package handlers

import (
	"net/http"

	"otaupdate/services"

	"github.com/fiskerinc/cloud-services/pkg/common"
	"github.com/fiskerinc/cloud-services/pkg/db/queries"
	"github.com/fiskerinc/cloud-services/pkg/httphandlers"
	uhelpers "github.com/fiskerinc/cloud-services/pkg/usecase_helpers"
	"github.com/fiskerinc/cloud-services/pkg/utils"
	"github.com/fiskerinc/cloud-services/pkg/loggerdataresp"
)

// HandleFleetUpdatesAdd godoc
// @Summary Add car updates by fleet
// @Description Create car updates assigning update package to cars, and send notifications
// @Accept  json
// @Produce  json
// @Param Authorization header string false "Bearer <ID token>"
// @Param Api-Key header string false "<API token>"
// @Param data body usecase_helpers.JSONFleetUpdatesRequest true "Update manifest or package id and, car ids"
// @Success 200 {object} common.JSONDBQueryResult "Created car updates result"
// @Failure 400 {object} common.JSONError "Bad request"
// @Failure 401 {object} common.JSONError "Unauthorized"
// @Failure 503 {object} common.JSONError "Service unavailable"
// @Router /fleetupdate [post]
func HandleFleetUpdatesAdd(w http.ResponseWriter, r *http.Request) {
	var req uhelpers.JSONFleetUpdatesRequest

	err := httphandlers.ParseRequest(r, &req)
	if loggerdataresp.BadDataErrorResp(w, err, http.StatusBadRequest) {
		return
	}

	manifest, err := getManifest(req.UpdateManifestID)
	if loggerdataresp.BadDataErrorResp(w, err, http.StatusServiceUnavailable, loggerdataresp.PostgresNoRowsErrorCheck) {
		return
	}

	username := httphandlers.GetClientID(r)

	err = sendManifestToFleets(req.FleetNames, manifest, username)
	if loggerdataresp.BadDataErrorResp(w, err, http.StatusServiceUnavailable) {
		return
	}

	utils.RespJSON(w, http.StatusOK, common.JSONDBQueryResult{
		Data: req.FleetNames,
	})
}

func sendManifestToFleets(fleetNames []string, manifest common.UpdateManifest, username string) error {
	var resultNames []string
	resC := make(chan string, len(fleetNames))
	// to avoid goroutines leak, we add buffer to the errC channel
	errC := make(chan error, len(fleetNames))

	for _, name := range fleetNames {
		go updateFleet(name, manifest, username, errC, resC)
	}

	for {
		select {
		case err := <-errC:
			return err
		case name := <-resC:
			resultNames = append(resultNames, name)
			if len(resultNames) == len(fleetNames) {
				return nil
			}
		}
	}
}

func updateFleet(name string, manifest common.UpdateManifest, username string, errC chan<- error, resC chan<- string) {
	client, err := services.GetMongoClient()
	if err != nil {
		errC <- err
		return
	}

	vins, err := client.GetFleets().GetVehiclesForFleet(name, "", &queries.PageQueryOptions{})
	if err != nil {
		errC <- err
		return
	}

	d := services.GetDB().GetCarUpdates()
	k := services.GetKafkaProducer()
	notifier := uhelpers.NewUpdateNotifier(d, k)
	_, err = notifier.Send(vins, manifest, username)
	if err != nil {
		errC <- err
		return
	}

	resC <- name
}