#!/bin/bash

if [ -z "$1" ]; then
  echo "Usage: $0 <program_name|--all>"
  echo "  program_name: track a specific program"
  echo "  --all:        track all processes system-wide"
  exit 1
fi

PROGRAM_NAME=$1
OUTPUT_FILE="process_stats.log"
TRACK_ALL=false

if [ "$PROGRAM_NAME" = "--all" ]; then
  TRACK_ALL=true
  OUTPUT_FILE="all_process_stats.log"
fi

touch $OUTPUT_FILE

if [ "$TRACK_ALL" = true ]; then
  echo "tracking system-wide CPU and memory usage..."

  echo "date time,total cpu %, total memory %" >> $OUTPUT_FILE

  while true; do
    TIMESTAMP=$(date "+%Y-%m-%d %H:%M:%S")

    TOTAL_CPU=$(top -bn1 | grep "Cpu(s)" | awk '{print $2}' | sed 's/%us,//')
    TOTAL_MEM=$(free | grep Mem | awk '{printf "%.1f", ($3/$2) * 100.0}')

    echo "$TIMESTAMP,$TOTAL_CPU,$TOTAL_MEM" >> $OUTPUT_FILE

    sleep 1
  done
else
  echo "date time,pid,total cpu %, total memory %" >> $OUTPUT_FILE
  while true; do
    PIDS=$(pgrep -x $PROGRAM_NAME | grep -v $$ | grep -v $(pgrep -x pgrep))

    if [ -n "$PIDS" ]; then
      PID=$(echo $PIDS | awk '{print $1}')
      echo "found process $PROGRAM_NAME with PID $PID"

      while kill -0 $PID 2>/dev/null; do
        TIMESTAMP=$(date "+%Y-%m-%d %H:%M:%S")

        echo -n "$TIMESTAMP," >> $OUTPUT_FILE
        ps -p $PID -o pid,%cpu,%mem,cmd --no-headers >> $OUTPUT_FILE

        sleep 1
      done

      echo "Process $PROGRAM_NAME with PID $PID has terminated"
      exit 0
    fi

    sleep 1
  done
fi