#! /usr/bin/env skint -s

;---------------------------------------------------------------------------------------------
; Skint n.sf precursor compiler (n.sf => n.c)
;---------------------------------------------------------------------------------------------

(import (only (skint hidden) 
  list2? list3?))


(define (path-strip-directory filename)
  (let loop ([l (reverse (string->list filename))] [r '()])
    (cond [(null? l) (list->string r)]
          [(memv (car l) '(#\\ #\/ #\:)) (list->string r)]
          [else (loop (cdr l) (cons (car l) r))])))

(define (path-strip-extension filename)
  (let ([l (reverse (string->list filename))])
    (let ([r (memv #\. l)])
      (if r (list->string (reverse (cdr r))) filename))))

(define (module-name filename)
  (path-strip-extension (path-strip-directory filename)))

(define *local-definitions*
  '("#ifdef NAN_BOXING" "#ifndef FLONUMS_BOXED" "#else" "#endif"))

(define (process-top-form x oport)
  (when (and (list2? x) (symbol? (car x)) (string? (cadr x)))
    (case (car x)
      [(%definition)
       ; make an exception for some conditional definitions!
       (when (member (cadr x) *local-definitions*)
         (display (cadr x) oport) (newline oport) (newline oport))]
      [(%localdef) (display (cadr x) oport) (newline oport) (newline oport)] ; does not go into n.h
      [(%include)]))) ; went into n.h

(define (process-file ifname . ?ofname)
  (define iport (open-input-file ifname)) ; relative to wd, not this script!
  (define oport (if (pair? ?ofname) (open-output-file (car ?ofname)) (current-output-port)))
  (define mname (module-name ifname))
  (display "/* " oport) (display mname oport) 
  (display ".c -- generated via skint nsf2c.ssc " oport) 
  (display (path-strip-directory ifname) oport) 
  (display " */" oport) (newline oport) (newline oport)
  (let loop ([x (read iport)] [end-of-includes? #f])
    (unless (eof-object? x)
      (cond [end-of-includes?
             (process-top-form x oport) 
             (loop (read iport) #t)]
            [(and (list2? x) (eq? (car x) '%include) (string? (cadr x)))
             (display "#include " oport) (write (cadr x) oport) (newline oport)
             (loop (read iport) #f)]
            [else ; switching to body forms
             (display "#include \"" oport) (display mname oport) 
             (display ".h\"" oport) (newline oport) (newline oport)
             (process-top-form x oport) 
             (loop (read iport) #t)])))
  (close-input-port iport)
  (if (pair? ?ofname) (close-output-port oport)))

(define (main args)
  (cond [(list2? args) (process-file (cadr args))]
        [(list3? args) (process-file (cadr args) (caddr args))]
        [else (error "usage: scint nsf2c.ssc INFILE [OUTFILE]" args)]))

; this is not a real #! script, so call main manually
(main (command-line))