Add DCTP (Delta Code Transfer Protocol) tool for efficient AI code transfers

DCTP enables efficient transfer of AI-generated code using delta operations
instead of sending complete files for each modification. Features include:

- Parser for DCTP control commands (NEW, DELETE, INSERT_AFTER, REPLACE, RENUMBER)
- Line-numbered code with language-specific comment formats
- Backup/Undo system with session management
- Diff generation for preview functionality
- CustomTkinter GUI with project management, preview, and diff views

dctp/.gitignore

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+__pycache__/
+*.pyc
+*.pyo
+.dctp_backups/
+.dctp_settings.json

dctp/CLAUDE.md

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+# DCTP - Delta Code Transfer Protocol
+
+Du generierst Code im DCTP-Format fuer effiziente Uebertragung.
+
+## Regeln
+
+1. **Zeilennummern am Ende jeder Zeile** im passenden Kommentar-Format
+2. **Immer mit ###FILE: beginnen** bei jedem Codeblock
+3. **Bei Korrekturen NUR die geaenderten Zeilen senden**, nie den ganzen File
+
+## Zeilennummern-Format
+
+- Python/Shell: `code  #Z1`
+- JavaScript/Java/C/C++: `code  //Z1`
+- HTML: `code  <!--Z1-->`
+- CSS: `code  /*Z1*/`
+- SQL: `code  --Z1`
+
+## Befehle
+
+| Befehl | Syntax | Beschreibung |
+|--------|--------|--------------|
+| `###FILE:` | `###FILE:pfad/datei.ext` | Datei angeben |
+| `###NEW` | | Neue Datei, kompletter Inhalt folgt |
+| `###DELETE:` | `###DELETE:Z5-Z12` | Zeilen 5-12 loeschen |
+| `###INSERT_AFTER:` | `###INSERT_AFTER:Z5` | Nach Zeile 5 einfuegen |
+| `###REPLACE:` | `###REPLACE:Z5-Z8` | Zeilen 5-8 ersetzen |
+| `###END` | | Ende des Blocks |
+| `###RENUMBER` | | Zeilennummern neu berechnen |
+| `###CHECKSUM:` | `###CHECKSUM:a3f2b8c1` | Optional: Hash zur Validierung |
+
+## Beispiel: Neue Datei
+
+```
+###FILE:src/calculator.py
+###NEW
+def add(a, b):  #Z1
+    return a + b  #Z2
+  #Z3
+def multiply(a, b):  #Z4
+    return a * b  #Z5
+###END
+```
+
+## Beispiel: Korrektur (REPLACE)
+
+```
+###FILE:src/calculator.py
+###REPLACE:Z4-Z5
+def multiply(a, b):  #Z4
+    """Multipliziert zwei Zahlen."""  #Z5
+    return a * b  #Z6
+###END
+###RENUMBER
+```
+
+## Beispiel: Zeilen einfuegen
+
+```
+###FILE:src/calculator.py
+###INSERT_AFTER:Z2
+  #Z3
+def subtract(a, b):  #Z4
+    return a - b  #Z5
+###END
+###RENUMBER
+```
+
+## Beispiel: Zeilen loeschen
+
+```
+###FILE:src/calculator.py
+###DELETE:Z10-Z15
+###RENUMBER
+```
+
+## Beispiel: Mehrere Dateien
+
+```
+###FILE:src/models/user.py
+###NEW
+class User:  #Z1
+    def __init__(self, name: str):  #Z2
+        self.name = name  #Z3
+###END
+
+###FILE:src/models/order.py
+###NEW
+from .user import User  #Z1
+  #Z2
+class Order:  #Z3
+    def __init__(self, user: User):  #Z4
+        self.user = user  #Z5
+###END
+```
+
+## Wichtig
+
+- Bei Korrekturen: NUR Delta senden, nie kompletten File
+- Nach INSERT/DELETE/REPLACE immer ###RENUMBER
+- Leerzeilen auch nummerieren
+- Zeilennummern werden beim Schreiben automatisch entfernt

dctp/README.md

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+# DCTP - Delta Code Transfer Protocol
+
+Ein Tool um KI-generierten Code effizient in lokale Dateien zu uebertragen. Statt bei jeder Korrektur den kompletten Code neu zu senden, werden nur Aenderungen (Deltas) uebertragen.
+
+## Das Problem
+
+Claude generiert 500 Zeilen Code. Eine kleine Korrektur = nochmal 500 Zeilen. Verschwendung.
+
+## Die Loesung
+
+Zeilennummerierter Code + Steueranweisungen fuer gezielte Aenderungen.
+
+## Installation
+
+```bash
+# Requirements installieren
+pip install -r requirements.txt
+
+# GUI starten
+python dctp_gui.py
+```
+
+## Schnellstart
+
+### 1. Projektverzeichnis waehlen
+
+Klicke auf "Waehlen" und waehle dein Projektverzeichnis.
+
+### 2. KI-Output einfuegen
+
+Kopiere den DCTP-formatierten Output aus deinem Claude-Chat in das Input-Feld.
+
+### 3. Analysieren
+
+Klicke "Analysieren" um eine Vorschau der Operationen zu sehen.
+
+### 4. Ausfuehren
+
+Klicke "Ausfuehren" um die Aenderungen auf deine Dateien anzuwenden.
+
+## DCTP-Format
+
+### Neue Datei erstellen
+
+```
+###FILE:src/calculator.py
+###NEW
+def add(a, b):  #Z1
+    return a + b  #Z2
+###END
+```
+
+### Zeilen ersetzen
+
+```
+###FILE:src/calculator.py
+###REPLACE:Z1-Z2
+def add(a: int, b: int) -> int:  #Z1
+    """Addiert zwei Zahlen."""  #Z2
+    return a + b  #Z3
+###END
+###RENUMBER
+```
+
+### Zeilen einfuegen
+
+```
+###FILE:src/calculator.py
+###INSERT_AFTER:Z2
+  #Z3
+def subtract(a, b):  #Z4
+    return a - b  #Z5
+###END
+###RENUMBER
+```
+
+### Zeilen loeschen
+
+```
+###FILE:src/calculator.py
+###DELETE:Z10-Z15
+###RENUMBER
+```
+
+## Zeilennummern-Format
+
+Die Zeilennummern werden automatisch entsprechend der Programmiersprache formatiert:
+
+| Sprache | Format | Beispiel |
+|---------|--------|----------|
+| Python | `#Z1` | `code  #Z1` |
+| JavaScript | `//Z1` | `code  //Z1` |
+| HTML | `<!--Z1-->` | `code  <!--Z1-->` |
+| CSS | `/*Z1*/` | `code  /*Z1*/` |
+| SQL | `--Z1` | `code  --Z1` |
+
+## Befehle
+
+| Befehl | Beschreibung |
+|--------|--------------|
+| `###FILE:pfad` | Zieldatei angeben |
+| `###NEW` | Neue Datei erstellen |
+| `###DELETE:Z5-Z12` | Zeilen loeschen |
+| `###INSERT_AFTER:Z5` | Nach Zeile einfuegen |
+| `###REPLACE:Z5-Z8` | Zeilen ersetzen |
+| `###END` | Block beenden |
+| `###RENUMBER` | Zeilennummern aktualisieren |
+| `###CHECKSUM:hash` | Datei-Hash validieren |
+
+## Features
+
+- **Vorschau**: Zeigt was passieren wird, bevor es ausgefuehrt wird
+- **Diff-Ansicht**: Zeigt Aenderungen farbig markiert (alt vs neu)
+- **Undo**: Stellt den letzten Zustand wieder her
+- **Backup**: Automatische Backups vor jeder Aenderung
+- **Multi-File**: Mehrere Dateien in einem Durchgang bearbeiten
+- **Checksum**: Optionale Validierung gegen externe Aenderungen
+
+## Einstellungen
+
+- **Projektpfad**: Standard-Projektverzeichnis
+- **Backup-Verzeichnis**: Wo Backups gespeichert werden
+- **Auto-Renumber**: Zeilennummern automatisch aktualisieren
+- **Checksum-Validierung**: Externe Aenderungen erkennen
+- **Theme**: Hell oder dunkel
+
+## Claude-Integration
+
+Kopiere den Inhalt von `CLAUDE.md` in deine Claude-Chats (als Custom Instructions oder am Anfang des Gespraechs), damit Claude im DCTP-Format antwortet.
+
+## Architektur
+
+```
+dctp/
+├── dctp_gui.py          # Hauptfenster (CustomTkinter)
+├── dctp_parser.py       # Core-Logik: parse Steueranweisungen
+├── dctp_executor.py     # Fuehrt Operationen aus
+├── dctp_backup.py       # Undo/Backup-Verwaltung
+├── dctp_diff.py         # Diff-Berechnung fuer Vorschau
+├── requirements.txt     # Dependencies
+├── CLAUDE.md            # Anweisung fuer KI
+└── README.md            # Diese Datei
+```
+
+## Lizenz
+
+MIT License

dctp/dctp_backup.py

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+"""
+DCTP Backup Manager - Handles backup and undo functionality.
+
+Creates timestamped backups before operations and supports
+restoring files to their previous state.
+"""
+
+import json
+import os
+import shutil
+from dataclasses import dataclass, asdict
+from datetime import datetime
+from pathlib import Path
+from typing import Optional
+
+
+@dataclass
+class FileBackup:
+    """Represents a single file backup."""
+    original: str
+    backup: str
+    existed: bool  # Whether the file existed before (for new file handling)
+
+
+@dataclass
+class BackupSession:
+    """Represents a backup session (one execution run)."""
+    timestamp: str
+    files: list[FileBackup]
+
+
+@dataclass
+class BackupInfo:
+    """Info about a backup for display purposes."""
+    timestamp: str
+    file_count: int
+    files: list[str]
+
+
+class BackupManager:
+    """Manages file backups for undo functionality."""
+
+    BACKUP_DIR_NAME = ".dctp_backups"
+    MANIFEST_FILE = "manifest.json"
+    MAX_SESSIONS = 50  # Keep last 50 sessions
+
+    def __init__(self, project_path: str):
+        """
+        Initialize backup manager.
+
+        Args:
+            project_path: Base project directory
+        """
+        self.project_path = Path(project_path)
+        self.backup_dir = self.project_path / self.BACKUP_DIR_NAME
+        self.manifest_path = self.backup_dir / self.MANIFEST_FILE
+        self._current_session: Optional[BackupSession] = None
+        self._ensure_backup_dir()
+
+    def _ensure_backup_dir(self) -> None:
+        """Create backup directory if it doesn't exist."""
+        self.backup_dir.mkdir(parents=True, exist_ok=True)
+
+        # Create .gitignore in backup dir
+        gitignore_path = self.backup_dir / ".gitignore"
+        if not gitignore_path.exists():
+            gitignore_path.write_text("*\n")
+
+    def _load_manifest(self) -> dict:
+        """Load the manifest file."""
+        if self.manifest_path.exists():
+            try:
+                return json.loads(self.manifest_path.read_text())
+            except (json.JSONDecodeError, IOError):
+                return {"sessions": []}
+        return {"sessions": []}
+
+    def _save_manifest(self, manifest: dict) -> None:
+        """Save the manifest file."""
+        self.manifest_path.write_text(json.dumps(manifest, indent=2))
+
+    def start_session(self) -> None:
+        """Start a new backup session."""
+        timestamp = datetime.now().strftime("%Y-%m-%dT%H:%M:%S")
+        self._current_session = BackupSession(timestamp=timestamp, files=[])
+
+    def backup(self, file_path: str) -> Optional[str]:
+        """
+        Create a backup of a file.
+
+        Args:
+            file_path: Path to the file (relative to project or absolute)
+
+        Returns:
+            Backup filename if successful, None if file doesn't exist
+        """
+        if self._current_session is None:
+            self.start_session()
+
+        # Normalize path
+        if os.path.isabs(file_path):
+            full_path = Path(file_path)
+            rel_path = full_path.relative_to(self.project_path)
+        else:
+            rel_path = Path(file_path)
+            full_path = self.project_path / rel_path
+
+        # Check if file exists
+        existed = full_path.exists()
+
+        if existed:
+            # Generate backup filename
+            timestamp = datetime.now().strftime("%Y-%m-%d_%H%M%S")
+            safe_name = str(rel_path).replace(os.sep, "_").replace("/", "_")
+            backup_name = f"{timestamp}_{safe_name}"
+
+            # Copy file to backup
+            backup_path = self.backup_dir / backup_name
+            shutil.copy2(full_path, backup_path)
+        else:
+            backup_name = ""
+
+        # Add to current session
+        self._current_session.files.append(FileBackup(
+            original=str(rel_path),
+            backup=backup_name,
+            existed=existed
+        ))
+
+        return backup_name if existed else None
+
+    def end_session(self) -> None:
+        """End the current backup session and save to manifest."""
+        if self._current_session is None or len(self._current_session.files) == 0:
+            self._current_session = None
+            return
+
+        manifest = self._load_manifest()
+
+        # Convert to dict for JSON storage
+        session_dict = {
+            "timestamp": self._current_session.timestamp,
+            "files": [asdict(f) for f in self._current_session.files]
+        }
+        manifest["sessions"].append(session_dict)
+
+        # Limit number of sessions
+        if len(manifest["sessions"]) > self.MAX_SESSIONS:
+            # Remove old sessions and their backup files
+            old_sessions = manifest["sessions"][:-self.MAX_SESSIONS]
+            for session in old_sessions:
+                for file_info in session["files"]:
+                    backup_file = self.backup_dir / file_info["backup"]
+                    if backup_file.exists():
+                        backup_file.unlink()
+            manifest["sessions"] = manifest["sessions"][-self.MAX_SESSIONS:]
+
+        self._save_manifest(manifest)
+        self._current_session = None
+
+    def restore_last(self) -> tuple[bool, list[str]]:
+        """
+        Restore files from the last backup session.
+
+        Returns:
+            Tuple of (success, list of restored files)
+        """
+        manifest = self._load_manifest()
+
+        if not manifest["sessions"]:
+            return False, []
+
+        # Get last session
+        last_session = manifest["sessions"].pop()
+        restored_files = []
+
+        for file_info in last_session["files"]:
+            original_path = self.project_path / file_info["original"]
+
+            if file_info["existed"]:
+                # Restore from backup
+                backup_path = self.backup_dir / file_info["backup"]
+                if backup_path.exists():
+                    # Ensure parent directory exists
+                    original_path.parent.mkdir(parents=True, exist_ok=True)
+                    shutil.copy2(backup_path, original_path)
+                    backup_path.unlink()  # Remove backup file
+                    restored_files.append(file_info["original"])
+            else:
+                # File was newly created, delete it
+                if original_path.exists():
+                    original_path.unlink()
+                    restored_files.append(f"{file_info['original']} (deleted)")
+
+        self._save_manifest(manifest)
+        return True, restored_files
+
+    def list_backups(self) -> list[BackupInfo]:
+        """
+        List all backup sessions.
+
+        Returns:
+            List of BackupInfo objects, newest first
+        """
+        manifest = self._load_manifest()
+        backups = []
+
+        for session in reversed(manifest["sessions"]):
+            files = [f["original"] for f in session["files"]]
+            backups.append(BackupInfo(
+                timestamp=session["timestamp"],
+                file_count=len(files),
+                files=files
+            ))
+
+        return backups
+
+    def get_file_backup_path(self, file_path: str) -> Optional[Path]:
+        """
+        Get the backup path for a file from the most recent session.
+
+        Args:
+            file_path: Original file path (relative to project)
+
+        Returns:
+            Path to backup file if found, None otherwise
+        """
+        manifest = self._load_manifest()
+
+        if not manifest["sessions"]:
+            return None
+
+        # Search from newest to oldest
+        for session in reversed(manifest["sessions"]):
+            for file_info in session["files"]:
+                if file_info["original"] == file_path and file_info["existed"]:
+                    backup_path = self.backup_dir / file_info["backup"]
+                    if backup_path.exists():
+                        return backup_path
+
+        return None
+
+    def clear_all_backups(self) -> int:
+        """
+        Clear all backups.
+
+        Returns:
+            Number of backup files deleted
+        """
+        count = 0
+        if self.backup_dir.exists():
+            for item in self.backup_dir.iterdir():
+                if item.name != ".gitignore":
+                    if item.is_file():
+                        item.unlink()
+                        count += 1
+                    elif item.is_dir():
+                        shutil.rmtree(item)
+                        count += 1
+
+        # Reset manifest
+        self._save_manifest({"sessions": []})
+        return count
+
+
+def main():
+    """Test the backup manager."""
+    import tempfile
+
+    # Create a temporary project directory
+    with tempfile.TemporaryDirectory() as tmpdir:
+        # Create some test files
+        test_file = Path(tmpdir) / "test.py"
+        test_file.write_text("print('hello')\n")
+
+        # Initialize backup manager
+        manager = BackupManager(tmpdir)
+
+        # Start a session and backup the file
+        manager.start_session()
+        backup_name = manager.backup("test.py")
+        print(f"Created backup: {backup_name}")
+
+        # Modify the file
+        test_file.write_text("print('modified')\n")
+        print(f"File content after modification: {test_file.read_text()}")
+
+        # End session
+        manager.end_session()
+
+        # List backups
+        backups = manager.list_backups()
+        print(f"Backup sessions: {len(backups)}")
+        for b in backups:
+            print(f"  {b.timestamp}: {b.file_count} files")
+
+        # Restore
+        success, restored = manager.restore_last()
+        print(f"Restore successful: {success}")
+        print(f"Restored files: {restored}")
+        print(f"File content after restore: {test_file.read_text()}")
+
+
+if __name__ == "__main__":
+    main()

dctp/dctp_diff.py

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+"""
+DCTP Diff Generator - Generates diffs for preview display.
+
+Compares old and new content and produces colored diff output
+for the GUI preview.
+"""
+
+import difflib
+from dataclasses import dataclass
+from enum import Enum
+from typing import Optional
+
+
+class DiffType(Enum):
+    UNCHANGED = "unchanged"
+    ADDED = "added"
+    REMOVED = "removed"
+    CONTEXT = "context"
+
+
+@dataclass
+class DiffLine:
+    """Represents a single line in a diff."""
+    type: DiffType
+    line_number_old: Optional[int]  # Line number in old file
+    line_number_new: Optional[int]  # Line number in new file
+    content: str
+
+    @property
+    def prefix(self) -> str:
+        """Get the diff prefix character."""
+        if self.type == DiffType.ADDED:
+            return "+"
+        elif self.type == DiffType.REMOVED:
+            return "-"
+        else:
+            return " "
+
+    def __str__(self) -> str:
+        old_num = str(self.line_number_old) if self.line_number_old else ""
+        new_num = str(self.line_number_new) if self.line_number_new else ""
+        return f"{old_num:>4} {new_num:>4} {self.prefix} {self.content}"
+
+
+@dataclass
+class DiffBlock:
+    """A block of related diff lines."""
+    start_old: int
+    end_old: int
+    start_new: int
+    end_new: int
+    lines: list[DiffLine]
+
+    @property
+    def header(self) -> str:
+        """Generate a unified diff style header."""
+        return f"@@ -{self.start_old},{self.end_old - self.start_old + 1} +{self.start_new},{self.end_new - self.start_new + 1} @@"
+
+
+@dataclass
+class FileDiff:
+    """Complete diff for a file."""
+    filename: str
+    old_content: list[str]
+    new_content: list[str]
+    blocks: list[DiffBlock]
+    lines: list[DiffLine]
+
+    @property
+    def has_changes(self) -> bool:
+        return any(line.type in (DiffType.ADDED, DiffType.REMOVED) for line in self.lines)
+
+    @property
+    def additions(self) -> int:
+        return sum(1 for line in self.lines if line.type == DiffType.ADDED)
+
+    @property
+    def deletions(self) -> int:
+        return sum(1 for line in self.lines if line.type == DiffType.REMOVED)
+
+
+class DiffGenerator:
+    """Generates diffs between old and new content."""
+
+    def __init__(self, context_lines: int = 3):
+        """
+        Initialize diff generator.
+
+        Args:
+            context_lines: Number of context lines around changes
+        """
+        self.context_lines = context_lines
+
+    def generate(
+        self,
+        old_lines: list[str],
+        new_lines: list[str],
+        filename: str = ""
+    ) -> FileDiff:
+        """
+        Generate a diff between old and new content.
+
+        Args:
+            old_lines: Original content lines
+            new_lines: New content lines
+            filename: Optional filename for display
+
+        Returns:
+            FileDiff object with all diff information
+        """
+        diff_lines: list[DiffLine] = []
+
+        # Use difflib to compute differences
+        matcher = difflib.SequenceMatcher(None, old_lines, new_lines)
+
+        old_line_num = 1
+        new_line_num = 1
+
+        for tag, i1, i2, j1, j2 in matcher.get_opcodes():
+            if tag == 'equal':
+                for idx in range(i2 - i1):
+                    diff_lines.append(DiffLine(
+                        type=DiffType.UNCHANGED,
+                        line_number_old=old_line_num,
+                        line_number_new=new_line_num,
+                        content=old_lines[i1 + idx]
+                    ))
+                    old_line_num += 1
+                    new_line_num += 1
+
+            elif tag == 'replace':
+                # Show removed lines first, then added
+                for idx in range(i2 - i1):
+                    diff_lines.append(DiffLine(
+                        type=DiffType.REMOVED,
+                        line_number_old=old_line_num,
+                        line_number_new=None,
+                        content=old_lines[i1 + idx]
+                    ))
+                    old_line_num += 1
+
+                for idx in range(j2 - j1):
+                    diff_lines.append(DiffLine(
+                        type=DiffType.ADDED,
+                        line_number_old=None,
+                        line_number_new=new_line_num,
+                        content=new_lines[j1 + idx]
+                    ))
+                    new_line_num += 1
+
+            elif tag == 'delete':
+                for idx in range(i2 - i1):
+                    diff_lines.append(DiffLine(
+                        type=DiffType.REMOVED,
+                        line_number_old=old_line_num,
+                        line_number_new=None,
+                        content=old_lines[i1 + idx]
+                    ))
+                    old_line_num += 1
+
+            elif tag == 'insert':
+                for idx in range(j2 - j1):
+                    diff_lines.append(DiffLine(
+                        type=DiffType.ADDED,
+                        line_number_old=None,
+                        line_number_new=new_line_num,
+                        content=new_lines[j1 + idx]
+                    ))
+                    new_line_num += 1
+
+        # Generate blocks with context
+        blocks = self._generate_blocks(diff_lines)
+
+        return FileDiff(
+            filename=filename,
+            old_content=old_lines,
+            new_content=new_lines,
+            blocks=blocks,
+            lines=diff_lines
+        )
+
+    def _generate_blocks(self, diff_lines: list[DiffLine]) -> list[DiffBlock]:
+        """Generate diff blocks with context."""
+        if not diff_lines:
+            return []
+
+        blocks: list[DiffBlock] = []
+        current_block_lines: list[DiffLine] = []
+        in_change = False
+        unchanged_count = 0
+
+        for line in diff_lines:
+            is_change = line.type in (DiffType.ADDED, DiffType.REMOVED)
+
+            if is_change:
+                if not in_change:
+                    # Starting a new change block, include context
+                    in_change = True
+                    unchanged_count = 0
+                current_block_lines.append(line)
+
+            else:  # Unchanged line
+                if in_change:
+                    unchanged_count += 1
+                    if unchanged_count <= self.context_lines:
+                        current_block_lines.append(line)
+                    else:
+                        # End current block and start fresh
+                        if current_block_lines:
+                            blocks.append(self._create_block(current_block_lines))
+                        current_block_lines = []
+                        in_change = False
+                        unchanged_count = 0
+                else:
+                    # Keep track of potential context lines
+                    current_block_lines.append(line)
+                    if len(current_block_lines) > self.context_lines:
+                        current_block_lines.pop(0)
+
+        # Don't forget the last block
+        if current_block_lines and any(
+            l.type in (DiffType.ADDED, DiffType.REMOVED) for l in current_block_lines
+        ):
+            blocks.append(self._create_block(current_block_lines))
+
+        return blocks
+
+    def _create_block(self, lines: list[DiffLine]) -> DiffBlock:
+        """Create a DiffBlock from a list of lines."""
+        old_nums = [l.line_number_old for l in lines if l.line_number_old is not None]
+        new_nums = [l.line_number_new for l in lines if l.line_number_new is not None]
+
+        return DiffBlock(
+            start_old=min(old_nums) if old_nums else 0,
+            end_old=max(old_nums) if old_nums else 0,
+            start_new=min(new_nums) if new_nums else 0,
+            end_new=max(new_nums) if new_nums else 0,
+            lines=lines
+        )
+
+    def generate_unified_diff(
+        self,
+        old_lines: list[str],
+        new_lines: list[str],
+        old_filename: str = "a/file",
+        new_filename: str = "b/file"
+    ) -> str:
+        """
+        Generate a unified diff string.
+
+        Args:
+            old_lines: Original content lines
+            new_lines: New content lines
+            old_filename: Label for old file
+            new_filename: Label for new file
+
+        Returns:
+            Unified diff as string
+        """
+        diff = difflib.unified_diff(
+            old_lines,
+            new_lines,
+            fromfile=old_filename,
+            tofile=new_filename,
+            lineterm=""
+        )
+        return "\n".join(diff)
+
+    def generate_side_by_side(
+        self,
+        old_lines: list[str],
+        new_lines: list[str],
+        width: int = 80
+    ) -> list[tuple[str, str, str]]:
+        """
+        Generate a side-by-side diff representation.
+
+        Args:
+            old_lines: Original content lines
+            new_lines: New content lines
+            width: Width for each column
+
+        Returns:
+            List of tuples (left_line, marker, right_line)
+        """
+        result = []
+        half_width = (width - 3) // 2
+
+        matcher = difflib.SequenceMatcher(None, old_lines, new_lines)
+
+        for tag, i1, i2, j1, j2 in matcher.get_opcodes():
+            if tag == 'equal':
+                for idx in range(i2 - i1):
+                    line = old_lines[i1 + idx][:half_width]
+                    result.append((line, " ", line))
+
+            elif tag == 'replace':
+                max_len = max(i2 - i1, j2 - j1)
+                for idx in range(max_len):
+                    old_line = old_lines[i1 + idx][:half_width] if idx < i2 - i1 else ""
+                    new_line = new_lines[j1 + idx][:half_width] if idx < j2 - j1 else ""
+                    result.append((old_line, "|", new_line))
+
+            elif tag == 'delete':
+                for idx in range(i2 - i1):
+                    old_line = old_lines[i1 + idx][:half_width]
+                    result.append((old_line, "<", ""))
+
+            elif tag == 'insert':
+                for idx in range(j2 - j1):
+                    new_line = new_lines[j1 + idx][:half_width]
+                    result.append(("", ">", new_line))
+
+        return result
+
+
+def format_diff_for_display(diff: FileDiff, use_colors: bool = True) -> str:
+    """
+    Format a FileDiff for terminal/GUI display.
+
+    Args:
+        diff: The FileDiff to format
+        use_colors: Whether to use ANSI colors
+
+    Returns:
+        Formatted string
+    """
+    lines = []
+
+    if diff.filename:
+        lines.append(f"--- {diff.filename}")
+        lines.append(f"+++ {diff.filename}")
+
+    for line in diff.lines:
+        if use_colors:
+            if line.type == DiffType.ADDED:
+                prefix = "\033[32m+"  # Green
+                suffix = "\033[0m"
+            elif line.type == DiffType.REMOVED:
+                prefix = "\033[31m-"  # Red
+                suffix = "\033[0m"
+            else:
+                prefix = " "
+                suffix = ""
+        else:
+            prefix = line.prefix
+            suffix = ""
+
+        lines.append(f"{prefix} {line.content}{suffix}")
+
+    return "\n".join(lines)
+
+
+def main():
+    """Test the diff generator."""
+    old_content = [
+        "def calculate_tax(amount):",
+        "    rate = 0.19",
+        "    if amount > 1000:",
+        "        rate = 0.25",
+        "    return amount * rate",
+    ]
+
+    new_content = [
+        "def calculate_tax(amount):",
+        "    rate = 0.19",
+        "    if amount > 10000:",
+        "        rate = 0.22",
+        "    elif amount > 1000:",
+        "        rate = 0.19",
+        "    return amount * rate",
+    ]
+
+    generator = DiffGenerator()
+    diff = generator.generate(old_content, new_content, "calculator.py")
+
+    print(f"File: {diff.filename}")
+    print(f"Additions: {diff.additions}, Deletions: {diff.deletions}")
+    print()
+    print("Diff output:")
+    print(format_diff_for_display(diff))
+
+
+if __name__ == "__main__":
+    main()

dctp/dctp_executor.py

@@ -0,0 +1,584 @@
+"""
+DCTP Executor - Executes DCTP operations on files.
+
+Handles CREATE, DELETE, INSERT_AFTER, REPLACE, and RENUMBER operations
+with backup support and checksum validation.
+"""
+
+import hashlib
+import os
+import re
+from dataclasses import dataclass
+from enum import Enum
+from pathlib import Path
+from typing import Optional
+
+from dctp_parser import DCTPParser, Operation, OperationType
+from dctp_backup import BackupManager
+from dctp_diff import DiffGenerator, FileDiff
+
+
+class ResultStatus(Enum):
+    SUCCESS = "success"
+    WARNING = "warning"
+    ERROR = "error"
+    SKIPPED = "skipped"
+
+
+@dataclass
+class ExecutionResult:
+    """Result of executing a single operation."""
+    status: ResultStatus
+    operation: Operation
+    message: str
+    diff: Optional[FileDiff] = None
+
+    def __str__(self) -> str:
+        status_symbols = {
+            ResultStatus.SUCCESS: "✅",
+            ResultStatus.WARNING: "⚠️",
+            ResultStatus.ERROR: "❌",
+            ResultStatus.SKIPPED: "⏭️",
+        }
+        return f"{status_symbols[self.status]} {self.message}"
+
+
+@dataclass
+class PreviewResult:
+    """Result of previewing operations before execution."""
+    operation: Operation
+    description: str
+    diff: Optional[FileDiff] = None
+    warnings: list[str] = None
+
+    def __post_init__(self):
+        if self.warnings is None:
+            self.warnings = []
+
+
+class DCTPExecutor:
+    """Executes DCTP operations on files."""
+
+    # Line number patterns (same as parser)
+    LINE_NUMBER_PATTERNS = [
+        re.compile(r'\s*#Z(\d+)\s*$'),
+        re.compile(r'\s*//Z(\d+)\s*$'),
+        re.compile(r'\s*<!--Z(\d+)-->\s*$'),
+        re.compile(r'\s*/\*Z(\d+)\*/\s*$'),
+        re.compile(r'\s*--Z(\d+)\s*$'),
+    ]
+
+    def __init__(
+        self,
+        project_path: str,
+        backup_manager: Optional[BackupManager] = None,
+        auto_renumber: bool = True,
+        validate_checksums: bool = True
+    ):
+        """
+        Initialize the executor.
+
+        Args:
+            project_path: Base project directory
+            backup_manager: Optional backup manager for undo support
+            auto_renumber: Automatically renumber after operations
+            validate_checksums: Validate checksums before operations
+        """
+        self.project_path = Path(project_path)
+        self.backup_manager = backup_manager or BackupManager(project_path)
+        self.auto_renumber = auto_renumber
+        self.validate_checksums = validate_checksums
+        self.diff_generator = DiffGenerator()
+        self.parser = DCTPParser()
+
+    def preview(self, operations: list[Operation]) -> list[PreviewResult]:
+        """
+        Preview operations without executing them.
+
+        Args:
+            operations: List of operations to preview
+
+        Returns:
+            List of preview results
+        """
+        previews = []
+
+        for op in operations:
+            preview = self._preview_operation(op)
+            previews.append(preview)
+
+        return previews
+
+    def _preview_operation(self, op: Operation) -> PreviewResult:
+        """Generate preview for a single operation."""
+        file_path = self.project_path / op.file
+        warnings = []
+
+        if op.type == OperationType.NEW:
+            if file_path.exists():
+                warnings.append(f"File already exists and will be overwritten")
+            return PreviewResult(
+                operation=op,
+                description=f"CREATE {op.file} ({len(op.content)} lines)",
+                warnings=warnings
+            )
+
+        elif op.type == OperationType.DELETE:
+            if not file_path.exists():
+                warnings.append(f"File does not exist")
+                return PreviewResult(
+                    operation=op,
+                    description=f"DELETE {op.file} Z{op.start_line}-Z{op.end_line} (file not found)",
+                    warnings=warnings
+                )
+
+            old_lines = self._read_file_lines(file_path)
+            if op.end_line > len(old_lines):
+                warnings.append(f"Line range exceeds file length ({len(old_lines)} lines)")
+
+            new_lines = old_lines.copy()
+            start_idx = op.start_line - 1
+            end_idx = min(op.end_line, len(old_lines))
+            del new_lines[start_idx:end_idx]
+
+            diff = self.diff_generator.generate(old_lines, new_lines, op.file)
+            return PreviewResult(
+                operation=op,
+                description=f"DELETE {op.file} Z{op.start_line}-Z{op.end_line}",
+                diff=diff,
+                warnings=warnings
+            )
+
+        elif op.type == OperationType.INSERT_AFTER:
+            if not file_path.exists():
+                warnings.append(f"File does not exist")
+                return PreviewResult(
+                    operation=op,
+                    description=f"INSERT_AFTER {op.file} Z{op.start_line} (file not found)",
+                    warnings=warnings
+                )
+
+            old_lines = self._read_file_lines(file_path)
+            if op.start_line > len(old_lines):
+                warnings.append(f"Line {op.start_line} exceeds file length ({len(old_lines)} lines)")
+
+            new_lines = old_lines.copy()
+            insert_idx = min(op.start_line, len(old_lines))
+            for i, line in enumerate(op.content):
+                new_lines.insert(insert_idx + i, line)
+
+            diff = self.diff_generator.generate(old_lines, new_lines, op.file)
+            return PreviewResult(
+                operation=op,
+                description=f"INSERT_AFTER {op.file} Z{op.start_line} ({len(op.content)} lines)",
+                diff=diff,
+                warnings=warnings
+            )
+
+        elif op.type == OperationType.REPLACE:
+            if not file_path.exists():
+                warnings.append(f"File does not exist")
+                return PreviewResult(
+                    operation=op,
+                    description=f"REPLACE {op.file} Z{op.start_line}-Z{op.end_line} (file not found)",
+                    warnings=warnings
+                )
+
+            old_lines = self._read_file_lines(file_path)
+            if op.end_line > len(old_lines):
+                warnings.append(f"Line range exceeds file length ({len(old_lines)} lines)")
+
+            new_lines = old_lines.copy()
+            start_idx = op.start_line - 1
+            end_idx = min(op.end_line, len(old_lines))
+            new_lines[start_idx:end_idx] = op.content
+
+            diff = self.diff_generator.generate(old_lines, new_lines, op.file)
+            return PreviewResult(
+                operation=op,
+                description=f"REPLACE {op.file} Z{op.start_line}-Z{op.end_line} ({len(op.content)} lines)",
+                diff=diff,
+                warnings=warnings
+            )
+
+        elif op.type == OperationType.RENUMBER:
+            return PreviewResult(
+                operation=op,
+                description=f"RENUMBER {op.file}",
+                warnings=warnings
+            )
+
+        return PreviewResult(
+            operation=op,
+            description=f"UNKNOWN {op.type}",
+            warnings=["Unknown operation type"]
+        )
+
+    def execute(
+        self,
+        operations: list[Operation],
+        skip_checksum_mismatch: bool = False
+    ) -> list[ExecutionResult]:
+        """
+        Execute a list of operations.
+
+        Args:
+            operations: List of operations to execute
+            skip_checksum_mismatch: Continue even if checksums don't match
+
+        Returns:
+            List of execution results
+        """
+        results = []
+
+        # Start backup session
+        self.backup_manager.start_session()
+
+        try:
+            for op in operations:
+                result = self._execute_operation(op, skip_checksum_mismatch)
+                results.append(result)
+
+                # Stop on error
+                if result.status == ResultStatus.ERROR:
+                    break
+
+        finally:
+            # End backup session
+            self.backup_manager.end_session()
+
+        return results
+
+    def _execute_operation(
+        self,
+        op: Operation,
+        skip_checksum_mismatch: bool = False
+    ) -> ExecutionResult:
+        """Execute a single operation."""
+        file_path = self.project_path / op.file
+
+        try:
+            if op.type == OperationType.NEW:
+                return self._execute_new(op, file_path)
+            elif op.type == OperationType.DELETE:
+                return self._execute_delete(op, file_path, skip_checksum_mismatch)
+            elif op.type == OperationType.INSERT_AFTER:
+                return self._execute_insert_after(op, file_path, skip_checksum_mismatch)
+            elif op.type == OperationType.REPLACE:
+                return self._execute_replace(op, file_path, skip_checksum_mismatch)
+            elif op.type == OperationType.RENUMBER:
+                return self._execute_renumber(op, file_path)
+            else:
+                return ExecutionResult(
+                    status=ResultStatus.ERROR,
+                    operation=op,
+                    message=f"Unknown operation type: {op.type}"
+                )
+        except PermissionError:
+            return ExecutionResult(
+                status=ResultStatus.ERROR,
+                operation=op,
+                message=f"Permission denied: {file_path}"
+            )
+        except Exception as e:
+            return ExecutionResult(
+                status=ResultStatus.ERROR,
+                operation=op,
+                message=f"Error: {str(e)}"
+            )
+
+    def _execute_new(self, op: Operation, file_path: Path) -> ExecutionResult:
+        """Execute a NEW operation (create file)."""
+        # Backup if file exists
+        if file_path.exists():
+            self.backup_manager.backup(str(op.file))
+
+        # Create parent directories
+        file_path.parent.mkdir(parents=True, exist_ok=True)
+
+        # Write content
+        content = "\n".join(op.content)
+        if op.content and not content.endswith("\n"):
+            content += "\n"
+        file_path.write_text(content)
+
+        return ExecutionResult(
+            status=ResultStatus.SUCCESS,
+            operation=op,
+            message=f"CREATE {op.file} ({len(op.content)} lines)"
+        )
+
+    def _execute_delete(
+        self,
+        op: Operation,
+        file_path: Path,
+        skip_checksum_mismatch: bool
+    ) -> ExecutionResult:
+        """Execute a DELETE operation."""
+        if not file_path.exists():
+            return ExecutionResult(
+                status=ResultStatus.WARNING,
+                operation=op,
+                message=f"File not found: {op.file}"
+            )
+
+        # Validate checksum if provided
+        if op.checksum and self.validate_checksums:
+            if not self._validate_checksum(file_path, op.checksum):
+                if not skip_checksum_mismatch:
+                    return ExecutionResult(
+                        status=ResultStatus.WARNING,
+                        operation=op,
+                        message=f"Checksum mismatch for {op.file} - file was modified externally"
+                    )
+
+        # Backup file
+        self.backup_manager.backup(str(op.file))
+
+        # Read file and delete lines
+        lines = self._read_file_lines(file_path)
+        old_lines = lines.copy()
+
+        if op.end_line > len(lines):
+            return ExecutionResult(
+                status=ResultStatus.WARNING,
+                operation=op,
+                message=f"Line range Z{op.start_line}-Z{op.end_line} exceeds file length ({len(lines)} lines)"
+            )
+
+        start_idx = op.start_line - 1
+        end_idx = op.end_line
+        del lines[start_idx:end_idx]
+
+        # Write back
+        self._write_file_lines(file_path, lines)
+
+        diff = self.diff_generator.generate(old_lines, lines, op.file)
+
+        return ExecutionResult(
+            status=ResultStatus.SUCCESS,
+            operation=op,
+            message=f"DELETE {op.file} Z{op.start_line}-Z{op.end_line}",
+            diff=diff
+        )
+
+    def _execute_insert_after(
+        self,
+        op: Operation,
+        file_path: Path,
+        skip_checksum_mismatch: bool
+    ) -> ExecutionResult:
+        """Execute an INSERT_AFTER operation."""
+        if not file_path.exists():
+            return ExecutionResult(
+                status=ResultStatus.WARNING,
+                operation=op,
+                message=f"File not found: {op.file}"
+            )
+
+        # Validate checksum if provided
+        if op.checksum and self.validate_checksums:
+            if not self._validate_checksum(file_path, op.checksum):
+                if not skip_checksum_mismatch:
+                    return ExecutionResult(
+                        status=ResultStatus.WARNING,
+                        operation=op,
+                        message=f"Checksum mismatch for {op.file} - file was modified externally"
+                    )
+
+        # Backup file
+        self.backup_manager.backup(str(op.file))
+
+        # Read file and insert lines
+        lines = self._read_file_lines(file_path)
+        old_lines = lines.copy()
+
+        if op.start_line > len(lines):
+            return ExecutionResult(
+                status=ResultStatus.WARNING,
+                operation=op,
+                message=f"Line Z{op.start_line} exceeds file length ({len(lines)} lines)"
+            )
+
+        insert_idx = op.start_line
+        for i, line in enumerate(op.content):
+            lines.insert(insert_idx + i, line)
+
+        # Write back
+        self._write_file_lines(file_path, lines)
+
+        diff = self.diff_generator.generate(old_lines, lines, op.file)
+
+        return ExecutionResult(
+            status=ResultStatus.SUCCESS,
+            operation=op,
+            message=f"INSERT_AFTER {op.file} Z{op.start_line} ({len(op.content)} lines)",
+            diff=diff
+        )
+
+    def _execute_replace(
+        self,
+        op: Operation,
+        file_path: Path,
+        skip_checksum_mismatch: bool
+    ) -> ExecutionResult:
+        """Execute a REPLACE operation."""
+        if not file_path.exists():
+            return ExecutionResult(
+                status=ResultStatus.WARNING,
+                operation=op,
+                message=f"File not found: {op.file}"
+            )
+
+        # Validate checksum if provided
+        if op.checksum and self.validate_checksums:
+            if not self._validate_checksum(file_path, op.checksum):
+                if not skip_checksum_mismatch:
+                    return ExecutionResult(
+                        status=ResultStatus.WARNING,
+                        operation=op,
+                        message=f"Checksum mismatch for {op.file} - file was modified externally"
+                    )
+
+        # Backup file
+        self.backup_manager.backup(str(op.file))
+
+        # Read file and replace lines
+        lines = self._read_file_lines(file_path)
+        old_lines = lines.copy()
+
+        if op.end_line > len(lines):
+            return ExecutionResult(
+                status=ResultStatus.WARNING,
+                operation=op,
+                message=f"Line range Z{op.start_line}-Z{op.end_line} exceeds file length ({len(lines)} lines)"
+            )
+
+        start_idx = op.start_line - 1
+        end_idx = op.end_line
+        lines[start_idx:end_idx] = op.content
+
+        # Write back
+        self._write_file_lines(file_path, lines)
+
+        diff = self.diff_generator.generate(old_lines, lines, op.file)
+
+        return ExecutionResult(
+            status=ResultStatus.SUCCESS,
+            operation=op,
+            message=f"REPLACE {op.file} Z{op.start_line}-Z{op.end_line} ({len(op.content)} lines)",
+            diff=diff
+        )
+
+    def _execute_renumber(self, op: Operation, file_path: Path) -> ExecutionResult:
+        """Execute a RENUMBER operation."""
+        if not file_path.exists():
+            return ExecutionResult(
+                status=ResultStatus.WARNING,
+                operation=op,
+                message=f"File not found: {op.file}"
+            )
+
+        # No backup needed for renumber (just updates line numbers)
+        lines = self._read_file_lines(file_path)
+        renumbered_lines = []
+
+        for i, line in enumerate(lines, 1):
+            # Remove existing line number
+            clean_line = self._remove_line_number(line)
+            # Add new line number
+            suffix = self.parser.get_line_number_suffix(op.file, i)
+            renumbered_lines.append(clean_line + suffix)
+
+        self._write_file_lines(file_path, renumbered_lines)
+
+        return ExecutionResult(
+            status=ResultStatus.SUCCESS,
+            operation=op,
+            message=f"RENUMBER {op.file} ({len(lines)} lines)"
+        )
+
+    def _read_file_lines(self, file_path: Path) -> list[str]:
+        """Read file and return lines without trailing newlines."""
+        content = file_path.read_text()
+        lines = content.split('\n')
+        # Remove trailing empty line if file ends with newline
+        if lines and lines[-1] == '':
+            lines = lines[:-1]
+        return lines
+
+    def _write_file_lines(self, file_path: Path, lines: list[str]) -> None:
+        """Write lines to file with trailing newline."""
+        content = '\n'.join(lines)
+        if lines and not content.endswith('\n'):
+            content += '\n'
+        file_path.write_text(content)
+
+    def _remove_line_number(self, line: str) -> str:
+        """Remove line number marker from end of line."""
+        for pattern in self.LINE_NUMBER_PATTERNS:
+            match = pattern.search(line)
+            if match:
+                return line[:match.start()]
+        return line
+
+    def _validate_checksum(self, file_path: Path, expected: str) -> bool:
+        """Validate file checksum."""
+        content = file_path.read_bytes()
+        actual = hashlib.md5(content).hexdigest()[:8]
+        return actual.lower() == expected.lower()
+
+    @staticmethod
+    def calculate_checksum(file_path: Path) -> str:
+        """Calculate checksum for a file."""
+        content = file_path.read_bytes()
+        return hashlib.md5(content).hexdigest()[:8]
+
+
+def main():
+    """Test the executor."""
+    import tempfile
+
+    test_input = """###FILE:calculator.py
+###NEW
+def add(a, b):  #Z1
+    return a + b  #Z2
+  #Z3
+def multiply(a, b):  #Z4
+    return a * b  #Z5
+###END
+"""
+
+    with tempfile.TemporaryDirectory() as tmpdir:
+        parser = DCTPParser()
+        result = parser.parse(test_input)
+
+        print("Parsed operations:")
+        for op in result.operations:
+            print(f"  {op}")
+
+        executor = DCTPExecutor(tmpdir)
+
+        # Preview
+        print("\nPreviews:")
+        previews = executor.preview(result.operations)
+        for preview in previews:
+            print(f"  {preview.description}")
+            if preview.warnings:
+                for w in preview.warnings:
+                    print(f"    ⚠️ {w}")
+
+        # Execute
+        print("\nExecution:")
+        exec_results = executor.execute(result.operations)
+        for r in exec_results:
+            print(f"  {r}")
+
+        # Verify file was created
+        file_path = Path(tmpdir) / "calculator.py"
+        if file_path.exists():
+            print(f"\nFile content:\n{file_path.read_text()}")
+
+
+if __name__ == "__main__":
+    main()

dctp/dctp_gui.py

@@ -0,0 +1,666 @@
+#!/usr/bin/env python3
+"""
+DCTP GUI - Delta Code Transfer Protocol graphical user interface.
+
+A CustomTkinter-based GUI for managing AI-generated code transfers
+using delta operations for efficient updates.
+"""
+
+import os
+import sys
+from datetime import datetime
+from pathlib import Path
+from tkinter import filedialog, messagebox
+from typing import Optional
+import json
+
+import customtkinter as ctk
+
+from dctp_parser import DCTPParser, ParseResult, Operation, OperationType
+from dctp_executor import DCTPExecutor, ExecutionResult, PreviewResult, ResultStatus
+from dctp_backup import BackupManager
+from dctp_diff import DiffType
+
+
+class SettingsDialog(ctk.CTkToplevel):
+    """Settings dialog window."""
+
+    def __init__(self, parent, settings: dict):
+        super().__init__(parent)
+
+        self.title("Einstellungen")
+        self.geometry("500x400")
+        self.resizable(False, False)
+
+        self.settings = settings.copy()
+        self.result = None
+
+        # Make modal
+        self.transient(parent)
+        self.grab_set()
+
+        self._create_widgets()
+
+        # Center on parent
+        self.update_idletasks()
+        x = parent.winfo_x() + (parent.winfo_width() - self.winfo_width()) // 2
+        y = parent.winfo_y() + (parent.winfo_height() - self.winfo_height()) // 2
+        self.geometry(f"+{x}+{y}")
+
+    def _create_widgets(self):
+        # Main frame
+        main_frame = ctk.CTkFrame(self)
+        main_frame.pack(fill="both", expand=True, padx=20, pady=20)
+
+        # Project path
+        ctk.CTkLabel(main_frame, text="Standard-Projektpfad:").pack(anchor="w", pady=(0, 5))
+        path_frame = ctk.CTkFrame(main_frame)
+        path_frame.pack(fill="x", pady=(0, 15))
+
+        self.path_entry = ctk.CTkEntry(path_frame, width=350)
+        self.path_entry.pack(side="left", fill="x", expand=True, padx=(0, 10))
+        self.path_entry.insert(0, self.settings.get("project_path", ""))
+
+        ctk.CTkButton(
+            path_frame,
+            text="...",
+            width=40,
+            command=self._browse_path
+        ).pack(side="right")
+
+        # Backup directory
+        ctk.CTkLabel(main_frame, text="Backup-Verzeichnis:").pack(anchor="w", pady=(0, 5))
+        backup_frame = ctk.CTkFrame(main_frame)
+        backup_frame.pack(fill="x", pady=(0, 15))
+
+        self.backup_entry = ctk.CTkEntry(backup_frame, width=350)
+        self.backup_entry.pack(side="left", fill="x", expand=True, padx=(0, 10))
+        self.backup_entry.insert(0, self.settings.get("backup_dir", ".dctp_backups"))
+
+        ctk.CTkButton(
+            backup_frame,
+            text="...",
+            width=40,
+            command=self._browse_backup
+        ).pack(side="right")
+
+        # Options
+        options_frame = ctk.CTkFrame(main_frame)
+        options_frame.pack(fill="x", pady=15)
+
+        self.auto_renumber_var = ctk.BooleanVar(
+            value=self.settings.get("auto_renumber", True)
+        )
+        ctk.CTkCheckBox(
+            options_frame,
+            text="Auto-Renumber nach Operationen",
+            variable=self.auto_renumber_var
+        ).pack(anchor="w", pady=5)
+
+        self.validate_checksum_var = ctk.BooleanVar(
+            value=self.settings.get("validate_checksum", True)
+        )
+        ctk.CTkCheckBox(
+            options_frame,
+            text="Checksum-Validierung aktiviert",
+            variable=self.validate_checksum_var
+        ).pack(anchor="w", pady=5)
+
+        # Theme
+        ctk.CTkLabel(main_frame, text="Theme:").pack(anchor="w", pady=(15, 5))
+        self.theme_var = ctk.StringVar(value=self.settings.get("theme", "dark"))
+        theme_frame = ctk.CTkFrame(main_frame)
+        theme_frame.pack(fill="x", pady=(0, 15))
+
+        ctk.CTkRadioButton(
+            theme_frame,
+            text="Dunkel",
+            variable=self.theme_var,
+            value="dark"
+        ).pack(side="left", padx=(0, 20))
+
+        ctk.CTkRadioButton(
+            theme_frame,
+            text="Hell",
+            variable=self.theme_var,
+            value="light"
+        ).pack(side="left")
+
+        # Buttons
+        button_frame = ctk.CTkFrame(main_frame)
+        button_frame.pack(fill="x", pady=(20, 0))
+
+        ctk.CTkButton(
+            button_frame,
+            text="Abbrechen",
+            command=self._cancel
+        ).pack(side="right", padx=(10, 0))
+
+        ctk.CTkButton(
+            button_frame,
+            text="Speichern",
+            command=self._save
+        ).pack(side="right")
+
+    def _browse_path(self):
+        path = filedialog.askdirectory(
+            initialdir=self.path_entry.get() or os.path.expanduser("~")
+        )
+        if path:
+            self.path_entry.delete(0, "end")
+            self.path_entry.insert(0, path)
+
+    def _browse_backup(self):
+        path = filedialog.askdirectory(
+            initialdir=os.path.expanduser("~")
+        )
+        if path:
+            self.backup_entry.delete(0, "end")
+            self.backup_entry.insert(0, path)
+
+    def _save(self):
+        self.result = {
+            "project_path": self.path_entry.get(),
+            "backup_dir": self.backup_entry.get(),
+            "auto_renumber": self.auto_renumber_var.get(),
+            "validate_checksum": self.validate_checksum_var.get(),
+            "theme": self.theme_var.get()
+        }
+        self.destroy()
+
+    def _cancel(self):
+        self.result = None
+        self.destroy()
+
+
+class DCTPApp(ctk.CTk):
+    """Main DCTP application window."""
+
+    SETTINGS_FILE = ".dctp_settings.json"
+
+    def __init__(self):
+        super().__init__()
+
+        self.title("DCTP - Delta Code Transfer")
+        self.geometry("1200x900")
+        self.minsize(800, 600)
+
+        # Initialize components
+        self.parser = DCTPParser()
+        self.executor: Optional[DCTPExecutor] = None
+        self.backup_manager: Optional[BackupManager] = None
+        self.current_operations: list[Operation] = []
+        self.current_previews: list[PreviewResult] = []
+
+        # Load settings
+        self.settings = self._load_settings()
+        ctk.set_appearance_mode(self.settings.get("theme", "dark"))
+
+        # Create UI
+        self._create_widgets()
+
+        # Initialize project if path is set
+        if self.settings.get("project_path"):
+            self._init_project(self.settings["project_path"])
+
+        self._log("Bereit")
+
+    def _load_settings(self) -> dict:
+        """Load settings from file."""
+        settings_path = Path.home() / self.SETTINGS_FILE
+        if settings_path.exists():
+            try:
+                return json.loads(settings_path.read_text())
+            except (json.JSONDecodeError, IOError):
+                pass
+        return {
+            "project_path": "",
+            "backup_dir": ".dctp_backups",
+            "auto_renumber": True,
+            "validate_checksum": True,
+            "theme": "dark"
+        }
+
+    def _save_settings(self):
+        """Save settings to file."""
+        settings_path = Path.home() / self.SETTINGS_FILE
+        settings_path.write_text(json.dumps(self.settings, indent=2))
+
+    def _create_widgets(self):
+        """Create all UI widgets."""
+        # Top bar - project selection
+        top_frame = ctk.CTkFrame(self)
+        top_frame.pack(fill="x", padx=10, pady=10)
+
+        ctk.CTkLabel(top_frame, text="Projekt:").pack(side="left", padx=(0, 10))
+
+        self.project_entry = ctk.CTkEntry(top_frame, width=400)
+        self.project_entry.pack(side="left", fill="x", expand=True, padx=(0, 10))
+        self.project_entry.insert(0, self.settings.get("project_path", ""))
+
+        ctk.CTkButton(
+            top_frame,
+            text="Waehlen",
+            width=100,
+            command=self._browse_project
+        ).pack(side="left", padx=(0, 10))
+
+        ctk.CTkButton(
+            top_frame,
+            text="Einstellungen",
+            width=100,
+            command=self._open_settings
+        ).pack(side="left")
+
+        # Main content area with paned layout
+        content_frame = ctk.CTkFrame(self)
+        content_frame.pack(fill="both", expand=True, padx=10, pady=(0, 10))
+
+        # Left side - Input and preview
+        left_frame = ctk.CTkFrame(content_frame)
+        left_frame.pack(side="left", fill="both", expand=True, padx=(0, 5))
+
+        # Input area
+        input_label_frame = ctk.CTkFrame(left_frame)
+        input_label_frame.pack(fill="x", pady=(5, 5), padx=5)
+        ctk.CTkLabel(
+            input_label_frame,
+            text="Input (KI-Output hier einfuegen)",
+            font=ctk.CTkFont(weight="bold")
+        ).pack(side="left")
+
+        self.input_text = ctk.CTkTextbox(
+            left_frame,
+            height=250,
+            font=ctk.CTkFont(family="Consolas", size=12)
+        )
+        self.input_text.pack(fill="both", expand=True, padx=5, pady=(0, 10))
+
+        # Buttons
+        button_frame = ctk.CTkFrame(left_frame)
+        button_frame.pack(fill="x", padx=5, pady=(0, 10))
+
+        self.analyze_btn = ctk.CTkButton(
+            button_frame,
+            text="Analysieren",
+            command=self._analyze,
+            width=120
+        )
+        self.analyze_btn.pack(side="left", padx=(0, 10))
+
+        self.execute_btn = ctk.CTkButton(
+            button_frame,
+            text="Ausfuehren",
+            command=self._execute,
+            width=120,
+            state="disabled"
+        )
+        self.execute_btn.pack(side="left", padx=(0, 10))
+
+        self.undo_btn = ctk.CTkButton(
+            button_frame,
+            text="Undo",
+            command=self._undo,
+            width=80
+        )
+        self.undo_btn.pack(side="left", padx=(0, 10))
+
+        ctk.CTkButton(
+            button_frame,
+            text="Clear",
+            command=self._clear,
+            width=80
+        ).pack(side="left")
+
+        # Preview operations
+        preview_label_frame = ctk.CTkFrame(left_frame)
+        preview_label_frame.pack(fill="x", pady=(5, 5), padx=5)
+        ctk.CTkLabel(
+            preview_label_frame,
+            text="Vorschau Operationen",
+            font=ctk.CTkFont(weight="bold")
+        ).pack(side="left")
+
+        self.preview_text = ctk.CTkTextbox(
+            left_frame,
+            height=150,
+            font=ctk.CTkFont(family="Consolas", size=11)
+        )
+        self.preview_text.pack(fill="both", expand=True, padx=5, pady=(0, 10))
+        self.preview_text.configure(state="disabled")
+
+        # Right side - Diff and file tree
+        right_frame = ctk.CTkFrame(content_frame)
+        right_frame.pack(side="right", fill="both", expand=True, padx=(5, 0))
+
+        # Diff view
+        diff_label_frame = ctk.CTkFrame(right_frame)
+        diff_label_frame.pack(fill="x", pady=(5, 5), padx=5)
+        ctk.CTkLabel(
+            diff_label_frame,
+            text="Diff-Ansicht",
+            font=ctk.CTkFont(weight="bold")
+        ).pack(side="left")
+
+        self.diff_text = ctk.CTkTextbox(
+            right_frame,
+            height=300,
+            font=ctk.CTkFont(family="Consolas", size=11)
+        )
+        self.diff_text.pack(fill="both", expand=True, padx=5, pady=(0, 10))
+        self.diff_text.configure(state="disabled")
+
+        # File tree
+        tree_label_frame = ctk.CTkFrame(right_frame)
+        tree_label_frame.pack(fill="x", pady=(5, 5), padx=5)
+        ctk.CTkLabel(
+            tree_label_frame,
+            text="Projektdateien",
+            font=ctk.CTkFont(weight="bold")
+        ).pack(side="left")
+
+        ctk.CTkButton(
+            tree_label_frame,
+            text="Aktualisieren",
+            width=80,
+            command=self._refresh_file_tree
+        ).pack(side="right")
+
+        self.tree_text = ctk.CTkTextbox(
+            right_frame,
+            height=150,
+            font=ctk.CTkFont(family="Consolas", size=11)
+        )
+        self.tree_text.pack(fill="both", expand=True, padx=5, pady=(0, 10))
+        self.tree_text.configure(state="disabled")
+
+        # Bottom - Log
+        log_label_frame = ctk.CTkFrame(self)
+        log_label_frame.pack(fill="x", padx=10, pady=(0, 5))
+        ctk.CTkLabel(
+            log_label_frame,
+            text="Log",
+            font=ctk.CTkFont(weight="bold")
+        ).pack(side="left")
+
+        self.log_text = ctk.CTkTextbox(
+            self,
+            height=120,
+            font=ctk.CTkFont(family="Consolas", size=10)
+        )
+        self.log_text.pack(fill="x", padx=10, pady=(0, 10))
+        self.log_text.configure(state="disabled")
+
+    def _log(self, message: str, level: str = "info"):
+        """Add a message to the log."""
+        timestamp = datetime.now().strftime("%H:%M:%S")
+        prefix = ""
+        if level == "error":
+            prefix = "ERROR "
+        elif level == "warning":
+            prefix = "WARN  "
+
+        self.log_text.configure(state="normal")
+        self.log_text.insert("end", f"{timestamp}  {prefix}{message}\n")
+        self.log_text.see("end")
+        self.log_text.configure(state="disabled")
+
+    def _init_project(self, path: str):
+        """Initialize project with given path."""
+        if not os.path.isdir(path):
+            self._log(f"Verzeichnis existiert nicht: {path}", "error")
+            return False
+
+        self.backup_manager = BackupManager(path)
+        self.executor = DCTPExecutor(
+            path,
+            self.backup_manager,
+            auto_renumber=self.settings.get("auto_renumber", True),
+            validate_checksums=self.settings.get("validate_checksum", True)
+        )
+        self.settings["project_path"] = path
+        self._save_settings()
+        self._log(f"Projekt geladen: {path}")
+        self._refresh_file_tree()
+        return True
+
+    def _browse_project(self):
+        """Open directory browser for project selection."""
+        initial_dir = self.project_entry.get() or os.path.expanduser("~")
+        path = filedialog.askdirectory(initialdir=initial_dir)
+        if path:
+            self.project_entry.delete(0, "end")
+            self.project_entry.insert(0, path)
+            self._init_project(path)
+
+    def _open_settings(self):
+        """Open settings dialog."""
+        dialog = SettingsDialog(self, self.settings)
+        self.wait_window(dialog)
+
+        if dialog.result:
+            old_theme = self.settings.get("theme")
+            self.settings.update(dialog.result)
+            self._save_settings()
+
+            # Apply theme change
+            if dialog.result.get("theme") != old_theme:
+                ctk.set_appearance_mode(dialog.result["theme"])
+
+            # Reinitialize project with new settings
+            if self.settings.get("project_path"):
+                self._init_project(self.settings["project_path"])
+
+            self._log("Einstellungen gespeichert")
+
+    def _analyze(self):
+        """Analyze input and show preview."""
+        # Ensure project is initialized
+        project_path = self.project_entry.get()
+        if not project_path:
+            messagebox.showerror("Fehler", "Bitte waehle ein Projektverzeichnis")
+            return
+
+        if not self.executor or self.settings.get("project_path") != project_path:
+            if not self._init_project(project_path):
+                return
+
+        # Get input
+        input_text = self.input_text.get("1.0", "end-1c")
+        if not input_text.strip():
+            self._log("Kein Input vorhanden", "warning")
+            return
+
+        # Parse
+        self._log("Analysiere...")
+        result = self.parser.parse(input_text)
+
+        # Handle errors
+        if result.has_errors:
+            self._log(f"{len(result.errors)} Parse-Fehler gefunden", "error")
+            for error in result.errors:
+                self._log(f"  Zeile {error.line_number}: {error.message}", "error")
+            return
+
+        if not result.operations:
+            self._log("Keine Operationen gefunden", "warning")
+            return
+
+        self.current_operations = result.operations
+        self._log(f"{len(result.operations)} Operationen gefunden")
+
+        # Generate previews
+        self.current_previews = self.executor.preview(result.operations)
+
+        # Display previews
+        self._display_previews()
+
+        # Enable execute button
+        self.execute_btn.configure(state="normal")
+
+    def _display_previews(self):
+        """Display operation previews."""
+        self.preview_text.configure(state="normal")
+        self.preview_text.delete("1.0", "end")
+
+        self.diff_text.configure(state="normal")
+        self.diff_text.delete("1.0", "end")
+
+        for preview in self.current_previews:
+            # Add to preview list
+            self.preview_text.insert("end", f"{preview.description}\n")
+            for warning in preview.warnings:
+                self.preview_text.insert("end", f"  WARNING {warning}\n")
+
+            # Add diff if available
+            if preview.diff and preview.diff.has_changes:
+                self.diff_text.insert("end", f"--- {preview.diff.filename} ---\n")
+                for line in preview.diff.lines:
+                    if line.type == DiffType.ADDED:
+                        self.diff_text.insert("end", f"+ {line.content}\n")
+                    elif line.type == DiffType.REMOVED:
+                        self.diff_text.insert("end", f"- {line.content}\n")
+                    elif line.type == DiffType.UNCHANGED:
+                        self.diff_text.insert("end", f"  {line.content}\n")
+                self.diff_text.insert("end", "\n")
+
+        self.preview_text.configure(state="disabled")
+        self.diff_text.configure(state="disabled")
+
+    def _execute(self):
+        """Execute the analyzed operations."""
+        if not self.current_operations:
+            self._log("Keine Operationen zum Ausfuehren", "warning")
+            return
+
+        if not self.executor:
+            self._log("Kein Projekt initialisiert", "error")
+            return
+
+        # Confirm
+        count = len(self.current_operations)
+        if not messagebox.askyesno(
+            "Bestaetigen",
+            f"{count} Operationen ausfuehren?"
+        ):
+            return
+
+        self._log(f"Fuehre {count} Operationen aus...")
+
+        # Execute
+        results = self.executor.execute(self.current_operations)
+
+        # Log results
+        success_count = 0
+        for result in results:
+            if result.status == ResultStatus.SUCCESS:
+                self._log(f"OK {result.message}")
+                success_count += 1
+            elif result.status == ResultStatus.WARNING:
+                self._log(f"WARN {result.message}", "warning")
+            elif result.status == ResultStatus.ERROR:
+                self._log(f"ERROR {result.message}", "error")
+
+        self._log(f"Abgeschlossen: {success_count}/{count} erfolgreich")
+
+        # Clear current operations
+        self.current_operations = []
+        self.current_previews = []
+        self.execute_btn.configure(state="disabled")
+
+        # Refresh file tree
+        self._refresh_file_tree()
+
+    def _undo(self):
+        """Undo last operation."""
+        if not self.backup_manager:
+            self._log("Kein Projekt initialisiert", "error")
+            return
+
+        success, restored = self.backup_manager.restore_last()
+
+        if success:
+            self._log(f"Undo erfolgreich: {len(restored)} Dateien wiederhergestellt")
+            for f in restored:
+                self._log(f"  -> {f}")
+            self._refresh_file_tree()
+        else:
+            self._log("Kein Backup zum Wiederherstellen", "warning")
+
+    def _clear(self):
+        """Clear input and preview areas."""
+        self.input_text.delete("1.0", "end")
+
+        self.preview_text.configure(state="normal")
+        self.preview_text.delete("1.0", "end")
+        self.preview_text.configure(state="disabled")
+
+        self.diff_text.configure(state="normal")
+        self.diff_text.delete("1.0", "end")
+        self.diff_text.configure(state="disabled")
+
+        self.current_operations = []
+        self.current_previews = []
+        self.execute_btn.configure(state="disabled")
+
+        self._log("Eingabe geloescht")
+
+    def _refresh_file_tree(self):
+        """Refresh the file tree display."""
+        self.tree_text.configure(state="normal")
+        self.tree_text.delete("1.0", "end")
+
+        project_path = self.project_entry.get()
+        if not project_path or not os.path.isdir(project_path):
+            self.tree_text.insert("end", "(Kein Projekt geladen)")
+            self.tree_text.configure(state="disabled")
+            return
+
+        # Build simple tree
+        try:
+            self._add_tree_items(Path(project_path), 0)
+        except Exception as e:
+            self.tree_text.insert("end", f"Fehler: {e}")
+
+        self.tree_text.configure(state="disabled")
+
+    def _add_tree_items(self, path: Path, level: int, max_items: int = 100):
+        """Recursively add items to tree display."""
+        if level > 5:  # Limit depth
+            return
+
+        indent = "  " * level
+
+        try:
+            items = sorted(path.iterdir(), key=lambda x: (not x.is_dir(), x.name.lower()))
+            count = 0
+
+            for item in items:
+                if count >= max_items:
+                    self.tree_text.insert("end", f"{indent}  ... (mehr Dateien)\n")
+                    break
+
+                # Skip hidden files and backup directory
+                if item.name.startswith('.'):
+                    continue
+
+                if item.is_dir():
+                    self.tree_text.insert("end", f"{indent}DIR {item.name}/\n")
+                    self._add_tree_items(item, level + 1, max_items=20)
+                else:
+                    self.tree_text.insert("end", f"{indent}FILE {item.name}\n")
+
+                count += 1
+
+        except PermissionError:
+            self.tree_text.insert("end", f"{indent}  (Zugriff verweigert)\n")
+
+
+def main():
+    """Main entry point."""
+    app = DCTPApp()
+    app.mainloop()
+
+
+if __name__ == "__main__":
+    main()

dctp/dctp_parser.py

@@ -0,0 +1,307 @@
+"""
+DCTP Parser - Parses DCTP control commands and code blocks.
+
+Handles line-numbered code with language-specific comment formats:
+- Python/Shell: #Z1
+- JavaScript/Java/C/C++: //Z1
+- HTML: <!--Z1-->
+- CSS: /*Z1*/
+- SQL: --Z1
+"""
+
+import re
+from dataclasses import dataclass, field
+from typing import Optional
+from enum import Enum
+
+
+class OperationType(Enum):
+    NEW = "NEW"
+    DELETE = "DELETE"
+    INSERT_AFTER = "INSERT_AFTER"
+    REPLACE = "REPLACE"
+    RENUMBER = "RENUMBER"
+
+
+@dataclass
+class Operation:
+    """Represents a single DCTP operation."""
+    type: OperationType
+    file: str
+    start_line: Optional[int] = None
+    end_line: Optional[int] = None
+    content: list[str] = field(default_factory=list)
+    checksum: Optional[str] = None
+    raw_content: list[str] = field(default_factory=list)  # Content with line numbers
+
+    def __str__(self) -> str:
+        if self.type == OperationType.NEW:
+            return f"CREATE {self.file} ({len(self.content)} lines)"
+        elif self.type == OperationType.DELETE:
+            return f"DELETE {self.file} Z{self.start_line}-Z{self.end_line}"
+        elif self.type == OperationType.INSERT_AFTER:
+            return f"INSERT_AFTER {self.file} Z{self.start_line} ({len(self.content)} lines)"
+        elif self.type == OperationType.REPLACE:
+            return f"REPLACE {self.file} Z{self.start_line}-Z{self.end_line} ({len(self.content)} lines)"
+        elif self.type == OperationType.RENUMBER:
+            return f"RENUMBER {self.file}"
+        return f"{self.type.value} {self.file}"
+
+
+@dataclass
+class ParseError:
+    """Represents a parsing error."""
+    line_number: int
+    line_content: str
+    message: str
+
+
+@dataclass
+class ParseResult:
+    """Result of parsing DCTP input."""
+    operations: list[Operation]
+    errors: list[ParseError]
+
+    @property
+    def has_errors(self) -> bool:
+        return len(self.errors) > 0
+
+
+class DCTPParser:
+    """Parser for DCTP (Delta Code Transfer Protocol) format."""
+
+    # Regex patterns for line number markers in different languages
+    LINE_NUMBER_PATTERNS = [
+        re.compile(r'\s*#Z(\d+)\s*$'),           # Python, Shell
+        re.compile(r'\s*//Z(\d+)\s*$'),          # JavaScript, Java, C, C++
+        re.compile(r'\s*<!--Z(\d+)-->\s*$'),     # HTML
+        re.compile(r'\s*/\*Z(\d+)\*/\s*$'),      # CSS
+        re.compile(r'\s*--Z(\d+)\s*$'),          # SQL
+    ]
+
+    # Control command patterns
+    FILE_PATTERN = re.compile(r'^###FILE:(.+)$')
+    NEW_PATTERN = re.compile(r'^###NEW\s*$')
+    DELETE_PATTERN = re.compile(r'^###DELETE:Z(\d+)(?:-Z(\d+))?\s*$')
+    INSERT_AFTER_PATTERN = re.compile(r'^###INSERT_AFTER:Z(\d+)\s*$')
+    REPLACE_PATTERN = re.compile(r'^###REPLACE:Z(\d+)(?:-Z(\d+))?\s*$')
+    END_PATTERN = re.compile(r'^###END\s*$')
+    RENUMBER_PATTERN = re.compile(r'^###RENUMBER\s*$')
+    CHECKSUM_PATTERN = re.compile(r'^###CHECKSUM:([a-fA-F0-9]+)\s*$')
+
+    def parse(self, text: str) -> ParseResult:
+        """
+        Parse DCTP formatted text into a list of operations.
+
+        Args:
+            text: The DCTP formatted input text
+
+        Returns:
+            ParseResult containing operations and any errors
+        """
+        operations: list[Operation] = []
+        errors: list[ParseError] = []
+
+        current_file: Optional[str] = None
+        current_op: Optional[Operation] = None
+        buffer: list[str] = []
+        raw_buffer: list[str] = []
+
+        lines = text.split('\n')
+
+        for line_num, line in enumerate(lines, 1):
+            # Skip empty lines outside of content blocks
+            if not line.strip() and current_op is None:
+                continue
+
+            # Check for FILE command
+            file_match = self.FILE_PATTERN.match(line)
+            if file_match:
+                current_file = file_match.group(1).strip()
+                continue
+
+            # Check for NEW command
+            if self.NEW_PATTERN.match(line):
+                if current_file is None:
+                    errors.append(ParseError(line_num, line, "###NEW without ###FILE"))
+                    continue
+                current_op = Operation(type=OperationType.NEW, file=current_file)
+                buffer = []
+                raw_buffer = []
+                continue
+
+            # Check for DELETE command
+            delete_match = self.DELETE_PATTERN.match(line)
+            if delete_match:
+                if current_file is None:
+                    errors.append(ParseError(line_num, line, "###DELETE without ###FILE"))
+                    continue
+                start = int(delete_match.group(1))
+                end = int(delete_match.group(2)) if delete_match.group(2) else start
+                operations.append(Operation(
+                    type=OperationType.DELETE,
+                    file=current_file,
+                    start_line=start,
+                    end_line=end
+                ))
+                continue
+
+            # Check for INSERT_AFTER command
+            insert_match = self.INSERT_AFTER_PATTERN.match(line)
+            if insert_match:
+                if current_file is None:
+                    errors.append(ParseError(line_num, line, "###INSERT_AFTER without ###FILE"))
+                    continue
+                current_op = Operation(
+                    type=OperationType.INSERT_AFTER,
+                    file=current_file,
+                    start_line=int(insert_match.group(1))
+                )
+                buffer = []
+                raw_buffer = []
+                continue
+
+            # Check for REPLACE command
+            replace_match = self.REPLACE_PATTERN.match(line)
+            if replace_match:
+                if current_file is None:
+                    errors.append(ParseError(line_num, line, "###REPLACE without ###FILE"))
+                    continue
+                start = int(replace_match.group(1))
+                end = int(replace_match.group(2)) if replace_match.group(2) else start
+                current_op = Operation(
+                    type=OperationType.REPLACE,
+                    file=current_file,
+                    start_line=start,
+                    end_line=end
+                )
+                buffer = []
+                raw_buffer = []
+                continue
+
+            # Check for END command
+            if self.END_PATTERN.match(line):
+                if current_op:
+                    current_op.content = buffer.copy()
+                    current_op.raw_content = raw_buffer.copy()
+                    operations.append(current_op)
+                    current_op = None
+                    buffer = []
+                    raw_buffer = []
+                continue
+
+            # Check for RENUMBER command
+            if self.RENUMBER_PATTERN.match(line):
+                if current_file is None:
+                    errors.append(ParseError(line_num, line, "###RENUMBER without ###FILE"))
+                    continue
+                operations.append(Operation(type=OperationType.RENUMBER, file=current_file))
+                continue
+
+            # Check for CHECKSUM command
+            checksum_match = self.CHECKSUM_PATTERN.match(line)
+            if checksum_match:
+                if current_op:
+                    current_op.checksum = checksum_match.group(1)
+                continue
+
+            # Regular code line - add to buffer if we're in an operation
+            if current_op is not None:
+                raw_buffer.append(line)
+                clean_line = self._remove_line_number(line)
+                buffer.append(clean_line)
+
+        # Handle unclosed operation
+        if current_op is not None:
+            errors.append(ParseError(
+                len(lines),
+                "",
+                f"Unclosed operation: {current_op.type.value} for {current_op.file}"
+            ))
+
+        return ParseResult(operations=operations, errors=errors)
+
+    def _remove_line_number(self, line: str) -> str:
+        """Remove line number marker from end of line."""
+        for pattern in self.LINE_NUMBER_PATTERNS:
+            match = pattern.search(line)
+            if match:
+                return line[:match.start()]
+        return line
+
+    def extract_line_number(self, line: str) -> Optional[int]:
+        """Extract line number from a code line."""
+        for pattern in self.LINE_NUMBER_PATTERNS:
+            match = pattern.search(line)
+            if match:
+                return int(match.group(1))
+        return None
+
+    @staticmethod
+    def get_line_number_suffix(filename: str, line_num: int) -> str:
+        """Get the appropriate line number suffix for a file type."""
+        ext = filename.rsplit('.', 1)[-1].lower() if '.' in filename else ''
+
+        if ext in ('py', 'sh', 'bash', 'zsh', 'yaml', 'yml', 'toml', 'ini', 'conf', 'rb', 'pl'):
+            return f"  #Z{line_num}"
+        elif ext in ('js', 'ts', 'jsx', 'tsx', 'java', 'c', 'cpp', 'h', 'hpp', 'cs', 'go', 'rs', 'swift', 'kt', 'scala'):
+            return f"  //Z{line_num}"
+        elif ext in ('html', 'htm', 'xml', 'svg'):
+            return f"  <!--Z{line_num}-->"
+        elif ext in ('css', 'scss', 'sass', 'less'):
+            return f"  /*Z{line_num}*/"
+        elif ext in ('sql',):
+            return f"  --Z{line_num}"
+        else:
+            # Default to Python style
+            return f"  #Z{line_num}"
+
+
+def main():
+    """Test the parser with example input."""
+    test_input = """###FILE:src/calculator.py
+###NEW
+def add(a, b):  #Z1
+    return a + b  #Z2
+  #Z3
+def multiply(a, b):  #Z4
+    return a * b  #Z5
+###END
+
+###FILE:src/calculator.py
+###REPLACE:Z4-Z5
+def multiply(a, b):  #Z4
+    \"\"\"Multipliziert zwei Zahlen.\"\"\"  #Z5
+    return a * b  #Z6
+###END
+###RENUMBER
+
+###FILE:src/calculator.py
+###INSERT_AFTER:Z2
+  #Z3
+def subtract(a, b):  #Z4
+    return a - b  #Z5
+###END
+###RENUMBER
+
+###FILE:src/calculator.py
+###DELETE:Z10-Z15
+###RENUMBER
+"""
+
+    parser = DCTPParser()
+    result = parser.parse(test_input)
+
+    print("Operations found:")
+    for op in result.operations:
+        print(f"  {op}")
+
+    if result.has_errors:
+        print("\nErrors:")
+        for error in result.errors:
+            print(f"  Line {error.line_number}: {error.message}")
+            print(f"    {error.line_content}")
+
+
+if __name__ == "__main__":
+    main()

dctp/requirements.txt

@@ -0,0 +1 @@
+customtkinter>=5.2.0