;; Copyright 2016-2017
;; Kaz Kylheku <kaz@kylheku.com>
;; Vancouver, Canada
;; All rights reserved.
;;
;; Redistribution and use in source and binary forms, with or without
;; modification, are permitted provided that the following conditions are met:
;;
;; 1. Redistributions of source code must retain the above copyright notice, this
;;    list of conditions and the following disclaimer.
;;
;; 2. Redistributions in binary form must reproduce the above copyright notice,
;;    this list of conditions and the following disclaimer in the documentation
;;    and/or other materials provided with the distribution.
;;
;; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
;; ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
;; WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
;; DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
;; FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
;; DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
;; SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
;; CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
;; OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
;; OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

(load "conv.tl")

(defstruct sys:awk-state ()
  (rs "\n") krs
  fs ft kfs
  fw fw-prev fw-ranges
  (ofs " ")
  (ors "\n")
  (inputs)
  (output *stdout*)
  (file-num 0)
  file-name
  (file-rec-num 0)
  (rec-num 0)
  rec orig-rec fields nf
  rng-vec (rng-n 0)
  par-mode par-mode-fs par-mode-prev-fs
  (streams (hash :equal-based))
  (:fini (self)
    (dohash (k v self.streams)
      (close-stream v)))
  (:postinit (self)
    (set self.inputs (or self.inputs (zap *args*) (list *stdin*)))
    (if (plusp self.rng-n)
      (set self.rng-vec (vector self.rng-n)))
    (unless (streamp self.output)
      (let ((stream (open-file self.output "w")))
        (set [self.streams ^(:outf ,self.output)] stream
             self.output stream)))))

(defstruct sys:awk-compile-time ()
  inputs output name lets
  begin-file-actions end-file-actions
  begin-actions end-actions
  cond-actions
  (nranges 0)
  (rng-rec-temp (gensym))
  rng-expr-temps
  rng-exprs
  outer-env)

(defmeth sys:awk-state rec-to-f (self)
  (cond
    (self.fw
      (unless (eq self.fw-prev self.fw)
        (let ((ranges (reduce-left
                        (tb ((list . sum) item)
                          (let ((ns (+ sum item)))
                            ^((,*list #R(,sum ,ns)) . ,ns)))
                        self.fw '(nil . 0))))
        (set self.fw-prev self.fw
             self.fw-ranges (car ranges))))
      (let ((i 0) end
            (l (length self.rec)))
        (set self.fields
             (build (each ((r self.fw-ranges))
                      (set end (to r))
                      (if (>= (from r) l)
                        (return nil))
                      (add [self.rec r])
                      (inc i))
               (if (< end l)
                 (add [self.rec end..:])))
             self.nf i)))
    (self.fs
      (when self.ft
        (throwf 'eval-error "awk: both fs and ft set"))
      (if (and (not self.kfs) (equal self.rec ""))
        (set self.fields nil
             self.nf 0)
        (let ((eff-fs (if self.par-mode
                        (if (equal self.fs self.par-mode-prev-fs)
                          self.par-mode-fs
                          (set self.par-mode-prev-fs self.fs
                               self.par-mode-fs
                               (regex-compile ^(or ,(if (regexp self.fs)
                                                      (regex-source self.fs)
                                                      self.fs)
                                                   "\n"))))
                        self.fs)))
          (set self.fields (split-str self.rec eff-fs self.kfs)
               self.nf (length self.fields)))))
    (self.ft
      (set self.fields (tok-str self.rec self.ft self.kfs)
           self.nf (length self.fields)))
    ((set self.fields (tok-str self.rec #/[^ \t\n]+/ self.kfs)
          self.nf (length self.fields)))))

(defmeth sys:awk-state f-to-rec (self)
  (set self.rec `@{self.fields self.ofs}`))

(defmeth sys:awk-state nf-to-f (self)
  (set self.fields (take self.nf (append self.fields (repeat '("")))))
  self.(f-to-rec))

(defmeth sys:awk-state loop (aws func beg-file-func end-file-func)
  (whilet ((in (pop aws.inputs)))
    (block :awk-file
      (inc aws.file-num)
      (set aws.file-name (if (streamp in)
                           (stream-get-prop in :name)
                           in))
      (when beg-file-func
        [beg-file-func aws])
      (let* ((*stdin* (cond
                        ((streamp in) in)
                        ((listp in) (make-strlist-input-stream in))
                        ((open-file in))))
             (noted-rs (not aws.rs))
             (noted-krs (not aws.krs))
             (cached-rr nil))
        (flet ((get-rec-reader (*stdin*)
                 (cond
                   ((and (equal noted-rs aws.rs) (eq noted-krs aws.krs))
                    cached-rr)
                   (t
                     (set noted-rs aws.rs noted-krs aws.krs)
                     (set cached-rr
                          (cond
                            ((and (equal aws.rs "\n") (not aws.krs))
                               (set aws.par-mode nil)
                               (lambda () (get-line *stdin*)))
                            ((null aws.rs)
                               (set aws.par-mode t)
                               (let ((rin (record-adapter #/\n[ \n\t]*\n/))
                                     (flag t))
                                 (lambda ()
                                   (let ((r (get-line rin)))
                                     (cond
                                       (flag
                                         (set flag nil)
                                         (if (equal r "")
                                           (get-line rin)
                                           r))
                                       (t r))))))
                            (t
                              (set aws.par-mode nil)
                              (let ((rin (record-adapter (if (regexp aws.rs)
                                                           aws.rs
                                                           (regex-compile aws.rs))
                                                         *stdin*
                                                         aws.krs)))
                                (lambda () (get-line rin))))))))))
          (set aws.file-rec-num 0)
          (unwind-protect
            (whilet ((rr (get-rec-reader *stdin*))
                     (rec (call rr)))
              (set aws.rec rec aws.orig-rec rec)
              (inc aws.rec-num)
              (inc aws.file-rec-num)
              (while* (eq :awk-again (block :awk-rec [func aws]))
                aws.(rec-to-f)))
            (when end-file-func
              [end-file-func aws])))))))

(defmeth sys:awk-state prn (self . args)
  (cond
    (args (for ((a args) next) (a) ((set a next))
            (put-string `@(car a)`)
            (put-string (if (set next (cdr a)) self.ofs self.ors))))
    (t (put-string self.rec)
       (put-string self.ors))))

(defmeth sys:awk-state ensure-stream (self kind path mode)
  (hash-update-1 self.streams
                 ^(,kind ,path)
                 (do or @1 (caseq kind
                             ((:inf :outf) (open-file path mode))
                             ((:inp :outp) (open-command path mode))))
                 nil))

(defmeth sys:awk-state close-or-flush (self stream kind path val)
  (cond
    ((eq val :close) (whenlet ((s (del [self.streams ^(,kind ,path)])))
                       (close-stream s)))
    ((memq kind '(:outf outp)) (flush-stream stream) val)
    (val)))

(defun sys:awk-test (val rec)
  (caseq (typeof val)
    ((regex fun) (call val rec))
    (t val)))

(defmacro sys:awk-redir (aws-sym stream-var kind mode path body)
  (with-gensyms (res-sym)
    ^(let ((,stream-var (qref ,aws-sym (ensure-stream ,kind ,path, mode))))
       ,(if body
          ^(qref ,aws-sym (close-or-flush ,stream-var ,kind ,path
                                          (progn ,*body)))
          stream-var))))

(defun sys:awk-expander (outer-env clauses)
  (let ((awc (new sys:awk-compile-time outer-env outer-env)))
    (each ((cl clauses))
      (tree-case cl
        ((pattern . actions) (caseql pattern
                               (:inputs
                                 (when awc.inputs
                                   (throwf 'eval-error
                                           "awk: duplicate :input clauses"))
                                 (set awc.inputs actions))
                               (:output
                                 (when awc.output
                                   (throwf 'eval-error
                                           "awk: duplicate :input clauses"))
                                 (when (or (atom actions) (cdr actions))
                                   (throwf 'eval-error
                                           "awk: bad :output syntax"))
                                 (set awc.output (car actions)))
                               (:name
                                 (when awc.name
                                   (throwf 'eval-error
                                           "awk: duplicate :name clauses"))
                                 (when (or (atom actions) (cdr actions))
                                   (throwf 'eval-error
                                           "awk: bad :name syntax"))
                                 (unless (car actions)
                                   (throwf 'eval-error
                                           "awk: null :name not permitted"))
                                 (unless (symbolp (car actions))
                                   (throwf 'eval-error
                                           "awk: :name must be a symbol"))
                                 (set awc.name (car actions)))
                               (:let (push actions awc.lets))
                               (:begin (push actions awc.begin-actions))
                               (:set (push ^((set ,*actions)) awc.begin-actions))
                               (:end (push actions awc.end-actions))
                               (:begin-file (push actions awc.begin-file-actions))
                               (:set-file (push ^((set ,*actions)) awc.begin-actions))
                               (:end-file (push actions awc.end-file-actions))
                               (t (push (if actions
                                          cl
                                          ^(,pattern (prn)))
                                        awc.cond-actions))))
        (junk (throwf 'eval-error "awk: bad clause syntax ~s" junk))))
    (set awc.lets [apply append (nreverse awc.lets)]
         awc.begin-actions [apply append (nreverse awc.begin-actions)]
         awc.end-actions [apply append (nreverse awc.end-actions)]
         awc.begin-file-actions [apply append (nreverse awc.begin-file-actions)]
         awc.end-file-actions [apply append (nreverse awc.end-file-actions)]
         awc.cond-actions (nreverse awc.cond-actions))
    awc))

(defun sys:awk-code-move-check (awc aws-sym mainform subform
                                suspicious-vars kind)
  (when suspicious-vars
    (compile-warning mainform "~!form ~s\n\
                               is moved out of the apparent scope\n\
                               and thus cannot refer to ~s ~s"
                     subform kind suspicious-vars)))

(defmacro sys:awk-mac-let (awc aws-sym . body)
  ^(symacrolet ((rec (rslot ,aws-sym 'rec 'rec-to-f))
                (orec (rslot ,aws-sym 'orig-rec 'rec-to-f))
                (f (rslot ,aws-sym 'fields 'f-to-rec))
                (nf (rslot ,aws-sym 'nf 'nf-to-f))
                (nr (qref ,aws-sym rec-num))
                (fnr (qref ,aws-sym file-rec-num))
                (arg (qref ,aws-sym file-num))
                (fname (qref ,aws-sym file-name))
                (rs (qref ,aws-sym rs))
                (krs (qref ,aws-sym krs))
                (fs (qref ,aws-sym fs))
                (ft (qref ,aws-sym ft))
                (fw (qref ,aws-sym fw))
                (kfs (qref ,aws-sym kfs))
                (ofs (qref ,aws-sym ofs))
                (ors (qref ,aws-sym ors)))
     (macrolet ((next () '(return-from :awk-rec))
                (again () '(return-from :awk-rec :awk-again))
                (next-file () '(return-from :awk-file))
                (sys:rng (form from-expr to-expr :env e)
                  (let ((style (car form))
                        (ix (pinc (qref ,awc nranges)))
                        (rng-temp (gensym))
                        (from-expr-ex (sys:expand from-expr e))
                        (to-expr-ex (sys:expand to-expr e))
                        (flag-old (gensym))
                        (flag-act (gensym))
                        (flag-deact (gensym)))
                    (tree-bind ((from-expr-ex fe-fv fe-ff fe-ev fe-ef)
                                (to-expr-ex te-fv te-ff te-ev te-ef)
                                (from-expr-orig to-expr-orig))
                               (list
                                 (sys:expand-with-free-refs from-expr e
                                                            ,awc.outer-env)
                                 (sys:expand-with-free-refs to-expr e
                                                            ,awc.outer-env)
                                 (list (cadr form) (caddr form)))
                      (sys:awk-code-move-check ,awc ',aws-sym
                                               form from-expr-orig
                                               (set-diff fe-ev fe-fv)
                                               'variables)
                      (sys:awk-code-move-check ,awc ',aws-sym
                                               form from-expr-orig
                                               (set-diff fe-ef fe-ff)
                                               'functions)
                      (sys:awk-code-move-check ,awc ',aws-sym
                                               form to-expr-orig
                                               (set-diff te-ev te-fv)
                                               'variables)
                      (sys:awk-code-move-check ,awc ',aws-sym
                                               form to-expr-orig
                                               (set-diff te-ef te-ff)
                                               'functions)
                      (push rng-temp (qref ,awc rng-expr-temps))
                      (push ^(placelet ((flag (vecref (qref ,',aws-sym rng-vec) ,ix)))
                               (let ((,flag-old flag) ,flag-act ,flag-deact)
                                 (when (or ,flag-old ,from-expr-ex)
                                   (set ,flag-act t))
                                 (when (and ,flag-act ,to-expr-ex)
                                   (set ,flag-act nil)
                                   (set ,flag-deact t))
                                 ,*(caseq style
                                     (rng ^((or (set flag ,flag-act)
                                                ,(if (and (plusp sys:compat)
                                                          (<= sys:compat 177))
                                                   flag-old
                                                   flag-deact))))
                                     (-rng- ^((and (set flag ,flag-act) ,flag-old)))
                                     (rng- ^((set flag ,flag-act)))
                                     (-rng ^((set flag ,flag-act) ,flag-old)))))
                            (qref ,awc rng-exprs))
                      rng-temp)))
                (rng (:form form from-expr to-expr)
                  ^(sys:rng ,form
                            (sys:awk-test ,from-expr ,(qref ,awc rng-rec-temp))
                            (sys:awk-test ,to-expr ,(qref ,awc rng-rec-temp))))
                (-rng (:form form from-expr to-expr)
                  ^(sys:rng ,form
                            (sys:awk-test ,from-expr ,(qref ,awc rng-rec-temp))
                            (sys:awk-test ,to-expr ,(qref ,awc rng-rec-temp))))
                (rng- (:form form from-expr to-expr)
                  ^(sys:rng ,form
                            (sys:awk-test ,from-expr ,(qref ,awc rng-rec-temp))
                            (sys:awk-test ,to-expr ,(qref ,awc rng-rec-temp))))
                (-rng- (:form form from-expr to-expr)
                  ^(sys:rng ,form
                            (sys:awk-test ,from-expr ,(qref ,awc rng-rec-temp))
                            (sys:awk-test ,to-expr ,(qref ,awc rng-rec-temp))))
                (ff (. opip-args)
                  ^(symacrolet ((f (rslot ,',aws-sym 'fields 'f-to-rec)))
                     (set f [(opip ,*opip-args) f])))
                (mf (. opip-args)
                  ^(symacrolet ((f (rslot ,',aws-sym 'fields 'f-to-rec)))
                     (set f (mapcar (opip ,*opip-args) f))))
                (fconv (. conv-args)
                  ^(set f (sys:conv (,*conv-args) f)))
                (-> (path . body)
                  ^(sys:awk-redir ,',aws-sym *stdout* :outf "w" ,path ,body))
                (->> (path . body)
                  ^(sys:awk-redir ,',aws-sym *stdout* :apf "a" ,path ,body))
                (<- (path . body)
                  ^(sys:awk-redir ,',aws-sym *stdin* :inf "r" ,path ,body))
                (!> (path . body)
                  ^(sys:awk-redir ,',aws-sym *stdout* :outp "w" ,path ,body))
                (<! (path . body)
                  ^(sys:awk-redir ,',aws-sym *stdin* :inp "r" ,path ,body)))
       ,*body)))

(defmacro sys:awk-fun-let (aws-sym . body)
  ^(flet ((prn (. args)
            (qref ,aws-sym (prn . args))))
     ,*body))

(defun sys:awk-fun-shadowing-env (up-env)
  (make-env nil '((prn . sys:special)) up-env))

(defmacro awk (:env outer-env . clauses)
  (let ((awc (sys:awk-expander outer-env clauses)))
    (with-gensyms (aws-sym awk-begf-fun awk-fun awk-endf-fun awk-retval)
      (let* ((p-actions-xform-unex (mapcar (aret ^(when (sys:awk-test ,@1 rec)
                                                    ,*@rest))
                                           awc.cond-actions))
             (p-actions-xform (sys:expand
                                ^(sys:awk-mac-let ,awc ,aws-sym
                                   ,*p-actions-xform-unex)
                                (sys:awk-fun-shadowing-env outer-env))))
        ^(block ,(or awc.name 'awk)
           (let* (,*awc.lets ,awk-retval
                  (,aws-sym (new sys:awk-state
                                 ,*(if awc.inputs ^(inputs (list ,*awc.inputs)))
                                 ,*(if awc.output ^(output ,awc.output))
                                 rng-n (macro-time (qref ,awc nranges)))))
             (sys:awk-mac-let ,awc ,aws-sym
               (sys:awk-fun-let ,aws-sym
                 (let* (,*(if awc.output
                            ^((*stdout* (qref ,aws-sym output))))
                        ,*(if (and awc.cond-actions awc.begin-file-actions)
                            ^((,awk-begf-fun (lambda (,aws-sym)
                                 ,*awc.begin-file-actions))))
                        ,*(if (and awc.cond-actions awc.end-file-actions)
                            ^((,awk-endf-fun (lambda (,aws-sym)
                                ,*awc.end-file-actions))))
                        ,*(if (or awc.cond-actions awc.begin-file-actions
                                  awc.end-file-actions awc.end-actions)
                            ^((,awk-fun (lambda (,aws-sym)
                                          ,(if awc.rng-exprs
                                             ^(let* ((,awc.rng-rec-temp rec)
                                                 ,*(nreverse
                                                     (zip awc.rng-expr-temps
                                                          awc.rng-exprs)))
                                                ,p-actions-xform)
                                             p-actions-xform))))))
                   ,*awc.begin-actions
                     (unwind-protect
                       ,(if (or awc.cond-actions awc.begin-file-actions
                                awc.end-file-actions awc.end-actions)
                          ^(qref ,aws-sym (loop ,awk-fun
                                            ,(if awc.begin-file-actions
                                               awk-begf-fun)
                                            ,(if awc.end-file-actions
                                               awk-endf-fun))))
                       (set ,awk-retval (progn ,*awc.end-actions))
                       (call-finalizers ,aws-sym))
                     ,awk-retval)))))))))