package xorg

import (
	"context"
	"fmt"
	"time"

	"github.com/jezek/xgb"
	"k8s.io/apimachinery/pkg/util/wait"

	"edge-infra.dev/pkg/sds/display/displaymanager/waiter"
	"edge-infra.dev/pkg/sds/lib/xorg/xrandr"
)

const tick = time.Second

// Returns a DisplayWaiter which waits for Xorg to be ready.
//
// The Xorg waiter will always wait for the specified minimum wait time
// and will exit with error if the timeout is reached.
func NewXorgDisplayWaiter(r xrandr.Xrandr, minWaitTime, timeout time.Duration) waiter.DisplayWaiter {
	return &displayWaiter{
		Xrandr:      r,
		minWaitTime: minWaitTime,
		timeout:     timeout,
	}
}

type displayWaiter struct {
	xrandr.Xrandr

	minWaitTime time.Duration
	timeout     time.Duration
}

func (x *displayWaiter) Wait(ctx context.Context) error {
	// wait for successful connection to X
	if err := waitForXgbConnection(ctx, x.timeout); err != nil {
		return fmt.Errorf("unable to connect to X: %w", err)
	}

	return x.Xrandr.WaitUntilReady(x.minWaitTime, x.timeout)
}

type ConditionWithContextFunc func(context.Context) (done bool, err error)

func waitForXgbConnection(ctx context.Context, timeout time.Duration) error {
	return wait.PollUntilContextTimeout(ctx, tick, timeout, true, func(_ context.Context) (bool, error) {
		_, err := xgb.NewConn()
		return err == nil, err
	})
}