//go:build !js

package portforward

import (
	"context"
	"net"
	"testing"
	"time"

	"github.com/libp2p/go-nat"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

type mockNAT struct {
	natType          string
	deviceAddr       net.IP
	externalAddr     net.IP
	internalAddr     net.IP
	mappings         map[int]int
	addMappingErr    error
	deleteMappingErr error
}

func newMockNAT() *mockNAT {
	return &mockNAT{
		natType:      "Mock-NAT",
		deviceAddr:   net.ParseIP("192.168.1.1"),
		externalAddr: net.ParseIP("203.0.113.50"),
		internalAddr: net.ParseIP("192.168.1.100"),
		mappings:     make(map[int]int),
	}
}

func (m *mockNAT) Type() string {
	return m.natType
}

func (m *mockNAT) GetDeviceAddress() (net.IP, error) {
	return m.deviceAddr, nil
}

func (m *mockNAT) GetExternalAddress() (net.IP, error) {
	return m.externalAddr, nil
}

func (m *mockNAT) GetInternalAddress() (net.IP, error) {
	return m.internalAddr, nil
}

func (m *mockNAT) AddPortMapping(ctx context.Context, protocol string, internalPort int, description string, timeout time.Duration) (int, error) {
	if m.addMappingErr != nil {
		return 0, m.addMappingErr
	}
	externalPort := internalPort
	m.mappings[internalPort] = externalPort
	return externalPort, nil
}

func (m *mockNAT) DeletePortMapping(ctx context.Context, protocol string, internalPort int) error {
	if m.deleteMappingErr != nil {
		return m.deleteMappingErr
	}
	delete(m.mappings, internalPort)
	return nil
}

func TestManager_CreateMapping(t *testing.T) {
	m := NewManager()
	m.wgPort = 51820

	gateway := newMockNAT()
	mapping, err := m.createMapping(context.Background(), gateway)
	require.NoError(t, err)
	require.NotNil(t, mapping)

	assert.Equal(t, "udp", mapping.Protocol)
	assert.Equal(t, uint16(51820), mapping.InternalPort)
	assert.Equal(t, uint16(51820), mapping.ExternalPort)
	assert.Equal(t, "Mock-NAT", mapping.NATType)
	assert.Equal(t, net.ParseIP("203.0.113.50").To4(), mapping.ExternalIP.To4())
}

func TestManager_GetMapping_ReturnsNilWhenNotReady(t *testing.T) {
	m := NewManager()
	assert.Nil(t, m.GetMapping())
}

func TestManager_GetMapping_ReturnsCopy(t *testing.T) {
	m := NewManager()
	m.mapping = &Mapping{
		Protocol:     "udp",
		InternalPort: 51820,
		ExternalPort: 51820,
	}

	mapping := m.GetMapping()
	require.NotNil(t, mapping)
	assert.Equal(t, uint16(51820), mapping.InternalPort)

	// Mutating the returned copy should not affect the manager's mapping.
	mapping.ExternalPort = 9999
	assert.Equal(t, uint16(51820), m.GetMapping().ExternalPort)
}

func TestManager_Cleanup_DeletesMapping(t *testing.T) {
	m := NewManager()
	m.mapping = &Mapping{
		Protocol:     "udp",
		InternalPort: 51820,
		ExternalPort: 51820,
	}

	gateway := newMockNAT()
	// Seed the mock so we can verify deletion.
	gateway.mappings[51820] = 51820

	m.cleanup(context.Background(), gateway)

	_, exists := gateway.mappings[51820]
	assert.False(t, exists, "mapping should be deleted from gateway")
	assert.Nil(t, m.GetMapping(), "in-memory mapping should be cleared")
}

func TestManager_Cleanup_NilMapping(t *testing.T) {
	m := NewManager()
	gateway := newMockNAT()

	// Should not panic or call gateway.
	m.cleanup(context.Background(), gateway)
}

func TestState_Cleanup(t *testing.T) {
	origDiscover := discoverGateway
	defer func() { discoverGateway = origDiscover }()

	mockGateway := newMockNAT()
	mockGateway.mappings[51820] = 51820
	discoverGateway = func(ctx context.Context) (nat.NAT, error) {
		return mockGateway, nil
	}

	state := &State{
		Protocol:     "udp",
		InternalPort: 51820,
	}

	err := state.Cleanup()
	assert.NoError(t, err)

	_, exists := mockGateway.mappings[51820]
	assert.False(t, exists, "mapping should be deleted after cleanup")
}

func TestState_Name(t *testing.T) {
	state := &State{}
	assert.Equal(t, "port_forward_state", state.Name())
}