function doPost(e) {
  var msg = JSON.parse(e.postData.contents);
  console.log(msg);

  var replyToken = msg.events[0].replyToken;

  var CHANNEL_ACCESS_TOKEN = 'X3FqcjDi8bpmEsRj8dPACo0ZmvudcQzWhO6nnMkXPVSnyVRDQi1QqlNDFQ9n6M+CSgeQSLSLgcSC9aw9dcSwlbV3TYKo2j4iq1aS9uUXj6IgBTJ5A4Sixi8/fuYc+uI9BL6gjuxBfQkifCSvL766EAdB04t89/1O/w1cDnyilFU=';
  var url = 'https://api.line.me/v2/bot/message/reply';

  var type = msg.events[0].type
  switch(type){
  case 'message':
    var userMessage = msg.events[0].message.text;
    if(userMessage == 'test'){  //使用者輸入test，出現按鈕選單
      UrlFetchApp.fetch(url, {
        'headers': {
          'Content-Type': 'application/json; charset=UTF-8',
          'Authorization': 'Bearer ' + CHANNEL_ACCESS_TOKEN,
        },
        'method': 'post',
        'payload': JSON.stringify({
          'replyToken': replyToken,
          'messages': [{
            "type": "template",
            "altText": "this is a buttons template",
            "template": {
              "type": "buttons",
              "actions": [{
                "type": "postback",
                "label": "button1",
                "text": "click",
                "data": "data"
              }],
              "text": "test"
            }
          }]
        }),
      });
    }
    break;

  case 'postback':
    var pdata = msg.events[0].postback.data;
    //取data post(pdata)
    post('postback:' + pdata);
    break;

  default:
    break;
  }
}

function post(pdata){
  var CHANNEL_ACCESS_TOKEN = 'X3FqcjDi8bpmEsRj8dPACo0ZmvudcQzWhO6nnMkXPVSnyVRDQi1QqlNDFQ9n6M+CSgeQSLSLgcSC9aw9dcSwlbV3TYKo2j4iq1aS9uUXj6IgBTJ5A4Sixi8/fuYc+uI9BL6gjuxBfQkifCSvL766EAdB04t89/1O/w1cDnyilFU=';
  var url = 'https://api.line.me/v2/bot/message/push';
  var userId = 'Uf19366d12489b5298c3a9f7411c27fbd';
  if(!pdata){  //如果回傳值是空的，送出訊息'nothing'
    pdata = 'nothing';
  }

  UrlFetchApp.fetch(url, {
    'headers': {
      'Content-Type': 'application/json; charset=UTF-8',
      'Authorization': 'Bearer ' + CHANNEL_ACCESS_TOKEN,
    },
    'method': 'post',
    'payload': JSON.stringify({
      'to':  userId,
      'messages': [{
        'type':'text',
        'text': pdata
      }]
    }),
  });
}