package windows

import (
	"context"
	"fmt"
	"time"
)

type pidWaitHandle interface {
	Wait(time.Duration) (bool, error)
	Close() error
}

type pidOpener func(int) (pidWaitHandle, error)

func waitForProcessExit(ctx context.Context, pid int, timeout time.Duration, open pidOpener) error {
	if pid <= 0 {
		return fmt.Errorf("process PID must be positive")
	}
	if timeout <= 0 {
		return fmt.Errorf("process wait timeout must be positive")
	}
	handle, err := open(pid)
	if err != nil {
		return fmt.Errorf("open process %d: %w", pid, err)
	}
	defer handle.Close()
	deadline := time.NewTimer(timeout)
	defer deadline.Stop()
	for {
		if err := ctx.Err(); err != nil {
			return err
		}
		exited, err := handle.Wait(250 * time.Millisecond)
		if err != nil {
			return fmt.Errorf("wait for process %d: %w", pid, err)
		}
		if exited {
			return nil
		}
		select {
		case <-ctx.Done():
			return ctx.Err()
		case <-deadline.C:
			return context.DeadlineExceeded
		default:
		}
	}
}