#!/usr/bin/env bash
# description: Launch/list/activate applications via D-Bus and KService. Args: <list|launch|activate> [app_name_or_desktop_file]
set -euo pipefail

cmd="${1:-list}"

case "$cmd" in
    list)
        # List running applications via KWin
        if command -v wmctrl &>/dev/null; then
            echo "CLASS	TITLE"
            wmctrl -l -x | while read -r wid desktop class host title; do
                echo "$class	$title"
            done
        elif command -v xdotool &>/dev/null; then
            echo "WID	NAME"
            xdotool search --onlyvisible --name '' 2>/dev/null | while read -r wid; do
                name=$(xdotool getwindowname "$wid" 2>/dev/null || echo '?')
                echo "$wid	$name"
            done
        else
            # D-Bus fallback: list org.freedesktop.DBus registered names
            echo "ERROR: install wmctrl or xdotool for window listing" >&2
            exit 1
        fi
        ;;
    launch)
        app="${2:?usage: gui_apps launch <app_name_or_desktop_file>}"

        # Try gtk-launch first (handles .desktop files)
        if command -v gtk-launch &>/dev/null; then
            gtk-launch "$app" 2>/dev/null && { echo "launched: $app"; exit 0; }
        fi

        # Try kioclient
        if command -v kioclient5 &>/dev/null || command -v kioclient &>/dev/null; then
            kio=$(command -v kioclient5 || command -v kioclient)
            "$kio" exec "applications:$app.desktop" 2>/dev/null && { echo "launched: $app"; exit 0; }
        fi

        # Try gio
        if command -v gio &>/dev/null; then
            # Find .desktop file
            desktop_file=$(find /usr/share/applications ~/.local/share/applications \
                -name "*${app}*.desktop" 2>/dev/null | head -1)
            if [ -n "$desktop_file" ]; then
                gio launch "$desktop_file" && { echo "launched: $app"; exit 0; }
            fi
        fi

        # Try D-Bus activation
        gdbus call --session \
            --dest org.freedesktop.DBus \
            --object-path /org/freedesktop/DBus \
            --method org.freedesktop.DBus.StartServiceByName \
            "$app" 0 2>/dev/null && { echo "activated: $app"; exit 0; }

        # Last resort: just exec it
        if command -v "$app" &>/dev/null; then
            setsid "$app" &>/dev/null &
            echo "launched: $app (pid $!)"
        else
            echo "ERROR: cannot find or launch '$app'" >&2
            exit 1
        fi
        ;;
    activate)
        app="${2:?usage: gui_apps activate <title_or_class>}"
        # Focus existing window
        if command -v wmctrl &>/dev/null; then
            # Try by class first
            wid=$(wmctrl -l -x | grep -i "$app" | head -1 | awk '{print $1}')
            if [ -n "$wid" ]; then
                wmctrl -i -a "$wid"
                echo "activated: $wid"
                exit 0
            fi
        fi
        if command -v xdotool &>/dev/null; then
            wid=$(xdotool search --name "$app" 2>/dev/null | head -1)
            if [ -n "$wid" ]; then
                xdotool windowactivate "$wid"
                echo "activated: $wid"
                exit 0
            fi
        fi
        echo "ERROR: no window matching '$app'" >&2
        exit 1
        ;;
    installed)
        # List installed .desktop files
        find /usr/share/applications ~/.local/share/applications \
            -name '*.desktop' 2>/dev/null | \
            xargs grep -l '^Name=' | \
            while read -r f; do
                name=$(grep '^Name=' "$f" | head -1 | cut -d= -f2)
                echo "$(basename "$f" .desktop)	$name"
            done | sort
        ;;
    *)
        echo "usage: gui_apps <list|launch|activate|installed> [app]" >&2
        exit 1
        ;;
esac