package twofactor

import (
	"context"
	"crypto/rand"
	"errors"
	model "git.sendico.io/tech/sxchnge/product/twofactor/model"
	vmodel "git.sendico.io/tech/sxchnge/product/verification/model"
	verification "git.sendico.io/tech/sxchnge/product/verification/store"
	merrors "git.sendico.io/tech/sxchnge/shared/errors"
	"go.mongodb.org/mongo-driver/v2/bson"
	"time"
)

func isRejection(err error) bool {
	return errors.Is(err, verification.ErrTokenNotFound) || errors.Is(err, verification.ErrTokenAlreadyUsed) || errors.Is(err, verification.ErrTokenExpired) || errors.Is(err, verification.ErrTokenAttemptsExceeded)
}
func (s *Service) saveProfile(ctx context.Context, p *model.Profile) error {
	_, err := s.store.Profile(ctx, p.ID)
	if errors.Is(err, merrors.ErrNoData) {
		return s.store.CreateProfile(ctx, p)
	}
	if err != nil {
		return err
	}
	return s.store.UpdateProfile(ctx, p)
}
func (s *Service) Settings(ctx context.Context, subject bson.ObjectID) (model.Settings, error) {
	_, p, _, err := s.profile(ctx, subject)
	if err != nil {
		return model.Settings{}, err
	}
	result := model.Settings{Required: true, Preferred: p.Preferred}
	for _, f := range p.Factors {
		if f.Verified {
			if driver := s.drivers[f.Channel]; driver != nil {
				result.Factors = append(result.Factors, model.Choice{ID: f.ID, Channel: f.Channel, Target: driver.Mask(f.Address)})
			}
		}
	}
	return result, nil
}
func (s *Service) Enroll(ctx context.Context, subject bson.ObjectID, channel model.Channel, address, key, ip string) (model.Challenge, error) {
	driver := s.drivers[channel]
	if driver == nil {
		return model.Challenge{}, merrors.NotImplemented("second-factor channel is not supported")
	}
	normalized, err := driver.Normalize(address)
	if err != nil {
		return model.Challenge{}, err
	}
	_, p, _, err := s.profile(ctx, subject)
	if err != nil {
		return model.Challenge{}, err
	}
	if len(p.Factors) >= 5 {
		return model.Challenge{}, merrors.InvalidArgument("maximum enrolled factors reached")
	}
	for _, f := range p.Factors {
		if f.Channel == channel && f.Address == normalized {
			return model.Challenge{}, merrors.DataConflict("factor already enrolled")
		}
	}
	f := model.Factor{ID: s.key("factor", subject.Hex(), string(channel), normalized)[:24], Channel: channel, Address: normalized}
	scope := model.Scope{Purpose: vmodel.PurposeFactorEnrollment, ContextRef: "enroll:" + f.ID}
	return s.begin(ctx, model.Request{Subject: subject, Scope: scope, IdempotencyKey: key, IP: ip}, &f)
}
func (s *Service) ConfirmEnrollment(ctx context.Context, subject bson.ObjectID, id, code string) (model.Settings, error) {
	cid, err := bson.ObjectIDFromHex(id)
	if err != nil {
		return model.Settings{}, verification.ErorrTokenNotFound()
	}
	r, err := s.store.Challenge(ctx, cid)
	if err != nil {
		return model.Settings{}, err
	}
	if r.Subject != subject || r.Scope.Purpose != vmodel.PurposeFactorEnrollment {
		return model.Settings{}, verification.ErorrTokenNotFound()
	}
	err = s.complete(ctx, subject, r.Scope, id, code, func(tx context.Context) error {
		_, p, _, err := s.profile(tx, subject)
		if err != nil {
			return err
		}
		if len(p.Factors) >= 5 {
			return merrors.InvalidArgument("maximum enrolled factors reached")
		}
		for _, f := range p.Factors {
			if f.ID == r.Factor.ID {
				return merrors.DataConflict("factor already enrolled")
			}
		}
		factor := r.Factor
		factor.Verified = true
		p.Factors = append(p.Factors, factor)
		p.Revision = rand.Text()
		return s.saveProfile(tx, p)
	})
	if err != nil {
		return model.Settings{}, err
	}
	return s.Settings(ctx, subject)
}
func (s *Service) BeginPreference(ctx context.Context, subject bson.ObjectID, factorID, key, ip string) (model.Challenge, error) {
	_, p, _, err := s.profile(ctx, subject)
	if err != nil {
		return model.Challenge{}, err
	}
	if !s.available(p, factorID) {
		return model.Challenge{}, merrors.InvalidArgument("verified supported factor required")
	}
	return s.Begin(ctx, model.Request{Subject: subject, Scope: preferenceScope(factorID), IdempotencyKey: key, IP: ip, Deadline: time.Now().Add(TTL)})
}
func (s *Service) ConfirmPreference(ctx context.Context, subject bson.ObjectID, factorID, id, code string) (model.Settings, error) {
	scope := preferenceScope(factorID)
	err := s.Complete(ctx, subject, scope, id, code, func(tx context.Context) error {
		_, p, _, err := s.profile(tx, subject)
		if err != nil {
			return err
		}
		if !s.available(p, factorID) {
			return merrors.InvalidArgument("verified supported factor required")
		}
		p.Preferred = factorID
		p.Revision = rand.Text()
		return s.saveProfile(tx, p)
	})
	if err != nil {
		return model.Settings{}, err
	}
	return s.Settings(ctx, subject)
}
func (s *Service) available(p *model.Profile, id string) bool {
	for _, f := range p.Factors {
		if f.ID == id && f.Verified && s.drivers[f.Channel] != nil {
			return true
		}
	}
	return false
}

// ResendSettings cannot be used to send or authorize a pending login challenge.
func (s *Service) ResendSettings(ctx context.Context, subject bson.ObjectID, id, key, ip string) (model.Challenge, error) {
	cid, err := bson.ObjectIDFromHex(id)
	if err != nil {
		return model.Challenge{}, verification.ErorrTokenNotFound()
	}
	r, err := s.store.Challenge(ctx, cid)
	if err != nil {
		return model.Challenge{}, err
	}
	if r.Subject != subject || (r.Scope.Purpose != vmodel.PurposeFactorEnrollment && r.Scope.Purpose != vmodel.PurposeFactorPreference) {
		return model.Challenge{}, verification.ErorrTokenNotFound()
	}
	return s.Resend(ctx, model.Request{Subject: subject, Scope: r.Scope, IdempotencyKey: key, IP: ip}, id)
}