Add integration with git hooks

DEVELOPMENT.md

@@ -34,6 +34,8 @@ PyComet includes a comprehensive test suite that verifies functionality across m
 
 ### Running Tests
 
+#### Local Test Execution
+
 Basic test execution:
 ```bash
 # Run all tests
@@ -49,6 +51,26 @@ uv run pytest tests/ --show-llm-output
 uv run pytest tests/ -k "gemini" --show-llm-output
 ```
 
+#### Docker Test Execution
+
+You can also run tests in an isolated Docker environment:
+
+```bash
+# Make the script executable (if not already)
+chmod +x docker-test.sh
+
+# Run all tests (excluding integration tests)
+./docker-test.sh all
+
+# Run only git hooks tests
+./docker-test.sh hooks
+
+# Run specific tests with custom arguments
+./docker-test.sh tests/test_git.py -v
+```
+
+The Docker testing environment ensures consistent test execution across different development setups.
+
 For detailed information about testing options and configurations, see [tests/README.md](tests/README.md).
 
 ## Code Quality
@@ -91,6 +113,35 @@ uv run pre-commit install
 uv run pre-commit run --all-files
 ```
 
+## Git Hooks Integration
+
+PyComet can integrate with Git's `prepare-commit-msg` hook to automatically generate AI-powered commit messages when you run `git commit`.
+
+### Setting up Git Hooks
+
+To install the Git hooks integration:
+
+```bash
+# Install the prepare-commit-msg hook
+pycomet hooks install
+
+# To uninstall the hook
+pycomet hooks uninstall
+```
+
+When the hook is installed, running `git commit` (without a `-m` message) will:
+1. Generate an AI-powered commit message based on staged changes
+2. Pre-fill the commit message in your editor
+3. Allow you to edit the message before finalizing the commit
+
+The hook won't run when you provide a message with `git commit -m "message"` or during 
+merge/rebase operations.
+
+To temporarily disable the hook for a specific commit, you can run:
+```bash
+git -c core.hooksPath=/dev/null commit
+```
+
 ## Contributing
 
 1. Fork the repository

Dockerfile.test

@@ -0,0 +1,18 @@
+FROM python:3.12-slim
+
+# Install git
+RUN apt-get update && apt-get install -y \
+    git \
+    && rm -rf /var/lib/apt/lists/*
+
+# Set up work directory
+WORKDIR /app
+
+# Copy project files
+COPY . .
+
+# Set up Python path for running tests
+ENV PYTHONPATH="${PYTHONPATH}:/app"
+
+# Run tests by default (with -k option to specify test module)
+CMD ["pytest", "tests/", "-v"]

README.md

@@ -95,6 +95,7 @@ After configuration, edit `~/.config/pycomet/config.yaml` to add your API key an
 - 🔧 **Customizable**: Configure prompts, formats, and preferences
 - 📊 **Usage Tracking**: Monitor token usage and costs
 - 🚀 **Rate Limiting**: Automatic handling of API rate limits
+- 🪝 **Git Hooks**: Integrate with git's prepare-commit-msg hook
 
 ## Basic Commands
 
@@ -131,6 +132,22 @@ uv run pycomet commit --prompt "$(cat my-prompt.txt)"
 uv run pycomet commit --editor vim
 ```
 
+## Git Hooks Integration
+
+PyComet can integrate with Git's built-in hooks system to automatically generate commit messages:
+
+```bash
+# Install the prepare-commit-msg hook
+pycomet hooks install
+
+# Uninstall the hook
+pycomet hooks uninstall
+```
+
+When the hook is installed, running `git commit` will automatically generate an AI commit message and pre-fill it in your editor. You can still edit the message before the commit is finalized.
+
+See [DEVELOPMENT.md](DEVELOPMENT.md#git-hooks-integration) for more details.
+
 ## Configuration
 
 PyComet uses a YAML config file at `~/.config/pycomet/config.yaml`. For detailed configuration options and examples for all supported AI providers, see [CONFIGS.md](CONFIGS.md).

docker-compose.yml

@@ -0,0 +1,25 @@
+version: '3'
+
+services:
+  pycomet-tests:
+    build:
+      context: .
+      dockerfile: Dockerfile.test
+    volumes:
+      - .:/app
+    environment:
+      # You can uncomment and provide these for integration tests if needed
+      # TEST_ANTHROPIC_API_KEY: ${TEST_ANTHROPIC_API_KEY}
+      # TEST_OPENAI_API_KEY: ${TEST_OPENAI_API_KEY}
+      # TEST_GEMINI_API_KEY: ${TEST_GEMINI_API_KEY}
+    # By default, run unit tests only
+    command: pytest tests/ -v -m "not integration"
+
+  # Service for running git hooks specific tests
+  hooks-tests:
+    build:
+      context: .
+      dockerfile: Dockerfile.test
+    volumes:
+      - .:/app
+    command: pytest tests/test_git.py tests/test_cli_hooks.py -v

docker-test.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+set -e
+
+# Colors for terminal output
+GREEN='\033[0;32m'
+BLUE='\033[0;34m'
+RED='\033[0;31m'
+NC='\033[0m' # No Color
+
+print_section() {
+    echo -e "\n${BLUE}===============================================${NC}"
+    echo -e "${GREEN}$1${NC}"
+    echo -e "${BLUE}===============================================${NC}\n"
+}
+
+# Build the Docker image
+print_section "Building Docker test image..."
+docker build -f Dockerfile.test -t pycomet-test .
+
+# Run specific tests based on arguments
+if [ "$1" == "hooks" ]; then
+    print_section "Running Git Hooks tests..."
+    docker run --rm -v "$(pwd):/app" pycomet-test pytest tests/test_git.py tests/test_cli_hooks.py -v
+elif [ "$1" == "all" ]; then
+    print_section "Running all tests (excluding integration tests)..."
+    docker run --rm -v "$(pwd):/app" pycomet-test pytest tests/ -v -m "not integration"
+else
+    print_section "Running tests with custom command..."
+    docker run --rm -v "$(pwd):/app" pycomet-test pytest "$@"
+fi

src/pycomet/cli.py

@@ -247,5 +247,51 @@ def preview(
         click.echo(f"Error: {str(e)}", err=True)
 
 
+@cli.group()
+def hooks() -> None:
+    """Manage git hooks integration"""
+    pass
+
+
+@hooks.command("install")
+@click.option(
+    "--verbose", "-v", is_flag=True, help="Show detailed execution information"
+)
+def hooks_install(verbose: bool) -> None:
+    """Install git hooks for automatic commit message generation"""
+    if verbose:
+        click.echo("Installing prepare-commit-msg hook...")
+
+    git = GitRepo()
+    success, message = git.install_prepare_commit_msg_hook()
+
+    if success:
+        click.echo(f"✅ {message}")
+        click.echo("\nThe hook will generate AI commit messages when you run:")
+        click.echo("  git commit")
+        click.echo("\nYou can still use PyComet directly with:")
+        click.echo("  pycomet commit")
+    else:
+        click.echo(f"❌ {message}", err=True)
+
+
+@hooks.command("uninstall")
+@click.option(
+    "--verbose", "-v", is_flag=True, help="Show detailed execution information"
+)
+def hooks_uninstall(verbose: bool) -> None:
+    """Uninstall PyComet git hooks"""
+    if verbose:
+        click.echo("Uninstalling prepare-commit-msg hook...")
+
+    git = GitRepo()
+    success, message = git.uninstall_prepare_commit_msg_hook()
+
+    if success:
+        click.echo(f"✅ {message}")
+    else:
+        click.echo(f"❌ {message}", err=True)
+
+
 if __name__ == "__main__":
     cli()

src/pycomet/git.py

@@ -1,7 +1,9 @@
 import os
+import stat
 import subprocess
 import tempfile
-from typing import List, Optional
+from pathlib import Path
+from typing import List, Optional, Tuple
 
 
 class GitRepo:
@@ -62,3 +64,119 @@ def has_staged_changes() -> bool:
             # Log unexpected errors but assume no changes for safety
             print(f"Error checking staged changes: {str(e)}")
             return False
+
+    @staticmethod
+    def get_git_root() -> Optional[str]:
+        """Get the git repository root directory.
+        Returns the path to the repository root or None if not in a git repo.
+        """
+        try:
+            return GitRepo._run_git_command(["rev-parse", "--show-toplevel"]).strip()
+        except Exception:
+            return None
+
+    @staticmethod
+    def install_prepare_commit_msg_hook() -> Tuple[bool, str]:
+        """Install the prepare-commit-msg git hook.
+        Returns (success, message) tuple.
+        """
+        git_root = GitRepo.get_git_root()
+        if not git_root:
+            return False, "Not in a git repository"
+
+        hooks_dir = Path(git_root) / ".git" / "hooks"
+        hook_path = hooks_dir / "prepare-commit-msg"
+
+        # Create the hook script
+        hook_content = """#!/bin/sh
+# PyComet AI-powered commit message hook
+# https://github.com/JayDoubleu/PyComet
+
+# Get the commit message file path from Git
+COMMIT_MSG_FILE=$1
+COMMIT_SOURCE=$2
+
+# Skip if not an interactive commit (e.g., merge commit, commit with -m)
+if [ "$COMMIT_SOURCE" = "message" ] || [ "$COMMIT_SOURCE" = "template" ] || \\
+   [ "$COMMIT_SOURCE" = "merge" ] || [ "$COMMIT_SOURCE" = "squash" ]; then
+    exit 0
+fi
+
+# Generate commit message with PyComet and save to commit message file
+pycomet preview --no-detailed 2>/dev/null | \\
+    awk 'BEGIN{f=0} /^-+$/{f=!f; next} f{print}' > "$COMMIT_MSG_FILE.pycomet"
+if [ -s "$COMMIT_MSG_FILE.pycomet" ]; then
+    cat "$COMMIT_MSG_FILE.pycomet" > "$COMMIT_MSG_FILE"
+    rm "$COMMIT_MSG_FILE.pycomet"
+    echo "# PyComet: Generated AI commit message. Edit as needed." >> "$COMMIT_MSG_FILE"
+    echo "# To disable the PyComet hook: git config --local core.hooksPath /dev/null" \\
+        >> "$COMMIT_MSG_FILE"
+fi
+"""
+        try:
+            # Ensure hooks directory exists
+            hooks_dir.mkdir(exist_ok=True, parents=True)
+
+            # Check if hook already exists
+            if hook_path.exists():
+                with open(hook_path, "r") as f:
+                    existing_content = f.read()
+                    if "PyComet" in existing_content:
+                        return True, "Prepare-commit-msg hook is already installed"
+                    else:
+                        # Backup existing hook
+                        backup_path = Path(str(hook_path) + ".backup")
+                        hook_path.rename(backup_path)
+                        backup_msg = f" (existing hook backed up to {backup_path})"
+            else:
+                backup_msg = ""
+
+            # Write the hook script
+            with open(hook_path, "w") as f:
+                f.write(hook_content)
+
+            # Make the hook executable
+            hook_mode = os.stat(hook_path).st_mode
+            executable_mode = stat.S_IXUSR | stat.S_IXGRP | stat.S_IXOTH
+            os.chmod(hook_path, hook_mode | executable_mode)
+
+            return True, f"Prepare-commit-msg hook installed successfully{backup_msg}"
+
+        except Exception as e:
+            return False, f"Failed to install hook: {str(e)}"
+
+    @staticmethod
+    def uninstall_prepare_commit_msg_hook() -> Tuple[bool, str]:
+        """Uninstall the prepare-commit-msg git hook.
+        Returns (success, message) tuple.
+        """
+        git_root = GitRepo.get_git_root()
+        if not git_root:
+            return False, "Not in a git repository"
+
+        hook_path = Path(git_root) / ".git" / "hooks" / "prepare-commit-msg"
+        backup_path = Path(str(hook_path) + ".backup")
+
+        if not hook_path.exists():
+            return True, "Prepare-commit-msg hook is not installed"
+
+        try:
+            # Check if it's the PyComet hook
+            with open(hook_path, "r") as f:
+                content = f.read()
+                is_pycomet_hook = "PyComet" in content
+
+            # Remove the hook
+            if is_pycomet_hook:
+                # Restore backup if it exists
+                if backup_path.exists():
+                    backup_path.rename(hook_path)
+                    return True, "PyComet hook removed and original hook restored"
+                else:
+                    hook_path.unlink()
+                    return True, "PyComet hook removed"
+            else:
+                return False, "The prepare-commit-msg hook is not a PyComet hook"
+
+        except Exception as e:
+            return False, f"Failed to uninstall hook: {str(e)}"