package scheduler_test

import (
	"testing"

	"github.com/jfraeys/fetch_ml/internal/scheduler"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func TestPortAllocator_BasicAllocation(t *testing.T) {
	pa := scheduler.NewPortAllocator(10000, 10010)

	// Allocate first port
	port1, err := pa.Allocate("service-1")
	require.NoError(t, err)
	assert.Equal(t, 10000, port1)

	// Allocate second port
	port2, err := pa.Allocate("service-2")
	require.NoError(t, err)
	assert.Equal(t, 10001, port2)
}

func TestPortAllocator_Exhaustion(t *testing.T) {
	pa := scheduler.NewPortAllocator(10000, 10002) // Only 3 ports available

	// Allocate all ports
	port1, _ := pa.Allocate("service-1")
	assert.Equal(t, 10000, port1)

	port2, _ := pa.Allocate("service-2")
	assert.Equal(t, 10001, port2)

	port3, _ := pa.Allocate("service-3")
	assert.Equal(t, 10002, port3)

	// Should fail - no ports left
	_, err := pa.Allocate("service-4")
	assert.Error(t, err)
}

func TestPortAllocator_Release(t *testing.T) {
	pa := scheduler.NewPortAllocator(10000, 10005)

	// Allocate and release
	port, _ := pa.Allocate("service-1")
	assert.Equal(t, 10000, port)

	pa.Release(port)

	// Should be able to allocate again
	port2, err := pa.Allocate("service-2")
	require.NoError(t, err)
	assert.Equal(t, 10000, port2) // Reuses released port
}

func TestPortAllocator_DuplicateServiceID(t *testing.T) {
	pa := scheduler.NewPortAllocator(10000, 10010)

	// Allocate for service
	port1, err := pa.Allocate("service-1")
	require.NoError(t, err)

	// Allocate again with same service ID - gets new port (current behavior)
	port2, err := pa.Allocate("service-1")
	require.NoError(t, err)
	assert.NotEqual(t, port1, port2) // Each call returns new port
}

func TestPortAllocator_ConcurrentAccess(t *testing.T) {
	pa := scheduler.NewPortAllocator(10000, 10100) // 101 ports
	done := make(chan bool, 10)

	// Concurrent allocations
	for i := 0; i < 10; i++ {
		go func(id int) {
			for j := 0; j < 10; j++ {
				pa.Allocate("service-")
			}
			done <- true
		}(i)
	}

	for i := 0; i < 10; i++ {
		<-done
	}

	// All 100 ports should be allocated
	// (10 goroutines * 10 allocations, but only 100 unique service IDs)
}