package security

import (
	"os"
	"path/filepath"
	"testing"
)

func TestFlock_acquireAndRelease(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "test.lock")

	release, err := Flock(path)
	if err != nil {
		t.Fatalf("Flock: %v", err)
	}
	if _, statErr := os.Stat(path); statErr != nil {
		t.Fatalf("lock file not created: %v", statErr)
	}
	release()
}

func TestFlock_reentrantAfterRelease(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "test.lock")

	r1, err := Flock(path)
	if err != nil {
		t.Fatalf("first Flock: %v", err)
	}
	r1()

	r2, err := Flock(path)
	if err != nil {
		t.Fatalf("second Flock after release: %v", err)
	}
	r2()
}

func TestFlock_concurrentBlocks(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "test.lock")

	r1, err := Flock(path)
	if err != nil {
		t.Fatalf("first Flock: %v", err)
	}
	defer r1()

	done := make(chan error, 1)
	go func() {
		_, err := Flock(path)
		done <- err
	}()

	select {
	case <-done:
		t.Fatal("second Flock should block while first holds the lock")
	default:
	}
}