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

# Global (not per-monitor) wallpaper per workspace 1..9 for Hyprland + wpaperd (wpaperctl v1.2.1)
#
# Expected images:
#   ~/nixos_conf/wallpaperstuff/pictures/wallpaper{1..9}.jpg
#
# What it does:
# - Maintains a single symlink:
#     ~/nixos_conf/wallpaperstuff/current/workspace.jpg
# - Writes/ensures wpaperd config:
#     ~/.config/wpaperd/config.toml
#   with:
#     [default] mode = "stretch"
#     [any] path = "<symlink>"
# - On workspace change, updates symlink and runs:
#     wpaperctl reload-wallpaper
#
# Notes:
# - This is intentionally NOT per-monitor. If you have 2 monitors on different workspaces at once,
#   the wallpaper will follow the *currently active/focused workspace*.

log() { echo "[wpaperd-ws] $*" >&2; }

PICTURES_DIR="${HOME}/nixos_conf/wallpaperstuff/pictures"
STATE_DIR="${HOME}/nixos_conf/wallpaperstuff/current"
SYMLINK="${STATE_DIR}/workspace.jpg"

XDG_CONFIG_HOME="${XDG_CONFIG_HOME:-$HOME/.config}"
WPAPERD_DIR="${XDG_CONFIG_HOME}/wpaperd"
CONF="${WPAPERD_DIR}/config.toml"

: "${XDG_RUNTIME_DIR:?XDG_RUNTIME_DIR not set}"
: "${HYPRLAND_INSTANCE_SIGNATURE:?HYPRLAND_INSTANCE_SIGNATURE not set}"
SOCK="${XDG_RUNTIME_DIR}/hypr/${HYPRLAND_INSTANCE_SIGNATURE}/.socket2.sock"

mkdir -p "$STATE_DIR" "$WPAPERD_DIR"

# Wait for Hyprland socket so we don't exit too early
for i in $(seq 1 120); do
  [[ -S "$SOCK" ]] && break
  sleep 0.1
done
[[ -S "$SOCK" ]] || { log "Hyprland socket not found: $SOCK"; exit 1; }

ws_num() {
  # workspace name might be "8" or "8:foo"
  local w="${1%%:*}"
  [[ "$w" =~ ^[0-9]+$ ]] || return 1
  printf '%s\n' "$w"
}

img_for_ws() {
  local n="$1"
  case "$n" in
    1|2|3|4|5|6|7|8|9) printf '%s/wallpaper%s.jpg\n' "$PICTURES_DIR" "$n" ;;
    *) return 1 ;;
  esac
}

ensure_config() {
  # Keep it simple and stable: always ensure config points [any] to the symlink.
  # wpaperd reads this path by default.
  cat >"$CONF" <<EOF
[default]
mode = "stretch"

[any]
path = "$SYMLINK"
EOF
}

reload_wallpaper() {
  # wpaperctl v1.2.1 supports reload-wallpaper
  wpaperctl reload-wallpaper >/dev/null 2>&1 || true
}

apply_workspace() {
  local ws_raw="$1"
  local n img

  n="$(ws_num "$ws_raw")" || { log "Ignoring non-numeric workspace: $ws_raw"; return 0; }
  img="$(img_for_ws "$n")" || return 0

  if [[ ! -f "$img" ]]; then
    log "Missing image for ws=$n: $img"
    return 0
  fi

  # If already set, skip work
  if [[ -L "$SYMLINK" ]] && [[ "$(readlink -f "$SYMLINK")" == "$(readlink -f "$img")" ]]; then
    return 0
  fi

  ln -sf "$img" "$SYMLINK"
  log "Workspace $n -> $img"
  ensure_config
  reload_wallpaper
}

apply_initial() {
  # Use focused monitor's active workspace as "current workspace" for the global wallpaper.
  # This keeps behavior consistent with "per workspace (focused)".
  local ws
  ws="$(hyprctl -j monitors | jq -r '.[] | select(.focused==true) | .activeWorkspace.name' | head -n1)"
  if [[ -n "$ws" && "$ws" != "null" ]]; then
    apply_workspace "$ws"
  else
    log "Could not determine initial focused workspace"
  fi
}

handle_line() {
  case "$1" in
    # workspace>>NAME
    workspace\>\>*)
      apply_workspace "${1#workspace>>}"
      ;;

    # workspacev2>>ID,NAME
    workspacev2\>\>*)
      local payload="${1#workspacev2>>}"
      apply_workspace "${payload#*,}"
      ;;

    # focusedmon>>MON,WORKSPACE (also catches some focus-driven changes)
    focusedmon\>\>*)
      local payload="${1#focusedmon>>}"
      local ws="${payload#*,}"
      apply_workspace "$ws"
      ;;
  esac
}

ensure_config
apply_initial

log "Listening on $SOCK"
exec socat -U - "UNIX-CONNECT:$SOCK" \
  | while IFS= read -r line; do
      handle_line "$line" || true
    done