package api

import (
	"context"
	"fmt"
	"go.opentelemetry.io/otel"
	"go.opentelemetry.io/otel/trace"
	"strings"

	"google.golang.org/protobuf/proto"

	auditV1 "dev.azure.com/schwarzit/schwarzit.stackit-public/audit-go.git/gen/go/audit/v1"

	"github.com/bufbuild/protovalidate-go"
)

// MockAuditApi is an implementation of AuditApi that does nothing and has no dependency to external systems.
type MockAuditApi struct {
	tracer    trace.Tracer
	validator ProtobufValidator
}

func NewMockAuditApi() (AuditApi, error) {
	validator, err := protovalidate.New()
	if err != nil {
		return nil, err
	}
	var protobufValidator ProtobufValidator = validator
	var auditApi AuditApi = &MockAuditApi{
		tracer:    otel.Tracer("mock-audit-api"),
		validator: protobufValidator,
	}
	return auditApi, nil
}

// Log implements AuditApi.Log.
// Validates and serializes the event but doesn't send it.
func (a *MockAuditApi) Log(
	ctx context.Context,
	event *auditV1.AuditLogEntry,
	visibility auditV1.Visibility,
	routableIdentifier *RoutableIdentifier,
) error {

	_, err := a.ValidateAndSerialize(ctx, event, visibility, routableIdentifier)
	return err
}

// ValidateAndSerialize implements AuditApi.ValidateAndSerialize
func (a *MockAuditApi) ValidateAndSerialize(
	ctx context.Context,
	event *auditV1.AuditLogEntry,
	visibility auditV1.Visibility,
	routableIdentifier *RoutableIdentifier,
) (*CloudEvent, error) {

	ctx, span := a.tracer.Start(ctx, "validate-and-serialize")
	defer span.End()

	routableEvent, err := validateAndSerializePartially(a.validator, event, visibility, routableIdentifier)
	if err != nil {
		return nil, err
	}

	// Reject event type data-access as the downstream services
	// cannot handle it at the moment
	if strings.HasSuffix(event.LogName, string(EventTypeDataAccess)) {
		return nil, ErrUnsupportedEventTypeDataAccess
	}

	routableEventBytes, err := proto.Marshal(routableEvent)
	if err != nil {
		return nil, err
	}

	traceParent, traceState := TraceParentAndStateFromContext(ctx)

	message := CloudEvent{
		SpecVersion:     "1.0",
		Source:          event.ProtoPayload.ServiceName,
		Id:              event.InsertId,
		Time:            event.ProtoPayload.RequestMetadata.RequestAttributes.Time.AsTime(),
		DataContentType: "application/cloudevents+protobuf",
		DataType:        fmt.Sprintf("%v", routableEvent.ProtoReflect().Descriptor().FullName()),
		Subject:         event.ProtoPayload.ResourceName,
		Data:            routableEventBytes,
		TraceParent:     &traceParent,
		TraceState:      &traceState,
	}

	return &message, nil
}

// Send implements AuditApi.Send
func (a *MockAuditApi) Send(context.Context, *RoutableIdentifier, *CloudEvent) error {
	return nil
}