/*************************************************************************
*									 *
*	 YAP Prolog 							 *
*									 *
*	Yap Prolog was developed at NCCUP - Universidade do Porto	 *
*									 *
* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997	 *
*									 *
**************************************************************************
*									 *
* File:		readline.c *
* Last rev:	5/2/88							 *
* mods:									 *
* comments:	Input/Output C implemented predicates			 *
*									 *
*************************************************************************/
#ifdef SCCS
static char SccsId[] = "%W% %G%";
#endif

/*
 * This file includes the interface to the readline library, if installed in the
 *system.
 *
 */

#include "Yap.h"
#include "Yatom.h"
#include "YapHeap.h"
#include "yapio.h"
#include <stdlib.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_STDARG_H
#include <stdarg.h>
#endif
#ifdef _WIN32
#if HAVE_IO_H
/* Windows */
#include <io.h>
#endif
#if HAVE_SOCKET
#include <winsock2.h>
#endif
#include <windows.h>
#ifndef S_ISDIR
#define S_ISDIR(x) (((x)&_S_IFDIR) == _S_IFDIR)
#endif
#endif

#include "iopreds.h"

#if defined(USE_READLINE)

#include <readline/readline.h>
#include <readline/history.h>

static int ReadlineGetc(int);
static int ReadlinePutc(int, int);

static const char *history_file;

#define READLINE_OUT_BUF_MAX 256

typedef struct scan_atoms {
  Int pos;
  Atom atom;
} scan_atoms_t;

static char *atom_enumerate(const char *prefix, int state) {
  CACHE_REGS
  struct scan_atoms *index;
  Atom catom;
  Int i;

  if (!state) {
    index = (struct scan_atoms *)malloc(sizeof(struct scan_atoms));
    i = 0;
    catom = NIL;
  } else {
    CACHE_REGS
    index = LOCAL_search_atoms;
    catom = index->atom;
    i = index->pos;
  }

  while (catom != NIL || i < AtomHashTableSize) {
    //    if ( is_signalled() )		/* Notably allow windows version */
    //      PL_handle_signals();		/* to break out on ^C */
    AtomEntry *ap;

    if (catom == NIL) {
      /* move away from current hash table line */
      READ_LOCK(HashChain[i].AERWLock);
      catom = HashChain[i].Entry;
      READ_UNLOCK(HashChain[i].AERWLock);
      i++;
    } else {
      ap = RepAtom(catom);
      READ_LOCK(ap->ARWLock);
      if (strstr((char *)ap->StrOfAE, prefix) == (char *)ap->StrOfAE) {
        index->pos = i;
        index->atom = ap->NextOfAE;
        LOCAL_search_atoms = index;
        READ_UNLOCK(ap->ARWLock);
        return ap->StrOfAE;
      }
      catom = ap->NextOfAE;
      READ_UNLOCK(ap->ARWLock);
    }
  }
  LOCAL_search_atoms = NULL;
  free(index);
  return NULL;
}

static char *atom_generator(const char *prefix, int state) {
  char *s = atom_enumerate(prefix, state);

  if (s) {
    char *copy = malloc(1 + strlen(s));

    if (copy) /* else pretend no completion */
      strcpy(copy, s);
    s = copy;
  }

  return s;
}

static char **prolog_completion(const char *text, int start, int end) {
  char **matches = NULL;

  if ((start == 1 && rl_line_buffer[0] == '[') || /* [file */
      (start == 2 && strncmp(rl_line_buffer, "['", 2)))
    matches = rl_completion_matches((char *)text, /* for pre-4.2 */
                                    rl_filename_completion_function);
  else
    matches = rl_completion_matches((char *)text, atom_generator);

  return matches;
}

void Yap_ReadlineFlush(int sno) {
  if (GLOBAL_Stream[sno].status & Tty_Stream_f &&
      GLOBAL_Stream[sno].status & Output_Stream_f) {
    rl_redisplay();
  }
}

bool Yap_ReadlinePrompt(StreamDesc *s) {
  if (s->status & Tty_Stream_f) {
    s->stream_getc = ReadlineGetc;
    if (GLOBAL_Stream[0].status & Tty_Stream_f &&
        s->name == GLOBAL_Stream[0].name)
      s->stream_putc = ReadlinePutc;
    return true;
  }
  return false;
}

bool Yap_ReadlineOps(StreamDesc *s) {
  if (s->status & Tty_Stream_f) {
    if (GLOBAL_Stream[0].status & Tty_Stream_f &&
        is_same_tty(s->file, GLOBAL_Stream[0].file))
      s->stream_putc = ReadlinePutc;
    s->stream_getc = ReadlineGetc;
    return true;
  }
  return false;
}

static int prolog_complete(int ignore, int key) {
  if (rl_point > 0 && rl_line_buffer[rl_point - 1] != ' ') {
#if HAVE_DECL_RL_CATCH_SIGNALS_ /* actually version >= 1.2, or true readline   \
                                   */
    rl_begin_undo_group();
    rl_complete(ignore, key);
    if (rl_point > 0 && rl_line_buffer[rl_point - 1] == ' ') {
      rl_delete_text(rl_point - 1, rl_point);
      rl_point -= 1;
      rl_delete(-1, key);
    }
    rl_end_undo_group();
#endif
  } else
    rl_complete(ignore, key);

  return 0;
}

static void InitReadline(void) {
  // don't call readline within emacs
  // if (getenv("ËMACS"))
  //  return;
  GLOBAL_Stream[StdInStream].u.irl.buf = NULL;
  GLOBAL_Stream[StdInStream].u.irl.ptr = NULL;
#if _MSC_VER || defined(__MINGW32__)
  rl_instream = stdin;
#endif
  rl_outstream = stderr;
  using_history();
  char *s = Yap_AbsoluteFile("~/.YAP.history", NULL, true);
  if (!read_history(s)) {
    FILE *f = fopen(s, "w");
    if (f) {
      fclose(f);
      read_history(s);
    }
  }
  rl_readline_name = "Prolog";
  rl_attempted_completion_function = prolog_completion;
#ifdef HAVE_RL_COMPLETION_FUNC_T
  rl_add_defun("prolog-complete", prolog_complete, '\t');
#else
  rl_add_defun("prolog-complete", (void *)prolog_complete, '\t');
#endif
}

static bool getLine(int inp, int out) {
  CACHE_REGS
  rl_instream = GLOBAL_Stream[inp].file;
  rl_outstream = GLOBAL_Stream[out].file;
  const char *myrl_line;
  StreamDesc *s = GLOBAL_Stream + inp;

  if (!(s->status & Tty_Stream_f))
    return false;

  /* window of vulnerability opened */
  LOCAL_PrologMode |= ConsoleGetcMode;

  if (GLOBAL_Stream[out].linepos == 0) { // no output so far
    fflush(NULL);
    myrl_line = readline(LOCAL_Prompt);
  } else {
    LOCAL_PrologMode |= ConsoleGetcMode;
    myrl_line = readline(NULL);
  }
  /* Do it the gnu way */
  if (LOCAL_PrologMode & InterruptMode) {
    Yap_external_signal(0, YAP_INT_SIGNAL);
    LOCAL_PrologMode &= ~ConsoleGetcMode;
    if (LOCAL_PrologMode & AbortMode) {
      Yap_Error(ABORT_EVENT, TermNil, "");
      LOCAL_ErrorMessage = "Abort";
      return console_post_process_eof(s);
    }
  } else {
    LOCAL_PrologMode &= ~ConsoleGetcMode;
  }
  strncpy(LOCAL_Prompt, RepAtom(LOCAL_AtPrompt)->StrOfAE, MAX_PROMPT);
  /* window of vulnerability closed */
  if (myrl_line == NULL)
    return false;
  if (myrl_line[0] != '\0' && myrl_line[1] != '\0') {
    add_history(myrl_line);
    append_history(1, history_file);
  }
  s->u.irl.ptr = s->u.irl.buf = myrl_line;
  return true;
}

static int ReadlinePutc(int sno, int ch) {
  StreamDesc *s = &GLOBAL_Stream[sno];
#if MAC || _MSC_VER || defined(__MINGW32__)
  if (ch == 10) {
    putc('\n', s->file);
  } else
#endif
    putc(ch, s->file);
  console_count_output_char(ch, s);
  if (ch == 10) {
    Yap_ReadlineFlush(sno);
  }
  return ((int)ch);
}

/*
  reading from the console is complicated because we need to
  know whether to prompt and so on...
*/
static int ReadlineGetc(int sno) {
  StreamDesc *s = &GLOBAL_Stream[sno];
  int ch;
  bool fetch = (s->u.irl.buf == NULL);

  if (!fetch || getLine(sno, StdErrStream)) {
    const char *ttyptr = s->u.irl.ptr++, *myrl_line = s->u.irl.buf;
    ch = *ttyptr;
    if (ch == '\0') {
      ch = '\n';
      free((void *)myrl_line);
      s->u.irl.ptr = s->u.irl.buf = NULL;
    }
  } else {
    return EOF;
  }
  return console_post_process_read_char(ch, s);
}

int Yap_ReadlineForSIGINT(void) {
  CACHE_REGS
  int ch;
  StreamDesc *s = &GLOBAL_Stream[StdInStream];
  const char *myrl_line = s->u.irl.buf;

  if ((LOCAL_PrologMode & ConsoleGetcMode) && myrl_line != (char *)NULL) {
    ch = myrl_line[0];
    free((void *)myrl_line);
    myrl_line = NULL;
    return ch;
  } else {
    myrl_line = readline("Action (h for help): ");
    if (!myrl_line) {
      ch = EOF;
      return ch;
    } else {
      ch = myrl_line[0];
      free((void *)myrl_line);
      myrl_line = NULL;
      return ch;
    }
  }
}

static Int has_readline(USES_REGS1) {
#if USE_READLINE
  return true;
#else
  return false;
#endif
}

void Yap_InitReadline(void) {
  Yap_InitCPred("$has_readline", 0, has_readline,
                SafePredFlag | HiddenPredFlag);
  InitReadline();
}

#endif