//go:build linux

package enforce

import (
	"context"
	"fmt"

	"github.com/jezek/xgbutil"
	"github.com/jezek/xgbutil/ewmh"
	"github.com/jezek/xgbutil/icccm"
)

// NewGuard returns the real X11 window-minimize guard.
func NewGuard() Guard { return x11Guard{} }

type x11Guard struct{}

// MinimizeActive iconifies the currently-focused window by sending an ICCCM
// WM_CHANGE_STATE -> IconicState client message to the root window. It opens a
// short-lived X connection per call: enforcement fires at most once per drift
// observation (which is debounce-gated upstream), so there is no shared
// connection or event loop to manage, and nothing to race on shutdown. Any X
// failure is returned for the caller to log; the caller never blocks on it.
func (x11Guard) MinimizeActive(_ context.Context) error {
	X, err := xgbutil.NewConn()
	if err != nil {
		return fmt.Errorf("enforce: cannot connect to X server: %w", err)
	}
	defer X.Conn().Close()

	active, err := ewmh.ActiveWindowGet(X)
	if err != nil {
		return fmt.Errorf("enforce: no active window: %w", err)
	}
	if active == 0 {
		return nil // nothing focused; nothing to minimize
	}
	if err := ewmh.ClientEvent(X, active, "WM_CHANGE_STATE", icccm.StateIconic); err != nil {
		return fmt.Errorf("enforce: minimize request failed: %w", err)
	}
	return nil
}