package databag

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

func SetChannelSubject(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"]

  var subject Subject
  if err := ParseRequest(r, w, &subject); err != nil {
    ErrResponse(w, http.StatusBadRequest, err)
    return
  }

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

  // determine affected contact list
  cards := make(map[string]store.Card)
  for _, card := range slot.Channel.Cards {
    cards[card.GUID] = card
  }
  for _, group := range slot.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.Model(&slot.Channel).Update("data", subject.Data).Error; res != nil {
      return res
    }
    if res := tx.Model(&slot.Channel).Update("data_type", subject.DataType).Error; res != nil {
      return res
    }
    if res := tx.Model(&slot.Channel).Update("detail_revision", account.ChannelRevision + 1).Error; res != nil {
      return res
    }
    if res := tx.Model(&slot).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)
  }
  WriteResponse(w, getChannelModel(&slot, true, true));
}