git-diff.sh

#!/bin/bash

# git-diff-json.sh - Get Git diff information in JSON format
# 
# Usage:
#   ./git-diff-json.sh [directory] [options]
#
# Options:
#   --compare-branch, -c    Branch to compare against (default: main)
#   --no-local-changes, -n  Don't include local changes in comparison
#   --name-only             Return only file names instead of full diff
#   --summary, -s           Return only summary of changes
#   --output, -o            Output file (default: .git-diff.json in CWD)
#   --help, -h              Show this help message

# Default values
COMPARE_BRANCH="main"
INCLUDE_LOCAL_CHANGES=true
NAME_ONLY=false
SUMMARY=false
OUTPUT_FILE=""
DIRECTORY="$(pwd)"

# Function to show help
show_help() {
    grep '^#' "$0" | grep -v '#!/bin/bash' | sed 's/^# \?//'
    exit 0
}

# Parse arguments
while [[ $# -gt 0 ]]; do
    case "$1" in
        --compare-branch|-c)
            COMPARE_BRANCH="$2"
            shift 2
            ;;
        --no-local-changes|-n)
            INCLUDE_LOCAL_CHANGES=false
            shift
            ;;
        --name-only)
            NAME_ONLY=true
            shift
            ;;
        --summary|-s)
            SUMMARY=true
            shift
            ;;
        --output|-o)
            OUTPUT_FILE="$2"
            shift 2
            ;;
        --help|-h)
            show_help
            ;;
        *)
            # If the argument doesn't start with a dash, treat it as a directory
            if [[ ! "$1" =~ ^- ]]; then
                DIRECTORY="$1"
            else
                echo "Unknown option: $1"
                exit 1
            fi
            shift
            ;;
    esac
done

# Set default output file if not specified
if [ -z "$OUTPUT_FILE" ]; then
    OUTPUT_FILE="$DIRECTORY/.git-diff.json"
fi

# Check if directory exists and is a git repository
if [ ! -d "$DIRECTORY" ]; then
    echo "Error: Directory '$DIRECTORY' does not exist" >&2
    exit 1
fi

# Save current directory to return to it later
ORIGINAL_DIR=$(pwd)

# Move to the specified directory
cd "$DIRECTORY" || { echo "Error: Cannot change to directory '$DIRECTORY'" >&2; exit 1; }

# Check if this is a git repository
if ! git rev-parse --git-dir > /dev/null 2>&1; then
    echo "Error: Not a git repository: '$DIRECTORY'" >&2
    cd "$ORIGINAL_DIR"
    exit 1
fi

# Get current branch
CURRENT_BRANCH=$(git symbolic-ref --short HEAD 2>/dev/null || git rev-parse HEAD)

# Build diff command options
DIFF_OPTIONS=""
if [ "$NAME_ONLY" = true ]; then
    DIFF_OPTIONS="$DIFF_OPTIONS --name-only"
fi

if [ "$SUMMARY" = true ]; then
    DIFF_OPTIONS="$DIFF_OPTIONS --stat"
fi

# Get diff result based on options
if [ "$INCLUDE_LOCAL_CHANGES" = true ]; then
    # Compare working tree to specified branch
    DIFF_RESULT=$(git diff $DIFF_OPTIONS "$COMPARE_BRANCH")
    DIFF_MODE="local-to-branch"
else
    # Compare current branch to specified branch without local changes
    DIFF_RESULT=$(git diff $DIFF_OPTIONS "${COMPARE_BRANCH}...${CURRENT_BRANCH}")
    DIFF_MODE="branch-to-branch"
fi

# Get repository information
REPO_DIR=$(git rev-parse --show-toplevel)
REPO_NAME=$(basename "$REPO_DIR")
REMOTE_URL=$(git remote get-url origin 2>/dev/null || echo "")

# Create JSON output
# Escape JSON special characters
DIFF_RESULT_ESCAPED=$(echo "$DIFF_RESULT" | sed 's/\\/\\\\/g' | sed 's/"/\\"/g' | sed 's/\n/\\n/g' | tr -d '\r')

JSON_OUTPUT="{
  \"repository\": \"$REPO_NAME\",
  \"directory\": \"$REPO_DIR\",
  \"remote\": \"$REMOTE_URL\",
  \"currentBranch\": \"$CURRENT_BRANCH\",
  \"compareBranch\": \"$COMPARE_BRANCH\",
  \"mode\": \"$DIFF_MODE\",
  \"includeLocalChanges\": $INCLUDE_LOCAL_CHANGES,
  \"timestamp\": \"$(date -u +"%Y-%m-%dT%H:%M:%SZ")\",
  \"diff\": \"$DIFF_RESULT_ESCAPED\"
}"

# Output JSON
if [ -z "$OUTPUT_FILE" ] || [ "$OUTPUT_FILE" = "-" ]; then
    echo "$JSON_OUTPUT"
else
    echo "$JSON_OUTPUT" > "$OUTPUT_FILE"
    echo "Diff information saved to $OUTPUT_FILE"
fi

# Return to original directory
cd "$ORIGINAL_DIR"