// Updates or creates a principal from a PrincipalConfig structure.
func updatePrincipal(dbc *db.DatabaseContext, newInfo PrincipalConfig, isUser bool, allowReplace bool) (replaced bool, err error) {
	// Get the existing principal, or if this is a POST make sure there isn't one:
	var princ auth.Principal
	var user auth.User
	authenticator := dbc.Authenticator()
	if isUser {
		user, err = authenticator.GetUser(internalUserName(*newInfo.Name))
		princ = user
	} else {
		princ, err = authenticator.GetRole(*newInfo.Name)
	}
	if err != nil {
		return
	}

	replaced = (princ != nil)
	if !replaced {
		// If user/role didn't exist already, instantiate a new one:
		if isUser {
			user, err = authenticator.NewUser(internalUserName(*newInfo.Name), "", nil)
			princ = user
		} else {
			princ, err = authenticator.NewRole(*newInfo.Name, nil)
		}
		if err != nil {
			return
		}
	} else if !allowReplace {
		err = base.HTTPErrorf(http.StatusConflict, "Already exists")
		return
	}

	// Now update the Principal object from the properties in the request, first the channels:
	updatedChannels := princ.ExplicitChannels()
	if updatedChannels == nil {
		updatedChannels = ch.TimedSet{}
	}
	lastSeq, err := dbc.LastSequence()
	if err != nil {
		return
	}
	updatedChannels.UpdateAtSequence(newInfo.ExplicitChannels, lastSeq+1)
	princ.SetExplicitChannels(updatedChannels)

	// Then the roles:
	if isUser {
		user.SetEmail(newInfo.Email)
		if newInfo.Password != nil {
			user.SetPassword(*newInfo.Password)
		}
		user.SetDisabled(newInfo.Disabled)
		user.SetExplicitRoleNames(newInfo.ExplicitRoleNames)
	}

	// And finally save the Principal:
	err = authenticator.Save(princ)
	return
}

// Common behavior of putUser and putRole
func putPrincipal(r http.ResponseWriter, rq *http.Request, context *context, name string, princ auth.Principal) error {
	context.auth.InvalidateChannels(princ)

	if rq.Method == "POST" {
		name = princ.Name()
		if name == "" {
			return &base.HTTPError{http.StatusBadRequest, "Missing name property"}
		}
	} else if princ.Name() != name {
		return &base.HTTPError{http.StatusBadRequest, "Name mismatch (can't change name)"}
	}
	err := context.auth.Save(princ)
	if err == nil {
		r.WriteHeader(http.StatusCreated)
	}
	return err
}

// Recomputes the set of channels a User/Role has been granted access to by sync() functions.
// This is part of the ChannelComputer interface defined by the Authenticator.
func (context *DatabaseContext) ComputeChannelsForPrincipal(princ auth.Principal) (channels.TimedSet, error) {
	key := princ.Name()
	if _, ok := princ.(auth.User); !ok {
		key = "role:" + key // Roles are identified in access view by a "role:" prefix
	}

	var vres struct {
		Rows []struct {
			Value channels.TimedSet
		}
	}

	opts := map[string]interface{}{"stale": false, "key": key}
	if verr := context.Bucket.ViewCustom("sync_gateway", "access", opts, &vres); verr != nil {
		return nil, verr
	}
	channelSet := channels.TimedSet{}
	for _, row := range vres.Rows {
		channelSet.Add(row.Value)
	}
	return channelSet, nil
}

func (dbc *DatabaseContext) GetPrincipal(name string, isUser bool) (info *PrincipalConfig, err error) {
	var princ auth.Principal
	if isUser {
		princ, err = dbc.Authenticator().GetUser(name)
	} else {
		princ, err = dbc.Authenticator().GetRole(name)
	}
	if princ == nil {
		return
	}
	info = new(PrincipalConfig)
	info.Name = &name
	info.ExplicitChannels = princ.ExplicitChannels().AsSet()
	if user, ok := princ.(auth.User); ok {
		info.Channels = user.InheritedChannels().AsSet()
		info.Email = user.Email()
		info.Disabled = user.Disabled()
		info.ExplicitRoleNames = user.ExplicitRoles().AllChannels()
		info.RoleNames = user.RoleNames().AllChannels()
	} else {
		info.Channels = princ.Channels().AsSet()
	}
	return
}

func marshalPrincipal(princ auth.Principal) ([]byte, error) {
	name := externalUserName(princ.Name())
	info := PrincipalJSON{
		Name:             &name,
		ExplicitChannels: princ.ExplicitChannels().AsSet(),
		Channels:         princ.Channels().AsSet(),
	}
	if user, ok := princ.(auth.User); ok {
		info.Email = user.Email()
		info.Disabled = user.Disabled()
		info.ExplicitRoleNames = user.ExplicitRoleNames()
		info.RoleNames = user.RoleNames()
	}
	return json.Marshal(info)
}

// Handles PUT and POST for a user or a role.
func (h *handler) updatePrincipal(name string, isUser bool) error {
	h.assertAdminOnly()
	// Unmarshal the request body into a PrincipalJSON struct:
	body, _ := ioutil.ReadAll(h.rq.Body)
	var newInfo PrincipalJSON
	var err error
	if err = json.Unmarshal(body, &newInfo); err != nil {
		return err
	}

	var princ auth.Principal
	var user auth.User
	if h.rq.Method == "POST" {
		// On POST, take the name from the "name" property in the request body:
		if newInfo.Name == nil {
			return &base.HTTPError{http.StatusBadRequest, "Missing name property"}
		}
		name = *newInfo.Name
	} else {
		// ON PUT, verify the name matches, if given:
		if newInfo.Name != nil && *newInfo.Name != name {
			return &base.HTTPError{http.StatusBadRequest, "Name mismatch (can't change name)"}
		}
	}

	// Get the existing principal, or if this is a POST make sure there isn't one:
	if isUser {
		user, err = h.db.Authenticator().GetUser(internalUserName(name))
		princ = user
	} else {
		princ, err = h.db.Authenticator().GetRole(name)
	}
	if err != nil {
		return err
	}

	status := http.StatusOK
	if princ == nil {
		// If user/role didn't exist already, instantiate a new one:
		status = http.StatusCreated
		if isUser {
			user, err = h.db.Authenticator().NewUser(internalUserName(name), "", nil)
			princ = user
		} else {
			princ, err = h.db.Authenticator().NewRole(name, nil)
		}
		if err != nil {
			return err
		}
	} else if h.rq.Method == "POST" {
		return &base.HTTPError{http.StatusConflict, "Already exists"}
	}

	// Now update the Principal object from the properties in the request, first the channels:
	updatedChannels := princ.ExplicitChannels()
	if updatedChannels == nil {
		updatedChannels = ch.TimedSet{}
	}
	updatedChannels.UpdateAtSequence(newInfo.ExplicitChannels, h.db.LastSequence()+1)
	princ.SetExplicitChannels(updatedChannels)

	// Then the roles:
	if isUser {
		user.SetEmail(newInfo.Email)
		if newInfo.Password != nil {
			user.SetPassword(*newInfo.Password)
		}
		user.SetDisabled(newInfo.Disabled)
		user.SetExplicitRoleNames(newInfo.ExplicitRoleNames)
	}

	// And finally save the Principal:
	if err = h.db.Authenticator().Save(princ); err != nil {
		return err
	}
	h.response.WriteHeader(status)
	return nil
}

// Updates or creates a principal from a PrincipalConfig structure.
func updatePrincipal(dbc *db.DatabaseContext, newInfo PrincipalConfig, isUser bool, allowReplace bool) (replaced bool, err error) {
	// Get the existing principal, or if this is a POST make sure there isn't one:
	var princ auth.Principal
	var user auth.User
	authenticator := dbc.Authenticator()
	if isUser {
		user, err = authenticator.GetUser(internalUserName(*newInfo.Name))
		princ = user
	} else {
		princ, err = authenticator.GetRole(*newInfo.Name)
	}
	if err != nil {
		return
	}

	replaced = (princ != nil)
	if !replaced {
		// If user/role didn't exist already, instantiate a new one:
		if isUser {
			user, err = authenticator.NewUser(internalUserName(*newInfo.Name), "", nil)
			princ = user
		} else {
			princ, err = authenticator.NewRole(*newInfo.Name, nil)
		}
		if err != nil {
			return
		}
	} else if !allowReplace {
		err = base.HTTPErrorf(http.StatusConflict, "Already exists")
		return
	}

	// Now update the Principal object from the properties in the request, first the channels:
	updatedChannels := princ.ExplicitChannels()
	if updatedChannels == nil {
		updatedChannels = ch.TimedSet{}
	}
	lastSeq, err := dbc.LastSequence()
	if err != nil {
		return
	}
	updatedChannels.UpdateAtSequence(newInfo.ExplicitChannels, lastSeq+1)
	princ.SetExplicitChannels(updatedChannels)

	// Then the user-specific fields like roles:
	if isUser {
		user.SetEmail(newInfo.Email)
		if newInfo.Password != nil {
			user.SetPassword(*newInfo.Password)
		}
		user.SetDisabled(newInfo.Disabled)

		// Convert the array of role strings into a TimedSet by reapplying the current sequences
		// for existing roles, and using the database's last sequence for any new roles.
		newRoles := ch.TimedSet{}
		oldRoles := user.ExplicitRoles()
		var currentSequence uint64
		for _, roleName := range newInfo.ExplicitRoleNames {
			since, found := oldRoles[roleName]
			if !found {
				if currentSequence == 0 {
					currentSequence, _ = dbc.LastSequence()
					if currentSequence == 0 {
						currentSequence = 1
					}
				}
				since = currentSequence
			}
			newRoles[roleName] = since
		}
		user.SetExplicitRoles(newRoles)
	}

	// And finally save the Principal:
	err = authenticator.Save(princ)
	return
}

// Updates or creates a principal from a PrincipalConfig structure.
func (dbc *DatabaseContext) UpdatePrincipal(newInfo PrincipalConfig, isUser bool, allowReplace bool) (replaced bool, err error) {
	// Get the existing principal, or if this is a POST make sure there isn't one:
	var princ auth.Principal
	var user auth.User
	authenticator := dbc.Authenticator()
	if isUser {
		if newInfo.Password != nil && len(*(newInfo.Password)) < 3 {
			err = base.HTTPErrorf(http.StatusBadRequest, "Passwords must be at least three 3 characters")
			return
		}
		user, err = authenticator.GetUser(*newInfo.Name)
		princ = user
	} else {
		princ, err = authenticator.GetRole(*newInfo.Name)
	}
	if err != nil {
		return
	}

	changed := false
	replaced = (princ != nil)
	if !replaced {
		// If user/role didn't exist already, instantiate a new one:
		if isUser {
			user, err = authenticator.NewUser(*newInfo.Name, "", nil)
			princ = user
		} else {
			princ, err = authenticator.NewRole(*newInfo.Name, nil)
		}
		if err != nil {
			return
		}
		changed = true
	} else if !allowReplace {
		err = base.HTTPErrorf(http.StatusConflict, "Already exists")
		return
	}

	// Update the persistent sequence number of this principal:
	nextSeq, err := dbc.sequences.nextSequence()
	if err != nil {
		return
	}
	princ.SetSequence(nextSeq)

	// Now update the Principal object from the properties in the request, first the channels:
	updatedChannels := princ.ExplicitChannels()
	if updatedChannels == nil {
		updatedChannels = ch.TimedSet{}
	}
	if updatedChannels.UpdateAtSequence(newInfo.ExplicitChannels, nextSeq) {
		princ.SetExplicitChannels(updatedChannels)
		changed = true
	}

	// Then the user-specific fields like roles:
	if isUser {
		if newInfo.Email != user.Email() {
			user.SetEmail(newInfo.Email)
			changed = true
		}
		if newInfo.Password != nil {
			user.SetPassword(*newInfo.Password)
			changed = true
		}
		if newInfo.Disabled != user.Disabled() {
			user.SetDisabled(newInfo.Disabled)
			changed = true
		}

		updatedRoles := user.ExplicitRoles()
		if updatedRoles == nil {
			updatedRoles = ch.TimedSet{}
		}
		if updatedRoles.UpdateAtSequence(base.SetFromArray(newInfo.ExplicitRoleNames), nextSeq) {
			user.SetExplicitRoles(updatedRoles)
			changed = true
		}
	}

	// And finally save the Principal:
	if changed {
		err = authenticator.Save(princ)
	}
	return
}