#!/bin/bash

# Install Gitleaks Pre-Commit Hook
# Created in response to Anthropic API key exposure incident (2025-10-21)
# Implements inst_070: Pre-Commit Secret Detection

set -e

echo "═══════════════════════════════════════════════════════════"
echo "  INSTALL GITLEAKS PRE-COMMIT HOOK"
echo "═══════════════════════════════════════════════════════════"
echo ""

# Check if gitleaks is installed
echo "▶ 1. Checking gitleaks installation..."
if ! command -v gitleaks &> /dev/null; then
    echo "  ✗ gitleaks not found"
    echo ""
    echo "  Please install gitleaks first:"
    echo ""
    echo "  macOS (Homebrew):"
    echo "    brew install gitleaks"
    echo ""
    echo "  Ubuntu/Debian:"
    echo "    sudo apt-get update"
    echo "    sudo apt-get install gitleaks"
    echo ""
    echo "  Or download from: https://github.com/gitleaks/gitleaks/releases"
    echo ""
    exit 1
fi

GITLEAKS_VERSION=$(gitleaks version 2>&1 | head -1 || echo "unknown")
echo "  ✓ gitleaks found: $GITLEAKS_VERSION"
echo ""

# Check if we're in a git repository
echo "▶ 2. Checking git repository..."
if [ ! -d .git ]; then
    echo "  ✗ Not a git repository (no .git directory found)"
    echo "  Run this script from the root of your git repository"
    exit 1
fi
echo "  ✓ Git repository detected"
echo ""

# Create .gitleaksignore if it doesn't exist
echo "▶ 3. Creating .gitleaksignore file..."
if [ -f .gitleaksignore ]; then
    echo "  ⚠  .gitleaksignore already exists (not overwriting)"
else
    cat > .gitleaksignore << 'EOF'
# Gitleaks Ignore File
# Created: 2025-10-21 (Post-breach security enhancement)
#
# Add false positives here with explanations
# Format: regex pattern (one per line)
#
# Example:
# sk-ant-api03-EXAMPLE-REDACTED-NEVER-USE  # Documentation placeholder

# Documentation placeholders (safe patterns)
sk-ant-api03-EXAMPLE-REDACTED
sk_live_EXAMPLE_REDACTED
pk_live_EXAMPLE_REDACTED
your-password-here
your-token-here
REDACTED

# Test fixtures (if needed)
# Add specific test patterns here with comments
EOF
    echo "  ✓ Created .gitleaksignore with default placeholders"
fi
echo ""

# Create pre-commit hook
echo "▶ 4. Creating pre-commit hook..."
HOOK_FILE=.git/hooks/pre-commit

if [ -f "$HOOK_FILE" ]; then
    # Backup existing hook
    BACKUP_FILE="${HOOK_FILE}.backup-$(date +%s)"
    cp "$HOOK_FILE" "$BACKUP_FILE"
    echo "  ⚠  Existing pre-commit hook backed up to:"
    echo "     $(basename $BACKUP_FILE)"
    echo ""
    echo "  You may need to manually merge hooks if you had custom logic."
    echo ""
fi

cat > "$HOOK_FILE" << 'EOF'
#!/bin/bash

# Gitleaks Pre-Commit Hook
# Created: 2025-10-21 (Post-breach security enhancement)
# Implements: inst_070 (Pre-Commit Secret Detection)
#
# This hook runs gitleaks on staged files before allowing commits.
# If secrets are detected, the commit is BLOCKED.

echo "🔍 Running gitleaks secret detection..."

# Run gitleaks on staged files
if ! gitleaks protect --staged --verbose; then
    echo ""
    echo "❌ COMMIT BLOCKED: Secrets detected by gitleaks"
    echo ""
    echo "Actions:"
    echo "  1. Review the detected secrets above"
    echo "  2. Remove actual secrets from staged files"
    echo "  3. If false positive:"
    echo "     - Verify it's NOT a real secret"
    echo "     - Add pattern to .gitleaksignore with explanation"
    echo "     - Get human approval before committing"
    echo "     - Document in commit message"
    echo ""
    echo "NEVER bypass this hook without explicit user approval"
    echo ""
    exit 1
fi

echo "✅ No secrets detected - commit allowed"
exit 0
EOF

chmod +x "$HOOK_FILE"
echo "  ✓ Pre-commit hook created and made executable"
echo ""

# Test the hook
echo "▶ 5. Testing hook installation..."
if [ -x "$HOOK_FILE" ]; then
    echo "  ✓ Hook is executable"
else
    echo "  ✗ Hook is not executable (this should not happen)"
    exit 1
fi
echo ""

echo "═══════════════════════════════════════════════════════════"
echo "  ✅ INSTALLATION COMPLETE"
echo "═══════════════════════════════════════════════════════════"
echo ""
echo "The pre-commit hook will now run automatically on every commit."
echo ""
echo "To test it:"
echo "  1. Create a test file with a fake secret:"
echo "     echo 'sk-ant-api03-REAL_SECRET_KEY' > test-secret.txt"
echo "  2. Stage and attempt to commit:"
echo "     git add test-secret.txt"
echo "     git commit -m 'test'"
echo "  3. Commit should be BLOCKED with gitleaks error"
echo "  4. Clean up:"
echo "     git reset HEAD test-secret.txt"
echo "     rm test-secret.txt"
echo ""
echo "Files created:"
echo "  - .git/hooks/pre-commit (executable hook)"
echo "  - .gitleaksignore (allowed patterns)"
echo ""
echo "Implements: inst_070 (Pre-Commit Secret Detection)"
echo ""