                
                // 전체 데이터 헥스 덤프
                Console.WriteLine("=== Raw Data Hex Dump ===");
                Console.WriteLine(V2GDecoder.BytesToHex(rawData));
                Console.WriteLine();
                
                // V2G 메시지 디코딩 시도
                Console.WriteLine("=== V2G Message Analysis ===");
                
                // 전체 데이터에서 V2G 메시지 찾기
                AnalyzeV2GMessages(rawData);
                
                // 네트워크 패킷 분석 (이더넷/IPv6/TCP 헤더 포함인 경우)
                AnalyzeNetworkPacket(rawData);
                
                Console.WriteLine("\nPress any key to exit...");
                Console.ReadKey();
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Error: {ex.Message}");
                Console.WriteLine(ex.StackTrace);
            }
        }

        static void AnalyzeV2GMessages(byte[] data)
        {
            // V2G Transfer Protocol 시그니처 찾기
            for (int i = 0; i < data.Length - 8; i++)
            {
                if (data[i] == 0x01 && data[i + 1] == 0xFE) // V2G TP Header
                {
                    Console.WriteLine($"Potential V2G message found at offset 0x{i:X4}");
                    
                    try
                    {
                        byte[] messageData = new byte[data.Length - i];
                        Array.Copy(data, i, messageData, 0, messageData.Length);
                        
                        var message = V2GDecoder.DecodeMessage(messageData);
                        
                        Console.WriteLine($"  Version: 0x{message.Version:X2}");
                        Console.WriteLine($"  Inverse Version: 0x{message.InverseVersion:X2}");
                        Console.WriteLine($"  Payload Type: 0x{(ushort)message.PayloadType:X4} ({message.PayloadType})");
                        Console.WriteLine($"  Payload Length: {message.PayloadLength} bytes");
                        Console.WriteLine($"  Valid: {message.IsValid}");
                        Console.WriteLine();
                        
                        if (message.IsValid && message.Payload != null)
                        {
                            Console.WriteLine("=== Decoded Message Content ===");
                            Console.WriteLine(message.DecodedContent);
                            Console.WriteLine();
                        }
                    }
                    catch (Exception ex)
                    {
                        Console.WriteLine($"  Error decoding message: {ex.Message}");
                    }
                }
            }
        }
        
        static void AnalyzeNetworkPacket(byte[] data)
        {
            Console.WriteLine("=== Network Packet Analysis ===");
            
            if (data.Length < 54) // Minimum Ethernet + IPv6 + TCP header size
            {
                Console.WriteLine("Data too short for network packet analysis");
                return;
            }
            
            try
            {
                // 이더넷 헤더 분석 (14 bytes)
                Console.WriteLine("Ethernet Header:");
                Console.WriteLine($"  Destination MAC: {string.Join(":", data[0..6].Select(b => b.ToString("X2")))}");
                Console.WriteLine($"  Source MAC: {string.Join(":", data[6..12].Select(b => b.ToString("X2")))}");
                Console.WriteLine($"  EtherType: 0x{(data[12] << 8 | data[13]):X4}");
                
                ushort etherType = (ushort)(data[12] << 8 | data[13]);
                
                if (etherType == 0x86DD) // IPv6
                {
                    Console.WriteLine("\nIPv6 Header:");
                    int ipv6Offset = 14;
                    byte versionTrafficClass = data[ipv6Offset];
                    Console.WriteLine($"  Version: {(versionTrafficClass >> 4) & 0xF}");
                    Console.WriteLine($"  Traffic Class: 0x{((versionTrafficClass & 0xF) << 4 | (data[ipv6Offset + 1] >> 4)):X2}");
                    
                    ushort payloadLength = (ushort)(data[ipv6Offset + 4] << 8 | data[ipv6Offset + 5]);
                    byte nextHeader = data[ipv6Offset + 6];
                    byte hopLimit = data[ipv6Offset + 7];
                    
                    Console.WriteLine($"  Payload Length: {payloadLength}");
                    Console.WriteLine($"  Next Header: 0x{nextHeader:X2} ({(nextHeader == 6 ? "TCP" : "Other")})");
                    Console.WriteLine($"  Hop Limit: {hopLimit}");
                    
                    // IPv6 주소는 16바이트씩
                    var srcAddr = data[(ipv6Offset + 8)..(ipv6Offset + 24)];
                    var dstAddr = data[(ipv6Offset + 24)..(ipv6Offset + 40)];
                    
                    Console.WriteLine($"  Source Address: {string.Join(":", Enumerable.Range(0, 8).Select(i => $"{srcAddr[i*2]:X2}{srcAddr[i*2+1]:X2}"))}");
                    Console.WriteLine($"  Destination Address: {string.Join(":", Enumerable.Range(0, 8).Select(i => $"{dstAddr[i*2]:X2}{dstAddr[i*2+1]:X2}"))}");
                    
                    if (nextHeader == 6) // TCP
                    {
                        int tcpOffset = ipv6Offset + 40;
                        if (data.Length > tcpOffset + 20)
                        {
                            Console.WriteLine("\nTCP Header:");
                            ushort srcPort = (ushort)(data[tcpOffset] << 8 | data[tcpOffset + 1]);
                            ushort dstPort = (ushort)(data[tcpOffset + 2] << 8 | data[tcpOffset + 3]);
                            
                            Console.WriteLine($"  Source Port: {srcPort}");
                            Console.WriteLine($"  Destination Port: {dstPort}");
                            
                            // V2G는 일반적으로 포트 15118을 사용
                            if (srcPort == 15118 || dstPort == 15118)
                            {
                                Console.WriteLine("  -> V2G Communication detected (port 15118)!");
                            }
                            
                            // TCP 데이터 시작 위치 계산
                            byte dataOffset = (byte)((data[tcpOffset + 12] >> 4) * 4);
                            int tcpDataOffset = tcpOffset + dataOffset;
                            
                            if (tcpDataOffset < data.Length)
                            {
                                Console.WriteLine($"\nTCP Payload (starting at offset 0x{tcpDataOffset:X4}):");
                                byte[] tcpPayload = data[tcpDataOffset..];
                                
                                // TCP 페이로드에서 V2G 메시지 찾기
                                if (tcpPayload.Length > 8 && tcpPayload[0] == 0x01 && tcpPayload[1] == 0xFE)
                                {
                                    Console.WriteLine("V2G Message found in TCP payload!");
                                    var v2gMessage = V2GDecoder.DecodeMessage(tcpPayload);
                                    Console.WriteLine(v2gMessage.DecodedContent);
                                }
                                else
                                {
                                    Console.WriteLine("TCP Payload hex dump:");
                                    Console.WriteLine(V2GDecoder.BytesToHex(tcpPayload));
                                }
                            }
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Error analyzing network packet: {ex.Message}");
            }
        }
    }
}