package option

import (
	"context"
	"testing"

	C "github.com/sagernet/sing-box/constant"
	"github.com/sagernet/sing/common/json"
	"github.com/sagernet/sing/service"
	"github.com/stretchr/testify/require"
)

type stubDNSTransportOptionsRegistry struct{}

func (stubDNSTransportOptionsRegistry) CreateOptions(transportType string) (any, bool) {
	switch transportType {
	case C.DNSTypeUDP:
		return new(RemoteDNSServerOptions), true
	case C.DNSTypeFakeIP:
		return new(FakeIPDNSServerOptions), true
	default:
		return nil, false
	}
}

func TestDNSOptionsRejectsLegacyFakeIPOptions(t *testing.T) {
	t.Parallel()

	ctx := service.ContextWith[DNSTransportOptionsRegistry](context.Background(), stubDNSTransportOptionsRegistry{})
	var options DNSOptions
	err := json.UnmarshalContext(ctx, []byte(`{
		"fakeip": {
			"enabled": true,
			"inet4_range": "198.18.0.0/15"
		}
	}`), &options)
	require.EqualError(t, err, legacyDNSFakeIPRemovedMessage)
}

func TestDNSServerOptionsRejectsLegacyFormats(t *testing.T) {
	t.Parallel()

	ctx := service.ContextWith[DNSTransportOptionsRegistry](context.Background(), stubDNSTransportOptionsRegistry{})
	testCases := []string{
		`{"address":"1.1.1.1"}`,
		`{"type":"legacy","address":"1.1.1.1"}`,
	}
	for _, content := range testCases {
		var options DNSServerOptions
		err := json.UnmarshalContext(ctx, []byte(content), &options)
		require.EqualError(t, err, legacyDNSServerRemovedMessage)
	}
}

func TestDNSOptionsAcceptsTypedServers(t *testing.T) {
	t.Parallel()

	ctx := service.ContextWith[DNSTransportOptionsRegistry](context.Background(), stubDNSTransportOptionsRegistry{})
	var options DNSOptions
	err := json.UnmarshalContext(ctx, []byte(`{
		"servers": [
			{"type": "udp", "tag": "default", "server": "1.1.1.1"},
			{"type": "fakeip", "tag": "fake", "inet4_range": "198.18.0.0/15"}
		]
	}`), &options)
	require.NoError(t, err)
	require.Len(t, options.Servers, 2)
	require.Equal(t, C.DNSTypeUDP, options.Servers[0].Type)
	require.Equal(t, "1.1.1.1", options.Servers[0].Options.(*RemoteDNSServerOptions).Server)
	require.Equal(t, C.DNSTypeFakeIP, options.Servers[1].Type)
}