package nfs

import (
	"sync"
	"testing"

	"github.com/darroyo/nasctl/internal/system"
)

func TestUniqueFSIDNoCollision(t *testing.T) {
	const goroutines = 100
	results := make(chan uint32, goroutines)
	var wg sync.WaitGroup

	for i := 0; i < goroutines; i++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			n, err := system.GenerateRandomFSID()
			if err != nil {
				t.Errorf("generateRandomFSID failed: %v", err)
				return
			}
			results <- n
		}()
	}

	wg.Wait()
	close(results)

	seen := make(map[uint32]struct{})
	for n := range results {
		if _, dup := seen[n]; dup {
			t.Errorf("duplicate fsid generated: %d", n)
		}
		seen[n] = struct{}{}
	}
}

func TestUniqueFSIDWithUsedSet(t *testing.T) {
	used := map[uint32]struct{}{
		1: {}, 2: {}, 3: {},
	}

	for i := 0; i < 50; i++ {
		n, err := UniqueFSID(used)
		if err != nil {
			t.Fatalf("UniqueFSID failed at iteration %d: %v", i, err)
		}
		if n == 0 {
			t.Fatalf("fsid 0 is reserved")
		}
		if _, dup := used[n]; dup {
			t.Fatalf("returned duplicate fsid: %d", n)
		}
		used[n] = struct{}{}
	}
}