#!/usr/bin/env bash
# ==============================================================================
# Motion Wallpaper — gum-powered TUI for mpvpaper on Omarchy / Hyprland.
#
# Actions:
#   toggle   (default)  Interactive TUI. If running, offers Stop / Change.
#   start               Non-interactive start from saved state (for systemd).
#   stop                Stop mpvpaper and restore the normal wallpaper.
#   change              Pick a new video while already running.
#   status              Print current state (TUI header via gum).
#
# Files:
#   ~/.config/motion-wallpaper/state        last video + target monitor
#   ~/Videos/Wallpapers/                    optional quick-pick library
#   ~/.cache/motion-wallpaper.log           runtime log
# ==============================================================================

set -euo pipefail

APP_NAME="Motion Wallpaper"
STATE_DIR="${XDG_CONFIG_HOME:-$HOME/.config}/motion-wallpaper"
STATE_FILE="$STATE_DIR/state"
LOG_DIR="${XDG_CACHE_HOME:-$HOME/.cache}"
LOG_FILE="$LOG_DIR/motion-wallpaper.log"
LIBRARY_DIR="$HOME/Videos/Wallpapers"

# mpv options forwarded via mpvpaper -o. An input-ipc-server socket is opened
# so our companion watcher can send pause/resume commands when Hyprland
# reports a fullscreen window (mpvpaper's own -p is unreliable on 0.54.x).
RUNTIME_DIR="${XDG_RUNTIME_DIR:-/run/user/$(id -u)}"
MPV_IPC_SOCK="$RUNTIME_DIR/motion-wallpaper-mpv.sock"
MPV_OPTS="--loop --no-audio --mute=yes --vo=gpu --profile=high-quality --input-ipc-server=$MPV_IPC_SOCK"

# ===== theme colors ===========================================================
# Pull TUI accents from the active Omarchy theme so the interface follows the
# system color scheme (the file is a symlink that swaps when the user runs
# omarchy-theme-set). Defaults below are Catppuccin Mocha and only kick in if
# colors.toml is missing or unreadable.
THEME_COLORS_FILE="$HOME/.config/omarchy/current/theme/colors.toml"

load_theme_colors() {
  COLOR_ACCENT="#cba6f7"
  COLOR_ERROR="#f38ba8"
  COLOR_OK="#a6e3a1"
  COLOR_MUTED="#6c7086"
  [ -r "$THEME_COLORS_FILE" ] || return 0

  local key val
  while IFS='=' read -r key val; do
    key="${key// /}"
    val="${val// /}"; val="${val//\"/}"
    case "$key" in
      accent) COLOR_ACCENT="$val" ;;  # primary accent
      color1) COLOR_ERROR="$val"  ;;  # ANSI red    → errors
      color2) COLOR_OK="$val"     ;;  # ANSI green  → success
      color8) COLOR_MUTED="$val"  ;;  # ANSI bright black → muted lines
    esac
  done < "$THEME_COLORS_FILE"
}
load_theme_colors

# ===== layout =================================================================
# Center the status panel horizontally in the floating window. gum style's
# --margin shifts the whole box right; we compute the side margin from the
# real terminal width (tput cols) so the panel sits centered regardless of
# how the user has sized the floating window.
TERM_COLS="$(tput cols 2>/dev/null || echo "${COLUMNS:-80}")"
TERM_ROWS="$(tput lines 2>/dev/null || echo "${LINES:-24}")"
PANEL_WIDTH=52
# Clamp panel width on narrow terminals so the box can never exceed the
# window — gum style would otherwise wrap the border into the next column.
[ "$PANEL_WIDTH" -gt "$TERM_COLS" ] && PANEL_WIDTH="$TERM_COLS"
PANEL_MARGIN=$(( (TERM_COLS - PANEL_WIDTH) / 2 ))
[ "$PANEL_MARGIN" -lt 0 ] && PANEL_MARGIN=0
# Reusable indent string for rows gum doesn't know how to position itself
# (menu items, header labels, success/error lines).
PANEL_INDENT="$(printf '%*s' "$PANEL_MARGIN" '')"

# Vertical centering: estimate the total rows the centered block occupies
# (panel ≈ 9, gap 1, label 1, hint 1, ~5 menu rows = ~17). The top pad is
# half the slack between the terminal height and that estimate, clamped to
# ≥0 so tiny floating windows still show everything.
EST_CONTENT_ROWS=17
TOP_PAD_ROWS=$(( (TERM_ROWS - EST_CONTENT_ROWS) / 2 ))
[ "$TOP_PAD_ROWS" -lt 0 ] && TOP_PAD_ROWS=0

# Clear and push the cursor down before each interactive gum prompt so the
# rendered UI sits vertically centered. Without this, gum draws at the
# current cursor position (top of window on first call, then below previous
# output as the user navigates) and the panel looks lost in dead space.
center_screen() {
  printf '\033[2J\033[H'
  local i
  for ((i = 0; i < TOP_PAD_ROWS; i++)); do printf '\n'; done
}

# Push the loaded theme into gum's own widget chrome (cursor, selected item,
# headers, prompts, confirm buttons). Without this, gum keeps its built-in
# pink/cyan defaults regardless of $COLOR_* values, so the menu cursor and
# highlighted row never follow the system theme.
export GUM_CHOOSE_CURSOR_FOREGROUND="$COLOR_ACCENT"
export GUM_CHOOSE_SELECTED_FOREGROUND="$COLOR_ACCENT"
export GUM_CHOOSE_HEADER_FOREGROUND="$COLOR_ACCENT"
export GUM_CONFIRM_PROMPT_FOREGROUND="$COLOR_ACCENT"
export GUM_CONFIRM_SELECTED_BACKGROUND="$COLOR_ACCENT"
export GUM_CONFIRM_SELECTED_FOREGROUND="$COLOR_MUTED"
export GUM_INPUT_PROMPT_FOREGROUND="$COLOR_ACCENT"
export GUM_INPUT_CURSOR_FOREGROUND="$COLOR_ACCENT"
export GUM_FILE_HEADER_FOREGROUND="$COLOR_ACCENT"
export GUM_FILTER_INDICATOR_FOREGROUND="$COLOR_ACCENT"
export GUM_FILTER_HEADER_FOREGROUND="$COLOR_ACCENT"
export GUM_SPIN_SPINNER_FOREGROUND="$COLOR_ACCENT"
# Pad gum's cursor with the panel's left margin so the menu items render at
# the same column as the centered panel above them. Inactive rows are padded
# automatically to match the cursor's printable width.
export GUM_CHOOSE_CURSOR="${PANEL_INDENT}> "
# Hide gum's built-in help footer — it renders flush-left and can't be
# indented. We draw our own centered hint as part of prompt_header instead.
export GUM_CHOOSE_SHOW_HELP=false
export GUM_FILTER_SHOW_HELP=false
export GUM_FILE_SHOW_HELP=false

# ===== user-facing strings ====================================================
# All copy lives here so the wording can be retuned without hunting through
# the action handlers. Format strings use printf-style %s; menu items must
# match verbatim because case branches compare against them.

# Header panel labels + values
TXT_TITLE="◐ $APP_NAME"
TXT_LBL_STATUS="status:   "
TXT_LBL_TARGET="target:   "
TXT_LBL_VIDEO="video:    "
TXT_LBL_AUTO="autostart:"
TXT_VAL_RUNNING="running"
TXT_VAL_STOPPED="stopped"
TXT_VAL_NONE="(none)"
TXT_VAL_AUTO_ON="enabled"
TXT_VAL_AUTO_OFF="disabled"

# Menu / picker headers
TXT_HDR_MAIN="What would you like to do?"
TXT_HDR_MONITOR="Select a monitor"
TXT_HDR_LIBRARY_FMT="Choose a video from %s"
TXT_HDR_BROWSE_FMT="Browse: %s"

# Menu items (used in case branches → keep verbatim)
TXT_BTN_STOP="Stop motion wallpaper"
TXT_BTN_CHANGE="Change video"
TXT_BTN_PICK="Pick a video and start"
TXT_BTN_AUTOSTART_ON="Turn autostart ON"
TXT_BTN_AUTOSTART_OFF="Turn autostart OFF"
TXT_BTN_CANCEL="Cancel"
TXT_BTN_START_FMT="Start with %s"
TXT_BTN_ALL_MONITORS="All monitors"
TXT_BTN_UP="── Up one folder ──"
TXT_BTN_BROWSE="── Browse filesystem… ──"

# Confirms
TXT_CONFIRM_DISABLE_AUTOSTART="Autostart is still enabled — also disable it so the wallpaper doesn't resume after reboot?"
TXT_CONFIRM_STOP_RUNNING="Motion wallpaper is still running — stop it now too?"
TXT_CONFIRM_OFFER_AUTOSTART="Start motion wallpaper automatically after login / reboot?"

# Success messages
TXT_OK_STOPPED="Stopped. Normal wallpaper restored."
TXT_OK_SWAPPED_FMT="Swapped to %s."
TXT_OK_STARTED_FMT="Started %s on %s."
TXT_OK_AUTOSTART_ON="Autostart enabled."
TXT_OK_AUTOSTART_ON_REBOOT="Autostart enabled — wallpaper will resume after reboot."
TXT_OK_AUTOSTART_ON_LATER="Autostart enabled — wallpaper will resume after reboot (once started)."
TXT_OK_AUTOSTART_OFF="Autostart disabled."

# Errors
TXT_ERR_NO_HYPRCTL="hyprctl not found. Are you in Hyprland?"
TXT_ERR_NO_JQ="jq is not installed."
TXT_ERR_NO_HIS="HYPRLAND_INSTANCE_SIGNATURE is not set — the launcher didn't inherit the Hyprland session. Try running motion-wallpaper-toggle from a regular terminal."
TXT_ERR_HYPRCTL_FMT="Could not read monitors from hyprctl. See %s."
TXT_ERR_NO_UNIT="motion-wallpaper.service is not installed. Re-run wallpaper.sh."
TXT_ERR_AUTOSTART_FAIL="Failed to enable autostart (systemctl error)."
TXT_ERR_FILE_FMT="File not found: %s"
TXT_ERR_NOT_RUNNING="Motion wallpaper is not running."
TXT_ERR_MPVP_FMT="mpvpaper failed to start. See %s for details."
TXT_ERR_EMPTY_DIR="No subfolders or videos in this folder."

# Notifications
TXT_NOTIFY_STARTED_FMT="Motion wallpaper started on %s."
TXT_NOTIFY_STOPPED="Motion wallpaper stopped."
TXT_NOTIFY_UPDATED="Motion wallpaper updated."

# Misc
TXT_PRESS_ENTER="Press enter to close…"
TXT_HINT_NAV="↑/↓ navigate  ·  enter select  ·  esc cancel"

# Backwards-compat alias used by pick_video's "browse" sentinel match.
BROWSE_SENTINEL="$TXT_BTN_BROWSE"

mkdir -p "$STATE_DIR" "$LOG_DIR"

# ===== helpers ================================================================

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

require_gum() {
  if ! command -v gum >/dev/null 2>&1; then
    echo "ERROR: gum is not installed. Run: sudo pacman -S gum" >&2
    exit 1
  fi
}

require_tty() {
  if [ ! -t 0 ] || [ ! -t 1 ]; then
    cat >&2 <<MSG
$APP_NAME: interactive mode requires a terminal.
Run from a terminal, or use a non-interactive action:
  $0 start | stop | status
MSG
    exit 1
  fi
}

tui_err() {
  gum style --margin="0 $PANEL_MARGIN" --foreground="$COLOR_ERROR" --bold "ERROR: $1"
  log "ERROR: $1"
  # Hold the terminal open so launcher-spawned windows don't flash away.
  if [ -t 0 ]; then
    gum input --placeholder="$TXT_PRESS_ENTER" >/dev/null 2>&1 || true
  fi
}

tui_ok() {
  gum style --margin="0 $PANEL_MARGIN" --foreground="$COLOR_OK" "✓ $1"
  log "$1"
}

notify() {
  # Fire-and-forget system notification so the user sees results after the
  # TUI terminal closes.
  if command -v notify-send >/dev/null 2>&1; then
    notify-send "$APP_NAME" "$1" || true
  fi
  log "$1"
}

load_state() {
  LAST_VIDEO=""
  LAST_TARGET=""
  LAST_DIR=""
  [ -f "$STATE_FILE" ] || return 0
  # Parse KEY="VALUE" lines directly instead of `source`, so a maliciously
  # crafted video path (e.g. containing `";rm -rf …`) can't execute.
  local key val
  while IFS='=' read -r key val; do
    val="${val#\"}"
    val="${val%\"}"
    case "$key" in
      LAST_VIDEO)  LAST_VIDEO="$val"  ;;
      LAST_TARGET) LAST_TARGET="$val" ;;
      LAST_DIR)    LAST_DIR="$val"    ;;
    esac
  done < "$STATE_FILE"
}

save_state() {
  # $1 video, $2 target, $3 (optional) last dir — defaults to dirname of $1
  # so the filesystem browser re-opens where the user last landed.
  local dir="${3:-$(dirname "$1")}"
  umask 077
  # Atomic write: avoids leaving a truncated file if the process dies mid-cat.
  local tmp="$STATE_FILE.tmp"
  cat > "$tmp" <<STATE
LAST_VIDEO="$1"
LAST_TARGET="$2"
LAST_DIR="$dir"
STATE
  mv -f "$tmp" "$STATE_FILE"
}

is_running() {
  pgrep -x mpvpaper >/dev/null 2>&1
}

# ===== autostart (systemd user unit) ==========================================

autostart_installed() {
  systemctl --user list-unit-files motion-wallpaper.service >/dev/null 2>&1
}

autostart_enabled() {
  systemctl --user is-enabled motion-wallpaper.service >/dev/null 2>&1
}

autostart_enable() {
  if ! autostart_installed; then
    tui_err "$TXT_ERR_NO_UNIT"
    return 1
  fi
  if ! systemctl --user enable motion-wallpaper.service >/dev/null 2>&1; then
    tui_err "$TXT_ERR_AUTOSTART_FAIL"
    return 1
  fi
  log "autostart enabled"
  return 0
}

autostart_disable() {
  systemctl --user disable motion-wallpaper.service >/dev/null 2>&1 || true
  log "autostart disabled"
}

# Returns the status panel as a string. Used both as a stand-alone display
# (action_status / show_header) and as the --header of gum prompts so the
# status stays visible while the user interacts in a small floating window.
header_text() {
  load_state
  local status_line target_line video_line autostart_line
  if is_running; then
    status_line="$TXT_LBL_STATUS $(gum style --foreground="$COLOR_OK" "$TXT_VAL_RUNNING")"
  else
    status_line="$TXT_LBL_STATUS $(gum style --foreground="$COLOR_MUTED" "$TXT_VAL_STOPPED")"
  fi
  target_line="$TXT_LBL_TARGET ${LAST_TARGET:-$(gum style --foreground="$COLOR_MUTED" --italic "$TXT_VAL_NONE")}"
  video_line="$TXT_LBL_VIDEO ${LAST_VIDEO:-$(gum style --foreground="$COLOR_MUTED" --italic "$TXT_VAL_NONE")}"
  if autostart_enabled; then
    autostart_line="$TXT_LBL_AUTO $(gum style --foreground="$COLOR_OK" "$TXT_VAL_AUTO_ON")"
  else
    autostart_line="$TXT_LBL_AUTO $(gum style --foreground="$COLOR_MUTED" "$TXT_VAL_AUTO_OFF")"
  fi
  # Title centered, data lines left-aligned with consistent label indent —
  # the box itself is shifted right by PANEL_MARGIN so it sits centered in
  # the floating window.
  local title_block
  title_block="$(gum style --align=center --width=$((PANEL_WIDTH - 4)) \
                  --bold --foreground="$COLOR_ACCENT" "$TXT_TITLE")"
  gum style --border=rounded --border-foreground="$COLOR_ACCENT" \
            --padding="0 2" --width="$PANEL_WIDTH" \
            --margin="0 $PANEL_MARGIN" \
            "$title_block" \
            "" \
            "$status_line" \
            "$target_line" \
            "$video_line" \
            "$autostart_line"
}

show_header() {
  header_text
}

# Build a multi-line --header value combining the persistent status panel
# (TUI_HEADER, set once per interactive session) with a per-prompt label
# and a centered, muted navigation hint that replaces gum's flush-left
# default footer (which can't be indented). All three lines line up with
# the panel's left edge via PANEL_INDENT.
prompt_header() {
  local label="$1"
  local hint
  hint="$(gum style --foreground="$COLOR_MUTED" --italic "$TXT_HINT_NAV")"
  if [ -n "${TUI_HEADER:-}" ]; then
    printf '%s\n\n%s%s\n%s%s' \
      "$TUI_HEADER" \
      "$PANEL_INDENT" "$label" \
      "$PANEL_INDENT" "$hint"
  else
    printf '%s%s\n%s%s' \
      "$PANEL_INDENT" "$label" \
      "$PANEL_INDENT" "$hint"
  fi
}

# ===== selection ==============================================================

ensure_hyprland_env() {
  # The TUI can be launched from contexts whose HYPRLAND_INSTANCE_SIGNATURE
  # isn't usable. Three failure modes, all silent:
  #   1) HIS unset (fresh login shell, cron, ssh).
  #   2) HIS set but points to a dead session — the `hypr/<sig>/` directory
  #      and its socket files can linger on disk after the Hyprland process
  #      exits, so a dir-exists check is not enough.
  #   3) Walker's env retained an old HIS across a Hyprland restart.
  # `hyprctl instances` is the source of truth: it only reports live
  # instances. Always cross-check against it and rewrite HIS if ours isn't
  # in the list.
  local his="${HYPRLAND_INSTANCE_SIGNATURE:-}"
  local live
  live="$(hyprctl instances 2>/dev/null | awk '/^instance /{sub(/:$/,"",$2); print $2}')"
  if [ -z "$live" ]; then
    # No live Hyprland — nothing we can do, let the caller surface an error.
    return 0
  fi
  if [ -n "$his" ] && printf '%s\n' "$live" | grep -qxF "$his"; then
    return 0
  fi
  local sig
  sig="$(printf '%s\n' "$live" | head -n 1)"
  export HYPRLAND_INSTANCE_SIGNATURE="$sig"
  if [ -n "$his" ]; then
    log "replaced stale HYPRLAND_INSTANCE_SIGNATURE ($his → $sig)"
  else
    log "recovered HYPRLAND_INSTANCE_SIGNATURE=$sig from hyprctl instances"
  fi
}

get_monitors() {
  # hyprctl's failure modes are noisy: when HYPRLAND_INSTANCE_SIGNATURE isn't
  # set (can happen when the TUI is spawned from a launcher whose env doesn't
  # inherit the Hyprland session), hyprctl prints a plain-text error to stdout
  # and exits 0 — which then makes jq complain loudly. Validate the JSON and
  # fall back to parsing the human-readable form.
  ensure_hyprland_env
  local mon_json mon_text
  mon_json="$(hyprctl monitors -j 2>/dev/null || true)"
  if [ -n "$mon_json" ] && printf '%s' "$mon_json" | jq -e . >/dev/null 2>&1; then
    printf '%s' "$mon_json" | jq -r '.[].name'
    return 0
  fi
  mon_text="$(hyprctl monitors 2>/dev/null || true)"
  if [ -n "$mon_text" ]; then
    printf '%s\n' "$mon_text" \
      | awk '/^Monitor /{print $2; ok=1} END{exit !ok}' \
      && return 0
  fi
  log "get_monitors: hyprctl produced no usable output (HIS=${HYPRLAND_INSTANCE_SIGNATURE:-unset})"
  return 1
}

pick_target() {
  command -v hyprctl >/dev/null || { tui_err "$TXT_ERR_NO_HYPRCTL"; return 1; }
  command -v jq      >/dev/null || { tui_err "$TXT_ERR_NO_JQ";      return 1; }

  local monitors
  if ! monitors="$(get_monitors)" || [ -z "$monitors" ]; then
    if [ -z "${HYPRLAND_INSTANCE_SIGNATURE:-}" ]; then
      tui_err "$TXT_ERR_NO_HIS"
    else
      tui_err "$(printf "$TXT_ERR_HYPRCTL_FMT" "$LOG_FILE")"
    fi
    return 1
  fi

  local count
  count="$(printf '%s\n' "$monitors" | wc -l)"
  if [ "$count" -eq 1 ]; then
    printf '%s' "$monitors"
    return 0
  fi

  local selected
  center_screen
  selected=$( { echo "$TXT_BTN_ALL_MONITORS"; printf '%s\n' "$monitors"; } \
    | gum choose --header="$(prompt_header "$TXT_HDR_MONITOR")") || return 1

  if [ "$selected" = "$TXT_BTN_ALL_MONITORS" ]; then
    printf '%s' '*'
  else
    printf '%s' "$selected"
  fi
}

browse_filesystem() {
  # Custom browser built on gum choose so we can hard-confine navigation to
  # $HOME — gum file exposes a built-in "up" key we can't intercept, which
  # let users wander above $HOME by mistake. By owning the entry list, the
  # "Up one folder" item simply isn't offered at $HOME, so escape is impossible.
  # Side benefit: gum choose stays in the main screen (no alt-screen takeover),
  # so the status panel remains visible the whole way through.
  load_state
  local cur="${LAST_DIR:-}"
  if [ -z "$cur" ] && [ -n "${LAST_VIDEO:-}" ]; then
    cur="$(dirname "$LAST_VIDEO")"
  fi
  case "$cur" in
    "$HOME"|"$HOME"/*) : ;;
    *) cur="$HOME" ;;
  esac
  [ -d "$cur" ] || cur="$HOME"

  local entries name rel label choice

  while true; do
    entries=()
    [ "$cur" != "$HOME" ] && entries+=("$TXT_BTN_UP")

    # Directories first (skip hidden), then video files (skip hidden).
    while IFS= read -r -d '' name; do
      entries+=("$(basename "$name")/")
    done < <(find "$cur" -mindepth 1 -maxdepth 1 -type d ! -name '.*' \
      -print0 2>/dev/null | sort -z)

    while IFS= read -r -d '' name; do
      entries+=("$(basename "$name")")
    done < <(find "$cur" -mindepth 1 -maxdepth 1 -type f ! -name '.*' \
      \( -iname '*.mp4' -o -iname '*.mkv' -o -iname '*.webm' \
         -o -iname '*.mov' -o -iname '*.avi' \) \
      -print0 2>/dev/null | sort -z)

    if [ ${#entries[@]} -eq 0 ]; then
      gum style --margin="0 $PANEL_MARGIN" --foreground="$COLOR_ERROR" "$TXT_ERR_EMPTY_DIR"
      # Bounce back to $HOME instead of getting stuck on an empty leaf.
      # If $HOME itself is empty we'd loop forever, so bail with an error.
      if [ "$cur" = "$HOME" ]; then
        return 1
      fi
      cur="$HOME"
      continue
    fi

    rel="${cur#"$HOME"}"; [ -z "$rel" ] && rel="/"
    label="$(printf "$TXT_HDR_BROWSE_FMT" "~$rel")"

    center_screen
    choice=$(printf '%s\n' "${entries[@]}" \
      | gum choose --height=20 --header="$(prompt_header "$label")") || return 1

    case "$choice" in
      "$TXT_BTN_UP") cur="$(dirname "$cur")" ;;
      */)            cur="$cur/${choice%/}"  ;;
      *)             printf '%s' "$cur/$choice"; return 0 ;;
    esac
  done
}

pick_video() {
  local library=() basenames=() v
  if [ -d "$LIBRARY_DIR" ]; then
    while IFS= read -r -d '' f; do
      library+=("$f")
    done < <(
      find "$LIBRARY_DIR" -maxdepth 1 -type f \
        \( -iname '*.mp4' -o -iname '*.mkv' -o -iname '*.webm' -o -iname '*.mov' -o -iname '*.avi' \) \
        -print0 2>/dev/null | sort -z
    )
  fi

  if [ ${#library[@]} -eq 0 ]; then
    browse_filesystem || return 1
    return 0
  fi

  for v in "${library[@]}"; do
    basenames+=("$(basename "$v")")
  done

  local choice
  center_screen
  choice=$( { printf '%s\n' "${basenames[@]}"; echo "$TXT_BTN_BROWSE"; } \
    | gum choose --header="$(prompt_header "$(printf "$TXT_HDR_LIBRARY_FMT" "$LIBRARY_DIR")")") || return 1

  if [ "$choice" = "$TXT_BTN_BROWSE" ]; then
    browse_filesystem
  else
    printf '%s' "$LIBRARY_DIR/$choice"
  fi
}

# ===== mpvpaper control =======================================================

kill_static_wallpapers() {
  pkill -x hyprpaper 2>/dev/null || true
  pkill -x swaybg    2>/dev/null || true
}

kill_watcher() {
  pkill -f motion-wallpaper-watcher       2>/dev/null || true
  pkill -f motion-wallpaper-theme-watcher 2>/dev/null || true
}

# Locate a sibling script — first in PATH, then in this script's dir. Used
# for both watchers because launcher-spawned PATH is minimal.
locate_sibling() {
  local name="$1" path
  path="$(command -v "$name" 2>/dev/null || true)"
  if [ -z "$path" ]; then
    local self_dir
    self_dir="$(dirname "$(readlink -f "$0")")"
    if [ -x "$self_dir/$name" ]; then
      path="$self_dir/$name"
    fi
  fi
  printf '%s' "$path"
}

start_watcher() {
  local watcher theme_watcher
  watcher="$(locate_sibling motion-wallpaper-watcher)"
  theme_watcher="$(locate_sibling motion-wallpaper-theme-watcher)"

  kill_watcher

  if [ -n "$watcher" ]; then
    setsid "$watcher" < /dev/null >> "$LOG_FILE" 2>&1 &
    disown 2>/dev/null || true
    log "auto-pause watcher spawned via $watcher"
  else
    log "auto-pause watcher binary not found — auto-pause disabled"
  fi

  if [ -n "$theme_watcher" ]; then
    setsid "$theme_watcher" < /dev/null >> "$LOG_FILE" 2>&1 &
    disown 2>/dev/null || true
    log "theme watcher spawned via $theme_watcher"
  else
    log "theme watcher binary not found — theme-change auto-stop disabled"
  fi
}

restore_static_wallpaper() {
  local omarchy_bg="$HOME/.config/omarchy/current/background"
  if [ -e "$omarchy_bg" ]; then
    # Stop may be called twice in quick succession when the TUI stops the
    # wallpaper and systemd's ExecStop fires right after. Skip if someone
    # else already put swaybg back so we don't kill-and-respawn (causes a
    # visible flicker).
    if pgrep -x swaybg >/dev/null 2>&1 && ! pgrep -x mpvpaper >/dev/null 2>&1; then
      log "swaybg already running, skipping restore"
      return 0
    fi
    pkill -x hyprpaper 2>/dev/null || true
    pkill -x swaybg    2>/dev/null || true
    if command -v uwsm-app >/dev/null 2>&1; then
      setsid uwsm-app -- swaybg -i "$omarchy_bg" -m fill >/dev/null 2>&1 &
    else
      setsid swaybg -i "$omarchy_bg" -m fill >/dev/null 2>&1 &
    fi
    disown 2>/dev/null || true
    log "restored swaybg -> $omarchy_bg"
  elif command -v hyprpaper >/dev/null 2>&1; then
    hyprctl dispatch exec hyprpaper >/dev/null 2>&1 || true
    log "restored hyprpaper"
  else
    log "no known static wallpaper daemon to restore"
  fi
}

start_mpvpaper_fg() {
  local target="$1" video="$2"
  kill_static_wallpapers
  pkill -x mpvpaper 2>/dev/null || true
  sleep 0.3
  log "systemd start target=$target video=$video"
  start_watcher
  # shellcheck disable=SC2086  # intentional word-splitting on MPV_OPTS
  exec mpvpaper -o "$MPV_OPTS" "$target" "$video"
}

start_mpvpaper_bg() {
  local target="$1" video="$2"
  kill_static_wallpapers
  pkill -x mpvpaper 2>/dev/null || true
  sleep 0.3
  log "start target=$target video=$video"
  # setsid detaches from the controlling terminal so mpvpaper survives the
  # TUI terminal closing; uwsm-app parents it to the user systemd scope
  # (matches how Omarchy autostarts swaybg). Without both, mpvpaper was
  # getting SIGHUP'd when the Walker-spawned terminal exited.
  # shellcheck disable=SC2086  # intentional word-splitting on MPV_OPTS
  if command -v uwsm-app >/dev/null 2>&1; then
    setsid uwsm-app -- mpvpaper -o "$MPV_OPTS" "$target" "$video" \
      < /dev/null >> "$LOG_FILE" 2>&1 &
  else
    # shellcheck disable=SC2086
    setsid mpvpaper -o "$MPV_OPTS" "$target" "$video" \
      < /dev/null >> "$LOG_FILE" 2>&1 &
  fi
  disown 2>/dev/null || true
  start_watcher
  sleep 0.8
  if ! is_running; then
    tui_err "$(printf "$TXT_ERR_MPVP_FMT" "$LOG_FILE")"
    return 1
  fi
}

stop_mpvpaper() {
  # Serialize stops so the TUI-initiated path and systemd's ExecStop (which
  # fires when the TUI kills mpvpaper) can't both be mid-restore at once.
  # `flock -n` → second caller skips cleanly if the first still holds it.
  (
    flock -n 9 || { log "stop already in progress, skipping"; exit 0; }
    kill_watcher
    pkill -x mpvpaper 2>/dev/null || true
    # mpv cleans up its IPC socket on exit; a hard kill can leave it dangling.
    rm -f "$MPV_IPC_SOCK" 2>/dev/null || true
    restore_static_wallpaper
    log "stopped"
  ) 9>"$STATE_DIR/.stop.lock"
}

# ===== actions ================================================================

action_toggle() {
  require_gum
  require_tty

  # Render the status panel once and reuse it as the --header of every gum
  # prompt below, so it stays visible while the user makes choices in a
  # small floating window (instead of flashing past on first paint).
  TUI_HEADER="$(header_text)"

  if is_running; then
    local autostart_label
    if autostart_enabled; then
      autostart_label="$TXT_BTN_AUTOSTART_OFF"
    else
      autostart_label="$TXT_BTN_AUTOSTART_ON"
    fi
    local choice
    center_screen
    choice=$(gum choose --header="$(prompt_header "$TXT_HDR_MAIN")" \
      "$TXT_BTN_STOP" "$TXT_BTN_CHANGE" "$autostart_label" "$TXT_BTN_CANCEL") || exit 0

    case "$choice" in
      "$TXT_BTN_STOP")
        stop_mpvpaper
        tui_ok "$TXT_OK_STOPPED"
        notify "$TXT_NOTIFY_STOPPED"
        # If autostart is on, a plain stop will let the wallpaper return on
        # next reboot. Offer to turn autostart off so "stop" means "stop".
        if autostart_enabled; then
          if gum confirm "$TXT_CONFIRM_DISABLE_AUTOSTART"; then
            autostart_disable
            tui_ok "$TXT_OK_AUTOSTART_OFF"
          fi
        fi
        ;;
      "$TXT_BTN_CHANGE")
        load_state
        local video
        video=$(pick_video) || exit 0
        [ -z "$video" ]  && exit 0
        [ -f "$video" ]  || { tui_err "$(printf "$TXT_ERR_FILE_FMT" "$video")"; exit 1; }
        save_state "$video" "$LAST_TARGET"
        start_mpvpaper_bg "$LAST_TARGET" "$video" || exit 1
        tui_ok "$(printf "$TXT_OK_SWAPPED_FMT" "$(basename "$video")")"
        notify "$TXT_NOTIFY_UPDATED"
        ;;
      "$TXT_BTN_AUTOSTART_ON")
        autostart_enable && tui_ok "$TXT_OK_AUTOSTART_ON_REBOOT"
        ;;
      "$TXT_BTN_AUTOSTART_OFF")
        autostart_disable
        tui_ok "$TXT_OK_AUTOSTART_OFF"
        # Motion wallpaper is still running at this point. Offer to also stop
        # it now so the label "turn off" matches visible behaviour.
        if is_running; then
          if gum confirm "$TXT_CONFIRM_STOP_RUNNING"; then
            stop_mpvpaper
            tui_ok "$TXT_OK_STOPPED"
            notify "$TXT_NOTIFY_STOPPED"
          fi
        fi
        ;;
      "$TXT_BTN_CANCEL") exit 0 ;;
    esac
    return 0
  fi

  # Stopped state: show a gum-choose menu first instead of dumping the user
  # straight into the (alt-screen) file picker. Keeps the status panel
  # visible and lets them reuse a saved video, toggle autostart, or back out
  # without committing to a file pick.
  load_state
  local options=()
  local last_label=""
  if [ -n "${LAST_VIDEO:-}" ] && [ -f "${LAST_VIDEO:-}" ]; then
    last_label="$(printf "$TXT_BTN_START_FMT" "$(basename "$LAST_VIDEO")")"
    options+=("$last_label")
  fi
  options+=("$TXT_BTN_PICK")
  if autostart_installed; then
    if autostart_enabled; then
      options+=("$TXT_BTN_AUTOSTART_OFF")
    else
      options+=("$TXT_BTN_AUTOSTART_ON")
    fi
  fi
  options+=("$TXT_BTN_CANCEL")

  local choice
  center_screen
  choice=$(gum choose --header="$(prompt_header "$TXT_HDR_MAIN")" "${options[@]}") || exit 0

  local target video
  case "$choice" in
    "$last_label")
      [ -n "$last_label" ] || exit 0
      target=$(pick_target) || exit 0
      [ -z "$target" ] && exit 0
      save_state "$LAST_VIDEO" "$target"
      start_mpvpaper_bg "$target" "$LAST_VIDEO" || exit 1
      tui_ok "$(printf "$TXT_OK_STARTED_FMT" "$(basename "$LAST_VIDEO")" "$target")"
      notify "$(printf "$TXT_NOTIFY_STARTED_FMT" "$target")"
      ;;
    "$TXT_BTN_PICK")
      target=$(pick_target) || exit 0
      [ -z "$target" ] && exit 0
      video=$(pick_video) || exit 0
      [ -z "$video" ]  && exit 0
      [ -f "$video" ]  || { tui_err "$(printf "$TXT_ERR_FILE_FMT" "$video")"; exit 1; }
      save_state "$video" "$target"
      start_mpvpaper_bg "$target" "$video" || exit 1
      tui_ok "$(printf "$TXT_OK_STARTED_FMT" "$(basename "$video")" "$target")"
      notify "$(printf "$TXT_NOTIFY_STARTED_FMT" "$target")"
      ;;
    "$TXT_BTN_AUTOSTART_ON")
      autostart_enable && tui_ok "$TXT_OK_AUTOSTART_ON_LATER"
      return 0
      ;;
    "$TXT_BTN_AUTOSTART_OFF")
      autostart_disable
      tui_ok "$TXT_OK_AUTOSTART_OFF"
      return 0
      ;;
    "$TXT_BTN_CANCEL"|*) exit 0 ;;
  esac

  # Offer autostart on first fresh start (skipped silently if already on or
  # if the systemd unit isn't installed).
  if autostart_installed && ! autostart_enabled; then
    if gum confirm "$TXT_CONFIRM_OFFER_AUTOSTART"; then
      autostart_enable && tui_ok "$TXT_OK_AUTOSTART_ON"
    fi
  fi
}

action_change() {
  require_gum
  require_tty
  if ! is_running; then
    tui_err "$TXT_ERR_NOT_RUNNING"
    exit 1
  fi
  load_state
  TUI_HEADER="$(header_text)"
  local video
  video=$(pick_video) || exit 0
  [ -z "$video" ]  && exit 0
  [ -f "$video" ]  || { tui_err "$(printf "$TXT_ERR_FILE_FMT" "$video")"; exit 1; }
  save_state "$video" "$LAST_TARGET"
  start_mpvpaper_bg "$LAST_TARGET" "$video" || exit 1
  tui_ok "$(printf "$TXT_OK_SWAPPED_FMT" "$(basename "$video")")"
  notify "$TXT_NOTIFY_UPDATED"
}

action_start() {
  load_state
  if [ -z "$LAST_VIDEO" ] || [ -z "$LAST_TARGET" ]; then
    log "autostart: no saved state, exiting cleanly"
    exit 0
  fi
  if [ ! -f "$LAST_VIDEO" ]; then
    log "autostart: saved video missing ($LAST_VIDEO)"
    exit 1
  fi
  start_mpvpaper_fg "$LAST_TARGET" "$LAST_VIDEO"
}

action_stop() {
  stop_mpvpaper
}

action_status() {
  if command -v gum >/dev/null 2>&1 && [ -t 1 ]; then
    show_header
  else
    load_state
    if is_running; then echo "status: running"; else echo "status: stopped"; fi
    if [ -n "${LAST_TARGET:-}" ]; then echo "target: $LAST_TARGET"; fi
    if [ -n "${LAST_VIDEO:-}"  ]; then echo "video:  $LAST_VIDEO";  fi
  fi
}

# ===== main ===================================================================

case "${1:-toggle}" in
  toggle) action_toggle ;;
  start)  action_start  ;;
  stop)   action_stop   ;;
  change) action_change ;;
  status) action_status ;;
  -h|--help)
    cat <<USAGE
$APP_NAME
Usage: ${0##*/} [toggle|start|stop|change|status]

  toggle   Interactive gum TUI (default). If running, offers Stop / Change.
  start    Start from saved state without prompting (for systemd).
  stop     Stop mpvpaper and restore the normal wallpaper.
  change   Pick a new video while already running.
  status   Print current state.
USAGE
    ;;
  *)
    echo "Unknown action: $1" >&2
    echo "Try: ${0##*/} --help" >&2
    exit 1
    ;;
esac