#!/usr/bin/env bash
# hypr-lid: clamshell + lid handling for Hyprland.
#
#   - Lid closed + external display connected  -> disable the built-in panel
#     (clamshell mode); external displays keep working.
#   - Lid closed + no external display         -> turn built-in off, lock after
#     LOCK_SECONDS, suspend after SUSPEND_SECONDS.
#   - Lid open                                 -> enable built-in, turn display on.
#
# Runs as a systemd user service (hypr-lid.service) and polls the lid + monitor
# state, so connecting/disconnecting a dock while the lid is closed is handled
# too. Lock/suspend use transient systemd timers, which pause during suspend and
# are recreated afterwards, so if the machine wakes while the lid stays closed
# it will sleep again after the full timeout.

set -uo pipefail

INTERNAL="desc:BOE 0x0BC9"
RUNTIME="/run/user/$(id -u)"
LOCK_SECONDS=60
SUSPEND_SECONDS=600
POLL_SECONDS=2

log() { printf '[hypr-lid] %s %s\n' "$(date '+%H:%M:%S')" "$*"; }

# Run hyprctl against the active Hyprland instance, if any.
hypr() {
  local sig=""
  for d in "$RUNTIME"/hypr/*/; do
    if [ -S "$d/.socket.sock" ]; then
      sig="$(basename "$d")"
      break
    fi
  done
  [ -n "$sig" ] || return 1
  HYPRLAND_INSTANCE_SIGNATURE="$sig" command hyprctl "$@"
}

lid_closed() {
  local state
  state="$(cat /proc/acpi/button/lid/*/state 2>/dev/null)" || return 1
  [[ "$state" == *closed* ]]
}

# True when Hyprland has any output up that is not the built-in panel/headless.
has_external() {
  hypr monitors -j 2>/dev/null | grep '"name": "' | grep -qvE '"(eDP|HEADLESS)-'
}

stop_timers() {
  systemctl --user stop hypr-lid-lock.timer hypr-lid-suspend.timer 2>/dev/null || true
}

# Re-create the named timer unless it is already waiting. Transient timers are
# collected after they fire, so this also restarts them after a suspend.
ensure_timer() {
  local name="$1" seconds="$2"
  shift 2
  if ! systemctl --user --quiet is-active "hypr-lid-$name.timer"; then
    systemd-run --user --quiet --unit="hypr-lid-$name" --on-active="${seconds}s" --collect "$@"
  fi
}

mode=unknown

while true; do
  if ! hypr monitors >/dev/null 2>&1; then
    # No Hyprland running (e.g. another compositor, or before first launch).
    mode=unknown
    sleep 3
    continue
  fi

  new_mode="open"
  if lid_closed; then
    if has_external; then
      new_mode="clamshell"
    else
      new_mode="regular"
    fi
  fi

  if [ "$new_mode" != "$mode" ]; then
    log "transition: $mode -> $new_mode"
    case "$new_mode" in
      open)
        hypr keyword monitor "$INTERNAL, preferred, auto, 1"
        hypr dispatch dpms on
        stop_timers
        ;;
      clamshell)
        hypr keyword monitor "$INTERNAL, disabled"
        stop_timers
        ;;
      regular)
        hypr keyword monitor "$INTERNAL, preferred, auto, 1"
        hypr dispatch dpms off
        ;;
    esac
    mode="$new_mode"
  fi

  if [ "$mode" = "regular" ]; then
    ensure_timer lock "$LOCK_SECONDS" loginctl lock-sessions
    ensure_timer suspend "$SUSPEND_SECONDS" systemctl suspend
  fi

  sleep "$POLL_SECONDS"
done