#!/bin/bash
#
# Process Terminator Script for macOS
# This script forcibly terminates a process and all its descendant processes
#

# Check if PID argument is provided
if [ $# -ne 1 ]; then
    echo "Usage: $0 <PID>"
    exit 1
fi

PID=$1

# Validate that input is a valid PID (numeric)
if ! [[ "$PID" =~ ^[0-9]+$ ]]; then
    echo "Error: The PID must be a numeric value"
    exit 1
fi

# Check if the process exists - using kill -0 which is more reliable on macOS
if ! kill -0 $PID 2>/dev/null; then
    echo "Warning: No process found with PID $PID"
    exit 0
fi

# Recursive function to find and kill all descendant processes
kill_descendants() {
    local parent=$1
    # Use ps -axo for macOS to ensure all processes are included
    local children=$(ps -axo pid=,ppid= | awk -v ppid=$parent '$2==ppid {print $1}')

    echo "Processing children of PID: $parent..."
    for child in $children; do
        kill_descendants "$child"
        echo "Terminating child process: $child"
        kill -9 "$child" 2>/dev/null || true
    done
}

echo "============================================"
echo "Starting termination of process $PID and all its descendants"
echo "============================================"

# Try graceful termination first
echo "Attempting graceful termination (SIGTERM) of PID: $PID"
kill -15 "$PID" 2>/dev/null || true
sleep 1

# If still running, fall back to kill_descendants
# Use the macOS-native 'kill -0' check
if kill -0 $PID 2>/dev/null; then
    echo "Process $PID did not exit after SIGTERM; proceeding with forced termination of its descendants and itself"
else
    echo "Process $PID exited cleanly after SIGTERM"
    exit 0
fi

# Find and kill all descendant processes
kill_descendants "$PID"

# Finally kill the main process
echo "Terminating main process: $PID"
kill -9 "$PID" 2>/dev/null || true

# Wait a little for process/port resources to be fully released
FINAL_WAIT_SECONDS=1
echo "Waiting ${FINAL_WAIT_SECONDS}s for resources to settle..."
sleep "$FINAL_WAIT_SECONDS"

echo "============================================"
echo "Process $PID and all its descendants have been terminated"
echo "============================================"

exit 0