#!/usr/bin/env bash
# swap_check.sh — swap usage percentage.
set -euo pipefail

if [ -r /proc/meminfo ]; then
  SWAP_TOTAL=$(awk '/^SwapTotal:/ {printf "%d", $2}' /proc/meminfo)
  SWAP_FREE=$(awk '/^SwapFree:/ {printf "%d", $2}' /proc/meminfo)
elif [ "$(uname)" = "Darwin" ]; then
  SP=$(sysctl vm.swapusage 2>/dev/null | awk '{print $4, $9}' | tr -d 'M' || echo "0 0")
  SWAP_TOTAL=$(echo "$SP" | awk '{printf "%.0f", $1*1024}')
  SWAP_FREE=$(echo "$SP" | awk '{printf "%.0f", ($1-$2)*1024}')
else
  SWAP_TOTAL=0
  SWAP_FREE=0
fi

if [ "$SWAP_TOTAL" -eq 0 ]; then
  echo "{\"health\":\"healthy\",\"metrics\":{\"swap_pct\":0}}"
else
  USED_PCT=$(awk "BEGIN {printf \"%.1f\", (1 - $SWAP_FREE/$SWAP_TOTAL)*100}")
  echo "{\"health\":\"healthy\",\"metrics\":{\"swap_pct\":$USED_PCT}}"
fi