#!/usr/bin/env sh
# Switch the COSMIC desktop between light and dark mode, and optionally the
# wallpaper with it: set SYSTEM_THEME_WALLPAPER_DARK and
# SYSTEM_THEME_WALLPAPER_LIGHT to image files, in the environment or in
# ~/.config/system-theme/config. Emacs's auto-dark follows the desktop's mode
# on its own. On another desktop, this is the file to rewrite.

CONFIG="${XDG_CONFIG_HOME:-$HOME/.config}"
COSMIC="$CONFIG/cosmic"
# shellcheck source=/dev/null
[ -f "$CONFIG/system-theme/config" ] && . "$CONFIG/system-theme/config"

set_wallpaper() {
    [ -n "$1" ] || return 0
    wallpaper="$(realpath "$1")" || return 1
    sed -i 's|^.*source: Path(".*"),$|    source: Path("'"$wallpaper"'"),|' \
        "$COSMIC/com.system76.CosmicBackground/v1/all"
}

case "$1" in
  dark)
    echo "true" > "$COSMIC/com.system76.CosmicTheme.Mode/v1/is_dark"
    set_wallpaper "${SYSTEM_THEME_WALLPAPER_DARK:-}"
    ;;
  light)
    echo "false" > "$COSMIC/com.system76.CosmicTheme.Mode/v1/is_dark"
    set_wallpaper "${SYSTEM_THEME_WALLPAPER_LIGHT:-}"
    ;;
  *)
    echo "usage: system-theme dark|light" >&2
    exit 1
    ;;
esac