(in-package :cl-user)
(defpackage chatikbot.eliza
  (:use :cl
        :chatikbot.patmatch
        :chatikbot.utils
        :alexandria)
  (:export :?is
           :?or
           :?and
           :?not
           :?*
           :?+
           :??
           :?if
           :eliza
           :read-from-string-no-punct))
(in-package :chatikbot.eliza)

(defun punctuation-p (char)
  (find char ".,;:'!?#-()\\\""))

(defun read-from-string-no-punct (input)
  "Read from an input string, ignoring punctuation."
  (read-from-string
   (concatenate 'string "(" (substitute-if #\space #'punctuation-p input) ")")))

(defun switch-viewpoint (words)
  "Change I to you and vice versa, and so on."
  (sublis '((I . you) (you . I) (me . you) (am . are)
            (я ты) (ты я) (меня тебя) (тебя меня))
          words))

(defun use-eliza-rules (input rules)
  "Find some rule with which to transform the input."
  (rule-based-translator input rules
                         :action #'(lambda (bindings responses)
                                     (sublis (switch-viewpoint bindings)
                                             (random-elt responses)))))

(defun eliza (input rules)
  (let ((r (use-eliza-rules input rules)))
    (cond
      ((null r) nil)
      ((and (consp (car r)) (eq 'function (caar r)))
       (apply (cadar r) (cdr r)))
      ((keywordp (car r)) r)
      (t (print-with-spaces (flatten r))))))