package stacks

import (
	"io"
	"log"
	"testing"
	"time"

	"gitea.dooplex.hu/admin/felhom-controller/internal/config"
)

// TestEnsureBaseStackSingleFlight proves the single-flight guard short-circuits: when infraMu is
// already held, EnsureBaseStack returns immediately (nil) WITHOUT touching docker. We hold the lock
// in this goroutine and call EnsureBaseStack in the same goroutine — Go mutexes are non-reentrant, so
// TryLock fails and the function returns before any docker network/inspect call. If the guard were
// missing, the call would shell out to docker (unavailable in unit tests) and not return nil cleanly.
func TestEnsureBaseStackSingleFlight(t *testing.T) {
	m := &Manager{
		cfg:    &config.Config{},
		logger: log.New(io.Discard, "", 0),
	}
	m.infraMu.Lock()
	defer m.infraMu.Unlock()

	done := make(chan error, 1)
	go func() { done <- m.EnsureBaseStack() }()

	select {
	case err := <-done:
		if err != nil {
			t.Fatalf("expected nil (single-flight no-op) while lock held, got %v", err)
		}
	case <-time.After(3 * time.Second):
		t.Fatal("EnsureBaseStack did not short-circuit while infraMu was held (single-flight guard missing?)")
	}
}