This script is a pre-commit Git hook that automatically generates commit messages using the Gemini AI API. It analyzes your staged changes, sends them to Gemini, and uses the generated message for your commit.

1. Prerequisites:

   • Git
   • curl
   • jq
   • Gemini API Key
   • A package manager like pnpm, npm, or yarn (for Husky installation)

2. Install Husky:

   • Navigate to your project's root directory in your terminal.

   • Install Husky:

     pnpm add husky --save-dev

     or

     npm install husky --save-dev

     or

     yarn add husky --save-dev

3. Enable Git Hooks:

   • Tell Git to use Husky's hooks:

     git config core.hooksPath .husky

4. Create the pre-commit Hook:

   • Create a file named pre-commit inside the .husky directory.

   • Copy and paste the following script into the pre-commit file:

     #!/bin/bash
     
     # Load environment variables from .env file (if it exists)
     if [ -f .env ]; then
       export $(grep -v '^#' .env | xargs)
     fi
     
     # Get the diff of staged changes
     DIFF=$(git diff --staged)
     
     if [ -z "$DIFF" ]; then
       echo "No staged changes. Skipping commit message generation."
       exit 0
     fi
     
     # Base64 encode the diff
     BASE64_DIFF=$(echo -n "$DIFF" | base64)
     
     # Prepare the prompt for Gemini API
     PROMPT="Write a concise commit message (30-50 words) based on the following git diff (Base64 encoded):\n\n$BASE64_DIFF"
     
     # Call Gemini API
     GEMINI_API_KEY="$GEMINI_API_KEY" # Read API key from environment variable
     
     # Check if the API key is set
     if [ -z "$GEMINI_API_KEY" ]; then
         echo "Error: GEMINI_API_KEY environment variable is not set."
         exit 1
     fi
     
     GEMINI_API_ENDPOINT="[https://generativelanguage.googleapis.com/v1beta/models/gemini-2.0-flash:generateContent?key=$GEMINI_API_KEY](https://generativelanguage.googleapis.com/v1beta/models/gemini-2.0-flash:generateContent?key=$GEMINI_API_KEY)"
     
     API_RESPONSE=$(curl -s -X POST \
       -H "Content-Type: application/json" \
       -d '{
         "contents": [{
           "parts": [{"text": "'"$PROMPT"'"}]
         }],
         "generationConfig": {
           "temperature": 0.3,
           "maxOutputTokens": 150
         }
       }' \
       "$GEMINI_API_ENDPOINT")
     
     # Check for curl errors
     if [ $? -ne 0 ]; then
         echo "Error: curl command failed. Check your network connection and API endpoint."
         exit 1
     fi
     
     # Extract the commit message
     COMMIT_MESSAGE=$(echo "$API_RESPONSE" | jq -r '.candidates[0].content.parts[0].text')
     
     # Handle API errors
     if [ -z "$COMMIT_MESSAGE" ]; then
         echo "Error: Failed to generate commit message from API response."
         exit 1
     fi
     
     # Clean up the commit message
     COMMIT_MESSAGE=$(echo "$COMMIT_MESSAGE" | sed -e 's/^[[:space:]]*//' -e 's/[[:space:]]*$//')
     
     # Display the generated commit message
     echo "Generated commit message:"
     echo "$COMMIT_MESSAGE"
     echo ""
     
     # Use the generated commit message in the commit, bypassing the hook
     git commit --no-verify -m "$COMMIT_MESSAGE"
     
     echo "Commit complete."

   • Make the pre-commit file executable:

     chmod +x .husky/pre-commit

5. Set Your API Key:

   • Create a .env file in the root of your project.

   • Add your Gemini API key to the .env file:

     GEMINI_API_KEY="YOUR_ACTUAL_API_KEY"
     

     Replace "YOUR_ACTUAL_API_KEY" with your actual API key.

   • Important: Add .env to your .gitignore file to prevent committing your API key.

1. Stage Your Changes:

   • Make changes to your project.
   • Stage the changes using git add . or git add <file>.

2. Commit Your Changes:

   • Run git commit.
   • The pre-commit hook will automatically run:
     • It will analyze your staged changes.
     • It will send the changes to the Gemini API.
     • It will use the generated commit message for your commit.

3. Troubleshooting:

   • If you encounter errors, check the terminal output for error messages.
   • Verify that your API key is correct and set in the .env file.
   • Ensure you have a stable internet connection.
   • Make sure jq and curl are installed.
   • If the commit message is not generated, check the API response (you can temporarily uncomment the echo "Raw API Response:" line to see it).

• Never commit your API key directly to your repository.
• Using environment variables and .env files is a safer approach.
• Always add .env to your .gitignore file.
• Be mindful of API usage and potential costs.