#!/usr/bin/env bash

set -euo pipefail
# shellcheck source=./framework.sh
source "${BASE_DIR}/framework.sh"

freeh=$(free -h)
freem=$(free -m)
meminfo=$(cat /proc/meminfo)

if [[ -d /proc/spl/kstat/zfs ]]; then
    # if zfs is in use on system
    arcstat=$(cat /proc/spl/kstat/zfs/arcstats)

    # convert units to kb for easy calculation with /proc/meminfo
    arc_current=$(awk '/^size/ { OFMT="%.0f"; print $3/1024 }' <<< "${arcstat}")
    arc_min=$(awk '/^c_min/ { OFMT="%.0f"; print $3/1024 }' <<< "${arcstat}")

    # zfs arc size is dynamic, but can't shrink below the min size
    arcsize=$(bc <<< "${arc_current}-${arc_min}")
else
    # if zfs isn't in use, set the arc to 0
    arcsize=0
fi

ram() {
    local availmem usedmem totalmem used avail total label percentage bar

    availmem=$(awk -v arcsize="${arcsize}" '/^MemAvailable:/ { print $2 + arcsize }' <<< "${meminfo}")
    usedmem=$(awk -v availmem="${availmem}" '/^MemTotal:/ { print $2 - availmem }' <<< "${meminfo}")
    totalmem=$(awk '/^MemTotal:/ { print $2 }' <<< "${meminfo}")

    # label display section
    used="$(numfmt --round=down --from-unit=1024 --to=iec <<< "${usedmem}")"
    avail="$(numfmt --round=down --from-unit=1024 --to=iec <<< "${availmem}")"
    total="$(numfmt --round=down --from-unit=1024 --to=iec <<< "${totalmem}")"
    label=$(print_split "${WIDTH}" "RAM - ${used} used, ${avail} available" "/ ${total}")

    # bar display section
    percentage=$(echo "${usedmem} / ${totalmem} * 100" | bc -l | xargs printf %.0f)
    bar=$(print_bar "${WIDTH}" "${percentage}")

    printf "%s\n%s" "${label}" "${bar}"
}

swap() {
    local swap total used available label percentage bar

    # Return if no swap
    [[ "$(awk '/Swap/ {print $2}' <<< "${freem}")" == 0 ]] && return

    swap=$(awk '/Swap/ {print $2,$3,$4}' <<< "${freeh}")
    IFS=" " read -r total used available <<< "${swap}"
    label=$(print_split "${WIDTH}" "Swap - ${used::-1} used, ${available::-1} available" "/ ${total::-1}")

    percentage=$(awk '/Swap/ {printf "%.0f", $3/$2*100}' <<< "${freem}")
    bar=$(print_bar "${WIDTH}" "${percentage}")

    printf "%s\n%s" "${label}" "${bar}"
}

out=$(ram)
swap=$(swap)
[[ -n "${swap}" ]] && out+="\n${swap}"

print_columns "Memory" "${out}"