#define PERL_NO_GET_CONTEXT 1
#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"
#include "hook_op_check.h"
#undef printf
#include "stolen_chunk_of_toke.c"
#include <stdio.h>
#include <string.h>

#define PERL_VERSION_DECIMAL(r,v,s) (r*1000000 + v*1000 + s)
#define PERL_DECIMAL_VERSION \
  PERL_VERSION_DECIMAL(PERL_REVISION,PERL_VERSION,PERL_SUBVERSION)
#define PERL_VERSION_GE(r,v,s) \
  (PERL_DECIMAL_VERSION >= PERL_VERSION_DECIMAL(r,v,s))

#ifndef Newx
# define Newx(v,n,t) New(0,v,n,t)
#endif /* !Newx */

#define DD_DEBUGf_UPDATED_LINESTR 1
#define DD_DEBUGf_TRACE 2

#define DD_DEBUG_UPDATED_LINESTR (dd_debug & DD_DEBUGf_UPDATED_LINESTR)
#define DD_DEBUG_TRACE (dd_debug & DD_DEBUGf_TRACE)
static int dd_debug = 0;

#define DD_CONST_VIA_RV2CV PERL_VERSION_GE(5,11,2)

#define DD_GROW_VIA_BLOCKHOOK PERL_VERSION_GE(5,13,3)

#define LEX_NORMAL    10
#define LEX_INTERPNORMAL   9

/* please try not to have a line longer than this :) */

#define DD_PREFERRED_LINESTR_SIZE 16384

/* flag to trigger removal of temporary declaree sub */

static int in_declare = 0;

/* in 5.10, PL_parser will be NULL if we aren't parsing, and PL_lex_stuff
   is a lookup into it - so if anything else we can use to tell, so we
   need to be a bit more careful if PL_parser exists */

#define DD_AM_LEXING_CHECK (PL_lex_state == LEX_NORMAL || PL_lex_state == LEX_INTERPNORMAL)

#if defined(PL_parser) || defined(PERL_5_9_PLUS)
#define DD_HAVE_PARSER PL_parser
#define DD_HAVE_LEX_STUFF (PL_parser && PL_lex_stuff)
#define DD_AM_LEXING (PL_parser && DD_AM_LEXING_CHECK)
#else
#define DD_HAVE_PARSER 1
#define DD_HAVE_LEX_STUFF PL_lex_stuff
#define DD_AM_LEXING DD_AM_LEXING_CHECK
#endif

/* thing that decides whether we're dealing with a declarator */

int dd_is_declarator(pTHX_ char* name) {
  HV* is_declarator;
  SV** is_declarator_pack_ref;
  HV* is_declarator_pack_hash;
  SV** is_declarator_flag_ref;
  int dd_flags;
  char* curstash_name;

  is_declarator = get_hv("Devel::Declare::declarators", FALSE);

  if (!is_declarator)
    return -1;

  /* $declarators{$current_package_name} */

  curstash_name = HvNAME(PL_curstash);
  if (!curstash_name)
    return -1;

  is_declarator_pack_ref = hv_fetch(is_declarator, curstash_name,
                             strlen(curstash_name), FALSE);

  if (!is_declarator_pack_ref || !SvROK(*is_declarator_pack_ref))
    return -1; /* not a hashref */

  is_declarator_pack_hash = (HV*) SvRV(*is_declarator_pack_ref);

  /* $declarators{$current_package_name}{$name} */

  is_declarator_flag_ref = hv_fetch(
    is_declarator_pack_hash, name,
    strlen(name), FALSE
  );

  /* requires SvIOK as well as TRUE since flags not being an int is useless */

  if (!is_declarator_flag_ref
        || !SvIOK(*is_declarator_flag_ref)
        || !SvTRUE(*is_declarator_flag_ref))
    return -1;

  dd_flags = SvIVX(*is_declarator_flag_ref);

  return dd_flags;
}

/* callback thingy */

void dd_linestr_callback (pTHX_ char* type, char* name) {

  char* linestr = SvPVX(PL_linestr);
  int offset = PL_bufptr - linestr;

  dSP;

  ENTER;
  SAVETMPS;

  PUSHMARK(SP);
  XPUSHs(sv_2mortal(newSVpv(type, 0)));
  XPUSHs(sv_2mortal(newSVpv(name, 0)));
  XPUSHs(sv_2mortal(newSViv(offset)));
  PUTBACK;

  call_pv("Devel::Declare::linestr_callback", G_VOID|G_DISCARD);

  FREETMPS;
  LEAVE;
}

char* dd_get_linestr(pTHX) {
  if (!DD_HAVE_PARSER) {
    return NULL;
  }
  return SvPVX(PL_linestr);
}

void dd_set_linestr(pTHX_ char* new_value) {
  unsigned int new_len = strlen(new_value);

  if (SvLEN(PL_linestr) < new_len) {
    croak("PL_linestr not long enough, was Devel::Declare loaded soon enough in %s",
      CopFILE(&PL_compiling)
    );
  }


  memcpy(SvPVX(PL_linestr), new_value, new_len+1);

  SvCUR_set(PL_linestr, new_len);

  PL_bufend = SvPVX(PL_linestr) + new_len;

  if ( DD_DEBUG_UPDATED_LINESTR && PERLDB_LINE && PL_curstash != PL_debstash) {
    /* Cribbed from toke.c */
    AV *fileav = CopFILEAV(&PL_compiling);
    if (fileav) {
      SV * const sv = NEWSV(85,0);

      sv_upgrade(sv, SVt_PVMG);
      sv_setpvn(sv,PL_bufptr,PL_bufend-PL_bufptr);
      (void)SvIOK_on(sv);
      SvIV_set(sv, 0);
      av_store(fileav,(I32)CopLINE(&PL_compiling),sv);
    }
  }
}

char* dd_get_lex_stuff(pTHX) {
  return (DD_HAVE_LEX_STUFF ? SvPVX(PL_lex_stuff) : "");
}

void dd_clear_lex_stuff(pTHX) {
  if (DD_HAVE_PARSER)
    PL_lex_stuff = (SV*)NULL;
}

char* dd_get_curstash_name(pTHX) {
  return HvNAME(PL_curstash);
}

int dd_get_linestr_offset(pTHX) {
  char* linestr;
  if (!DD_HAVE_PARSER) {
    return -1;
  }
  linestr = SvPVX(PL_linestr);
  return PL_bufptr - linestr;
}

char* dd_move_past_token (pTHX_ char* s) {

  /*
   *   buffer will be at the beginning of the declarator, -unless- the
   *   declarator is at EOL in which case it'll be the next useful line
   *   so we don't short-circuit out if we don't find the declarator
   */

  while (s < PL_bufend && isSPACE(*s)) s++;
  if (memEQ(s, PL_tokenbuf, strlen(PL_tokenbuf)))
    s += strlen(PL_tokenbuf);
  return s;
}

int dd_toke_move_past_token (pTHX_ int offset) {
  char* base_s = SvPVX(PL_linestr) + offset;
  char* s = dd_move_past_token(aTHX_ base_s);
  return s - base_s;
}

int dd_toke_scan_word(pTHX_ int offset, int handle_package) {
  char tmpbuf[sizeof PL_tokenbuf];
  char* base_s = SvPVX(PL_linestr) + offset;
  STRLEN len;
  char* s = scan_word(base_s, tmpbuf, sizeof tmpbuf, handle_package, &len);
  return s - base_s;
}

int dd_toke_scan_ident(pTHX_ int offset) {
    char tmpbuf[sizeof PL_tokenbuf];
    char* base_s = SvPVX(PL_linestr) + offset;
    char* s = scan_ident(base_s, PL_bufend, tmpbuf, sizeof tmpbuf, 0);
    return s - base_s;
}

int dd_toke_scan_str(pTHX_ int offset) {
  char* old_pvx = SvPVX(PL_linestr);
  SV* line_copy = sv_2mortal(newSVsv(PL_linestr));
  char* base_s = SvPVX(PL_linestr) + offset;
  char* s = scan_str(base_s, FALSE, FALSE);
  if(SvPVX(PL_linestr) != old_pvx)
    croak("PL_linestr reallocated during scan_str, "
      "Devel::Declare can't continue");
  if (!s)
    return 0;
  if (s <= base_s || memcmp(SvPVX(line_copy), SvPVX(PL_linestr), offset)) {
    s += SvCUR(line_copy);
    sv_catsv(line_copy, PL_linestr);
    dd_set_linestr(aTHX_ SvPV_nolen(line_copy));
  }
  return s - base_s;
}

int dd_toke_skipspace(pTHX_ int offset) {
  char* old_pvx = SvPVX(PL_linestr);
  char* base_s = SvPVX(PL_linestr) + offset;
  char* s = skipspace_force(base_s);
  if(SvPVX(PL_linestr) != old_pvx)
    croak("PL_linestr reallocated during skipspace, "
      "Devel::Declare can't continue");
  return s - base_s;
}

static void call_done_declare(pTHX) {
  dSP;

  if (DD_DEBUG_TRACE) {
    printf("Deconstructing declare\n");
    printf("PL_bufptr: %s\n", PL_bufptr);
    printf("bufend at: %i\n", (int)(PL_bufend - PL_bufptr));
    printf("linestr: %s\n", SvPVX(PL_linestr));
    printf("linestr len: %i\n", (int)(PL_bufend - SvPVX(PL_linestr)));
  }

  ENTER;
  SAVETMPS;

  PUSHMARK(SP);

  call_pv("Devel::Declare::done_declare", G_VOID|G_DISCARD);

  FREETMPS;
  LEAVE;

  if (DD_DEBUG_TRACE) {
    printf("PL_bufptr: %s\n", PL_bufptr);
    printf("bufend at: %i\n", (int)(PL_bufend - PL_bufptr));
    printf("linestr: %s\n", SvPVX(PL_linestr));
    printf("linestr len: %i\n", (int)(PL_bufend - SvPVX(PL_linestr)));
    printf("actual len: %i\n", (int)strlen(PL_bufptr));
  }
}

static int dd_handle_const(pTHX_ char *name);

#ifdef CV_NAME_NOTQUAL /* 5.21.5 */
# define Gv_or_CvNAME(g) (isGV(g) \
               ? GvNAME(g) \
               : SvPV_nolen(cv_name((CV *)SvRV(g), NULL, CV_NAME_NOTQUAL)))
#elif defined(CvNAMED) /* 5.21.4 */
# define Gv_or_CvNAME(g) (isGV(g) \
                            ? GvNAME(g) \
                            : CvNAMED(SvRV(g)) \
                                ? HEK_KEY(CvNAME_HEK((CV *)SvRV(g))) \
                                : GvNAME(CvGV(SvRV(g))))
#else
# define Gv_or_CvNAME(g) GvNAME(g)
#endif

/* replacement PL_check rv2cv entry */

STATIC OP *dd_ck_rv2cv(pTHX_ OP *o, void *user_data) {
  OP* kid;
  int dd_flags;
  char *gvname;

  PERL_UNUSED_VAR(user_data);

  if (!DD_AM_LEXING)
    return o; /* not lexing? */

  if (in_declare) {
    call_done_declare(aTHX);
    return o;
  }

  kid = cUNOPo->op_first;

  if (kid->op_type != OP_GV) /* not a GV so ignore */
    return o;

  if (!isGV(kGVOP_gv)
   && (!SvROK(kGVOP_gv) || SvTYPE(SvRV(kGVOP_gv)) != SVt_PVCV))
    return o;

  gvname = Gv_or_CvNAME(kGVOP_gv);

  if (DD_DEBUG_TRACE) {
    printf("Checking GV %s -> %s\n", HvNAME(GvSTASH(kGVOP_gv)), gvname);
  }

  dd_flags = dd_is_declarator(aTHX_ gvname);

  if (dd_flags == -1)
    return o;

  if (DD_DEBUG_TRACE) {
    printf("dd_flags are: %i\n", dd_flags);
    printf("PL_tokenbuf: %s\n", PL_tokenbuf);
  }

#if DD_CONST_VIA_RV2CV
  if (PL_expect != XOPERATOR) {
    if (!dd_handle_const(aTHX_ Gv_or_CvNAME(kGVOP_gv)))
      return o;
    CopLINE(PL_curcop) = PL_copline;
    /* The parser behaviour that we're simulating depends on what comes
       after the declarator. */
    if (*skipspace(PL_bufptr + strlen(gvname)) != '(') {
      if (in_declare) {
        call_done_declare(aTHX);
      } else {
        dd_linestr_callback(aTHX_ "rv2cv", gvname);
      }
    }
    return o;
  }
#endif /* DD_CONST_VIA_RV2CV */

  dd_linestr_callback(aTHX_ "rv2cv", gvname);

  return o;
}

#if DD_GROW_VIA_BLOCKHOOK

static void dd_block_start(pTHX_ int full)
{
  PERL_UNUSED_VAR(full);
  if (SvLEN(PL_linestr) < DD_PREFERRED_LINESTR_SIZE)
    (void) lex_grow_linestr(DD_PREFERRED_LINESTR_SIZE);
}

#else /* !DD_GROW_VIA_BLOCKHOOK */

OP* dd_pp_entereval(pTHX) {
  dSP;
  STRLEN len;
  const char* s;
  SV *sv;
#ifdef PERL_5_9_PLUS
  SV *saved_hh = NULL;
  if (PL_op->op_private & OPpEVAL_HAS_HH) {
    saved_hh = POPs;
  }
#endif
  sv = POPs;
  if (SvPOK(sv)) {
    if (DD_DEBUG_TRACE) {
      printf("mangling eval sv\n");
    }
    if (SvREADONLY(sv))
      sv = sv_2mortal(newSVsv(sv));
    s = SvPVX(sv);
    len = SvCUR(sv);
    if (!len || s[len-1] != ';') {
      if (!(SvFLAGS(sv) & SVs_TEMP))
        sv = sv_2mortal(newSVsv(sv));
      sv_catpvn(sv, "\n;", 2);
    }
    SvGROW(sv, DD_PREFERRED_LINESTR_SIZE);
  }
  PUSHs(sv);
#ifdef PERL_5_9_PLUS
  if (PL_op->op_private & OPpEVAL_HAS_HH) {
    PUSHs(saved_hh);
  }
#endif
  return PL_ppaddr[OP_ENTEREVAL](aTHX);
}

STATIC OP *dd_ck_entereval(pTHX_ OP *o, void *user_data) {
  PERL_UNUSED_VAR(user_data);

  if (o->op_ppaddr == PL_ppaddr[OP_ENTEREVAL])
    o->op_ppaddr = dd_pp_entereval;
  return o;
}

#endif /* !DD_GROW_VIA_BLOCKHOOK */

static I32 dd_filter_realloc(pTHX_ int idx, SV *sv, int maxlen)
{
  SV *filter_datasv;
  const I32 count = FILTER_READ(idx+1, sv, maxlen);
  SvGROW(sv, DD_PREFERRED_LINESTR_SIZE);
  /* Filters can only be deleted in the correct order (reverse of the
     order in which they were added).  Insisting on deleting the filter
     here would break if another filter were added after ours and is
     still around.  Not deleting the filter at all would break if another
     filter were added earlier and attempts to delete itself later.
     We can play nicely to the maximum possible extent by deleting our
     filter iff it is currently deletable (i.e., it is on the top of
     the filter stack).  Can still run into trouble in more complex
     situations, but can't avoid that. */
  if (PL_rsfp_filters && AvFILLp(PL_rsfp_filters) >= 0 &&
      (filter_datasv = FILTER_DATA(AvFILLp(PL_rsfp_filters))) &&
      IoANY(filter_datasv) == FPTR2DPTR(void *, dd_filter_realloc)) {
    filter_del(dd_filter_realloc);
  }
  return count;
}

static int dd_handle_const(pTHX_ char *name) {
  switch (PL_lex_inwhat) {
    case OP_QR:
    case OP_MATCH:
    case OP_SUBST:
    case OP_TRANS:
    case OP_BACKTICK:
    case OP_STRINGIFY:
      return 0;
      break;
    default:
      break;
  }

  if (strnEQ(PL_bufptr, "->", 2)) {
    return 0;
  }

  {
    char buf[256];
    STRLEN len;
    char *s = PL_bufptr;
    STRLEN old_offset = PL_bufptr - SvPVX(PL_linestr);

    s = scan_word(s, buf, sizeof buf, FALSE, &len);
    if (strnEQ(buf, name, len)) {
      char *d;
      SV *inject = newSVpvn(SvPVX(PL_linestr), PL_bufptr - SvPVX(PL_linestr));
      sv_catpvn(inject, buf, len);

      d = peekspace(s);
      sv_catpvn(inject, s, d - s);

      if ((PL_bufend - d) >= 2 && strnEQ(d, "=>", 2)) {
        return 0;
      }

      sv_catpv(inject, d);
      dd_set_linestr(aTHX_ SvPV_nolen(inject));
      PL_bufptr = SvPVX(PL_linestr) + old_offset;
      SvREFCNT_dec (inject);
    }
  }

  dd_linestr_callback(aTHX_ "const", name);

  return 1;
}

#if !DD_CONST_VIA_RV2CV

STATIC OP *dd_ck_const(pTHX_ OP *o, void *user_data) {
  int dd_flags;
  char* name;

  PERL_UNUSED_VAR(user_data);

  if (DD_HAVE_PARSER && PL_expect == XOPERATOR) {
    return o;
  }

  /* if this is set, we just grabbed a delimited string or something,
     not a bareword, so NO TOUCHY */

  if (DD_HAVE_LEX_STUFF)
    return o;

  /* don't try and look this up if it's not a string const */
  if (!SvPOK(cSVOPo->op_sv))
    return o;

  name = SvPVX(cSVOPo->op_sv);

  dd_flags = dd_is_declarator(aTHX_ name);

  if (dd_flags == -1)
    return o;

  dd_handle_const(aTHX_ name);

  return o;
}

#endif /* !DD_CONST_VIA_RV2CV */

STATIC void dd_initialize(pTHX) {
  static int initialized = 0;
  if (!initialized) {
    initialized = 1;
#if DD_GROW_VIA_BLOCKHOOK
    {
      static BHK bhk;
#if PERL_VERSION_GE(5,13,6)
      BhkENTRY_set(&bhk, bhk_start, dd_block_start);
#else /* <5.13.6 */
      BhkENTRY_set(&bhk, start, dd_block_start);
#endif /* <5.13.6 */
      Perl_blockhook_register(aTHX_ &bhk);
    }
#else /* !DD_GROW_VIA_BLOCKHOOK */
    hook_op_check(OP_ENTEREVAL, dd_ck_entereval, NULL);
#endif /* !DD_GROW_VIA_BLOCKHOOK */
    hook_op_check(OP_RV2CV, dd_ck_rv2cv, NULL);
#if !DD_CONST_VIA_RV2CV
    hook_op_check(OP_CONST, dd_ck_const, NULL);
#endif /* !DD_CONST_VIA_RV2CV */
  }
}

MODULE = Devel::Declare  PACKAGE = Devel::Declare

PROTOTYPES: DISABLE

void
initialize()
  CODE:
    dd_initialize(aTHX);

void
setup()
  CODE:
    dd_initialize(aTHX);
    filter_add(dd_filter_realloc, NULL);

char*
get_linestr()
  CODE:
    RETVAL = dd_get_linestr(aTHX);
  OUTPUT:
    RETVAL

void
set_linestr(char* new_value)
  CODE:
    dd_set_linestr(aTHX_ new_value);

char*
get_lex_stuff()
  CODE:
    RETVAL = dd_get_lex_stuff(aTHX);
  OUTPUT:
    RETVAL

void
clear_lex_stuff()
  CODE:
    dd_clear_lex_stuff(aTHX);

char*
get_curstash_name()
  CODE:
    RETVAL = dd_get_curstash_name(aTHX);
  OUTPUT:
    RETVAL

int
get_linestr_offset()
  CODE:
    RETVAL = dd_get_linestr_offset(aTHX);
  OUTPUT:
    RETVAL

int
toke_scan_word(int offset, int handle_package)
  CODE:
    RETVAL = dd_toke_scan_word(aTHX_ offset, handle_package);
  OUTPUT:
    RETVAL

int
toke_move_past_token(int offset);
  CODE:
    RETVAL = dd_toke_move_past_token(aTHX_ offset);
  OUTPUT:
    RETVAL

SV*
toke_scan_str(int offset);
  PREINIT:
    int len;
  CODE:
    len = dd_toke_scan_str(aTHX_ offset);
    RETVAL = len ? newSViv(len) : &PL_sv_undef;
  OUTPUT:
    RETVAL

int
toke_scan_ident(int offset)
  CODE:
    RETVAL = dd_toke_scan_ident(aTHX_ offset);
  OUTPUT:
    RETVAL

int
toke_skipspace(int offset)
  CODE:
    RETVAL = dd_toke_skipspace(aTHX_ offset);
  OUTPUT:
    RETVAL

int
get_in_declare()
  CODE:
    RETVAL = in_declare;
  OUTPUT:
    RETVAL

void
set_in_declare(int value)
  CODE:
    in_declare = value;

BOOT:
{
  char *endptr;
  char *debug_str = getenv ("DD_DEBUG");
  if (debug_str) {
    dd_debug = strtol (debug_str, &endptr, 10);
    if (*endptr != '\0') {
      dd_debug = 0;
    }
  }
}