avd/status-bar

#!/bin/bash

# Configurable variables
SEP=' | '

CPU_ON=1
CPU_SYM=

MEM_ON=1
MEM_SYM=

BL_ON=1
BL_SYM=

VOL_ON=1
VOL_SYM_LOW=
VOL_SYM_HI=
VOL_SYM_MUTE=

BAT_ON=1
BAT_SYM=
BAT_SYM_PLG=
BAT_SYM_UNK=
BAT_CNT=1

DT_ON=1
DT_SYM=''
DT_FMT='%a %d %I:%M%p'

status_cpu() {
  ps --no-headers -eo %cpu | awk '{cpu = cpu + $1} END {print cpu}'
}

status_mem() {
  printf '%.0f%%' "$(free | awk 'NR == 2 {print $3 * 100 / $2}')"
}

status_bl () {
  local bl
  local max_bl

  printf -v bl '%s' \
    "$(find /sys/class/backlight/*/brightness | head -n 1 | xargs cat)"
  printf -v max_bl '%s' \
    "$(find /sys/class/backlight/*/max_brightness | head -n 1 | xargs cat)"
  # Multiply by 10^3 inside the arithemetic expansion so the integer arithmetic
  # will preserve 3 digits after the decimal point. Applying e-3 would provide
  # 3 decimal points for printf, but since we want the result scaled by 100, we
  # only apply e-1. printf will round the result to the specified presion.
  printf '%.0f%%' "$((bl * 1000 / max_bl))e-1"
}

status_vol () {
  printf '%s%%' \
    "$(amixer get Master | tail -n 1 | sed -E 's/.*\[(.*)%\].*/\1/')"
}

status_vol_state() {
  local -r vol="${1:-0}"
  local state

  printf -v state '%s' \
    "$(amixer get Master | tail -n 1 | sed -E 's/.*\[(.*)\]/\1/')"
  case "${state}" in
    on)
      if [[ "${vol}" -lt 50 ]]; then printf '%s' "${VOL_SYM_LOW}";
      else printf '%s' "${VOL_SYM_HI}"; fi
      ;;
    *)
      printf '%s' "${VOL_SYM_MUTE}"
      ;;
  esac
}

status_bat_cap () {
  printf '%s' "$(find /sys/class/power_supply/BAT?/capacity \
    | head -n "${BAT_CNT}" | xargs cat | tr '\n' '% ' | sed 's/ *$//')"
}

status_bat_state() {
  local state

  printf -v state '%s' \
    "$(find /sys/class/power_supply/BAT?/status | head -n 1 | xargs cat)"
  case "${state}" in
    Discharging)
      printf '%s' "${BAT_SYM}"
      ;;
    Charging|Full)
      printf '%s' "${BAT_SYM_PLG}"
      ;;
    *)
      printf '%s' "${BAT_SYM_UNK}"
      ;;
  esac
}

status_dt () {
  printf '%s' "$(date +"${DT_FMT}")"
}

add_stat () {
  local -r val="$1"
  local -r sym="$2"
  local sep

  # Skip the separator for the first status section
  if [[ -n "${status}" ]]; then sep="${SEP}"; fi

  # Only output the status section if it has a value
  if [[ -n "${val}" ]]; then
    if [[ -n "${sym}" ]]; then status="${status}${sep}${sym} ${val}";
    else status="${status}${sep}${val}"; fi
  fi
}

while :; do
  status=''

  if [[ "${CPU_ON}" -ne 0 ]]; then
    add_stat "$(status_cpu)" "${CPU_SYM}"
  fi
  if [[ "${MEM_ON}" -ne 0 ]]; then
    add_stat "$(status_mem)" "${MEM_SYM}"
  fi
  if [[ "${BL_ON}" -ne 0 ]]; then
    add_stat "$(status_bl)" "${BL_SYM}"
  fi
  if [[ "${VOL_ON}" -ne 0 ]]; then
    vol="$(status_vol)"
    add_stat "${vol}" "$(status_vol_state "${vol:0:-1}")"
  fi
  if [[ "${BAT_ON}" -ne 0 ]]; then
    add_stat "$(status_bat_cap)" "$(status_bat_state)"
  fi
  if [[ "${DT_ON}" -ne 0 ]]; then
    add_stat "$(status_dt)" "${DT_SYM}"
  fi
  xprop -root -set WM_NAME " ${status} "

  # Sleep until the beginning of the next minute, this way when we are showing
  # the time, the status updates on the minute
  ## sleep $((60 - $(date +%S)))
  sleep 2
done