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

ROOT=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")/.." && pwd)
BUILD_DIR=${BUILD_DIR:-"$ROOT/build"}
PACKAGE_ID=dev.emil.lumen

for command_name in busctl plasmashell nohup; do
    command -v "$command_name" >/dev/null 2>&1 || {
        printf 'Lumen activation: missing command: %s\n' "$command_name" >&2
        exit 1
    }
done
if ! busctl --user call org.kde.plasmashell /PlasmaShell \
    org.kde.PlasmaShell wallpaper u 0 >/dev/null 2>&1; then
    printf 'Lumen activation: no running Plasma session was found\n' >&2
    exit 1
fi

BACKUP_DIR="$BUILD_DIR/activation-backup-$(date +%Y%m%d-%H%M%S)-$$"
mkdir -p "$BACKUP_DIR" "$HOME/.config/plasma-workspace/env"
: > "$BACKUP_DIR/wallpaper-plugins.txt"
for ((screen = 0; ; ++screen)); do
    if ! description=$(busctl --user call org.kde.plasmashell /PlasmaShell \
        org.kde.PlasmaShell wallpaper u "$screen" 2>/dev/null); then
        break
    fi
    printf '%s\n' "$description" > "$BACKUP_DIR/wallpaper-screen-$screen.txt"
    if [[ $description =~ \"wallpaperPlugin\"\ s\ \"([^\"]+)\" ]]; then
        printf '%d %s\n' "$screen" "${BASH_REMATCH[1]}" \
            >> "$BACKUP_DIR/wallpaper-plugins.txt"
    else
        break
    fi
done
if [[ ! -s "$BACKUP_DIR/wallpaper-plugins.txt" ]]; then
    printf 'Lumen activation: could not back up the current wallpaper plugins\n' >&2
    exit 1
fi

printf '%s\n' 'export QSG_RHI_BACKEND=vulkan' \
    > "$HOME/.config/plasma-workspace/env/lumen-vulkan.sh"

busctl --user call org.kde.plasmashell /PlasmaShell org.kde.PlasmaShell evaluateScript s \
    "desktops().forEach(function(d) { d.wallpaperPlugin = '$PACKAGE_ID'; });"

QSG_RHI_BACKEND=vulkan nohup plasmashell --replace \
    > "$BACKUP_DIR/plasmashell.log" 2>&1 &
printf 'Lumen Wallpaper activated. Backup: %s\n' "$BACKUP_DIR"