(define-module (language python module re)
  #:use-module (language python module re compile)
  #:use-module (language python module re flags)
  #:use-module (language python list)
  #:use-module (language python dict)
  #:use-module (language python try)
  #:use-module (language python bool)
  #:use-module (language python exceptions)
  #:use-module ((language python module _python) #:select (str isinstance range))
  #:use-module (language python string)
  #:use-module (language python for)
  #:use-module (language python def)
  #:use-module (language python yield)
  #:use-module (oop pf-objects)
  #:use-module ((parser stis-parser)
                #:select (f-checkr f-eof f-ftr f-pos f-pk
                                   f-seq! f-and! f-nl
                                   f-reg f-seq Ds f-or! ff* f-ftr))
  #:use-module ((ice-9 match) #:select ((match . ice-match)))
  #:re-export (A ASCII DEBUG I IGNORECASE L LOCALE M MULTILINE X VERBOSE
                 S DOTALL)
  #:export (compile match fullmatch search split splitm splitmm finditer findall sub subn
                    purge escape))

(define start (make-fluid 0))
(define end   (make-fluid 0))
(define e-start (f-pos (lambda (x n m) (fluid-set! start x))))
(define e-end   (f-pos (lambda (x n m) (fluid-set! end   x))))
(define (ge) (fluid-ref end))
(define (gs) (fluid-ref start))

(define maxsplit (make-fluid 0))
(define splitn   (make-fluid 0))
(define (set-maxsplit x)
  (fluid-set! maxsplit x)
  (fluid-set! splitn   0))

(define e-maxsplit (f-checkr
		    (lambda (c)
		      (let ((m (fluid-ref maxsplit))
			    (i (fluid-ref splitn)))
			(if (> m 0)
			    (if (< i m)
				(begin
				  (fluid-set! splitn (+ i 1))
				  #t)
				#f)
			    #t)))))

(define (e-fullmatch e)
  (f-seq e-start (f-and! e) e-end f-eof))

(define (e-search    e)
  (let lp ()
    (f-or! (f-seq! e-start (f-and! e) e-end) (f-seq (f-or! (f-reg ".") f-nl) (Ds (lp))))))
          
(define-python-class Regexp ()
  (define __init__
    (lam (self s (= flags 0))
      (set self 'flags    flags)
      (set self 'pattern  s)
      (let lp ((l s))
	(if (string? l)
	    (lp (compile-reg l))
	    (if (list? l)
		(begin
		  (set self '__re       (list-ref l 0))
		  (set self 'groups     (- (list-ref l 1) 1))
		  (set self 'groupindex (list-ref l 2)))
		(begin
		  (set self '__re       l)
		  (set self 'groups     0)
		  (set self 'groupindex '())))))))
		

  (define __repr__
    (lambda (self)
      (format #f "re.compile('~a')" (ref self 'pattern))))

  (define __str__ __repr__)
  (define findall
    (lam (self str (= flags 0))
	 (findall- self str flags)))

  (define finditer
    (lam (self str (= flags None))
	 (if (eq? flags None) (set! flags (ref self 'flags)))
	 (finditer- self str flags)))
    
  (define flags 0)
  (define fullmatch
    (lam (self str (= flags None))
	 (if (eq? flags None) (set! flags (ref self 'flags)))
	 (fullmatch- self str flags)))

  (define groupindex '())
  (define groups     '())
  (define match
    (lam (self str (= flags None))
	 (if (eq? flags None) (set! flags (ref self 'flags)))
	 (match- self str flags)))

  (define search
    (lam (self str (= flags None))
	 (if (eq? flags None) (set! flags (ref self 'flags)))
	 (search- self str flags)))

  (define split
    (lam (self str (= maxsplit 0) (= flags None))
	 (if (eq? flags None) (set! flags (ref self 'flags)))
	 (split- self str maxsplit flags)))

  (define sub
    (lam (self repl str (= count 0) (= flags None))
	 (if (eq? flags None) (set! flags (ref self 'flags)))
	 (sub- self repl str count flags)))

  (define subn
    (lam (self repl str (= count 0) (= flags None))
	 (if (eq? flags None) (set! flags (ref self 'flags)))
	 (subn- self repl str count flags))))


(def (match- re s (= flags 0))
  (if (isinstance re str)
      (match- (Regexp re) s flags)
      (begin
	(set-flags flags)
	(let ((m (parse s (f-seq e-start (ref re '__re) e-end))))
	  (if m
	      (ReMatch m re (gs) (ge) s)
	      None)))))

(define match match-)

(def (search- re s (= flags 0))
  (if (isinstance re str)
      (search- (Regexp re) s flags)
      (begin
	(set-flags flags)
	(let ((m (parse s (e-search (ref re '__re)))))
	  (if m
	      (ReMatch m re (gs) (ge) s)
	      None)))))

(define search search-)

(def (fullmatch- re ss (= flags 0))
  (if (isinstance re str)
      (fullmatch- (Regexp re) ss flags)
      (begin
	(set-flags flags)
	(let ((m (parse ss (e-fullmatch (ref re '__re)))))
	  (if m
	      (ReMatch m re (gs) (ge) ss)
	      None)))))

(define fullmatch fullmatch-)

(define (grps m) (reverse ((ref m 'groups))))

(define (mku re ss)
  (lambda (m)
    (ReMatch (caddr m) re (car m) (cadr m) ss)))

(define (mkid re ss) id)
  
(define-syntax-rule (mk split- grps mku)
(def (split- re ss (= maxsplit 0) (= flags 0))
  (if (not (isinstance re Regexp))
      (split- (Regexp re) ss maxsplit flags)
      (begin
	(set-flags    flags)
	(set-maxsplit maxsplit)
	(let ((m (parse ss (ff* (f-seq! e-maxsplit
					(e-search (ref re '__re))
					(f-ftr (lambda (c) (list (gs) (ge) c))))))))
	  (let lp ((s 0)
		   (l (map (mku re ss) m))
		   (r '()))
	    (if (pair? l)
		(let* ((m (car l))
		       (i ((ref m 'start)))
		       (j ((ref m 'end))))
		  (lp j (cdr l) (append
				 (grps m)
				 (list (pylist-slice ss s i None))
				 r)))
		(reverse (cons (pylist-slice ss s None None) r)))))))))

(mk split- grps mku)
(define split split-)

(define (id x) (list x))
(mk splitm- id mku)
(define splitm splitm-)

(define (id2 x) (list (ref x '__m)))
(mk splitmm- id2 mku)
(define splitmm splitmm-)

(def (finditer- re s (= flags 0))
  (if (isinstance re str)
      (finditer- (Regexp re) s flags)
      (let ((e (ref re '__re)))
	(set-flags flags)
	((make-generator ()
	   (lambda (yield)              
	     (parse s
		    (let lp ()
		      (f-seq
		       (f-or!
			(f-seq! e-start (f-and! e) e-end
				(f-ftr (lambda (c)
                                         (yield (ReMatch c re (gs) (ge) s))
                                         '())))
			(f-seq (f-reg ".")))
		       (Ds (lp)))))))))))

(define finditer finditer-)

(def (findall- re s (= flags 0))
     (for ((m : (finditer re s flags))) ((l '()))
	  (let ((grps ((ref m 'groups))))
	    (cons
	     (cond
	      ((null? grps)
	       ((ref m 'group)))
	      ((= (length grps) 1)
	       (car grps))
	      (else
	       grps))	     
	     l))
	  #:final (reverse l)))

(define findall findall-)


(define (mk-repl-str repl)
  (define (take n)
    (lambda (m)
      (let ((s (pylist-ref m n)))
	(if (eq? s None)
	    (set! s ""))
	(reverse
	 (string->list s)))))

  (define (comp r)
    (let lp ((r r) (l '()))
      (if (pair? r)
	  (let ((x (car r)))
	    (if (char? x)
		(lp (cdr r) (cons x l))
		(if (null? l)
		    r
		    (let ((l (reverse l)))
		      (cons (lambda (m) l) r)))))
	  (if (null? l)
	      '()
	      (let ((l (reverse l)))
		(cons (lambda (m) l) r))))))

  (define num? char-numeric?)
  
  (let* ((l (string->list repl))
	 (c (let lp ((l l) (r '()))
	      (ice-match l
		((#\\ (? num? x)  (? num? y) . l)
		 (lp l (cons (take (string->number
				    (list->string (list x y))))
			     (comp r))))
		((#\\ (? num? x) . l)
		 (lp l (cons (take (string->number
				    (list->string (list x))))
			     (comp r))))
		((#\\ #\n . l)
		 (lp l (cons #\newline r)))
		((x . l)
		 (lp l (cons x r)))
		(()
		 (reverse (comp r)))))))
    (lambda (m)
      (let lp ((c c) (r '()))
	(if (pair? c)
	    (let ((x (car c)))
	      (if (char? x)
		  (lp (cdr c) (cons x r))
		  (lp (cdr c) (append (x m) r))))
	    (list->string (reverse r)))))))


(define (mk-repl repl)
  (if (isinstance repl str)
      (mk-repl-str repl)
      repl))

(def (subn- re repl s (= count 0) (= flags 0))
     (let ((l (splitm re s count flags)))
       (define f (mk-repl repl))
       (let lp ((l l) (r '()) (i 0))
	 (ice-match l
	  ((x m . l)
	   (lp l (cons* (f m) x r) (+ i 1)))
	  ((x)
	   (list (py-join "" (reverse (cons x r))) i))
	  (()
	   (list (py-join "" (reverse r)) i))))))

(define subn subn-)

(def (sub- re repl s (= count 0) (= flags 0))
     (car (subn re repl s count flags)))

(define sub sub-)

(define (val x)
  (if (eq? x None)
      x
      (car x)))

(define (vali x)
  (if (not (bool x))
      (list -1 -1)
      (cdr x)))

(define-python-class ReMatch ()
  (define __init__
    (lambda (self m re s e ss)
      (set self 're       re)
      (set self '__start  s)
      (set self '__end    e)
      (set self 'string   ss)
      
      (let ((t (make-hash-table)))
	(for ((k v : (ref re 'groupindex))) ()
	     (hash-set! t k None))

	(for ((i : (range (ref re 'groups)))) ()
	     (hash-set! t i None))

	(if (string? (ref re 'pattern))
	    (let lp ((l (list-ref m 0)))	  
	      (ice-match l
	         ((((n . i) . v) . l)
		  (hash-set! t n v)
		  (hash-set! t i v)
		  (lp l))
		 (((i . v) . l)
		  (hash-set! t i v)
		  (lp l))
		 (() #t))))

	(set self '__m m)
	(set self '__t t)
	(set self 'regs (__regs self)))))

  (define er (list 'er))
  (define group
    (case-lambda
     ((self nm)
      (if (and (number? nm) (= nm 0))
	  (group self)
	  (let ((x (py-get (ref self '__t) nm er)))
	    (if (eq? x er)
		(raise (IndexError "no souch group in regexp match"))
		(val x)))))
     ((self)
      (pylist-slice (ref self 'string) (start self) (end self) None))))

  (define __getitem__
    (lambda (self k)
      (group self k)))
      
  (define groups
    (lam (self (= default None))
      (let ((t (ref self '__t))
	    (n (ref (ref self 're) 'groups)))
	(let lp ((i 1))
	  (if (<= i n)
	      (let ((w (val (hash-ref t i))))
		(cons (if (eq? w None) default w) (lp (+ i 1))))
	      '())))))

  (define __regs
    (lambda (self)
      (let ((t (ref self '__t))
	    (n (ref (ref self 're) 'groups)))
	(cons (span self)
	  (let lp ((i 1))
	    (if (<= i n)
		(cons (vali (hash-ref t i)) (lp (+ i 1)))
		'()))))))

  (define groupdict
    (lam (self (= default None))
      (let ((t (make-hash-table)))
	(for ((k v : (ref self '__t))) ()
	     (if (not (number? k))
		 (let ((w (val v)))
		   (hash-set! t k (if (eq? w None) default w))))
	     #:final t))))

  (define start
    (lambda (self)
      (ref self '__start)))
  
  (define end
    (lambda (self)
      (ref self '__end)))
  
  (define span
    (lambda (self)
      (list
       (ref self '__start)
       (ref self '__end))))

  (define expand
    (lambda (self template)
      ((mk-repl template) self)))
  
  (define __repr__
    (lambda (self)
      (format #f "ReMatch<~s>" (group self)))))

  
  
     
(def (compile s (= flags 0)) (Regexp s flags))

(define (purge) (values))

(define escape
  (let ((m (string->list "()[]#$*+-.^|\\")))
    (set! m (cons #\newline m))
    (lambda (x)
      (let lp ((l (string->list x)) (r '()))
	(ice-match l
	  ((x . l)
	   (lp l
	       (if (member x m)
                   (if (eq? x #\newline)
                       (cons* #\n #\\  r)
                       (cons* x   #\\  r))
		   (cons x r))))
	  (()
	   (list->string (reverse r))))))))