register.go

package donor

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

	"github.com/ministryofjustice/opg-go-common/template"
	"github.com/ministryofjustice/opg-modernising-lpa/internal/actor"
	"github.com/ministryofjustice/opg-modernising-lpa/internal/actor/actoruid"
	"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 {
	Info(msg string, args ...any)
	Warn(msg string, args ...any)
	Error(msg string, args ...any)
}

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 {
	SendActorSMS(ctx context.Context, to, lpaUID string, sms notify.SMS) error
}

type SessionStore interface {
	Login(r *http.Request) (*sesh.LoginSession, error)
	SetLogin(r *http.Request, w http.ResponseWriter, session *sesh.LoginSession) error
	OneLogin(r *http.Request) (*sesh.OneLoginSession, error)
	SetOneLogin(r *http.Request, w http.ResponseWriter, session *sesh.OneLoginSession) error
	SetPayment(r *http.Request, w http.ResponseWriter, session *sesh.PaymentSession) error
	Payment(r *http.Request) (*sesh.PaymentSession, error)
	ClearPayment(r *http.Request, w http.ResponseWriter) 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 {
	page.Localizer
}

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,
	commonTmpls, 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{
		sessionStore: sessionStore,
		donorStore:   donorStore,
		payClient:    payClient,
		randomString: random.String,
		appPublicURL: appPublicURL,
	}

	handleRoot := makeHandle(rootMux, errorHandler)

	handleRoot(page.Paths.Login,
		page.Login(oneLoginClient, sessionStore, random.String, page.Paths.LoginCallback))
	handleRoot(page.Paths.LoginCallback,
		page.LoginCallback(oneLoginClient, sessionStore, page.Paths.Dashboard, dashboardStore, actor.TypeDonor))

	handleWithDonor := makeLpaHandle(rootMux, sessionStore, errorHandler, donorStore)

	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.MakeANewLPA, page.None,
		Guidance(tmpls.Get("make_a_new_lpa.gohtml")))
	handleWithDonor(page.Paths.YourDetails, page.None,
		YourDetails(tmpls.Get("your_details.gohtml"), donorStore, sessionStore))
	handleWithDonor(page.Paths.YourName, page.None,
		YourName(tmpls.Get("your_name.gohtml"), donorStore))
	handleWithDonor(page.Paths.YourDateOfBirth, page.None,
		YourDateOfBirth(tmpls.Get("your_date_of_birth.gohtml"), donorStore))
	handleWithDonor(page.Paths.YourAddress, page.None,
		YourAddress(logger, tmpls.Get("your_address.gohtml"), addressClient, donorStore))
	handleWithDonor(page.Paths.WeHaveUpdatedYourDetails, page.None,
		Guidance(tmpls.Get("we_have_updated_your_details.gohtml")))
	handleWithDonor(page.Paths.YourPreferredLanguage, page.None,
		YourPreferredLanguage(commonTmpls.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, actoruid.New))
	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(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, actoruid.New))
	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(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, actoruid.New))
	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, actoruid.New))
	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(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, time.Now))
	handleWithDonor(page.Paths.CheckYourLpa, page.CanGoBack,
		CheckYourLpa(tmpls.Get("check_your_lpa.gohtml"), donorStore, shareCodeSender, notifyClient, certificateProviderStore, time.Now, appPublicURL))
	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(commonTmpls.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, errorHandler page.ErrorHandler) func(page.Path, page.Handler) {
	return func(path page.Path, h page.Handler) {
		mux.HandleFunc(path.String(), func(w http.ResponseWriter, r *http.Request) {
			ctx := r.Context()

			appData := page.AppDataFromContext(ctx)
			appData.Page = path.Format()
			appData.ActorType = actor.TypeDonor

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

func makeLpaHandle(mux *http.ServeMux, store SessionStore, errorHandler page.ErrorHandler, donorStore DonorStore) func(page.LpaPath, page.HandleOpt, Handler) {
	return func(path page.LpaPath, opt page.HandleOpt, h Handler) {
		mux.HandleFunc(path.String(), func(w http.ResponseWriter, r *http.Request) {
			ctx := r.Context()

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

			appData := page.AppDataFromContext(ctx)
			appData.CanGoBack = opt&page.CanGoBack != 0
			appData.ActorType = actor.TypeDonor
			appData.LpaID = r.PathValue("id")
			appData.SessionID = loginSession.SessionID()

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

			if loginSession.OrganisationID != "" {
				appData.IsSupporter = true
				appData.OrganisationName = loginSession.OrganisationName

				sessionData.OrganisationID = loginSession.OrganisationID
				sessionData.Email = loginSession.Email
			}

			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 {
	sessionStore SessionStore
	donorStore   DonorStore
	payClient    PayClient
	randomString func(int) string
	appPublicURL 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:   p.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 {
		return fmt.Errorf("error creating payment: %w", err)
	}

	if err = p.sessionStore.SetPayment(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)
}