You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: api_clearChannelCard.go
    path of file: ./repos/databag/net/server/internal
    
    the code of the file until where you have to start completion: package databag

import (
	"databag/internal/store"
	"errors"
	"github.com/gorilla/mux"
	"gorm.io/gorm"
	"net/http"
)

//ClearChannelCard removes card from channel membership
func ClearChannelCard(w http.ResponseWriter, r *http.Request) {

	account, code, err := ParamAgentToken(r, false)
	if err != nil {
		ErrResponse(w, code, err)
		return
	}

	// scan parameters
	params := mux.Vars(r)
	channelID := params["channelID"]
	cardID := params["cardID"]

	// load referenced channel
	var channelSlot store.ChannelSlot
	if err := store.DB.Preload("Channel.Members.Card.CardSlot").Preload("Channel.Groups.GroupSlot").Preload("Channel.Groups.Cards").Where("account_id = ? AND channel_slot_id = ?", account.ID, channelID).First(&channelSlot).Error; err != nil {
		if !errors.Is(err, gorm.ErrRecordNotFound) {
			ErrResponse(w, http.StatusInternalServerError, err)
		} else {
			ErrResponse(w, http.StatusNotFound, err)
		}
		return
	}
	if channelSlot.Channel == nil {
		ErrResponse(w, http.StatusNotFound, errors.New("channel has been deleted"))
		return
	}

	// load referenced card
	var cardSlot store.CardSlot
	if err := store.DB.Preload("Card.CardSlot").Where("account_id = ? AND card_slot_id = ?", account.ID, cardID).First(&cardSlot).Error; err != nil {
		if !errors.Is(err, gorm.ErrRecordNotFound) {
			ErrResponse(w, http.StatusInternalServerError, err)
		} else {
			ErrResponse(w, http.StatusNotFound, err)
		}
		return
	}
	if cardSlot.Card == nil {
		ErrResponse(w, http.StatusNotF
    
func ClearChannelCard(w http.ResponseWriter, r *http.Request) {

	account, code, err := ParamAgentToken(r, false)
	if err != nil {
		ErrResponse(w, code, err)
		return
	}

	// scan parameters
	params := mux.Vars(r)
	channelID := params["channelID"]
	cardID := params["cardID"]

	// load referenced channel
	var channelSlot store.ChannelSlot
	if err := store.DB.Preload("Channel.Members.Card.CardSlot").Preload("Channel.Groups.GroupSlot").Preload("Channel.Groups.Cards").Where("account_id = ? AND channel_slot_id = ?", account.ID, channelID).First(&channelSlot).Error; err != nil {
		if !errors.Is(err, gorm.ErrRecordNotFound) {
			ErrResponse(w, http.StatusInternalServerError, err)
		} else {
			ErrResponse(w, http.StatusNotFound, err)
		}
		return
	}
	if channelSlot.Channel == nil {
		ErrResponse(w, http.StatusNotFound, errors.New("channel has been deleted"))
		return
	}

	// load referenced card
	var cardSlot store.CardSlot
	if err := store.DB.Preload("Card.CardSlot").Where("account_id = ? AND card_slot_id = ?", account.ID, cardID).First(&cardSlot).Error; err != nil {
		if !errors.Is(err, gorm.ErrRecordNotFound) {
			ErrResponse(w, http.StatusInternalServerError, err)
		} else {
			ErrResponse(w, http.StatusNotFound, err)
		}
		return
	}
	if cardSlot.Card == nil {
		ErrResponse(w, http.StatusNotFound, errors.New("card has been deleted"))
		return
	}

	// determine contact list
	cards := make(map[string]store.Card)
	for _, member := range channelSlot.Channel.Members {
		cards[member.Card.GUID] = member.Card
	}
	for _, group := range channelSlot.Channel.Groups {
		for _, card := range group.Cards {
			cards[card.GUID] = card
		}
	}

	// save and update contact revision
	err = store.DB.Transaction(func(tx *gorm.DB) error {
		if res := tx.Where("channel_id = ? AND card_id = ?", channelSlot.Channel.ID, cardSlot.Card.ID).Delete(&store.Member{}).Error; res != nil {
			return res
		}
    if res := tx.Model(&store.Channel{}).Where("id = ?", channelSlot.Channel.ID).Update("detail_revision", account.ChannelRevision+1).Error; res != nil {
			return res
		}
    if res := tx.Model(&store.ChannelSlot{}).Where("id = ?", channelSlot.ID).Update("revision", account.ChannelRevision+1).Error; res != nil {
			return res
		}
		if res := tx.Model(&account).Update("channel_revision", account.ChannelRevision+1).Error; res != nil {
			return res
		}
		return nil
	})
	if err != nil {
		ErrResponse(w, http.StatusInternalServerError, err)
		return
	}

	// notify contacts of content change
	SetStatus(account)
	for _, card := range cards {
		SetContactChannelNotification(account, &card)
	}

  video := getBoolConfigValue(CNFEnableVideo, true);
  audio := getBoolConfigValue(CNFEnableAudio, true);
  image := getBoolConfigValue(CNFEnableImage, true);
	WriteResponse(w, getChannelModel(&channelSlot, true, true, image, audio, video))
}