#!/bin/bash

# idle_measurement.sh
# Usage: ./idle_measurement.sh output.csv

OUTPUT_FILE="$1"

if [[ -z "$OUTPUT_FILE" ]]; then
    echo "Usage: $0 output_file.csv"
    exit 1
fi

echo "Sample,CPU_idle_percent,Mem_available_MB" > "$OUTPUT_FILE"
echo "Starting idle measurement for 60 samples (1 per second)"
echo ""

CPU_TOTAL=0
MEM_TOTAL=0
SAMPLES=60

for i in $(seq 1 $SAMPLES); do
    # mpstat waits 1 second and returns average for that interval
    CPU_IDLE=$(mpstat 1 1 | awk '/Average/ && $NF ~ /[0-9.]+/ {print $NF}')
    MEM_AVAILABLE=$(free -m | awk '/^Mem:/ {print $7}')

    CPU_TOTAL=$(echo "$CPU_TOTAL + $CPU_IDLE" | bc)
    MEM_TOTAL=$(echo "$MEM_TOTAL + $MEM_AVAILABLE" | bc)

    echo "$i,$CPU_IDLE,$MEM_AVAILABLE" >> "$OUTPUT_FILE"
    printf "Sample %2d: CPU idle = %5.1f%% | Available memory = %6d MB\n" "$i" "$CPU_IDLE" "$MEM_AVAILABLE"
done

CPU_AVG=$(echo "scale=2; $CPU_TOTAL / $SAMPLES" | bc)
MEM_AVG=$(echo "scale=2; $MEM_TOTAL / $SAMPLES" | bc)

echo ""
echo "Results saved to: $OUTPUT_FILE"
echo "Average CPU idle: $CPU_AVG%"
echo "Average Free Memory: $MEM_AVG MB"