package telegram

import (
	json "github.com/pquerna/ffjson/ffjson"
	http "github.com/valyala/fasthttp"
)

// GetFile get basic info about a file and prepare it for downloading. For the
// moment, bots can download files of up to 20MB in size. On success, a File
// object is returned. The file can then be downloaded via the link
// https://api.telegram.org/file/bot<token>/<file_path>, where <file_path> is
// taken from the response. It is guaranteed that the link will be valid for at
// least 1 hour. When the link expires, a new one can be requested by calling
// getFile again.
//
// Note: This function may not preserve the original file name and MIME type. You
// should save the file's MIME type and name (if available) when the File object
// is received.
func (bot *Bot) GetFile(file string) (*File, error) {
	args := http.AcquireArgs()
	defer http.ReleaseArgs(args)
	args.Add("file_id", file)

	resp, err := bot.request(nil, "getFile", args)
	if err != nil {
		return nil, err
	}

	var data File
	err = json.Unmarshal(*resp.Result, &data)
	return &data, err
}