keepscreen

#!/usr/bin/env bash
set -euo pipefail

PROGRAM_NAME="keepscreen"

usage() {
  cat <<'EOF'
Usage:
  keepscreen on
  keepscreen off
  keepscreen status

Behavior:
  on:
    - Set all related settings to Never (keep screen on)
  off:
    - Restore preset values (3/5/5/5 minutes)

Options:
  --dry-run   Print commands without changing settings
  -h, --help  Show help
EOF
}

die() { echo "${PROGRAM_NAME}: $*" >&2; exit 1; }

DRY_RUN=0
ARGS=()
for arg in "$@"; do
  case "$arg" in
    --dry-run) DRY_RUN=1 ;;
    -h|--help) usage; exit 0 ;;
    *) ARGS+=("$arg") ;;
  esac
done

ACTION="${ARGS[0]:-}"
case "$ACTION" in
  on|off|status) ;;
  "" ) usage; exit 2 ;;
  * ) die "unknown command: $ACTION (expected: on|off|status)" ;;
esac

need_cmd() { command -v "$1" >/dev/null 2>&1 || die "missing required command: $1"; }
need_cmd defaults
need_cmd pmset

run() {
  if [[ "$DRY_RUN" == "1" ]]; then
    printf '%s\n' "+ $*"
    return 0
  fi
  "$@"
}

run_sudo() {
  if [[ "$DRY_RUN" == "1" ]]; then
    printf '%s\n' "+ sudo $*"
    return 0
  fi
  sudo "$@"
}

set_screensaver_idle_seconds() {
  local seconds="$1"
  run defaults -currentHost write com.apple.screensaver idleTime -int "$seconds"
}

set_password_required() {
  local enabled="$1" # 0|1
  local delay_seconds="$2"
  # macOS preference storage varies by version; set both global and per-host.
  run defaults write com.apple.screensaver askForPassword -int "$enabled"
  run defaults write com.apple.screensaver askForPasswordDelay -int "$delay_seconds"
  run defaults -currentHost write com.apple.screensaver askForPassword -int "$enabled"
  run defaults -currentHost write com.apple.screensaver askForPasswordDelay -int "$delay_seconds"
}

set_display_sleep_minutes() {
  local minutes="$1"
  run_sudo pmset -b displaysleep "$minutes"
  run_sudo pmset -c displaysleep "$minutes"
}

read_screensaver_idle_seconds() {
  # Returns integer seconds; defaults to 0 when unset.
  defaults -currentHost read com.apple.screensaver idleTime 2>/dev/null || echo 0
}

read_password_required() {
  local enabled delay enabled_host delay_host
  enabled_host="$(defaults -currentHost read com.apple.screensaver askForPassword 2>/dev/null || echo "")"
  delay_host="$(defaults -currentHost read com.apple.screensaver askForPasswordDelay 2>/dev/null || echo "")"
  enabled="$(defaults read com.apple.screensaver askForPassword 2>/dev/null || echo 0)"
  delay="$(defaults read com.apple.screensaver askForPasswordDelay 2>/dev/null || echo 0)"
  [[ -n "$enabled_host" ]] && enabled="$enabled_host"
  [[ -n "$delay_host" ]] && delay="$delay_host"
  printf '%s %s\n' "$enabled" "$delay"
}

read_display_sleep_minutes() {
  # Prints: "<battery_minutes> <ac_minutes>" (0 when unset/unknown)
  # pmset -g custom format varies slightly across macOS, so parse defensively.
  local out battery ac
  out="$(pmset -g custom 2>/dev/null || true)"
  battery="$(awk '
    $0 ~ /^Battery Power/ {inb=1; next}
    $0 ~ /^AC Power/ {inb=0}
    inb && $1=="displaysleep" {print $2; exit}
  ' <<<"$out")"
  ac="$(awk '
    $0 ~ /^AC Power/ {ina=1; next}
    $0 ~ /^Battery Power/ {ina=0}
    ina && $1=="displaysleep" {print $2; exit}
  ' <<<"$out")"
  [[ -n "${battery:-}" ]] || battery="0"
  [[ -n "${ac:-}" ]] || ac="0"
  printf '%s %s\n' "$battery" "$ac"
}

print_status() {
  local idle enabled delay battery ac
  idle="$(read_screensaver_idle_seconds)"
  read -r enabled delay < <(read_password_required)
  read -r battery ac < <(read_display_sleep_minutes)

  echo "Screen saver idleTime: ${idle}s"
  echo "Require password: ${enabled} (delay: ${delay}s)"
  echo "Display sleep: battery=${battery}m ac=${ac}m"
}

apply_on() {
  # Keep screen on: set everything to "Never".
  set_screensaver_idle_seconds 0
  set_display_sleep_minutes 0
  set_password_required 0 0

  # Encourage settings to refresh quickly.
  run killall cfprefsd >/dev/null 2>&1 || true
  run killall "System Settings" >/dev/null 2>&1 || true
  run killall "System Preferences" >/dev/null 2>&1 || true
}

apply_off() {
  # Restore preset values (matches the screenshot).
  set_screensaver_idle_seconds 180
  set_display_sleep_minutes 5
  set_password_required 1 300

  run killall cfprefsd >/dev/null 2>&1 || true
  run killall "System Settings" >/dev/null 2>&1 || true
  run killall "System Preferences" >/dev/null 2>&1 || true
}

case "$ACTION" in
  on) apply_on ;;
  off) apply_off ;;
  status) print_status ;;
esac