package integration

import (
	"reflect"
	"testing"
	"time"

	"github.com/pmezard/go-difflib/difflib"
	"github.com/stretchr/testify/assert"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
	"google.golang.org/protobuf/encoding/protojson"
	"google.golang.org/protobuf/proto"
	"google.golang.org/protobuf/types/known/timestamppb"

	resources_object "github.com/zitadel/zitadel/pkg/grpc/resources/object/v3alpha"
)

// Details is the interface that covers both v1 and v2 proto generated object details.
type Details interface {
	comparable
	GetSequence() uint64
	GetChangeDate() *timestamppb.Timestamp
	GetResourceOwner() string
}

// DetailsMsg is the interface that covers all proto messages which contain v1 or v2 object details.
type DetailsMsg[D Details] interface {
	GetDetails() D
}

type ListDetails interface {
	comparable
	GetTotalResult() uint64
	GetTimestamp() *timestamppb.Timestamp
}

type ListDetailsMsg[L ListDetails] interface {
	GetDetails() L
}

type ResourceListDetailsMsg interface {
	GetDetails() *resources_object.ListDetails
}

// AssertDetails asserts values in a message's object Details,
// if the object Details in expected is a non-nil value.
// It targets API v2 messages that have the `GetDetails()` method.
//
// Dynamically generated values are not compared with expected.
// Instead a sanity check is performed.
// For the sequence a non-zero value is expected.
// If the change date is populated, it is checked with a tolerance of 1 minute around Now.
//
// The resource owner is compared with expected.
func AssertDetails[D Details, M DetailsMsg[D]](t assert.TestingT, expected, actual M) {
	wantDetails, gotDetails := expected.GetDetails(), actual.GetDetails()
	var nilDetails D
	if wantDetails == nilDetails {
		assert.Nil(t, gotDetails)
		return
	}

	assert.NotZero(t, gotDetails.GetSequence())

	if wantDetails.GetChangeDate() != nil {
		wantChangeDate := time.Now()
		gotChangeDate := gotDetails.GetChangeDate().AsTime()
		assert.WithinRange(t, gotChangeDate, wantChangeDate.Add(-time.Minute), wantChangeDate.Add(time.Minute))
	}

	assert.Equal(t, wantDetails.GetResourceOwner(), gotDetails.GetResourceOwner())
}

func AssertResourceDetails(t assert.TestingT, expected *resources_object.Details, actual *resources_object.Details) {
	if expected.GetChanged() != nil {
		wantChangeDate := time.Now()
		gotChangeDate := actual.GetChanged().AsTime()
		assert.WithinRange(t, gotChangeDate, wantChangeDate.Add(-time.Minute), wantChangeDate.Add(time.Minute))
	}
	if expected.GetCreated() != nil {
		wantCreatedDate := time.Now()
		gotCreatedDate := actual.GetCreated().AsTime()
		assert.WithinRange(t, gotCreatedDate, wantCreatedDate.Add(-time.Minute), wantCreatedDate.Add(time.Minute))
	}
	if expected.GetOwner() != nil {
		expectedOwner := expected.GetOwner()
		actualOwner := actual.GetOwner()
		if !assert.NotNil(t, actualOwner) {
			return
		}
		assert.Equal(t, expectedOwner.GetId(), actualOwner.GetId())
		assert.Equal(t, expectedOwner.GetType(), actualOwner.GetType())
	}
	assert.NotEmpty(t, actual.GetId())
	if expected.GetId() != "" {
		assert.Equal(t, expected.GetId(), actual.GetId())
	}
}

func AssertListDetails[L ListDetails, D ListDetailsMsg[L]](t assert.TestingT, expected, actual D) {
	wantDetails, gotDetails := expected.GetDetails(), actual.GetDetails()
	var nilDetails L
	if wantDetails == nilDetails {
		assert.Nil(t, gotDetails)
		return
	}
	assert.Equal(t, wantDetails.GetTotalResult(), gotDetails.GetTotalResult())

	if wantDetails.GetTimestamp() != nil {
		gotCD := gotDetails.GetTimestamp().AsTime()
		wantCD := time.Now()
		assert.WithinRange(t, gotCD, wantCD.Add(-10*time.Minute), wantCD.Add(time.Minute))
	}
}

func AssertResourceListDetails[D ResourceListDetailsMsg](t assert.TestingT, expected, actual D) {
	wantDetails, gotDetails := expected.GetDetails(), actual.GetDetails()
	if wantDetails == nil {
		assert.Nil(t, gotDetails)
		return
	}

	assert.Equal(t, wantDetails.GetTotalResult(), gotDetails.GetTotalResult())
	assert.Equal(t, wantDetails.GetAppliedLimit(), gotDetails.GetAppliedLimit())

	if wantDetails.GetTimestamp() != nil {
		gotCD := gotDetails.GetTimestamp().AsTime()
		wantCD := time.Now()
		assert.WithinRange(t, gotCD, wantCD.Add(-10*time.Minute), wantCD.Add(time.Minute))
	}
}

func AssertGrpcStatus(t assert.TestingT, expected codes.Code, err error) {
	assert.Error(t, err)
	statusErr, ok := status.FromError(err)
	assert.True(t, ok)
	assert.Equal(t, expected, statusErr.Code())
}

// EqualProto is inspired by [assert.Equal], only that it tests equality of a proto message.
// A message diff is printed on the error test log if the messages are not equal.
//
// As [assert.Equal] is based on reflection, comparing 2 proto messages sometimes fails,
// due to their internal state.
// Expected messages are usually with a vanilla state, eg only exported fields contain data.
// Actual messages obtained from the gRPC client had unexported fields with data.
// This makes them hard to compare.
func EqualProto(t testing.TB, expected, actual proto.Message) bool {
	t.Helper()
	if proto.Equal(expected, actual) {
		return true
	}
	t.Errorf("Proto messages not equal: %s", diffProto(expected, actual))
	return false
}

func diffProto(expected, actual proto.Message) string {
	diff, err := difflib.GetUnifiedDiffString(difflib.UnifiedDiff{
		A:        difflib.SplitLines(protojson.Format(expected)),
		B:        difflib.SplitLines(protojson.Format(actual)),
		FromFile: "Expected",
		FromDate: "",
		ToFile:   "Actual",
		ToDate:   "",
		Context:  1,
	})
	if err != nil {
		panic(err)
	}
	return "\n\nDiff:\n" + diff
}

func AssertMapContains[M ~map[K]V, K comparable, V any](t *testing.T, m M, key K, expectedValue V) {
	val, exists := m[key]
	assert.True(t, exists, "Key '%s' should exist in the map", key)
	assert.Equal(t, expectedValue, val, "Key '%s' should have value '%d'", key, expectedValue)
}

// PartiallyDeepEqual is similar to reflect.DeepEqual,
// but only compares exported non-zero fields of the expectedValue
func PartiallyDeepEqual(expected, actual interface{}) bool {
	if expected == nil {
		return actual == nil
	}

	if actual == nil {
		return false
	}

	return partiallyDeepEqual(reflect.ValueOf(expected), reflect.ValueOf(actual))
}

func partiallyDeepEqual(expected, actual reflect.Value) bool {
	// Dereference pointers if needed
	if expected.Kind() == reflect.Ptr {
		if expected.IsNil() {
			return actual.IsNil()
		}

		expected = expected.Elem()
	}

	if actual.Kind() == reflect.Ptr {
		if actual.IsNil() {
			return false
		}

		actual = actual.Elem()
	}

	if expected.Type() != actual.Type() {
		return false
	}

	switch expected.Kind() { //nolint:exhaustive
	case reflect.Struct:
		for i := 0; i < expected.NumField(); i++ {
			field := expected.Type().Field(i)
			if field.PkgPath != "" { // Skip unexported fields
				continue
			}

			expectedField := expected.Field(i)
			actualField := actual.Field(i)

			// Skip zero-value fields in expected
			if reflect.DeepEqual(expectedField.Interface(), reflect.Zero(expectedField.Type()).Interface()) {
				continue
			}

			// Compare fields recursively
			if !partiallyDeepEqual(expectedField, actualField) {
				return false
			}
		}
		return true

	case reflect.Slice, reflect.Array:
		if expected.Len() > actual.Len() {
			return false
		}

		for i := 0; i < expected.Len(); i++ {
			if !partiallyDeepEqual(expected.Index(i), actual.Index(i)) {
				return false
			}
		}

		return true

	default:
		// Compare primitive types
		return reflect.DeepEqual(expected.Interface(), actual.Interface())
	}
}

func Must[T any](result T, error error) T {
	if error != nil {
		panic(error)
	}

	return result
}