#!/usr/bin/env bash
# ==============================================================================
# Motion Wallpaper — theme-change watcher.
#
# Polls the Omarchy background symlink (~/.config/omarchy/current/background).
# When the user switches themes (or cycles backgrounds), Omarchy points the
# symlink at a new image. mpvpaper would otherwise keep running on top of the
# new theme's static wallpaper, so we tear it down via the toggle script —
# which also respawns swaybg with the *new* symlink target.
#
# Runs as a sibling to mpvpaper. Spawned and killed by motion-wallpaper-toggle.
# ==============================================================================

set -euo pipefail

BG_LINK="$HOME/.config/omarchy/current/background"
LOG_FILE="${XDG_CACHE_HOME:-$HOME/.cache}/motion-wallpaper.log"
POLL_SECONDS=2

log() {
  printf '[%s] theme-watcher: %s\n' "$(date '+%Y-%m-%d %H:%M:%S')" "$*" >> "$LOG_FILE"
}

# Non-Omarchy systems won't have the symlink. Exit silently — auto-pause still
# works without us; we only matter on Omarchy where theme-set rotates the bg.
if [ ! -L "$BG_LINK" ] && [ ! -e "$BG_LINK" ]; then
  log "no Omarchy background symlink at $BG_LINK — exiting"
  exit 0
fi

initial="$(readlink -f "$BG_LINK" 2>/dev/null || true)"
if [ -z "$initial" ]; then
  log "could not resolve $BG_LINK — exiting"
  exit 0
fi
log "watching $BG_LINK (initial=$initial)"

# Locate the toggle binary in PATH first, then fall back to our own dir — same
# trick the auto-pause watcher uses, since launcher-spawned PATH is minimal.
TOGGLE="$(command -v motion-wallpaper-toggle 2>/dev/null || true)"
if [ -z "$TOGGLE" ]; then
  self_dir="$(dirname "$(readlink -f "$0")")"
  if [ -x "$self_dir/motion-wallpaper-toggle" ]; then
    TOGGLE="$self_dir/motion-wallpaper-toggle"
  fi
fi
if [ -z "$TOGGLE" ]; then
  log "motion-wallpaper-toggle not found — exiting"
  exit 0
fi

while sleep "$POLL_SECONDS"; do
  current="$(readlink -f "$BG_LINK" 2>/dev/null || true)"
  [ -z "$current" ] && continue
  if [ "$current" != "$initial" ]; then
    log "background changed ($initial → $current) — stopping motion wallpaper"
    "$TOGGLE" stop >/dev/null 2>&1 || true
    exit 0
  fi
done