docs: Update TODO.md with comprehensive V2G message implementation roadmap

- Remove completed/obsolete tasks from previous C# porting plan
- Add detailed roadmap for implementing 11 core V2G message types
- Prioritize DC charging essential messages (Phase 1: CableCheck, PreCharge, WeldingDetection, PowerDelivery)
- Define implementation order: C → VC2022 → dotnet for consistency
- Include infrastructure improvements and success metrics
- Focus on XML parsing/generation as primary gap

Next immediate step: CableCheckReq/Res implementation in C

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

TODO.md

@@ -1,50 +1,124 @@
-# V2GDecoderC C# Porting Task List
+# V2G EXI Decoder - Development Roadmap
 
-## 📋 Execution Plan
+## 📋 Current Status & Next Steps
 
-### Phase 1: Setup & Analysis ✅
-- [x] Create REPORT.md with comprehensive C code analysis
-- [x] Create TODO.md with execution plan
+### ✅ Completed Tasks
+- [x] Clean output implementation for VC2022 -decode/-encode options
+- [x] Usage message standardization across versions
+- [x] DEBUG_PRINTF macro implementation for conditional debug output
+- [x] Comprehensive message implementation status analysis
+- [x] Documentation of current capabilities and gaps
+- [x] Multi-platform build verification (C, VC2022, dotnet)
 
-### Phase 2: .NET Core/6+ Implementation
-- [ ] Create `csharp` folder structure
-- [ ] Create `csharp\dotnet` subfolder  
-- [ ] Port core EXI codec to .NET
-- [ ] Port V2G protocol implementations (ISO1, ISO2, DIN)
-- [ ] Create test harness for .NET version
-- [ ] Test with test1.exi → test1.xml → test1.exi roundtrip
-- [ ] Validate roundtrip integrity (original vs final)
-- [ ] **Git commit** .NET version
+### 🎯 Next Priority: V2G Message Implementation
 
-### Phase 3: .NET Framework 4.8 Implementation  
-- [ ] Create `csharp\dotnetfx` subfolder
-- [ ] Port .NET version to .NET Framework 4.8
-- [ ] Adjust for Framework-specific differences
-- [ ] Create test harness for .NET FX version
-- [ ] Test with test1.exi → test1.xml → test1.exi roundtrip
-- [ ] Validate roundtrip integrity (original vs final)
-- [ ] **Git commit** .NET Framework version
+#### Phase 1: DC Charging Core Messages (Highest Priority)
+Implementation order: C → VC2022 → dotnet
 
-### Testing Strategy
-```
-Original: test1.exi
-Step 1: Decode test1.exi → test1.xml
-Step 2: Encode test1.xml → test1_new.exi  
-Step 3: Binary compare test1.exi ≟ test1_new.exi
-Result: PASS/FAIL validation
-```
+1. **CableCheckReq/Res** - Cable insulation state verification
+   - [ ] C: XML parsing/generation logic
+   - [ ] C: EXI encoding/decoding integration
+   - [ ] VC2022: Port from C implementation
+   - [ ] dotnet: Port from C implementation
+   - [ ] Test with sample EXI files
 
-### Key Porting Considerations
-- **Memory Management**: C static allocation → C# managed memory
-- **Error Handling**: C return codes → C# exceptions
-- **String Handling**: C char arrays → C# string/byte[]
-- **Buffer Operations**: C memcpy → C# Array.Copy/Buffer.BlockCopy
-- **Platform Differences**: Endianness, type sizes
-- **Security**: Address C vulnerabilities in C# implementation
+2. **PreChargeReq/Res** - Pre-charging voltage matching
+   - [ ] C: XML parsing/generation logic
+   - [ ] C: EXI encoding/decoding integration
+   - [ ] VC2022: Port from C implementation
+   - [ ] dotnet: Port from C implementation
+   - [ ] Test with sample EXI files
 
-### Success Criteria
-1. ✅ Functional parity with C version
-2. ✅ Test roundtrip validation passes
-3. ✅ Clean separation of .NET/.NET FX versions
-4. ✅ Git commits for each major milestone
-5. ✅ Improved memory safety vs C version
+3. **WeldingDetectionReq/Res** - Post-charging welding detection
+   - [ ] C: XML parsing/generation logic
+   - [ ] C: EXI encoding/decoding integration
+   - [ ] VC2022: Port from C implementation
+   - [ ] dotnet: Port from C implementation
+   - [ ] Test with sample EXI files
+
+4. **PowerDeliveryReq/Res** - Charging start/stop control
+   - [ ] C: XML parsing/generation logic
+   - [ ] C: EXI encoding/decoding integration
+   - [ ] VC2022: Port from C implementation
+   - [ ] dotnet: Port from C implementation
+   - [ ] Test with sample EXI files
+
+#### Phase 2: Session & Service Management (High Priority)
+
+5. **SessionSetupReq/Res** - Charging session initialization
+   - [ ] C: XML parsing/generation logic
+   - [ ] VC2022: Port from C implementation
+   - [ ] dotnet: Port from C implementation
+
+6. **ServiceDiscoveryReq/Res** - Available charging services discovery
+   - [ ] C: XML parsing/generation logic
+   - [ ] VC2022: Port from C implementation
+   - [ ] dotnet: Port from C implementation
+
+7. **AuthorizationReq/Res** - Charging authorization verification
+   - [ ] C: XML parsing/generation logic
+   - [ ] VC2022: Port from C implementation
+   - [ ] dotnet: Port from C implementation
+
+8. **ChargeParameterDiscoveryReq/Res** - Charging parameter exchange
+   - [ ] C: XML parsing/generation logic
+   - [ ] VC2022: Port from C implementation
+   - [ ] dotnet: Port from C implementation
+
+#### Phase 3: Extended Features (Medium Priority)
+
+9. **PaymentServiceSelectionReq/Res** - Payment method selection
+   - [ ] C: XML parsing/generation logic
+   - [ ] VC2022: Port from C implementation
+   - [ ] dotnet: Port from C implementation
+
+10. **ChargingStatusReq/Res** - AC charging status (for AC support)
+    - [ ] C: XML parsing/generation logic
+    - [ ] VC2022: Port from C implementation
+    - [ ] dotnet: Port from C implementation
+
+11. **SessionStopReq/Res** - Charging session termination
+    - [ ] C: XML parsing/generation logic
+    - [ ] VC2022: Port from C implementation
+    - [ ] dotnet: Port from C implementation
+
+### 🔧 Infrastructure Improvements
+
+#### Code Quality & Testing
+- [ ] Implement comprehensive test suite for all message types
+- [ ] Create sample EXI files for each message type
+- [ ] Add roundtrip testing (EXI → XML → EXI validation)
+- [ ] Performance benchmarking across versions
+
+#### Build & Deployment
+- [ ] Automate build process for all platforms
+- [ ] Create release packaging scripts
+- [ ] Add continuous integration pipeline
+
+#### Documentation
+- [ ] Create API documentation for each version
+- [ ] Write usage examples for each message type
+- [ ] Document ISO 15118-2 compliance status
+
+### 📊 Success Metrics
+
+#### Functional Requirements
+- [ ] Support all 8 core DC charging messages
+- [ ] Pass ISO 15118-2 compliance validation
+- [ ] Maintain backward compatibility with existing CurrentDemand implementation
+- [ ] Clean output for production use (no debug messages)
+
+#### Quality Requirements
+- [ ] 100% roundtrip accuracy (EXI → XML → EXI)
+- [ ] Memory safety (no buffer overflows)
+- [ ] Performance parity with original C implementation
+- [ ] Consistent behavior across C/VC2022/dotnet versions
+
+### 🎯 Current Focus
+**Immediate Next Step**: Implement CableCheckReq/Res in original C version as foundation for other platform ports.
+
+### 📝 Notes
+- All message structures already exist in VC2022 and dotnet versions
+- Focus on XML parsing/generation logic implementation
+- Maintain DEBUG_PRINTF pattern for consistent debugging
+- Test each message with real V2G communication scenarios