#!/bin/bash

# Function to display usage information
usage() {
    echo "Usage: $0 [-n|--dry-run] <source_directory> <destination_directory>"
    echo "Options:"
    echo "  -n, --dry-run    Perform a trial run with no changes made"
    exit 1
}

# Default dry run flag
DRY_RUN=false

# Parse command-line arguments
ARGS=$(getopt -o n -l dry-run -n "$0" -- "$@")
if [ $? -ne 0 ]; then
    usage
fi

eval set -- "$ARGS"

# Process arguments
while true; do
    case "$1" in
        -n|--dry-run)
            DRY_RUN=true
            shift
            ;;
        --)
            shift
            break
            ;;
        *)
            usage
            ;;
    esac
done

# Check if source and destination paths are provided
if [ $# -ne 2 ]; then
    usage
fi

# Assign input arguments to variables
SOURCE_DIR="$1"
DEST_DIR="$2"

# Validate source directory exists
if [ ! -d "$SOURCE_DIR" ]; then
    echo "Error: Source directory does not exist"
    exit 1
fi

# Create destination directory if it doesn't exist (unless dry run)
if [ "$DRY_RUN" = false ]; then
    mkdir -p "$DEST_DIR"
fi

# Prepare rsync options
RSYNC_OPTS="-av"

# Add dry run option if specified
if [ "$DRY_RUN" = true ]; then
    RSYNC_OPTS+=" --dry-run"
    echo "=== PERFORMING DRY RUN (NO CHANGES WILL BE MADE) ==="
fi

# Add compression and delete options
RSYNC_OPTS+=" -z --delete"

# Perform rsync
rsync $RSYNC_OPTS "$SOURCE_DIR/" "$DEST_DIR"

# Check rsync exit status
if [ $? -eq 0 ]; then
    if [ "$DRY_RUN" = true ]; then
        echo "Dry run completed successfully. No changes were made."
    else
        echo "Synchronization completed successfully"
    fi
else
    echo "Synchronization failed"
    exit 1
fi