#!/bin/sh

# Pre-commit hook to check for trailing whitespace and missing newline at EOF

# Exit on first error
set -e

# Color codes for output
RED='\033[0;31m'
GREEN='\033[0;32m'
NC='\033[0m' # No Color

errors_found=0

# Get list of staged files
staged_files=$(git diff --cached --name-only --diff-filter=ACM)

if [ -z "$staged_files" ]; then
    exit 0
fi

# Check for trailing whitespace
echo "Checking for trailing whitespace..."
for file in $staged_files; do
    if [ -f "$file" ]; then
        # Check if file has trailing whitespace
        if grep -q '[[:space:]]$' "$file"; then
            echo "${RED}✗${NC} Trailing whitespace found in: $file"
            # Show lines with trailing whitespace
            grep -n '[[:space:]]$' "$file" | while IFS=: read -r line_num line_content; do
                echo "  Line $line_num: '${line_content}'"
            done
            errors_found=1
        fi
    fi
done

# Check for missing newline at end of file
echo "Checking for newline at end of files..."
for file in $staged_files; do
    if [ -f "$file" ]; then
        # Check if file ends with a newline
        if [ -n "$(tail -c 1 "$file")" ]; then
            echo "${RED}✗${NC} Missing newline at end of file: $file"
            errors_found=1
        fi
    fi
done

# Report results
if [ $errors_found -eq 0 ]; then
    echo "${GREEN}✓${NC} All checks passed!"
    exit 0
else
    echo ""
    echo "${RED}Pre-commit checks failed!${NC}"
    echo "Please fix the issues above and try again."
    echo ""
    echo "To fix trailing whitespace, you can use:"
    echo "  sed -i 's/[[:space:]]*$//' <filename>"
    echo ""
    echo "To add missing newline at EOF, you can use:"
    echo "  echo >> <filename>"
    exit 1
fi