func NewCursorEventsFromEvent(e hey.Event) CursorEvents {
return NewCursorFromSource(e.EventID(), e.CreatedAt())
}
func (r *EventRepository) findEvents(
clientID,
watcherID,
threadID uuid.UUID,
cursorStr string,
perPage int,
) ([]hey.Event, string, error) {
cursor := utils.NewCursorEvents(cursorStr)
lastEventID := cursor.LastEventID()
lastEventCreatedAt := cursor.LastCreatedAt()
cursor = utils.EmptyCursorEvents // reset cursor
if perPage <= 0 || perPage > PerPageMax {
perPage = PerPageDefault
}
var events = make([]hey.Event, perPage)
// var events []hey.Event
// find
// args for first page
var args = []interface{}{
clientID,
threadID,
perPage,
}
sqlFirstPage := `SELECT
t.event_id,
t.created_at
FROM threadline as t
WHERE t.client_id = $1 AND t.thread_id = $2
ORDER BY t.created_at DESC, t.event_id ASC LIMIT $3`
sqlNextPages := `SELECT
t.event_id,
t.created_at
FROM threadline as t
WHERE t.client_id = $1 AND t.thread_id = $2 AND
(t.created_at, t.event_id) < ($3, $4)
ORDER BY t.created_at DESC, t.event_id ASC LIMIT $5`
sql := sqlFirstPage
if !uuid.Equal(lastEventID, uuid.Nil) {
sql = sqlNextPages
args = []interface{}{
clientID,
threadID,
lastEventCreatedAt,
lastEventID,
perPage,
}
}
rows, err := r.db.Query(sql, args...)
if err != nil {
return events, "", err
}
var _event hey.Event
var _eventID uuid.UUID
var _createdAt time.Time
var i = 0
for rows.Next() {
if err = rows.Scan(
&_eventID,
&_createdAt,
); err != nil {
println("[ERR] error scan row", err.Error())
continue
}
_event, err = r.FindEvent(
clientID,
_eventID,
)
if err != nil {
println(
"[ERR] error find event by ID",
_eventID.String(),
err.Error())
continue
}
events[i] = _event
i++
}
if _event != nil {
cursor = utils.NewCursorFromSource(
_event.EventID(),
_event.CreatedAt(),
)
}
if i < perPage-1 {
// обрезать хвост у массива событий, если кол-во найденных меньше
// чем ожидаемое кол-во
events = events[:i]
}
return events, cursor.String(), err
}