// (Readline is GPLed, so that makes this file GPLed too, because this
// file will only run if it's linked against readline.)
//
// Copyright (c) 2002 Tony Garnock-Jones
// Copyright (c) 2006 Heath Johns (paren bouncing and auto-completion code)
// Copyright (c) 2014 Alexej Magura (added a lot of history functions and more)
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <sys/poll.h>
#include <errno.h>
#include <alloca.h>
#include <readline/readline.h>
#include <readline/history.h>

#include "foreign.h"
#include "musthaves.h"

static int gnu_readline_bounce_ms = 500;
static int gnu_history_newlines = 0;
static char *gnu_readline_buf = (void *)NULL;
static bool rl_egg_clear = false;

struct balance {
     int paren[3];
     int brace[3];
     int quote;
} balnc;

static void clear_parbar(char token)
{
     int idx = 0;
     for (; idx < 3; ++idx) {
	  if (token == '(' || token == ')')
	       balnc.paren[idx] = 0;
	  if (token == '[' || token == ']')
	       balnc.brace[idx] = 0;
     }
}

static int parbar_in_string(char *str, char add_token)
{
     int *idxp = NULL;
     char sub_token = '\0';
     if (add_token == '(') {
	  idxp = balnc.paren;
	  sub_token = ')';
     } else if (add_token == '[') {
	  idxp = balnc.brace;
	  sub_token = ']';
     }

     char *cp = strchr(str, '\0');

     if (cp == str)
	  return 0;

     do {
	  if (cp != str && cpeek(cp, str, false) == '\\')
	       continue;

	  RD_DBG("balnc.quote: %d\n", balnc.quote);
	  if (*cp == add_token && balnc.quote < 1) {
	       ++(*idxp); // increment total
	       ++(*(++idxp)); // move to open, and increment
	       --idxp; // move back to total
	  } else if (*cp == sub_token && balnc.quote < 1) {
	       --(*idxp); // deincrement total
	       ++idxp; // move to open
	       ++(*(++idxp)); // move to close and increment
	       --idxp; // move back to open
	       --idxp; // move back to total
	  }
     } while (cp-- != str);
     return *idxp;
}

static int quote_in_string(char *str)
{
  if (str == NULL)
    return 0;

  char *cp = strchr(str, '\0');

  if (cp == str)
    return 0;

  do {
    if (cp != str && cpeek(cp, str, false) == '\\')
      continue;

    if (*cp == '"') {
      ++balnc.quote;
    }
  } while (cp-- != str);

  if (balnc.quote == 0)
    return -1;
  RD_DBG("return balance.quote: %d\n", balnc.quote);
  return balnc.quote % 2;
}

static HIST_ENTRY *last_history_entry(const bool del_current, const bool script)
{
     HIST_ENTRY *he;

     using_history();
#if RD_DEBUG
     if ((he = current_history()) != 0)
	  RD_DBG("current history: `%s'\n", he->line);
#endif
     if (del_current && !(script)) {
	  if ((he = current_history()) != 0) {
	       RD_DBG("deleting: `%s'\n", he->line);
	       free_history_entry(remove_history(where_history()));
	  } else if ((he = previous_history()) != 0) {
	       RD_DBG("deleting: `%s'\n", he->line);
	       free_history_entry(remove_history(where_history()));
	  }
     } else if (!script) {
	  previous_history();
     }
     he = previous_history();
     using_history();
     return he;
}

/* End of static functions */

int gnu_readline_skip(int pos, char open_key, char close_key)
{
     while (--pos > -1) {
	  if (pos > 0 && rl_line_buffer[pos - 1] == '\\')
	       continue;
	  else if (rl_line_buffer[pos] == open_key)
	       return pos;
	  else if (rl_line_buffer[pos] == close_key)
	       pos = gnu_readline_skip(pos, open_key, close_key);
	  else if (rl_line_buffer[pos] == '"')
	       pos = gnu_readline_skip(pos, '"', '"');
     }
     return pos;
}

// Finds the matching paren (starting from just left of the cursor)
int gnu_readline_find_match(char key)
{
     if (key == ')')
	  return gnu_readline_skip(rl_point - 1, '(', ')');
     else if (key == ']')
	  return gnu_readline_skip(rl_point - 1, '[', ']');
     return 0;
}

// Delays, but returns early if key press occurs
void gnu_readline_timid_delay(int ms)
{
     struct pollfd pfd;

     pfd.fd = fileno(rl_instream);
     pfd.events = POLLIN | /* | */ POLLPRI;
     pfd.revents = 0;
     poll(&pfd, 1, ms);
}
/* *** END ***
 * Inline Functions
 */

// Bounces the cursor to the matching paren for a while
int gnu_readline_paren_bounce(int count, int key)
{
     int insert_success;
     int old_point;
     int matching;

     if (gnu_readline_bounce_ms == 0)
	  return 0;

     // Write the just entered paren out first
     insert_success = rl_insert(count, key);
     if (insert_success != 0)
	  return insert_success;
     rl_redisplay();

     // Need at least two chars to bounce...
     if (rl_point < 2) // rl_point set to next char (implicit +1)
	  return 0;

     // If it's an escaped paren, don't bounce...
     if (rl_line_buffer[rl_point - 2] == '\\')
	  return 0;

     // Bounce
     old_point = rl_point;
     matching = gnu_readline_find_match(key);
     if (matching < 0)
	  return 0;
     else
	  rl_point = matching;
     rl_redisplay();
     gnu_readline_timid_delay(gnu_readline_bounce_ms);
     rl_point = old_point;
     return 0;
}

#if 0
void paren_match_highlights(char *match_color, char *no_match_color)
{
  paren_colors.with_match = (match_color[0] == '\0'
      ? "\x1b[36m"
      : match_color);
  paren_colors.without_match = (no_match_color[0] == '\0'
      ? "\x1b[35m"
      : no_match_color);
}
#endif

////\\\\//// Tab Completion ////\\\\////

// Prototype for callback into scm
#if !RD_TEST
C_word gnu_readline_scm_complete(char *, int, int);

// Gets called (repeatedly) when readline tries to do a completion
// FIXME, I use _strncpy_, but I should probably use _strlcpy_ or _strncat_
char *gnu_readline_tab_complete(const char *text, int status)
{
     C_word result;
     char *str;
     int len;
     char *copied_str;

  /* All of this is for older versions of chicken (< 2.3), which don't
     reliably null-terminate strings */

  // Get scheme string for possible completion via callback
     result = gnu_readline_scm_complete((char *)text, strlen(text), status);

     if (result == C_SCHEME_FALSE)
	  return NULL;

     // Convert into C types
     str = C_c_string(result);
     len = C_num_to_int(C_i_string_length(result));

     if (len == 0)
	  return NULL;

     // Copy (note: the readline lib frees this copy)
     copied_str = (char *)malloc(len + 1);
     strncpy(copied_str, str, len); /* XXX this probably isn't the best, although it is safe
				       thanks to the next line, way to copy these strings. */
     copied_str[len] = '\0';
     return copied_str;
}
#endif

// grants RO access to the gnu_history_newlines variable.
int gnu_history_new_lines()
{
     return gnu_history_newlines;
}

int gnu_readline_append_history(char *filename)
{
     return append_history(gnu_history_newlines, filename);
}

#if 0
void gnu_readline_highlight_matches()
{
  RD_DBG("match-position: %d\n", find_match(')'));
}
#endif
#if 0
char *gnu_make_arrow_code()
{};
#endif

// Set everything up
#if !RD_TEST
void gnu_readline_init()
{
     using_history();
     rl_bind_key(')', gnu_readline_paren_bounce);
     rl_bind_key(']', gnu_readline_paren_bounce);
#if 0
     rl_bind_keyseq("", highlight_paren);
#endif
     rl_completion_entry_function = &gnu_readline_tab_complete;
     rl_variable_bind("rl_catch_signals", 0);
     rl_clear_signals();
     rl_set_signals();
     rl_completer_quote_characters = "\"";
}

inline void noop()
{}

#define RL_EGG_BUILDST(FAKE, RL_NAME, RL_VAR, RL_DO_1)			\
  FAKE ## RL_NAME (int set)						\
  {									\
    if (set == -1)							\
      goto check;							\
    else if (set == false)						\
      RL_VAR && (RL_VAR = false);					\
    else								\
      RL_VAR || (RL_VAR = true);					\
  check:								\
    if (RL_VAR)								\
      RL_DO_1();							\
    return RL_VAR;							\
  }

bool RL_EGG_BUILDST(, clear_hist, rl_egg_clear, clear_history);

// Called from scheme to get user input
char *gnu_readline_readline(char *prompt, char *prompt2, bool norec)
{
     HIST_ENTRY *entry;

     if (gnu_readline_buf != NULL) {
	  free(gnu_readline_buf);
	  gnu_readline_buf = NULL;
     }

     if (!(balnc.quote || balnc.paren[0] || balnc.brace[0]))
	  gnu_readline_buf = readline(prompt);
     else
	  gnu_readline_buf = readline(prompt2);

     RD_DBG("norec: `%d'\n", norec);

     if (norec)
	  goto skipped;

     if (gnu_readline_buf != NULL && *gnu_readline_buf != '\0') {
	  entry = history_get(history_base + history_length - 1);
	  if (entry == NULL || strcmp(entry->line, gnu_readline_buf) != 0) {
	       add_history(gnu_readline_buf);
	       ++gnu_history_newlines;
	  }
     }

skipped:
     if (rl_end > 0) {
	  int adx = quote_in_string(rl_line_buffer);
	  RD_DBG("quote_in_string: %d\n", adx);
	  int bdx = parbar_in_string(rl_line_buffer, '(');
	  int cdx = parbar_in_string(rl_line_buffer, '[');
	  balnc.quote = (adx == -1 ? 0 : adx);
	  if (bdx == -1)
	       clear_parbar('(');
	  if (cdx == -1)
	       clear_parbar('[');
     }
     clear_hist(-1);
     return (gnu_readline_buf);
}
#endif

bool int_to_bool(int boo)
{
     return (bool)boo;
}

void gnu_readline_signal_cleanup()
{
     clear_parbar('(');
     clear_parbar('[');
     free(gnu_readline_buf);
     gnu_readline_buf = NULL;
     rl_free_line_state();
     rl_cleanup_after_signal();
}

char gnu_unclosed_exp()
{
     if (balnc.quote)
	  return 'q';
     else if (balnc.brace[0])
	  return 'b';
     else if (balnc.paren[0])
	  return 'p';
     return '\0';
}

char *last_history_line(const bool del_current, const bool script)
{
     RD_DBG("del_current: `%d'\n", del_current);
     RD_DBG("script: `%d'\n", script);
     HIST_ENTRY *he;
     if ((he = last_history_entry(del_current, script)) == 0)
	  return ((char *)NULL);
     return he->line;
}

void insert_last_history_line(const bool del_current, const bool script, const bool add_eol)
{
     char *text = (add_eol
		   ? cat(last_history_line(del_current, script), "\n")
		   : last_history_line(del_current, script));
     if (text != NULL) {
	  char *endp = strchr(text, '\0');
	  for (char *s = text; s != endp; ++s) {
	       rl_stuff_char(*s);
	  }
     }
     if (add_eol)
	  free(text);
}

char *current_history_line()
{
     HIST_ENTRY *he;
     using_history();

     if ((he = current_history()) == 0)
	  return ((char *)NULL);
     return he->line;
}

bool gnu_histpmove(int pos)
{
     using_history();
     if (pos == -1)
	  return (current_history() == NULL);
     return (bool)history_set_pos(pos);
}

void run_last_history_line(const bool del_current, const bool script)
{
     insert_last_history_line(del_current, script, true);
}

void safely_remove_history(int pos)
{
     using_history();
     free_history_entry(remove_history(pos));
}

/* safely concatenates the history_list's entry strings and returns them via a pointer */
char *gnu_history_list() /* may look a bit messy, but it seems to work great ;D */
{
     HIST_ENTRY **hist_list = history_list();
     int idx;

     if (hist_list == NULL)
	  return NULL;

     /* should be free'd by Chicken Scheme */
     const size_t hsize = (history_total_bytes()+1);
     char *rlist = malloc(hsize * (sizeof(*rlist)));
     bzero(rlist, hsize);

     catm(rlist, hsize-1, hist_list[0]->line, "\n");
     RD_DBG("buf@%d: %s\n", __LINE__, rlist);

     for (idx = 1; idx < history_length; ++idx) {
	  catm(rlist, hsize, rlist, hist_list[idx]->line, "\n");
     }
     return rlist;
}

int gnu_history_list_length()
{
     return history_length;
}