package query

import (
	"context"
	"net/http"
	"strconv"

	"github.com/grafana/grafana-plugin-sdk-go/backend"
	"github.com/grafana/grafana/pkg/expr"
	"go.opentelemetry.io/otel/attribute"
	"go.opentelemetry.io/otel/codes"
	errorsK8s "k8s.io/apimachinery/pkg/api/errors"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/runtime/schema"
	"k8s.io/apiserver/pkg/endpoints/request"
	"k8s.io/apiserver/pkg/registry/rest"

	query "github.com/grafana/grafana/pkg/apis/query/v0alpha1"
	"github.com/grafana/grafana/pkg/infra/log"
	service "github.com/grafana/grafana/pkg/services/query"
	"github.com/grafana/grafana/pkg/web"
)

type sqlSchemaREST struct {
	logger  log.Logger
	builder *QueryAPIBuilder
}

var (
	_ rest.Storage              = (*sqlSchemaREST)(nil)
	_ rest.SingularNameProvider = (*sqlSchemaREST)(nil)
	_ rest.Connecter            = (*sqlSchemaREST)(nil)
	_ rest.Scoper               = (*sqlSchemaREST)(nil)
	_ rest.StorageMetadata      = (*sqlSchemaREST)(nil)
)

func newSQLSchemasREST(builder *QueryAPIBuilder) *sqlSchemaREST {
	return &sqlSchemaREST{
		logger:  log.New("query.sqlschemas"),
		builder: builder,
	}
}

func (r *sqlSchemaREST) New() runtime.Object {
	// This is added as the "ResponseType" regardless what ProducesObject() says :)
	return &query.SQLSchemas{}
}

func (r *sqlSchemaREST) Destroy() {}

func (r *sqlSchemaREST) NamespaceScoped() bool {
	return true
}

func (r *sqlSchemaREST) GetSingularName() string {
	return "SQLSchema" // Used for the
}

func (r *sqlSchemaREST) ProducesMIMETypes(verb string) []string {
	return []string{"application/json"} // and parquet!
}

func (r *sqlSchemaREST) ProducesObject(verb string) interface{} {
	return &query.SQLSchemas{}
}

func (r *sqlSchemaREST) ConnectMethods() []string {
	return []string{"POST"}
}

func (r *sqlSchemaREST) NewConnectOptions() (runtime.Object, bool, string) {
	return nil, false, "" // true means you can use the trailing path as a variable
}

// called by mt query service and also when queryServiceFromUI is enabled, can be both mt and st
func (r *sqlSchemaREST) Connect(connectCtx context.Context, name string, _ runtime.Object, incomingResponder rest.Responder) (http.Handler, error) {
	// See: /pkg/services/apiserver/builder/helper.go#L34
	// The name is set with a rewriter hack
	if name != "name" {
		r.logger.Debug("Connect name is not name")
		return nil, errorsK8s.NewNotFound(schema.GroupResource{}, name)
	}
	b := r.builder

	return http.HandlerFunc(func(w http.ResponseWriter, httpreq *http.Request) {
		ctx, span := b.tracer.Start(httpreq.Context(), "QueryService.GetSQLSchemas")
		defer span.End()
		ctx = request.WithNamespace(ctx, request.NamespaceValue(connectCtx))
		traceId := span.SpanContext().TraceID()
		connectLogger := b.log.New("traceId", traceId.String(), "rule_uid", httpreq.Header.Get("X-Rule-Uid"))
		responder := newResponderWrapper(incomingResponder,
			func(statusCode *int, obj runtime.Object) {
				if *statusCode/100 == 4 {
					span.SetStatus(codes.Error, strconv.Itoa(*statusCode))
				}

				if *statusCode >= 500 {
					o, ok := obj.(*query.QueryDataResponse)
					if ok && o.Responses != nil {
						for refId, response := range o.Responses {
							if response.ErrorSource == backend.ErrorSourceDownstream {
								*statusCode = http.StatusBadRequest //force this to be a 400 since it's downstream
								span.SetStatus(codes.Error, strconv.Itoa(*statusCode))
								span.SetAttributes(attribute.String("error.source", "downstream"))
								break
							} else if response.Error != nil {
								connectLogger.Debug("500 error without downstream error source", "error", response.Error, "errorSource", response.ErrorSource, "refId", refId)
								span.SetStatus(codes.Error, "500 error without downstream error source")
							} else {
								span.SetStatus(codes.Error, "500 error without downstream error source and no Error message")
								span.SetAttributes(attribute.String("error.ref_id", refId))
							}
						}
					}
				}
			},

			func(err error) {
				connectLogger.Error("error caught in handler", "err", err)
				span.SetStatus(codes.Error, "query error")

				if err == nil {
					return
				}

				span.RecordError(err)
			})

		raw := &query.QueryDataRequest{}
		err := web.Bind(httpreq, raw)
		if err != nil {
			connectLogger.Error("Hit unexpected error when reading query", "err", err)
			err = errorsK8s.NewBadRequest("error reading query")
			responder.Error(err)
			return
		}

		qdr, err := handleSQLSchemaQuery(ctx, *raw, *b, httpreq, *responder, connectLogger)
		if err != nil {
			responder.Error(err)
			return
		}

		responder.Object(200, &query.SQLSchemas{
			SQLSchemas: qdr,
		})
	}), nil
}

func handlePreparedSQLSchema(ctx context.Context, pq *preparedQuery) (expr.SQLSchemas, error) {
	resp, err := service.GetSQLSchemas(ctx, pq.logger, pq.cache, pq.exprSvc, pq.mReq, pq.builder, pq.headers)
	pq.reportMetrics()
	return resp, err
}

func handleSQLSchemaQuery(
	ctx context.Context,
	raw query.QueryDataRequest,
	b QueryAPIBuilder,
	httpreq *http.Request,
	responder responderWrapper,
	connectLogger log.Logger,
) (expr.SQLSchemas, error) {
	pq, err := prepareQuery(ctx, raw, b, httpreq, connectLogger)
	if err != nil {
		responder.Error(err)
		return nil, err
	}
	return handlePreparedSQLSchema(ctx, pq)
}