#!/usr/bin/env bash

BG_DIR_PATH="$HOME/Pictures/wallpapers/Linux-Dynamic-Wallpapers/"
PICK_CMD="shuf -n 1"

if pgrep -x "Hyprland" >/dev/null; then
    CURRENT_WALL=$(hyprctl hyprpaper listloaded)
    WALLPAPER=$(fd --type file --exclude "$(basename "$CURRENT_WALL")" . "$BG_DIR_PATH" | $PICK_CMD)
    hyprctl hyprpaper reload ,"$WALLPAPER"
elif pgrep -x "niri" >/dev/null; then
    # Read script flags
    FLAG_NOTIFY=false
    FLAG_DELAY=false
    while [[ $# -gt 0 ]]; do
        case "$1" in
        -n | --notify) FLAG_NOTIFY=true ;;
        -d | --delay) FLAG_DELAY=true ;;
        *) echo "Unknown option: $1" ;;
        esac
        shift
    done

    # Choose most-recent accessed file by default or least-recent to cycle
    BG_SELECT_PATH=$(fd --type file . "$BG_DIR_PATH" | $PICK_CMD)

    # Notify if needed
    if $FLAG_NOTIFY; then
        notify-send "Wallpaper Changed" $(basename "$BG_SELECT_PATH")
    fi

    # Get previous swaybg so we can stop it once we start a new instance
    PREV_SWAYBG_PID=$(pidof swaybg)

    # Update access on selected file, for cycling
    touch -ac $BG_SELECT_PATH
    swaybg -i "$BG_SELECT_PATH" &

    # Wait a bit and then stop prior swaybg instances (if present)
    # -> Delay because it can take a moment for new bg to load
    # -> If user spams this script, we can end up creating many instances of sway because of this delay!
    #    The kill command will clean them all up, but it's a bit messy
    if $FLAG_DELAY; then
        sleep 0.5
    fi

    # Close all prior swaybg instances (would be 'behind' current wallpaper)
    if [[ -n "$PREV_SWAYBG_PID" ]]; then
        kill $PREV_SWAYBG_PID
    fi
else
    notify-send --urgency critical --icon dialog-error "Wallpaper Script Error" "No compatible window manager found (Hyprland or Niri required)"
fi