package telegram

import json "github.com/pquerna/ffjson/ffjson"

// GetUpdatesParameters represents data for GetUpdates method.
type GetUpdatesParameters struct {
	// Identifier of the first update to be returned. Must be greater by one than
	// the highest among the identifiers of previously received updates. By
	// default, updates starting with the earliest unconfirmed update are
	// returned. An update is considered confirmed as soon as getUpdates is
	// called with an offset higher than its update_id. The negative offset can
	// be specified to retrieve updates starting from -offset update from the
	// end of the updates queue. All previous updates will forgotten.
	Offset int `json:"offset,omitempty"`

	// Limits the number of updates to be retrieved. Values between 1—100 are
	// accepted. Defaults to 100.
	Limit int `json:"limit,omitempty"`

	// Timeout in seconds for long polling. Defaults to 0, i.e. usual short
	// polling. Should be positive, short polling should be used for testing
	// purposes only.
	Timeout int `json:"timeout,omitempty"`

	// List the types of updates you want your bot to receive. For example,
	// specify [“message”, “edited_channel_post”, “callback_query”] to only
	// receive updates of these types. See Update for a complete list of
	// available update types. Specify an empty list to receive all updates
	// regardless of type (default). If not specified, the previous setting will
	// be used.
	//
	// Please note that this parameter doesn't affect updates created before the
	// call to the getUpdates, so unwanted updates may be received for a short
	// period of time.
	AllowedUpdates []string `json:"allowed_updates,omitempty"`
}

// GetUpdates receive incoming updates using long polling. An Array of
// Update objects is returned.
func (bot *Bot) GetUpdates(params *GetUpdatesParameters) (updates []Update, err error) {
	dst, err := json.Marshal(params)
	if err != nil {
		return
	}

	resp, err := bot.request(dst, MethodGetUpdates)
	if err != nil {
		return
	}

	if params == nil {
		params = new(GetUpdatesParameters)
		params.Limit = 100
	}

	updates = make([]Update, params.Limit)
	err = json.Unmarshal(*resp.Result, &updates)
	return
}