// Copyright (C) 2019 Storj Labs, Inc.
// See LICENSE for copying information.

package consoleweb

import (
	"context"
	"crypto/subtle"
	"encoding/json"
	"errors"
	"fmt"
	"html/template"
	"mime"
	"net"
	"net/http"
	"net/url"
	"os"
	"path"
	"path/filepath"
	"strconv"
	"strings"
	"time"

	"github.com/gorilla/mux"
	"github.com/graphql-go/graphql"
	"github.com/graphql-go/graphql/gqlerrors"
	"github.com/spacemonkeygo/monkit/v3"
	"github.com/zeebo/errs"
	"go.uber.org/zap"
	"golang.org/x/sync/errgroup"

	"storj.io/common/errs2"
	"storj.io/common/storj"
	"storj.io/common/uuid"
	"storj.io/storj/private/web"
	"storj.io/storj/satellite/accounting"
	"storj.io/storj/satellite/analytics"
	"storj.io/storj/satellite/console"
	"storj.io/storj/satellite/console/consoleauth"
	"storj.io/storj/satellite/console/consoleweb/consoleapi"
	"storj.io/storj/satellite/console/consoleweb/consoleql"
	"storj.io/storj/satellite/console/consoleweb/consolewebauth"
	"storj.io/storj/satellite/mailservice"
	"storj.io/storj/satellite/rewards"
)

const (
	contentType = "Content-Type"

	applicationJSON    = "application/json"
	applicationGraphql = "application/graphql"
)

var (
	// Error is satellite console error type.
	Error = errs.Class("satellite console error")

	mon = monkit.Package()
)

// Config contains configuration for console web server.
type Config struct {
	Address         string `help:"server address of the graphql api gateway and frontend app" devDefault:"" releaseDefault:":10100"`
	StaticDir       string `help:"path to static resources" default:""`
	ExternalAddress string `help:"external endpoint of the satellite if hosted" default:""`

	// TODO: remove after Vanguard release
	AuthToken       string `help:"auth token needed for access to registration token creation endpoint" default:""`
	AuthTokenSecret string `help:"secret used to sign auth tokens" releaseDefault:"" devDefault:"my-suppa-secret-key"`

	ContactInfoURL                  string `help:"url link to contacts page" default:"https://forum.storj.io"`
	FrameAncestors                  string `help:"allow domains to embed the satellite in a frame, space separated" default:"tardigrade.io storj.io"`
	LetUsKnowURL                    string `help:"url link to let us know page" default:"https://storjlabs.atlassian.net/servicedesk/customer/portals"`
	SEO                             string `help:"used to communicate with web crawlers and other web robots" default:"User-agent: *\nDisallow: \nDisallow: /cgi-bin/"`
	SatelliteName                   string `help:"used to display at web satellite console" default:"Storj"`
	SatelliteOperator               string `help:"name of organization which set up satellite" default:"Storj Labs" `
	TermsAndConditionsURL           string `help:"url link to terms and conditions page" default:"https://storj.io/storage-sla/"`
	AccountActivationRedirectURL    string `help:"url link for account activation redirect" default:""`
	VerificationPageURL             string `help:"url link to sign up verification page" devDefault:"" releaseDefault:"https://tardigrade.io/verify"`
	PartneredSatelliteNames         string `help:"names of partnered satellites" default:"US-Central-1,Europe-West-1,Asia-East-1"`
	GeneralRequestURL               string `help:"url link to general request page" default:"https://support.tardigrade.io/hc/en-us/requests/new?ticket_form_id=360000379291"`
	ProjectLimitsIncreaseRequestURL string `help:"url link to project limit increase request page" default:"https://support.tardigrade.io/hc/en-us/requests/new?ticket_form_id=360000683212"`
	GatewayCredentialsRequestURL    string `help:"url link for gateway credentials requests" default:"https://auth.us1.storjshare.io"`
	IsBetaSatellite                 bool   `help:"indicates if satellite is in beta" default:"false"`
	BetaSatelliteFeedbackURL        string `help:"url link for for beta satellite feedback" default:""`
	BetaSatelliteSupportURL         string `help:"url link for for beta satellite support" default:""`
	DocumentationURL                string `help:"url link to documentation" default:"https://docs.storj.io/"`
	CouponCodeUIEnabled             bool   `help:"indicates if user is allowed to add coupon codes to account" default:"false"`
	FileBrowserFlowDisabled         bool   `help:"indicates if file browser flow is disabled" default:"false"`
	CSPEnabled                      bool   `help:"indicates if Content Security Policy is enabled" devDefault:"false" releaseDefault:"true"`
	LinksharingURL                  string `help:"url link for linksharing requests" default:"https://link.us1.storjshare.io"`
	PathwayOverviewEnabled          bool   `help:"indicates if the overview onboarding step should render with pathways" default:"true"`

	RateLimit web.IPRateLimiterConfig

	console.Config
}

// Server represents console web server.
//
// architecture: Endpoint
type Server struct {
	log *zap.Logger

	config      Config
	service     *console.Service
	mailService *mailservice.Service
	partners    *rewards.PartnersService
	analytics   *analytics.Service

	listener    net.Listener
	server      http.Server
	cookieAuth  *consolewebauth.CookieAuth
	rateLimiter *web.IPRateLimiter
	nodeURL     storj.NodeURL

	stripePublicKey string

	schema    graphql.Schema
	templates struct {
		index               *template.Template
		notFound            *template.Template
		internalServerError *template.Template
		usageReport         *template.Template
		resetPassword       *template.Template
		success             *template.Template
		activated           *template.Template
	}
}

// NewServer creates new instance of console server.
func NewServer(logger *zap.Logger, config Config, service *console.Service, mailService *mailservice.Service, partners *rewards.PartnersService, analytics *analytics.Service, listener net.Listener, stripePublicKey string, nodeURL storj.NodeURL) *Server {
	server := Server{
		log:             logger,
		config:          config,
		listener:        listener,
		service:         service,
		mailService:     mailService,
		partners:        partners,
		analytics:       analytics,
		stripePublicKey: stripePublicKey,
		rateLimiter:     web.NewIPRateLimiter(config.RateLimit),
		nodeURL:         nodeURL,
	}

	logger.Debug("Starting Satellite UI.", zap.Stringer("Address", server.listener.Addr()))

	server.cookieAuth = consolewebauth.NewCookieAuth(consolewebauth.CookieSettings{
		Name: "_tokenKey",
		Path: "/",
	})

	if server.config.ExternalAddress != "" {
		if !strings.HasSuffix(server.config.ExternalAddress, "/") {
			server.config.ExternalAddress += "/"
		}
	} else {
		server.config.ExternalAddress = "http://" + server.listener.Addr().String() + "/"
	}

	if server.config.AccountActivationRedirectURL == "" {
		server.config.AccountActivationRedirectURL = server.config.ExternalAddress + "login?activated=true"
	}

	router := mux.NewRouter()
	fs := http.FileServer(http.Dir(server.config.StaticDir))

	router.HandleFunc("/registrationToken/", server.createRegistrationTokenHandler)
	router.HandleFunc("/populate-promotional-coupons", server.populatePromotionalCoupons).Methods(http.MethodPost)
	router.HandleFunc("/robots.txt", server.seoHandler)

	router.Handle("/api/v0/graphql", server.withAuth(http.HandlerFunc(server.graphqlHandler)))

	router.Handle(
		"/api/v0/projects/{id}/usage-limits",
		server.withAuth(http.HandlerFunc(server.projectUsageLimitsHandler)),
	).Methods(http.MethodGet)

	authController := consoleapi.NewAuth(logger, service, mailService, server.cookieAuth, partners, server.analytics, server.config.ExternalAddress, config.LetUsKnowURL, config.TermsAndConditionsURL, config.ContactInfoURL)
	authRouter := router.PathPrefix("/api/v0/auth").Subrouter()
	authRouter.Handle("/account", server.withAuth(http.HandlerFunc(authController.GetAccount))).Methods(http.MethodGet)
	authRouter.Handle("/account", server.withAuth(http.HandlerFunc(authController.UpdateAccount))).Methods(http.MethodPatch)
	authRouter.Handle("/account/change-email", server.withAuth(http.HandlerFunc(authController.ChangeEmail))).Methods(http.MethodPost)
	authRouter.Handle("/account/change-password", server.withAuth(http.HandlerFunc(authController.ChangePassword))).Methods(http.MethodPost)
	authRouter.Handle("/account/delete", server.withAuth(http.HandlerFunc(authController.DeleteAccount))).Methods(http.MethodPost)
	authRouter.HandleFunc("/logout", authController.Logout).Methods(http.MethodPost)
	authRouter.Handle("/token", server.rateLimiter.Limit(http.HandlerFunc(authController.Token))).Methods(http.MethodPost)
	authRouter.Handle("/register", server.rateLimiter.Limit(http.HandlerFunc(authController.Register))).Methods(http.MethodPost)
	authRouter.Handle("/forgot-password/{email}", server.rateLimiter.Limit(http.HandlerFunc(authController.ForgotPassword))).Methods(http.MethodPost)
	authRouter.Handle("/resend-email/{id}", server.rateLimiter.Limit(http.HandlerFunc(authController.ResendEmail))).Methods(http.MethodPost)

	paymentController := consoleapi.NewPayments(logger, service)
	paymentsRouter := router.PathPrefix("/api/v0/payments").Subrouter()
	paymentsRouter.Use(server.withAuth)
	paymentsRouter.HandleFunc("/cards", paymentController.AddCreditCard).Methods(http.MethodPost)
	paymentsRouter.HandleFunc("/cards", paymentController.MakeCreditCardDefault).Methods(http.MethodPatch)
	paymentsRouter.HandleFunc("/cards", paymentController.ListCreditCards).Methods(http.MethodGet)
	paymentsRouter.HandleFunc("/cards/{cardId}", paymentController.RemoveCreditCard).Methods(http.MethodDelete)
	paymentsRouter.HandleFunc("/account/charges", paymentController.ProjectsCharges).Methods(http.MethodGet)
	paymentsRouter.HandleFunc("/account/balance", paymentController.AccountBalance).Methods(http.MethodGet)
	paymentsRouter.HandleFunc("/account", paymentController.SetupAccount).Methods(http.MethodPost)
	paymentsRouter.HandleFunc("/billing-history", paymentController.BillingHistory).Methods(http.MethodGet)
	paymentsRouter.HandleFunc("/tokens/deposit", paymentController.TokenDeposit).Methods(http.MethodPost)
	paymentsRouter.HandleFunc("/paywall-enabled/{userId}", paymentController.PaywallEnabled).Methods(http.MethodGet)

	bucketsController := consoleapi.NewBuckets(logger, service)
	bucketsRouter := router.PathPrefix("/api/v0/buckets").Subrouter()
	bucketsRouter.Use(server.withAuth)
	bucketsRouter.HandleFunc("/bucket-names", bucketsController.AllBucketNames).Methods(http.MethodGet)

	apiKeysController := consoleapi.NewAPIKeys(logger, service)
	apiKeysRouter := router.PathPrefix("/api/v0/api-keys").Subrouter()
	apiKeysRouter.Use(server.withAuth)
	apiKeysRouter.HandleFunc("/delete-by-name", apiKeysController.DeleteByNameAndProjectID).Methods(http.MethodDelete)

	analyticsController := consoleapi.NewAnalytics(logger, service, server.analytics)
	analyticsRouter := router.PathPrefix("/api/v0/analytics").Subrouter()
	analyticsRouter.Use(server.withAuth)
	analyticsRouter.HandleFunc("/event", analyticsController.EventTriggered).Methods(http.MethodPost)

	if server.config.StaticDir != "" {
		router.HandleFunc("/activation/", server.accountActivationHandler)
		router.HandleFunc("/password-recovery/", server.passwordRecoveryHandler)
		router.HandleFunc("/cancel-password-recovery/", server.cancelPasswordRecoveryHandler)
		router.HandleFunc("/usage-report", server.bucketUsageReportHandler)
		router.PathPrefix("/static/").Handler(server.brotliMiddleware(http.StripPrefix("/static", fs)))
		router.PathPrefix("/").Handler(http.HandlerFunc(server.appHandler))
	}

	server.server = http.Server{
		Handler:        server.withRequest(router),
		MaxHeaderBytes: ContentLengthLimit.Int(),
	}

	return &server
}

// Run starts the server that host webapp and api endpoint.
func (server *Server) Run(ctx context.Context) (err error) {
	defer mon.Task()(&ctx)(&err)

	server.schema, err = consoleql.CreateSchema(server.log, server.service, server.mailService)
	if err != nil {
		return Error.Wrap(err)
	}

	err = server.initializeTemplates()
	if err != nil {
		// TODO: should it return error if some template can not be initialized or just log about it?
		return Error.Wrap(err)
	}

	ctx, cancel := context.WithCancel(ctx)
	var group errgroup.Group
	group.Go(func() error {
		<-ctx.Done()
		return server.server.Shutdown(context.Background())
	})
	group.Go(func() error {
		server.rateLimiter.Run(ctx)
		return nil
	})
	group.Go(func() error {
		defer cancel()
		err := server.server.Serve(server.listener)
		if errs2.IsCanceled(err) || errors.Is(err, http.ErrServerClosed) {
			err = nil
		}
		return err
	})

	return group.Wait()
}

// Close closes server and underlying listener.
func (server *Server) Close() error {
	return server.server.Close()
}

// appHandler is web app http handler function.
func (server *Server) appHandler(w http.ResponseWriter, r *http.Request) {
	header := w.Header()

	if server.config.CSPEnabled {
		cspValues := []string{
			"default-src 'self'",
			"connect-src 'self' api.segment.io *.tardigradeshare.io *.storjshare.io " + server.config.GatewayCredentialsRequestURL,
			"frame-ancestors " + server.config.FrameAncestors,
			"frame-src 'self' *.stripe.com",
			"img-src 'self' data: *.customer.io *.tardigradeshare.io *.storjshare.io",
			"script-src 'sha256-wAqYV6m2PHGd1WDyFBnZmSoyfCK0jxFAns0vGbdiWUA=' 'self' *.stripe.com cdn.segment.com *.customer.io",
		}

		header.Set("Content-Security-Policy", strings.Join(cspValues, "; "))
	}

	header.Set(contentType, "text/html; charset=UTF-8")
	header.Set("X-Content-Type-Options", "nosniff")
	header.Set("Referrer-Policy", "same-origin") // Only expose the referring url when navigating around the satellite itself.

	var data struct {
		ExternalAddress                 string
		SatelliteName                   string
		SatelliteNodeURL                string
		StripePublicKey                 string
		VerificationPageURL             string
		PartneredSatelliteNames         string
		DefaultProjectLimit             int
		GeneralRequestURL               string
		ProjectLimitsIncreaseRequestURL string
		GatewayCredentialsRequestURL    string
		IsBetaSatellite                 bool
		BetaSatelliteFeedbackURL        string
		BetaSatelliteSupportURL         string
		DocumentationURL                string
		CouponCodeUIEnabled             bool
		FileBrowserFlowDisabled         bool
		LinksharingURL                  string
		PathwayOverviewEnabled          bool
	}

	data.ExternalAddress = server.config.ExternalAddress
	data.SatelliteName = server.config.SatelliteName
	data.SatelliteNodeURL = server.nodeURL.String()
	data.StripePublicKey = server.stripePublicKey
	data.VerificationPageURL = server.config.VerificationPageURL
	data.PartneredSatelliteNames = server.config.PartneredSatelliteNames
	data.DefaultProjectLimit = server.config.DefaultProjectLimit
	data.GeneralRequestURL = server.config.GeneralRequestURL
	data.ProjectLimitsIncreaseRequestURL = server.config.ProjectLimitsIncreaseRequestURL
	data.GatewayCredentialsRequestURL = server.config.GatewayCredentialsRequestURL
	data.IsBetaSatellite = server.config.IsBetaSatellite
	data.BetaSatelliteFeedbackURL = server.config.BetaSatelliteFeedbackURL
	data.BetaSatelliteSupportURL = server.config.BetaSatelliteSupportURL
	data.DocumentationURL = server.config.DocumentationURL
	data.CouponCodeUIEnabled = server.config.CouponCodeUIEnabled
	data.FileBrowserFlowDisabled = server.config.FileBrowserFlowDisabled
	data.LinksharingURL = server.config.LinksharingURL
	data.PathwayOverviewEnabled = server.config.PathwayOverviewEnabled

	if server.templates.index == nil {
		server.log.Error("index template is not set")
		return
	}

	if err := server.templates.index.Execute(w, data); err != nil {
		server.log.Error("index template could not be executed", zap.Error(err))
		return
	}
}

// authMiddlewareHandler performs initial authorization before every request.
func (server *Server) withAuth(handler http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		var err error
		var ctx context.Context

		defer mon.Task()(&ctx)(&err)

		ctxWithAuth := func(ctx context.Context) context.Context {
			token, err := server.cookieAuth.GetToken(r)
			if err != nil {
				return console.WithAuthFailure(ctx, err)
			}

			ctx = consoleauth.WithAPIKey(ctx, []byte(token))

			auth, err := server.service.Authorize(ctx)
			if err != nil {
				return console.WithAuthFailure(ctx, err)
			}

			return console.WithAuth(ctx, auth)
		}

		ctx = ctxWithAuth(r.Context())

		handler.ServeHTTP(w, r.Clone(ctx))
	})
}

// withRequest ensures the http request itself is reachable from the context.
func (server *Server) withRequest(handler http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		handler.ServeHTTP(w, r.Clone(console.WithRequest(r.Context(), r)))
	})
}

// bucketUsageReportHandler generate bucket usage report page for project.
func (server *Server) bucketUsageReportHandler(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()
	var err error
	defer mon.Task()(&ctx)(&err)

	token, err := server.cookieAuth.GetToken(r)
	if err != nil {
		server.serveError(w, http.StatusUnauthorized)
		return
	}

	auth, err := server.service.Authorize(consoleauth.WithAPIKey(ctx, []byte(token)))
	if err != nil {
		server.serveError(w, http.StatusUnauthorized)
		return
	}

	ctx = console.WithAuth(ctx, auth)

	// parse query params
	projectID, err := uuid.FromString(r.URL.Query().Get("projectID"))
	if err != nil {
		server.serveError(w, http.StatusBadRequest)
		return
	}
	sinceStamp, err := strconv.ParseInt(r.URL.Query().Get("since"), 10, 64)
	if err != nil {
		server.serveError(w, http.StatusBadRequest)
		return
	}
	beforeStamp, err := strconv.ParseInt(r.URL.Query().Get("before"), 10, 64)
	if err != nil {
		server.serveError(w, http.StatusBadRequest)
		return
	}

	since := time.Unix(sinceStamp, 0).UTC()
	before := time.Unix(beforeStamp, 0).UTC()

	server.log.Debug("querying bucket usage report",
		zap.Stringer("projectID", projectID),
		zap.Stringer("since", since),
		zap.Stringer("before", before))

	bucketRollups, err := server.service.GetBucketUsageRollups(ctx, projectID, since, before)
	if err != nil {
		server.log.Error("bucket usage report error", zap.Error(err))
		server.serveError(w, http.StatusInternalServerError)
		return
	}

	if err = server.templates.usageReport.Execute(w, bucketRollups); err != nil {
		server.log.Error("bucket usage report error", zap.Error(err))
	}
}

// createRegistrationTokenHandler is web app http handler function.
func (server *Server) createRegistrationTokenHandler(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()
	defer mon.Task()(&ctx)(nil)
	w.Header().Set(contentType, applicationJSON)

	var response struct {
		Secret string `json:"secret"`
		Error  string `json:"error,omitempty"`
	}

	defer func() {
		err := json.NewEncoder(w).Encode(&response)
		if err != nil {
			server.log.Error(err.Error())
		}
	}()

	equality := subtle.ConstantTimeCompare(
		[]byte(r.Header.Get("Authorization")),
		[]byte(server.config.AuthToken),
	)
	if equality != 1 {
		w.WriteHeader(401)
		response.Error = "unauthorized"
		return
	}

	projectsLimitInput := r.URL.Query().Get("projectsLimit")

	projectsLimit, err := strconv.Atoi(projectsLimitInput)
	if err != nil {
		response.Error = err.Error()
		return
	}

	token, err := server.service.CreateRegToken(ctx, projectsLimit)
	if err != nil {
		response.Error = err.Error()
		return
	}

	response.Secret = token.Secret.String()
}

// populatePromotionalCoupons is web app http handler function for populating promotional coupons.
func (server *Server) populatePromotionalCoupons(w http.ResponseWriter, r *http.Request) {
	var err error
	var ctx context.Context

	defer mon.Task()(&ctx)(&err)

	handleError := func(status int, err error) {
		w.WriteHeader(status)
		w.Header().Set(contentType, applicationJSON)

		var response struct {
			Error string `json:"error"`
		}

		response.Error = err.Error()

		if err := json.NewEncoder(w).Encode(response); err != nil {
			server.log.Error("failed to write json error response", zap.Error(Error.Wrap(err)))
		}
	}

	ctx = r.Context()

	equality := subtle.ConstantTimeCompare(
		[]byte(r.Header.Get("Authorization")),
		[]byte(server.config.AuthToken),
	)
	if equality != 1 {
		handleError(http.StatusUnauthorized, errs.New("unauthorized"))
		return
	}

	if err = server.service.Payments().PopulatePromotionalCoupons(ctx); err != nil {
		handleError(http.StatusInternalServerError, err)
		return
	}
}

// accountActivationHandler is web app http handler function.
func (server *Server) accountActivationHandler(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()
	defer mon.Task()(&ctx)(nil)
	activationToken := r.URL.Query().Get("token")

	err := server.service.ActivateAccount(ctx, activationToken)
	if err != nil {
		server.log.Error("activation: failed to activate account",
			zap.String("token", activationToken),
			zap.Error(err))

		if console.ErrEmailUsed.Has(err) {
			server.serveError(w, http.StatusConflict)
			return
		}

		if console.Error.Has(err) {
			server.serveError(w, http.StatusInternalServerError)
			return
		}

		server.serveError(w, http.StatusNotFound)
		return
	}

	http.Redirect(w, r, server.config.AccountActivationRedirectURL, http.StatusTemporaryRedirect)
}

func (server *Server) passwordRecoveryHandler(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()
	defer mon.Task()(&ctx)(nil)

	recoveryToken := r.URL.Query().Get("token")
	if len(recoveryToken) == 0 {
		server.serveError(w, http.StatusNotFound)
		return
	}

	var data struct {
		SatelliteName string
	}

	data.SatelliteName = server.config.SatelliteName

	switch r.Method {
	case http.MethodPost:
		err := r.ParseForm()
		if err != nil {
			server.serveError(w, http.StatusNotFound)
			return
		}

		password := r.FormValue("password")
		passwordRepeat := r.FormValue("passwordRepeat")
		if strings.Compare(password, passwordRepeat) != 0 {
			server.serveError(w, http.StatusNotFound)
			return
		}

		err = server.service.ResetPassword(ctx, recoveryToken, password)
		if err != nil {
			server.serveError(w, http.StatusNotFound)
			return
		}

		if err := server.templates.success.Execute(w, data); err != nil {
			server.log.Error("success reset password template could not be executed", zap.Error(Error.Wrap(err)))
			return
		}
	case http.MethodGet:
		if err := server.templates.resetPassword.Execute(w, data); err != nil {
			server.log.Error("reset password template could not be executed", zap.Error(Error.Wrap(err)))
			return
		}
	default:
		server.serveError(w, http.StatusNotFound)
		return
	}
}

func (server *Server) cancelPasswordRecoveryHandler(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()
	defer mon.Task()(&ctx)(nil)
	recoveryToken := r.URL.Query().Get("token")

	// No need to check error as we anyway redirect user to support page
	_ = server.service.RevokeResetPasswordToken(ctx, recoveryToken)

	// TODO: Should place this link to config
	http.Redirect(w, r, "https://storjlabs.atlassian.net/servicedesk/customer/portals", http.StatusSeeOther)
}

// projectUsageLimitsHandler api handler for project usage limits.
func (server *Server) projectUsageLimitsHandler(w http.ResponseWriter, r *http.Request) {
	err := error(nil)
	ctx := r.Context()

	defer mon.Task()(&ctx)(&err)

	var ok bool
	var idParam string

	handleError := func(code int, err error) {
		w.WriteHeader(code)

		var jsonError struct {
			Error string `json:"error"`
		}

		// N.B. we are probably leaking internal details to the client
		jsonError.Error = err.Error()

		if err := json.NewEncoder(w).Encode(jsonError); err != nil {
			server.log.Error("error encoding project usage limits error", zap.Error(err))
		}
	}

	handleServiceError := func(err error) {
		switch {
		case console.ErrUnauthorized.Has(err):
			handleError(http.StatusUnauthorized, err)
		case accounting.ErrInvalidArgument.Has(err):
			handleError(http.StatusBadRequest, err)
		default:
			handleError(http.StatusInternalServerError, err)
		}
	}

	w.Header().Set("Content-Type", "application/json")

	if idParam, ok = mux.Vars(r)["id"]; !ok {
		handleError(http.StatusBadRequest, errs.New("missing project id route param"))
		return
	}

	projectID, err := uuid.FromString(idParam)
	if err != nil {
		handleError(http.StatusBadRequest, errs.New("invalid project id: %v", err))
		return
	}

	limits, err := server.service.GetProjectUsageLimits(ctx, projectID)
	if err != nil {
		handleServiceError(err)
		return
	}

	if err := json.NewEncoder(w).Encode(limits); err != nil {
		server.log.Error("error encoding project usage limits", zap.Error(err))
		return
	}
}

// graphqlHandler is graphql endpoint http handler function.
func (server *Server) graphqlHandler(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()
	defer mon.Task()(&ctx)(nil)

	handleError := func(code int, err error) {
		w.WriteHeader(code)

		var jsonError struct {
			Error string `json:"error"`
		}

		jsonError.Error = err.Error()

		if err := json.NewEncoder(w).Encode(jsonError); err != nil {
			server.log.Error("error graphql error", zap.Error(err))
		}
	}

	w.Header().Set(contentType, applicationJSON)

	query, err := getQuery(w, r)
	if err != nil {
		handleError(http.StatusBadRequest, err)
		return
	}

	rootObject := make(map[string]interface{})

	rootObject["origin"] = server.config.ExternalAddress
	rootObject[consoleql.ActivationPath] = "activation/?token="
	rootObject[consoleql.PasswordRecoveryPath] = "password-recovery/?token="
	rootObject[consoleql.CancelPasswordRecoveryPath] = "cancel-password-recovery/?token="
	rootObject[consoleql.SignInPath] = "login"
	rootObject[consoleql.LetUsKnowURL] = server.config.LetUsKnowURL
	rootObject[consoleql.ContactInfoURL] = server.config.ContactInfoURL
	rootObject[consoleql.TermsAndConditionsURL] = server.config.TermsAndConditionsURL

	result := graphql.Do(graphql.Params{
		Schema:         server.schema,
		Context:        ctx,
		RequestString:  query.Query,
		VariableValues: query.Variables,
		OperationName:  query.OperationName,
		RootObject:     rootObject,
	})

	getGqlError := func(err gqlerrors.FormattedError) error {
		if gerr, ok := err.OriginalError().(*gqlerrors.Error); ok {
			return gerr.OriginalError
		}

		return nil
	}

	parseConsoleError := func(err error) (int, error) {
		switch {
		case console.ErrUnauthorized.Has(err):
			return http.StatusUnauthorized, err
		case console.Error.Has(err):
			return http.StatusInternalServerError, err
		}

		return 0, nil
	}

	handleErrors := func(code int, errors gqlerrors.FormattedErrors) {
		w.WriteHeader(code)

		var jsonError struct {
			Errors []string `json:"errors"`
		}

		for _, err := range errors {
			jsonError.Errors = append(jsonError.Errors, err.Message)
		}

		if err := json.NewEncoder(w).Encode(jsonError); err != nil {
			server.log.Error("error graphql error", zap.Error(err))
		}
	}

	handleGraphqlErrors := func() {
		for _, err := range result.Errors {
			gqlErr := getGqlError(err)
			if gqlErr == nil {
				continue
			}

			code, err := parseConsoleError(gqlErr)
			if err != nil {
				handleError(code, err)
				return
			}
		}

		handleErrors(http.StatusOK, result.Errors)
	}

	if result.HasErrors() {
		handleGraphqlErrors()
		return
	}

	err = json.NewEncoder(w).Encode(result)
	if err != nil {
		server.log.Error("error encoding grapql result", zap.Error(err))
		return
	}

	server.log.Debug(fmt.Sprintf("%s", result))
}

// serveError serves error static pages.
func (server *Server) serveError(w http.ResponseWriter, status int) {
	w.WriteHeader(status)

	switch status {
	case http.StatusInternalServerError:
		err := server.templates.internalServerError.Execute(w, nil)
		if err != nil {
			server.log.Error("cannot parse internalServerError template", zap.Error(Error.Wrap(err)))
		}
	case http.StatusNotFound:
		err := server.templates.notFound.Execute(w, nil)
		if err != nil {
			server.log.Error("cannot parse pageNotFound template", zap.Error(Error.Wrap(err)))
		}
	case http.StatusConflict:
		err := server.templates.activated.Execute(w, nil)
		if err != nil {
			server.log.Error("cannot parse already activated template", zap.Error(Error.Wrap(err)))
		}
	}
}

// seoHandler used to communicate with web crawlers and other web robots.
func (server *Server) seoHandler(w http.ResponseWriter, req *http.Request) {
	header := w.Header()

	header.Set(contentType, mime.TypeByExtension(".txt"))
	header.Set("X-Content-Type-Options", "nosniff")

	_, err := w.Write([]byte(server.config.SEO))
	if err != nil {
		server.log.Error(err.Error())
	}
}

// brotliMiddleware is used to compress static content using brotli to minify resources if browser support such decoding.
func (server *Server) brotliMiddleware(fn http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Cache-Control", "public, max-age=31536000")
		w.Header().Set("X-Content-Type-Options", "nosniff")

		isBrotliSupported := strings.Contains(r.Header.Get("Accept-Encoding"), "br")
		if !isBrotliSupported {
			fn.ServeHTTP(w, r)
			return
		}

		info, err := os.Stat(server.config.StaticDir + strings.TrimPrefix(r.URL.Path, "/static") + ".br")
		if err != nil {
			fn.ServeHTTP(w, r)
			return
		}

		extension := filepath.Ext(info.Name()[:len(info.Name())-3])
		w.Header().Set(contentType, mime.TypeByExtension(extension))
		w.Header().Set("Content-Encoding", "br")

		newRequest := new(http.Request)
		*newRequest = *r
		newRequest.URL = new(url.URL)
		*newRequest.URL = *r.URL
		newRequest.URL.Path += ".br"

		fn.ServeHTTP(w, newRequest)
	})
}

// initializeTemplates is used to initialize all templates.
func (server *Server) initializeTemplates() (err error) {
	server.templates.index, err = template.ParseFiles(filepath.Join(server.config.StaticDir, "dist", "index.html"))
	if err != nil {
		server.log.Error("dist folder is not generated. use 'npm run build' command", zap.Error(err))
	}

	server.templates.activated, err = template.ParseFiles(filepath.Join(server.config.StaticDir, "static", "activation", "activated.html"))
	if err != nil {
		return Error.Wrap(err)
	}

	server.templates.success, err = template.ParseFiles(filepath.Join(server.config.StaticDir, "static", "resetPassword", "success.html"))
	if err != nil {
		return Error.Wrap(err)
	}

	server.templates.resetPassword, err = template.ParseFiles(filepath.Join(server.config.StaticDir, "static", "resetPassword", "resetPassword.html"))
	if err != nil {
		return Error.Wrap(err)
	}

	server.templates.usageReport, err = template.ParseFiles(path.Join(server.config.StaticDir, "static", "reports", "usageReport.html"))
	if err != nil {
		return Error.Wrap(err)
	}

	server.templates.notFound, err = template.ParseFiles(path.Join(server.config.StaticDir, "static", "errors", "404.html"))
	if err != nil {
		return Error.Wrap(err)
	}

	server.templates.internalServerError, err = template.ParseFiles(path.Join(server.config.StaticDir, "static", "errors", "500.html"))
	if err != nil {
		return Error.Wrap(err)
	}

	return nil
}