package agent

import (
	"testing"
)

func TestPortAllocator_Allocate(t *testing.T) {
	pa := NewPortAllocator()

	port, err := pa.Allocate()
	if err != nil {
		t.Fatalf("allocate: %v", err)
	}
	if port < portRangeMin || port >= portRangeMax {
		t.Fatalf("port %d out of range [%d, %d)", port, portRangeMin, portRangeMax)
	}
}

func TestPortAllocator_NoDuplicates(t *testing.T) {
	pa := NewPortAllocator()

	ports := make(map[int]bool)
	for range 20 {
		port, err := pa.Allocate()
		if err != nil {
			t.Fatalf("allocate: %v", err)
		}
		if ports[port] {
			t.Fatalf("duplicate port allocated: %d", port)
		}
		ports[port] = true
	}
}

func TestPortAllocator_Release(t *testing.T) {
	pa := NewPortAllocator()

	port, err := pa.Allocate()
	if err != nil {
		t.Fatalf("allocate: %v", err)
	}

	pa.Release(port)

	// After release, the port should no longer be tracked as allocated.
	pa.mu.Lock()
	if pa.allocated[port] {
		t.Fatal("port should not be tracked after release")
	}
	pa.mu.Unlock()
}

func TestPortAllocator_PortIsFree(t *testing.T) {
	pa := NewPortAllocator()

	port, err := pa.Allocate()
	if err != nil {
		t.Fatalf("allocate: %v", err)
	}

	// The port should be free (we only track it, we don't hold the listener).
	if !isPortFree(port) {
		t.Fatalf("allocated port %d should be free on the system", port)
	}
}