(require-extension telebot
                   (prefix telebot telebot:))

(use srfi-69)
(use extras)
(use data-structures)

(define (resolve-query query tree)
  (fold (lambda (x y) (alist-ref x y))
        tree
        query))

(define token (car (command-line-arguments)))
(define conversations (make-hash-table))

(define (send chat_id text)
  (print chat_id " <- \"" text "\"")
  (telebot:sendMessage token
                       chat_id: chat_id
                       text:    text))

(define (make-conversation chat_id)
  (let ((chat_id chat_id)
        (answer  (random 100)))
    (send chat_id
          "Hi there! I just generated a random number for you to guess!")
    (lambda (text)
      (let ((guess (string->number text)))
        (if (number? guess)
          (cond ((= guess answer)
                 (begin (send chat_id "Correct! Feel free to guess the next number.")
                        (set! answer (random 100))))
                ((< guess answer) (send chat_id "Too small. Try again."))
                ((> guess answer) (send chat_id "Too large. Try again.")))
          (send chat_id
                "This is not a number - please provide your guess in base 10."))))))

(define (handle-message m)
  (let ((chat_id (resolve-query '(message from id) m))
        (text    (resolve-query '(message text)    m)))
    (print chat_id " -> \"" text "\"")
    (if (hash-table-exists? conversations chat_id)
      ((hash-table-ref conversations chat_id) text)
      (hash-table-set! conversations
                       chat_id
                       (make-conversation chat_id)))))

(randomize)
(telebot:pollUpdates token
                     (lambda (u) (if (telebot:is-message? u)
                                   (handle-message u))))