package xray

import (
	"errors"
	"os/exec"
	"sync"
	"testing"
	"time"
)

// TestProcessLifecycleFieldsRaceSafe drives the lifecycle fields (cmd, done,
// exitErr) the way Start/startCommand and the waitForCommand goroutine do, while
// the status getters read them concurrently. Run with -race: any unsynchronized
// access to those fields is reported as a data race.
func TestProcessLifecycleFieldsRaceSafe(t *testing.T) {
	p := &process{logWriter: NewLogWriter()}

	var wg sync.WaitGroup
	stop := make(chan struct{})

	// Writer: churn cmd/done/exitErr like Start + waitForCommand.
	wg.Add(1)
	go func() {
		defer wg.Done()
		for {
			select {
			case <-stop:
				return
			default:
			}
			p.mu.Lock()
			p.cmd = &exec.Cmd{}
			p.done = make(chan struct{})
			p.mu.Unlock()
			p.setExitErr(errors.New("boom"))
		}
	}()

	// Readers: the concurrent status getters.
	for i := 0; i < 4; i++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			for {
				select {
				case <-stop:
					return
				default:
				}
				_ = p.IsRunning()
				_ = p.GetErr()
				_ = p.GetResult()
			}
		}()
	}

	time.Sleep(50 * time.Millisecond)
	close(stop)
	wg.Wait()
}