package usecase_helpers

import (
	"fmt"
	"net/http"
	"strings"

	"github.com/fiskerinc/cloud-services/pkg/common"
	"github.com/fiskerinc/cloud-services/pkg/common/carupdatestatus"
	"github.com/fiskerinc/cloud-services/pkg/db/queries"
	e "github.com/fiskerinc/cloud-services/pkg/errors"
	"github.com/fiskerinc/cloud-services/pkg/grpc/kafka_grpc"
	"github.com/fiskerinc/cloud-services/pkg/kafka"
	"github.com/pkg/errors"
	"google.golang.org/protobuf/proto"
)

type UpdateNotifierInterface interface {
	Send(vins []string, manifest common.UpdateManifest, username string) ([]common.CarUpdate, error)
}

func NewUpdateNotifier(
	cu queries.CarUpdatesInterface,
	pr kafka.ProducerInterface,
) UpdateNotifierInterface {
	return &updateNotifier{
		carUpdates: cu,
		producer:   pr,
	}
}

type updateNotifier struct {
	carUpdates    queries.CarUpdatesInterface
	producer      kafka.ProducerInterface
	targetService string
}

// Expect only ota or another service that actually sends the update to the car to call this
func (un *updateNotifier) Send(vins []string, manifest common.UpdateManifest, username string) ([]common.CarUpdate, error) {
	carUpdateList := make([]common.CarUpdate, len(vins))

	pendingVins := make([]string, 0)

	for _, vin := range vins {
		pending, err := un.carUpdates.HasPendingUpdates(manifest.ID, vin)
		if err != nil {
			return nil, err
		}

		if pending {
			pendingVins = append(pendingVins, vin)
		}
	}

	if len(pendingVins) > 0 {
		err := e.NewCustomError(fmt.Sprintf("pending update exists for %s", strings.Join(pendingVins, ", ")), http.StatusForbidden)
		return carUpdateList, errors.WithStack(err)
	}

	// For each car, we create a new car_update entry, and then try to send the manifest to the car
	for i, vin := range vins {
		carUpdate, err := un.insertCarUpdate(un.carUpdates, manifest.ID, vin, username)
		if err != nil {
			return carUpdateList, err
		}

		err = un.sendManifest(vin, username, carUpdate.ID)
		if err != nil {
			un.cancel(un.carUpdates, carUpdate.ID, vin, "Failed to queue message to Kafka, error: "+err.Error())
			return carUpdateList, err
		}

		carUpdateList[i] = carUpdate
	}

	return carUpdateList, nil
}

func (un *updateNotifier) sendManifest(vin string, username string, carUpdateID int64) error {

	data := &kafka_grpc.GRPC_AttendantPayload_UpdateManifest{
		UpdateManifest: &kafka_grpc.UpdateManifest{
			CarUpdateId: carUpdateID,
		},
	}
	kafkaMSG := kafka_grpc.GRPC_AttendantPayload{
		Handler: "send_manifest",
		Data:    data,
	}

	binaryPayload, _ := proto.Marshal(&kafkaMSG)
	return un.producer.ProduceBinary(kafka.AttendantServiceGRPCKafka, common.Service.Key(vin), binaryPayload, map[string][]byte{
		"id": []byte(username),
	})
}

func (un *updateNotifier) insertCarUpdate(db queries.CarUpdatesInterface, manifestID int64, vin string, username string) (common.CarUpdate, error) {
	up := common.CarUpdate{
		UpdateManifestID: manifestID,
		VIN:              vin,
		Status:           "pending",
		Username:         username,
		UpdateSource:     common.UPDATE_SOURCE_OTA,
	}
	_, err := db.Insert(&up)
	if err != nil {
		return up, err
	}

	_, err = db.LogStatus(&up)
	return up, err
}

func (un *updateNotifier) cancel(db queries.CarUpdatesInterface, updateID int64, vin string, info string) {
	up := common.CarUpdate{
		ID:     updateID,
		Status: carupdatestatus.ManifestCanceled,
		Info:   info,
	}
	db.UpdateStatus(&up)
}

type JSONCarUpdatesRequest struct {
	UpdateManifestID int64    `json:"manifest_id" validate:"required"`
	VINs             []string `json:"vins" validate:"required,gte=1,lte=1000,dive,vin"`
}

type JSONOneCarUpdatesRequest struct {
	UpdateManifestID int64  `json:"manifest_id" validate:"required"`
	VIN              string `json:"vin" validate:"required,vin"`
}

type JSONFleetUpdatesRequest struct {
	UpdateManifestID int64    `json:"manifest_id" validate:"required"`
	FleetNames       []string `json:"fleet_names" validate:"required,gte=1,lte=1000,dive,fleet"`
}