var token = "...";   // telegram bot token
var apikey = "...";  // openai api key
var weburi = "...."; // google webapp url removing the "https://script.google.com/macros/s/" and "/exec"

function doPost(e) {
  var contents = JSON.parse(e.postData.contents);
  var txt = "";  
  if (contents.message) {
    var id = contents.message.from.id;
    var text = contents.message.text;
    if( text.includes("/")) {
      return ;
    }
    if (text.length > 0) {
      txt = text.trim();
      if (txt.length > 0) {
        var url = call_dalle(apikey, txt);
        sendImage(token, url, id);
      }
      return;
    }
  }
}

function stop_bot() {
  var txt = codelib.RemoveWebhook(token);
  Logger.log(txt);
}

function bot_info() {
  var txt = codelib.WebhookInfo(token);
  Logger.log(txt);
}

function start_bot() {  
  var txt = codelib.setWebhook(token,weburi);
  Logger.log(txt);
}

function call_dalle(apikey, prompt) { 
  var dalle_url = 'https://api.openai.com/v1/images/generations';
  var options = {
    "method": 'POST',
    "headers": {
      'Content-Type': 'application/json',
      'Authorization': `Bearer ` + apikey
    },
    "payload": JSON.stringify({
      "model": "image-alpha-001",
      "prompt": prompt, // "a white siamese cat"
      "num_images": 1,
      "size": "256x256",
      "response_format": "url"
    }),
    muteHttpExceptions: true
  }  
  var response = UrlFetchApp.fetch(dalle_url, options);
  var responseJson = response.getContentText();
  var responseData = JSON.parse(responseJson);
  Logger.log(responseData);
  var image_url = responseData['data'][0]['url'];
  return image_url;
}

function sendImage(token, url, id) {
  var telegramUrl = "https://api.telegram.org/bot" + token;
  var request = UrlFetchApp.fetch(telegramUrl + "/sendPhoto", {
    method: "post",
    contentType: "application/json",
    payload: JSON.stringify({
      chat_id: id,
      photo: url,
    }),
  });
}