register.go

package donor

import (
	"context"
	"encoding/base64"
	"fmt"
	"io"
	"net/http"
	"strings"
	"time"

	"github.com/gorilla/sessions"
	"github.com/ministryofjustice/opg-go-common/template"
	"github.com/ministryofjustice/opg-modernising-lpa/internal/actor"
	"github.com/ministryofjustice/opg-modernising-lpa/internal/date"
	"github.com/ministryofjustice/opg-modernising-lpa/internal/event"
	"github.com/ministryofjustice/opg-modernising-lpa/internal/identity"
	"github.com/ministryofjustice/opg-modernising-lpa/internal/notify"
	"github.com/ministryofjustice/opg-modernising-lpa/internal/onelogin"
	"github.com/ministryofjustice/opg-modernising-lpa/internal/page"
	"github.com/ministryofjustice/opg-modernising-lpa/internal/pay"
	"github.com/ministryofjustice/opg-modernising-lpa/internal/place"
	"github.com/ministryofjustice/opg-modernising-lpa/internal/random"
	"github.com/ministryofjustice/opg-modernising-lpa/internal/sesh"
	"github.com/ministryofjustice/opg-modernising-lpa/internal/uid"
)

type Handler func(data page.AppData, w http.ResponseWriter, r *http.Request, donor *actor.DonorProvidedDetails) error

type Template func(io.Writer, interface{}) error

type Logger interface {
	Print(v ...interface{})
}

type DonorStore interface {
	Get(context.Context) (*actor.DonorProvidedDetails, error)
	Latest(context.Context) (*actor.DonorProvidedDetails, error)
	Put(context.Context, *actor.DonorProvidedDetails) error
	Delete(context.Context) error
}

type GetDonorStore interface {
	Get(context.Context) (*actor.DonorProvidedDetails, error)
}

type CertificateProviderStore interface {
	GetAny(ctx context.Context) (*actor.CertificateProviderProvidedDetails, error)
}

type AttorneyStore interface {
	GetAny(ctx context.Context) ([]*actor.AttorneyProvidedDetails, error)
}

type EvidenceReceivedStore interface {
	Get(context.Context) (bool, error)
}

type S3Client interface {
	PutObject(context.Context, string, []byte) error
	DeleteObject(context.Context, string) error
}

type PayClient interface {
	CreatePayment(context.Context, pay.CreatePaymentBody) (pay.CreatePaymentResponse, error)
	GetPayment(context.Context, string) (pay.GetPaymentResponse, error)
}

type AddressClient interface {
	LookupPostcode(ctx context.Context, postcode string) ([]place.Address, error)
}

type ShareCodeSender interface {
	SendCertificateProviderInvite(context.Context, page.AppData, *actor.DonorProvidedDetails) error
	SendCertificateProviderPrompt(context.Context, page.AppData, *actor.DonorProvidedDetails) error
}

type OneLoginClient interface {
	AuthCodeURL(state, nonce, locale string, identity bool) (string, error)
	Exchange(ctx context.Context, code, nonce string) (idToken, accessToken string, err error)
	UserInfo(ctx context.Context, accessToken string) (onelogin.UserInfo, error)
	ParseIdentityClaim(ctx context.Context, userInfo onelogin.UserInfo) (identity.UserData, error)
}

type NotifyClient interface {
	SendSMS(context.Context, string, notify.SMS) (string, error)
}

type SessionStore interface {
	Get(r *http.Request, name string) (*sessions.Session, error)
	New(r *http.Request, name string) (*sessions.Session, error)
	Save(r *http.Request, w http.ResponseWriter, s *sessions.Session) error
}

type WitnessCodeSender interface {
	SendToCertificateProvider(context.Context, *actor.DonorProvidedDetails, page.Localizer) error
	SendToIndependentWitness(context.Context, *actor.DonorProvidedDetails, page.Localizer) error
}

type UidClient interface {
	CreateCase(context.Context, *uid.CreateCaseRequestBody) (uid.CreateCaseResponse, error)
}

type RequestSigner interface {
	Sign(context.Context, *http.Request, string) error
}

type Payer interface {
	Pay(page.AppData, http.ResponseWriter, *http.Request, *actor.DonorProvidedDetails) error
}

type Localizer interface {
	Format(string, map[string]any) string
	T(string) string
	Count(messageID string, count int) string
	FormatCount(messageID string, count int, data map[string]interface{}) string
	ShowTranslationKeys() bool
	SetShowTranslationKeys(s bool)
	Possessive(s string) string
	Concat([]string, string) string
	FormatDate(date.TimeOrDate) string
	FormatDateTime(time.Time) string
}

type DocumentStore interface {
	GetAll(context.Context) (page.Documents, error)
	Put(context.Context, page.Document) error
	Delete(context.Context, page.Document) error
	DeleteInfectedDocuments(context.Context, page.Documents) error
	Create(context.Context, *actor.DonorProvidedDetails, string, []byte) (page.Document, error)
	Submit(context.Context, *actor.DonorProvidedDetails, page.Documents) error
}

type EventClient interface {
	SendReducedFeeRequested(context.Context, event.ReducedFeeRequested) error
}

type DashboardStore interface {
	GetAll(ctx context.Context) (donor, attorney, certificateProvider []page.LpaAndActorTasks, err error)
	SubExistsForActorType(ctx context.Context, sub string, actorType actor.Type) (bool, error)
}

type LpaStoreClient interface {
	SendLpa(context.Context, *actor.DonorProvidedDetails) error
}

type ErrorHandler func(http.ResponseWriter, *http.Request, error)

func Register(
	rootMux *http.ServeMux,
	logger Logger,
	tmpls template.Templates,
	sessionStore SessionStore,
	donorStore DonorStore,
	oneLoginClient OneLoginClient,
	addressClient AddressClient,
	appPublicURL string,
	payClient PayClient,
	shareCodeSender ShareCodeSender,
	witnessCodeSender WitnessCodeSender,
	errorHandler page.ErrorHandler,
	notFoundHandler page.Handler,
	certificateProviderStore CertificateProviderStore,
	attorneyStore AttorneyStore,
	notifyClient NotifyClient,
	evidenceReceivedStore EvidenceReceivedStore,
	documentStore DocumentStore,
	eventClient EventClient,
	dashboardStore DashboardStore,
	lpaStoreClient LpaStoreClient,
) {
	payer := &payHelper{
		logger:       logger,
		sessionStore: sessionStore,
		donorStore:   donorStore,
		payClient:    payClient,
		randomString: random.String,
	}

	handleRoot := makeHandle(rootMux, sessionStore, page.None, errorHandler, appPublicURL)

	handleRoot(page.Paths.Login, page.None,
		page.Login(oneLoginClient, sessionStore, random.String, page.Paths.LoginCallback))
	handleRoot(page.Paths.LoginCallback, page.None,
		page.LoginCallback(oneLoginClient, sessionStore, page.Paths.Dashboard, dashboardStore, actor.TypeDonor))

	lpaMux := http.NewServeMux()
	rootMux.Handle("/lpa/", page.RouteToPrefix("/lpa/", lpaMux, notFoundHandler))

	handleDonor := makeHandle(lpaMux, sessionStore, page.RequireSession, errorHandler, appPublicURL)
	handleWithDonor := makeLpaHandle(lpaMux, sessionStore, page.RequireSession, errorHandler, donorStore, appPublicURL)

	handleDonor(page.Paths.Root, page.None, notFoundHandler)

	handleWithDonor(page.Paths.DeleteThisLpa, page.None,
		DeleteLpa(tmpls.Get("delete_this_lpa.gohtml"), donorStore))
	handleWithDonor(page.Paths.WithdrawThisLpa, page.None,
		WithdrawLpa(tmpls.Get("withdraw_this_lpa.gohtml"), donorStore, time.Now))

	handleWithDonor(page.Paths.YourDetails, page.None,
		YourDetails(tmpls.Get("your_details.gohtml"), donorStore, sessionStore))
	handleWithDonor(page.Paths.YourAddress, page.None,
		YourAddress(logger, tmpls.Get("your_address.gohtml"), addressClient, donorStore))
	handleWithDonor(page.Paths.YourPreferredLanguage, page.None,
		YourPreferredLanguage(tmpls.Get("your_preferred_language.gohtml"), donorStore))
	handleWithDonor(page.Paths.LpaType, page.None,
		LpaType(tmpls.Get("lpa_type.gohtml"), donorStore))
	handleWithDonor(page.Paths.CheckYouCanSign, page.None,
		CheckYouCanSign(tmpls.Get("check_you_can_sign.gohtml"), donorStore))
	handleWithDonor(page.Paths.NeedHelpSigningConfirmation, page.None,
		Guidance(tmpls.Get("need_help_signing_confirmation.gohtml")))

	handleWithDonor(page.Paths.TaskList, page.None,
		TaskList(tmpls.Get("task_list.gohtml"), evidenceReceivedStore))

	handleWithDonor(page.Paths.ChooseAttorneysGuidance, page.None,
		Guidance(tmpls.Get("choose_attorneys_guidance.gohtml")))
	handleWithDonor(page.Paths.ChooseAttorneys, page.CanGoBack,
		ChooseAttorneys(tmpls.Get("choose_attorneys.gohtml"), donorStore, random.UuidString))
	handleWithDonor(page.Paths.ChooseAttorneysAddress, page.CanGoBack,
		ChooseAttorneysAddress(logger, tmpls.Get("choose_address.gohtml"), addressClient, donorStore))
	handleWithDonor(page.Paths.EnterTrustCorporation, page.CanGoBack,
		EnterTrustCorporation(tmpls.Get("enter_trust_corporation.gohtml"), donorStore))
	handleWithDonor(page.Paths.EnterTrustCorporationAddress, page.CanGoBack,
		EnterTrustCorporationAddress(logger, tmpls.Get("choose_address.gohtml"), addressClient, donorStore))
	handleWithDonor(page.Paths.ChooseAttorneysSummary, page.CanGoBack,
		ChooseAttorneysSummary(tmpls.Get("choose_attorneys_summary.gohtml")))
	handleWithDonor(page.Paths.RemoveAttorney, page.CanGoBack,
		RemoveAttorney(logger, tmpls.Get("remove_attorney.gohtml"), donorStore))
	handleWithDonor(page.Paths.RemoveTrustCorporation, page.CanGoBack,
		RemoveTrustCorporation(tmpls.Get("remove_attorney.gohtml"), donorStore, false))
	handleWithDonor(page.Paths.HowShouldAttorneysMakeDecisions, page.CanGoBack,
		HowShouldAttorneysMakeDecisions(tmpls.Get("how_should_attorneys_make_decisions.gohtml"), donorStore))

	handleWithDonor(page.Paths.DoYouWantReplacementAttorneys, page.None,
		WantReplacementAttorneys(tmpls.Get("do_you_want_replacement_attorneys.gohtml"), donorStore))
	handleWithDonor(page.Paths.ChooseReplacementAttorneys, page.CanGoBack,
		ChooseReplacementAttorneys(tmpls.Get("choose_replacement_attorneys.gohtml"), donorStore, random.UuidString))
	handleWithDonor(page.Paths.ChooseReplacementAttorneysAddress, page.CanGoBack,
		ChooseReplacementAttorneysAddress(logger, tmpls.Get("choose_address.gohtml"), addressClient, donorStore))
	handleWithDonor(page.Paths.EnterReplacementTrustCorporation, page.CanGoBack,
		EnterReplacementTrustCorporation(tmpls.Get("enter_replacement_trust_corporation.gohtml"), donorStore))
	handleWithDonor(page.Paths.EnterReplacementTrustCorporationAddress, page.CanGoBack,
		EnterReplacementTrustCorporationAddress(logger, tmpls.Get("choose_address.gohtml"), addressClient, donorStore))
	handleWithDonor(page.Paths.ChooseReplacementAttorneysSummary, page.CanGoBack,
		ChooseReplacementAttorneysSummary(tmpls.Get("choose_replacement_attorneys_summary.gohtml")))
	handleWithDonor(page.Paths.RemoveReplacementAttorney, page.CanGoBack,
		RemoveReplacementAttorney(logger, tmpls.Get("remove_attorney.gohtml"), donorStore))
	handleWithDonor(page.Paths.RemoveReplacementTrustCorporation, page.CanGoBack,
		RemoveTrustCorporation(tmpls.Get("remove_attorney.gohtml"), donorStore, true))
	handleWithDonor(page.Paths.HowShouldReplacementAttorneysStepIn, page.CanGoBack,
		HowShouldReplacementAttorneysStepIn(tmpls.Get("how_should_replacement_attorneys_step_in.gohtml"), donorStore))
	handleWithDonor(page.Paths.HowShouldReplacementAttorneysMakeDecisions, page.CanGoBack,
		HowShouldReplacementAttorneysMakeDecisions(tmpls.Get("how_should_replacement_attorneys_make_decisions.gohtml"), donorStore))

	handleWithDonor(page.Paths.WhenCanTheLpaBeUsed, page.None,
		WhenCanTheLpaBeUsed(tmpls.Get("when_can_the_lpa_be_used.gohtml"), donorStore))
	handleWithDonor(page.Paths.LifeSustainingTreatment, page.None,
		LifeSustainingTreatment(tmpls.Get("life_sustaining_treatment.gohtml"), donorStore))
	handleWithDonor(page.Paths.Restrictions, page.None,
		Restrictions(tmpls.Get("restrictions.gohtml"), donorStore))

	handleWithDonor(page.Paths.WhatACertificateProviderDoes, page.None,
		Guidance(tmpls.Get("what_a_certificate_provider_does.gohtml")))
	handleWithDonor(page.Paths.ChooseYourCertificateProvider, page.None,
		Guidance(tmpls.Get("choose_your_certificate_provider.gohtml")))
	handleWithDonor(page.Paths.ChooseNewCertificateProvider, page.None,
		ChooseNewCertificateProvider(tmpls.Get("choose_new_certificate_provider.gohtml"), donorStore))
	handleWithDonor(page.Paths.CertificateProviderDetails, page.CanGoBack,
		CertificateProviderDetails(tmpls.Get("certificate_provider_details.gohtml"), donorStore))
	handleWithDonor(page.Paths.HowWouldCertificateProviderPreferToCarryOutTheirRole, page.CanGoBack,
		HowWouldCertificateProviderPreferToCarryOutTheirRole(tmpls.Get("how_would_certificate_provider_prefer_to_carry_out_their_role.gohtml"), donorStore))
	handleWithDonor(page.Paths.CertificateProviderAddress, page.CanGoBack,
		CertificateProviderAddress(logger, tmpls.Get("choose_address.gohtml"), addressClient, donorStore))
	handleWithDonor(page.Paths.HowDoYouKnowYourCertificateProvider, page.CanGoBack,
		HowDoYouKnowYourCertificateProvider(tmpls.Get("how_do_you_know_your_certificate_provider.gohtml"), donorStore))
	handleWithDonor(page.Paths.HowLongHaveYouKnownCertificateProvider, page.CanGoBack,
		HowLongHaveYouKnownCertificateProvider(tmpls.Get("how_long_have_you_known_certificate_provider.gohtml"), donorStore))

	handleWithDonor(page.Paths.DoYouWantToNotifyPeople, page.CanGoBack,
		DoYouWantToNotifyPeople(tmpls.Get("do_you_want_to_notify_people.gohtml"), donorStore))
	handleWithDonor(page.Paths.ChoosePeopleToNotify, page.CanGoBack,
		ChoosePeopleToNotify(tmpls.Get("choose_people_to_notify.gohtml"), donorStore, random.UuidString))
	handleWithDonor(page.Paths.ChoosePeopleToNotifyAddress, page.CanGoBack,
		ChoosePeopleToNotifyAddress(logger, tmpls.Get("choose_address.gohtml"), addressClient, donorStore))
	handleWithDonor(page.Paths.ChoosePeopleToNotifySummary, page.CanGoBack,
		ChoosePeopleToNotifySummary(tmpls.Get("choose_people_to_notify_summary.gohtml")))
	handleWithDonor(page.Paths.RemovePersonToNotify, page.CanGoBack,
		RemovePersonToNotify(logger, tmpls.Get("remove_person_to_notify.gohtml"), donorStore))

	handleWithDonor(page.Paths.GettingHelpSigning, page.CanGoBack,
		Guidance(tmpls.Get("getting_help_signing.gohtml")))
	handleWithDonor(page.Paths.YourAuthorisedSignatory, page.CanGoBack,
		YourAuthorisedSignatory(tmpls.Get("your_authorised_signatory.gohtml"), donorStore))
	handleWithDonor(page.Paths.YourIndependentWitness, page.CanGoBack,
		YourIndependentWitness(tmpls.Get("your_independent_witness.gohtml"), donorStore))
	handleWithDonor(page.Paths.YourIndependentWitnessMobile, page.CanGoBack,
		YourIndependentWitnessMobile(tmpls.Get("your_independent_witness_mobile.gohtml"), donorStore))
	handleWithDonor(page.Paths.YourIndependentWitnessAddress, page.CanGoBack,
		YourIndependentWitnessAddress(logger, tmpls.Get("choose_address.gohtml"), addressClient, donorStore))

	handleWithDonor(page.Paths.YouCannotSignYourLpaYet, page.CanGoBack,
		YouCannotSignYourLpaYet(tmpls.Get("you_cannot_sign_your_lpa_yet.gohtml")))
	handleWithDonor(page.Paths.ConfirmYourCertificateProviderIsNotRelated, page.CanGoBack,
		ConfirmYourCertificateProviderIsNotRelated(tmpls.Get("confirm_your_certificate_provider_is_not_related.gohtml"), donorStore))
	handleWithDonor(page.Paths.CheckYourLpa, page.CanGoBack,
		CheckYourLpa(tmpls.Get("check_your_lpa.gohtml"), donorStore, shareCodeSender, notifyClient, certificateProviderStore, time.Now))
	handleWithDonor(page.Paths.LpaDetailsSaved, page.CanGoBack,
		LpaDetailsSaved(tmpls.Get("lpa_details_saved.gohtml")))

	handleWithDonor(page.Paths.AboutPayment, page.None,
		Guidance(tmpls.Get("about_payment.gohtml")))
	handleWithDonor(page.Paths.AreYouApplyingForFeeDiscountOrExemption, page.CanGoBack,
		AreYouApplyingForFeeDiscountOrExemption(tmpls.Get("are_you_applying_for_a_different_fee_type.gohtml"), payer, donorStore))
	handleWithDonor(page.Paths.WhichFeeTypeAreYouApplyingFor, page.CanGoBack,
		WhichFeeTypeAreYouApplyingFor(tmpls.Get("which_fee_type_are_you_applying_for.gohtml"), donorStore))
	handleWithDonor(page.Paths.PreviousApplicationNumber, page.None,
		PreviousApplicationNumber(tmpls.Get("previous_application_number.gohtml"), donorStore))
	handleWithDonor(page.Paths.PreviousFee, page.CanGoBack,
		PreviousFee(tmpls.Get("previous_fee.gohtml"), payer, donorStore))
	handleWithDonor(page.Paths.EvidenceRequired, page.CanGoBack,
		Guidance(tmpls.Get("evidence_required.gohtml")))
	handleWithDonor(page.Paths.HowWouldYouLikeToSendEvidence, page.CanGoBack,
		HowWouldYouLikeToSendEvidence(tmpls.Get("how_would_you_like_to_send_evidence.gohtml"), donorStore))
	handleWithDonor(page.Paths.UploadEvidence, page.CanGoBack,
		UploadEvidence(tmpls.Get("upload_evidence.gohtml"), logger, payer, documentStore))
	handleWithDonor(page.Paths.SendUsYourEvidenceByPost, page.CanGoBack,
		SendUsYourEvidenceByPost(tmpls.Get("send_us_your_evidence_by_post.gohtml"), payer, eventClient))
	handleWithDonor(page.Paths.FeeDenied, page.None,
		FeeDenied(tmpls.Get("fee_denied.gohtml"), payer))
	handleWithDonor(page.Paths.PaymentConfirmation, page.None,
		PaymentConfirmation(logger, tmpls.Get("payment_confirmation.gohtml"), payClient, donorStore, sessionStore))
	handleWithDonor(page.Paths.EvidenceSuccessfullyUploaded, page.None,
		Guidance(tmpls.Get("evidence_successfully_uploaded.gohtml")))
	handleWithDonor(page.Paths.WhatHappensNextPostEvidence, page.None,
		Guidance(tmpls.Get("what_happens_next_post_evidence.gohtml")))

	handleWithDonor(page.Paths.HowToConfirmYourIdentityAndSign, page.None,
		Guidance(tmpls.Get("how_to_confirm_your_identity_and_sign.gohtml")))
	handleWithDonor(page.Paths.ProveYourIdentity, page.CanGoBack,
		Guidance(tmpls.Get("prove_your_identity.gohtml")))
	handleWithDonor(page.Paths.IdentityWithOneLogin, page.CanGoBack,
		IdentityWithOneLogin(oneLoginClient, sessionStore, random.String))
	handleWithDonor(page.Paths.IdentityWithOneLoginCallback, page.CanGoBack,
		IdentityWithOneLoginCallback(tmpls.Get("identity_with_one_login_callback.gohtml"), oneLoginClient, sessionStore, donorStore))

	handleWithDonor(page.Paths.ReadYourLpa, page.None,
		Guidance(tmpls.Get("read_your_lpa.gohtml")))
	handleWithDonor(page.Paths.LpaYourLegalRightsAndResponsibilities, page.CanGoBack,
		Guidance(tmpls.Get("your_legal_rights_and_responsibilities.gohtml")))
	handleWithDonor(page.Paths.SignYourLpa, page.CanGoBack,
		SignYourLpa(tmpls.Get("sign_your_lpa.gohtml"), donorStore))
	handleWithDonor(page.Paths.SignTheLpaOnBehalf, page.CanGoBack,
		SignYourLpa(tmpls.Get("sign_the_lpa_on_behalf.gohtml"), donorStore))
	handleWithDonor(page.Paths.WitnessingYourSignature, page.None,
		WitnessingYourSignature(tmpls.Get("witnessing_your_signature.gohtml"), witnessCodeSender, donorStore))
	handleWithDonor(page.Paths.WitnessingAsIndependentWitness, page.None,
		WitnessingAsIndependentWitness(tmpls.Get("witnessing_as_independent_witness.gohtml"), donorStore, time.Now))
	handleWithDonor(page.Paths.ResendIndependentWitnessCode, page.CanGoBack,
		ResendWitnessCode(tmpls.Get("resend_witness_code.gohtml"), witnessCodeSender, actor.TypeIndependentWitness))
	handleWithDonor(page.Paths.ChangeIndependentWitnessMobileNumber, page.CanGoBack,
		ChangeMobileNumber(tmpls.Get("change_mobile_number.gohtml"), witnessCodeSender, actor.TypeIndependentWitness))
	handleWithDonor(page.Paths.WitnessingAsCertificateProvider, page.None,
		WitnessingAsCertificateProvider(tmpls.Get("witnessing_as_certificate_provider.gohtml"), donorStore, shareCodeSender, lpaStoreClient, time.Now))
	handleWithDonor(page.Paths.ResendCertificateProviderCode, page.CanGoBack,
		ResendWitnessCode(tmpls.Get("resend_witness_code.gohtml"), witnessCodeSender, actor.TypeCertificateProvider))
	handleWithDonor(page.Paths.ChangeCertificateProviderMobileNumber, page.CanGoBack,
		ChangeMobileNumber(tmpls.Get("change_mobile_number.gohtml"), witnessCodeSender, actor.TypeCertificateProvider))
	handleWithDonor(page.Paths.YouHaveSubmittedYourLpa, page.None,
		Guidance(tmpls.Get("you_have_submitted_your_lpa.gohtml")))

	handleWithDonor(page.Paths.Progress, page.CanGoBack,
		LpaProgress(tmpls.Get("lpa_progress.gohtml"), certificateProviderStore, attorneyStore))

	handleWithDonor(page.Paths.UploadEvidenceSSE, page.None,
		UploadEvidenceSSE(documentStore, 3*time.Minute, 2*time.Second, time.Now))
}

func makeHandle(mux *http.ServeMux, store sesh.Store, defaultOptions page.HandleOpt, errorHandler page.ErrorHandler, appPublicURL string) func(page.Path, page.HandleOpt, page.Handler) {
	return func(path page.Path, opt page.HandleOpt, h page.Handler) {
		opt = opt | defaultOptions

		mux.HandleFunc(path.String(), func(w http.ResponseWriter, r *http.Request) {
			ctx := r.Context()

			appData := page.AppDataFromContext(ctx)
			appData.Page = path.Format()
			appData.CanGoBack = opt&page.CanGoBack != 0
			appData.ActorType = actor.TypeDonor
			appData.AppPublicURL = appPublicURL

			if opt&page.RequireSession != 0 {
				donorSession, err := sesh.Login(store, r)
				if err != nil {
					http.Redirect(w, r, page.Paths.Start.Format(), http.StatusFound)
					return
				}

				appData.SessionID = base64.StdEncoding.EncodeToString([]byte(donorSession.Sub))

				sessionData, err := page.SessionDataFromContext(ctx)

				if err == nil {
					sessionData.SessionID = appData.SessionID
					ctx = page.ContextWithSessionData(ctx, sessionData)

					appData.LpaID = sessionData.LpaID
				} else {
					ctx = page.ContextWithSessionData(ctx, &page.SessionData{SessionID: appData.SessionID, LpaID: appData.LpaID})
				}
			}

			if err := h(appData, w, r.WithContext(page.ContextWithAppData(ctx, appData))); err != nil {
				errorHandler(w, r, err)
			}
		})
	}
}

func makeLpaHandle(mux *http.ServeMux, store sesh.Store, defaultOptions page.HandleOpt, errorHandler page.ErrorHandler, donorStore DonorStore, appPublicURL string) func(page.LpaPath, page.HandleOpt, Handler) {
	return func(path page.LpaPath, opt page.HandleOpt, h Handler) {

		opt = opt | defaultOptions

		mux.HandleFunc(path.String(), func(w http.ResponseWriter, r *http.Request) {
			ctx := r.Context()

			appData := page.AppDataFromContext(ctx)
			appData.CanGoBack = opt&page.CanGoBack != 0
			appData.ActorType = actor.TypeDonor
			appData.AppPublicURL = appPublicURL

			donorSession, err := sesh.Login(store, r)
			if err != nil {
				http.Redirect(w, r, page.Paths.Start.Format(), http.StatusFound)
				return
			}

			appData.SessionID = base64.StdEncoding.EncodeToString([]byte(donorSession.Sub))

			sessionData, err := page.SessionDataFromContext(ctx)

			if err == nil {
				sessionData.SessionID = appData.SessionID
				ctx = page.ContextWithSessionData(ctx, sessionData)

				appData.LpaID = sessionData.LpaID
			} else {
				ctx = page.ContextWithSessionData(ctx, &page.SessionData{SessionID: appData.SessionID, LpaID: appData.LpaID})
			}

			appData.Page = path.Format(appData.LpaID)

			lpa, err := donorStore.Get(ctx)
			if err != nil {
				errorHandler(w, r, err)
				return
			}

			if err := h(appData, w, r.WithContext(page.ContextWithAppData(ctx, appData)), lpa); err != nil {
				errorHandler(w, r, err)
			}
		})
	}
}

type payHelper struct {
	logger       Logger
	sessionStore sessions.Store
	donorStore   DonorStore
	payClient    PayClient
	randomString func(int) string
}

func (p *payHelper) Pay(appData page.AppData, w http.ResponseWriter, r *http.Request, donor *actor.DonorProvidedDetails) error {
	if donor.FeeType.IsNoFee() || donor.FeeType.IsHardshipFee() || donor.Tasks.PayForLpa.IsMoreEvidenceRequired() {
		donor.Tasks.PayForLpa = actor.PaymentTaskPending
		if err := p.donorStore.Put(r.Context(), donor); err != nil {
			return err
		}

		if donor.EvidenceDelivery.IsPost() {
			return page.Paths.WhatHappensNextPostEvidence.Redirect(w, r, appData, donor)
		}

		return page.Paths.EvidenceSuccessfullyUploaded.Redirect(w, r, appData, donor)
	}

	createPaymentBody := pay.CreatePaymentBody{
		Amount:      donor.FeeAmount(),
		Reference:   p.randomString(12),
		Description: "Property and Finance LPA",
		ReturnUrl:   appData.AppPublicURL + appData.Lang.URL(page.Paths.PaymentConfirmation.Format(donor.LpaID)),
		Email:       donor.Donor.Email,
		Language:    appData.Lang.String(),
	}

	resp, err := p.payClient.CreatePayment(r.Context(), createPaymentBody)
	if err != nil {
		p.logger.Print(fmt.Sprintf("Error creating payment: %s", err.Error()))
		return err
	}

	if err = sesh.SetPayment(p.sessionStore, r, w, &sesh.PaymentSession{PaymentID: resp.PaymentId}); err != nil {
		return err
	}

	if donor.Tasks.PayForLpa.IsDenied() {
		donor.FeeType = pay.FullFee
		donor.Tasks.PayForLpa = actor.PaymentTaskInProgress
		if err := p.donorStore.Put(r.Context(), donor); err != nil {
			return err
		}
	}

	nextUrl := resp.Links["next_url"].Href
	// If URL matches expected domain for GOV UK PAY redirect there. If not,
	// redirect to the confirmation code and carry on with flow.
	if strings.HasPrefix(nextUrl, pay.PaymentPublicServiceUrl) {
		http.Redirect(w, r, nextUrl, http.StatusFound)
		return nil
	}

	return page.Paths.PaymentConfirmation.Redirect(w, r, appData, donor)
}