// Copyright © 2023 Ory Corp
// SPDX-License-Identifier: Apache-2.0

package link

import (
	"context"
	"net/url"

	"github.com/pkg/errors"

	"github.com/ory/kratos/courier"
	"github.com/ory/kratos/courier/template"
	"github.com/ory/kratos/courier/template/email"
	"github.com/ory/kratos/driver/config"
	"github.com/ory/kratos/hydra"
	"github.com/ory/kratos/identity"
	"github.com/ory/kratos/selfservice/flow/recovery"
	"github.com/ory/kratos/selfservice/flow/verification"
	"github.com/ory/kratos/x"
	"github.com/ory/x/httpx"
	"github.com/ory/x/logrusx"
	"github.com/ory/x/sqlcon"
	"github.com/ory/x/urlx"
)

type (
	senderDependencies interface {
		courier.Provider
		courier.ConfigProvider

		identity.PoolProvider
		identity.ManagementProvider
		identity.PrivilegedPoolProvider
		logrusx.Provider
		config.Provider

		VerificationTokenPersistenceProvider
		RecoveryTokenPersistenceProvider

		hydra.Provider
		httpx.ClientProvider
	}
	SenderProvider interface {
		LinkSender() *Sender
	}

	Sender struct {
		r senderDependencies
	}
)

var ErrUnknownAddress = errors.New("verification requested for unknown address")

func NewSender(r senderDependencies) *Sender {
	return &Sender{r: r}
}

// SendRecoveryLink sends a recovery link to the specified address
//
// If the address does not exist in the store and dispatching invalid emails is enabled (CourierEnableInvalidDispatch is
// true), an email is still being sent to prevent account enumeration attacks. In that case, this function returns the
// ErrUnknownAddress error.
func (s *Sender) SendRecoveryLink(ctx context.Context, f *recovery.Flow, via, to string) error {
	s.r.Logger().
		WithField("via", via).
		WithSensitiveField("address", to).
		Debug("Preparing recovery link.")

	address, err := s.r.IdentityPool().FindRecoveryAddressByValue(ctx, via, to)
	if errors.Is(err, sqlcon.ErrNoRows()) {
		notifyUnknownRecipients := s.r.Config().SelfServiceFlowRecoveryNotifyUnknownRecipients(ctx)
		s.r.Logger().
			WithField("via", via).
			WithField("strategy", "link").
			WithSensitiveField("email_address", address).
			WithField("was_notified", notifyUnknownRecipients).
			Info("Account recovery was requested for an unknown address.")

		transientPayload, err := x.ParseRawMessageOrEmpty(f.GetTransientPayload())
		if err != nil {
			return errors.WithStack(err)
		}
		if !notifyUnknownRecipients {
			// do nothing
		} else if err := s.send(ctx, string(via), email.NewRecoveryInvalid(s.r, &email.RecoveryInvalidModel{
			To:               to,
			RequestURL:       f.GetRequestURL(),
			TransientPayload: transientPayload,
		})); err != nil {
			return err
		}
		return errors.WithStack(ErrUnknownAddress)
	} else if err != nil {
		// DB error
		return err
	}

	// Get the identity associated with the recovery address
	i, err := s.r.IdentityPool().GetIdentity(ctx, address.IdentityID, identity.ExpandDefault)
	if err != nil {
		return err
	}

	token := NewSelfServiceRecoveryToken(address, f, s.r.Config().SelfServiceLinkMethodLifespan(ctx))
	if err := s.r.RecoveryTokenPersister().CreateRecoveryToken(ctx, token); err != nil {
		return err
	}

	if err := s.SendRecoveryTokenTo(ctx, f, i, address, token); err != nil {
		return err
	}

	return nil
}

// SendVerificationLink sends a verification link to the specified address
//
// If the address does not exist in the store and dispatching invalid emails is enabled (CourierEnableInvalidDispatch is
// true), an email is still being sent to prevent account enumeration attacks. In that case, this function returns the
// ErrUnknownAddress error.
func (s *Sender) SendVerificationLink(ctx context.Context, f *verification.Flow, via, to string) error {
	s.r.Logger().
		WithField("via", via).
		WithSensitiveField("address", to).
		Debug("Preparing verification link.")

	address, err := s.r.IdentityPool().FindVerifiableAddressByValue(ctx, via, to)
	if errors.Is(err, sqlcon.ErrNoRows()) {
		notifyUnknownRecipients := s.r.Config().SelfServiceFlowVerificationNotifyUnknownRecipients(ctx)
		s.r.Logger().
			WithField("via", via).
			WithField("strategy", "link").
			WithSensitiveField("email_address", to).
			WithField("was_notified", notifyUnknownRecipients).
			Info("Address verification was requested for an unknown address.")

		transientPayload, err := x.ParseRawMessageOrEmpty(f.GetTransientPayload())
		if err != nil {
			return errors.WithStack(err)
		}
		if !notifyUnknownRecipients {
			// do nothing
		} else if err := s.send(ctx, string(via), email.NewVerificationInvalid(s.r, &email.VerificationInvalidModel{
			To:               to,
			RequestURL:       f.GetRequestURL(),
			TransientPayload: transientPayload,
		})); err != nil {
			return err
		}
		return errors.WithStack(ErrUnknownAddress)
	} else if err != nil {
		// DB error
		return err
	}

	// Get the identity associated with the verification address
	i, err := s.r.IdentityPool().GetIdentity(ctx, address.IdentityID, identity.ExpandDefault)
	if err != nil {
		return err
	}

	token := NewSelfServiceVerificationToken(address, f, s.r.Config().SelfServiceLinkMethodLifespan(ctx))
	if err := s.r.VerificationTokenPersister().CreateVerificationToken(ctx, token); err != nil {
		return err
	}

	if err := s.SendVerificationTokenTo(ctx, f, i, address, token); err != nil {
		return err
	}

	address.Status = identity.VerifiableAddressStatusSent
	return s.r.PrivilegedIdentityPool().UpdateVerifiableAddress(ctx, address, "status")
}

func (s *Sender) SendRecoveryTokenTo(ctx context.Context, f *recovery.Flow, i *identity.Identity, address *identity.RecoveryAddress, token *RecoveryToken) error {
	s.r.Logger().
		WithField("via", address.Via).
		WithField("identity_id", address.IdentityID).
		WithField("recovery_link_id", token.ID).
		WithSensitiveField("email_address", address.Value).
		WithSensitiveField("recovery_link_token", token.Token).
		Info("Sending out recovery email with recovery link.")

	model, err := x.StructToMap(i)
	if err != nil {
		return err
	}

	transientPayload, err := x.ParseRawMessageOrEmpty(f.GetTransientPayload())
	if err != nil {
		return errors.WithStack(err)
	}

	recoveryUrl := urlx.CopyWithQuery(
		urlx.AppendPaths(x.CourierBaseURL(f.GetCourierBaseURL(), s.r.Config().SelfPublicURL(ctx)), recovery.RouteSubmitFlow),
		url.Values{
			"token": {token.Token},
			"flow":  {f.ID.String()},
		}).
		String()

	return s.send(ctx, string(address.Via), email.NewRecoveryValid(s.r,
		&email.RecoveryValidModel{
			To:               address.Value,
			RecoveryURL:      recoveryUrl,
			Identity:         model,
			RequestURL:       f.GetRequestURL(),
			TransientPayload: transientPayload,
			ExpiresInMinutes: int(s.r.Config().SelfServiceLinkMethodLifespan(ctx).Minutes()),
		}))
}

func (s *Sender) SendVerificationTokenTo(ctx context.Context, f *verification.Flow, i *identity.Identity, sendable identity.VerifiableAddressLike, token *VerificationToken) error {
	address, via := sendable.Address(), sendable.DeliveryVia()
	s.r.Logger().
		WithField("via", via).
		WithField("identity_id", i.ID).
		WithField("verification_link_id", token.ID).
		WithSensitiveField("email_address", address).
		WithSensitiveField("verification_link_token", token.Token).
		Info("Sending out verification email with verification link.")

	model, err := x.StructToMap(i)
	if err != nil {
		return err
	}

	transientPayload, err := x.ParseRawMessageOrEmpty(f.GetTransientPayload())
	if err != nil {
		return errors.WithStack(err)
	}

	// If the flow was initiated by an OAuth2 login challenge, expose a scoped
	// view of the OAuth2 client to the courier templates so that messages can
	// be branded per client.
	if f.OAuth2LoginChallenge != "" && f.HydraLoginRequest == nil {
		hlr, err := s.r.Hydra().GetLoginRequest(ctx, string(f.OAuth2LoginChallenge))
		if err != nil {
			return errors.WithStack(err)
		}
		f.HydraLoginRequest = hlr
	}

	verificationUrl := urlx.CopyWithQuery(
		urlx.AppendPaths(x.CourierBaseURL(f.GetCourierBaseURL(), s.r.Config().SelfPublicURL(ctx)), verification.RouteSubmitFlow),
		url.Values{
			"flow":  {f.ID.String()},
			"token": {token.Token},
		}).String()

	if err := s.send(ctx, via, email.NewVerificationValid(s.r,
		&email.VerificationValidModel{
			To:                 address,
			VerificationURL:    verificationUrl,
			Identity:           model,
			RequestURL:         f.GetRequestURL(),
			TransientPayload:   transientPayload,
			ExpiresInMinutes:   int(s.r.Config().SelfServiceLinkMethodLifespan(ctx).Minutes()),
			OAuth2LoginRequest: template.NewOAuth2LoginRequest(f.HydraLoginRequest),
		})); err != nil {
		return err
	}
	return nil
}

func (s *Sender) send(ctx context.Context, via string, t courier.EmailTemplate) error {
	switch via {
	case identity.AddressTypeEmail:
		c, err := s.r.Courier(ctx)
		if err != nil {
			return err
		}
		_, err = c.QueueEmail(ctx, t)
		return err
	default:
		return errors.Errorf("received unexpected via type: %s", via)
	}
}