#!/bin/bash
set -e

# Sets the specified image as the current background.
# Updates state.json so the choice survives the next rebuild — without
# that write, themes/engine/files.nix re-resolves the wallpaper from
# `nomarchy.wallpaper` on the next home-manager switch and silently
# falls back to the active theme's default background, undoing the
# user's pick.

if [[ -z $1 ]]; then
  echo "Usage: nomarchy-theme-bg-set <path-to-image>" >&2
  exit 1
fi

BACKGROUND="$1"

if [[ ! -f "$BACKGROUND" ]]; then
  echo "Background image not found: $BACKGROUND" >&2
  exit 1
fi

STATE_DIR="$HOME/.config/nomarchy"
STATE_FILE="$STATE_DIR/state.json"
CURRENT_BACKGROUND_LINK="$STATE_DIR/current/background"

mkdir -p "$STATE_DIR"
[[ ! -f $STATE_FILE ]] && echo "{}" > "$STATE_FILE"

# Persist the choice for the next rebuild.
TMP_JSON=$(mktemp)
jq --arg wp "$BACKGROUND" '.wallpaper = $wp' "$STATE_FILE" > "$TMP_JSON" && mv "$TMP_JSON" "$STATE_FILE"

# Create symlink to the new background
ln -nsf "$BACKGROUND" "$CURRENT_BACKGROUND_LINK"

# Kill existing swaybg and start new one
pkill -x swaybg
setsid uwsm-app -- swaybg -i "$CURRENT_BACKGROUND_LINK" -m fill >/dev/null 2>&1 &