#!/usr/bin/env bash

set -euo pipefail

has_gum() {
    command -v gum >/dev/null 2>&1
}

die() {
    if has_gum; then
        gum style --foreground 196 --bold "error:" "$1"
    else
        echo "error: $1" >&2
    fi
    exit 1
}

if [ -z "${1:-}" ]; then
    die "usage: $0 <PID>"
fi

PID=$1

if ! ps -p "$PID" >/dev/null 2>&1; then
    die "process with PID $PID does not exist"
fi

VMRSS_KB=$(awk '/^VmRSS:/ { print $2 }' /proc/"$PID"/status)
[ -z "$VMRSS_KB" ] && die "could not read VmRSS for PID $PID"

VMRSS_MB=$(awk -v kb="$VMRSS_KB" 'BEGIN { printf "%.2f", kb / 1024 }')

if has_gum; then
    echo "$(gum style --bold "PID:") $(gum style --faint "$PID")"
    echo "$(gum style --foreground 240 "VmRSS:") $(gum style --foreground 33 "${VMRSS_KB} kB") ($(gum style --foreground 244 "${VMRSS_MB} MB"))"
else
    echo "PID: $PID"
    echo "VmRSS: $VMRSS_KB kB ($VMRSS_MB MB)"
fi