#include "kernel.h"
#include "stdinc.h"

typedef struct _wr_line
{
  struct _wr_line *next;
  char *s;
}
WrLine;

typedef struct
{
  void *previous;
  char *prevprompt;
  void (*exit_handler) (void *w, void *arg, int arglen);
  void (*old_inp_h) (char *str);
  char *prompt;
  void *arg;
  int arglen;
  int flags;
  int max_lines;
  int num_lines;
  WrLine *first, *last;
}
WrHead;

static void write_handler (char *line);

void start_writer (char *h, char *p, void *arg, int arglen,
		   void handler (void *x, void *arg, int arglen),
		   int flags, int max_lines)
{
  WrHead *w;
  
  if (handler == NULL || h == NULL || p == NULL || max_lines <= 0)
    return;
  w = NEW (WrHead, 1);
  w->previous = cur_player->writer;
  w->prevprompt = COPY (cur_player->prompt);
  w->exit_handler = handler;
  w->old_inp_h = cur_player->inp_handler->inp_handler;
  w->prompt = COPY (p);
  w->arg = BCOPY (arg, arglen);
  w->arglen = arglen;
  w->flags = flags;
  w->max_lines = max_lines;
  w->num_lines = 0;
  w->first = NULL;
  w->last = NULL;
  cur_player->writer = w;
  strcpy (cur_player->prompt, p);
  bprintf ("%s\n\n", h);
  write_handler (NULL);
}

static void write_handler (char *line)
{
  WrHead *w = (WrHead *) cur_player->writer;
  WrLine *l;
  int k;
  
  if ((k = (w->flags & WR_CMDCH)) == 0)
    k = '*';
  if (line == NULL)
    {
      replace_input_handler (write_handler);
    }
  else if (*line == k)
    {
      if (line[1] == k && line[2] == '\0')
	{
	  /* Exit writer. */
	  replace_input_handler (w->old_inp_h);   /* Back to old handler */
	  free (w->prompt);	/* Don't need the prompt any more */
	  if (w->first == NULL)
	    {			/* Let it point to text instead */
	      w->prompt = NULL;
	    }
	  else
	    {
	      w->prompt = w->first->s;
	    }
	  cur_player->writer = w->previous;
	  strcpy (cur_player->prompt, w->prevprompt);
	  free (w->prevprompt);
	  /* Don't need max lines anymore, use it for unget buffer */
	  w->max_lines = EOF;
	  w->exit_handler (w, w->arg, w->arglen);
	  bprintf ("\r%s", cur_player->prompt);
	  return;		/* Don't increment num_lines. */
	}
      else if ((w->flags & WR_CMD) != 0)
	{
	  gamecom (line + 1, True);
	}
      else
	{
	  bprintf ("You cannot execute any commands now.\n");
	}
    }
  else if (w->num_lines == w->max_lines)
    {
      bprintf ("You cannot type in more lines.\n");
    }
  else
    {
      l = NEW (WrLine, 1);
      l->s = COPY (line);
      l->next = NULL;
      if (w->first == NULL)
	{			/* First line. */
	  w->first = w->last = l;
	}
      else
	{
	  w->last->next = l;
	  w->last = l;
	}
      ++w->num_lines;
    }
  bprintf ("\r%s", cur_player->prompt);
}

int wnum_lines (void *x)
{
  WrHead *w = x;
  return w == 0 ? 0 : w->num_lines;
}

int wnum_chars (void *x)
{
  WrHead *w = x;
  WrLine *n;
  int k = 0;
  
  if (w == 0)
    return 0;
  for (n = w->first; n != 0; n = n->next)
    k += strlen (n->s);
  return k;
}

int wgetc (void *x)
{
  WrHead *w = x;
  WrLine *l;
  WrLine *n;
  int k;
  
  if (w == NULL)
    return EOF;
  if ((k = w->max_lines) != EOF)
    {
      w->max_lines = EOF;
      return k;			/* return unget character */
    }
  if (w->prompt == NULL)
    {
      free (w->arg);
      free (w);
      return EOF;
    }
  if ((k = *w->prompt++) == '\0')
    {
      /* End of this line, kill it and return '\n' */
      l = w->first;
      if ((n = w->first = l->next) == NULL)
	{
	  w->prompt = NULL;
	}
      else
	{
	  w->prompt = n->s;
	}
      w->num_lines--;
      free (l->s);
      free (l);
      return '\n';
    }
  else
    {
      return k;
    }
}

int wungetc (int c, void *x)
{
  WrHead *w;
  WrLine *l;
  
  if ((w = x) == NULL)
    return EOF;
  if (c == EOF)
    {
      while ((l = w->first) != NULL)
	{
	  w->first = l->next;
	  free (l->s);
	  free (l);
	}
      w->prompt = NULL;
      w->num_lines = 0;
      return EOF;
    }
  if ((l = w->first) != NULL && w->prompt > l->s)
    {
      *--(w->prompt) = c;
      return c;
    }
  /* Try to put it into max_lines */
  if (w->max_lines != EOF)
    return EOF;			/* Unable to push character back */
  w->max_lines = c;
  return c;
}

char *wgets (char *buf, int buflen, void *w)
{
  int i, k;
  char *s = buf;
  
  for (i = 1; i < buflen; i++)
    {
      if ((k = wgetc (w)) == EOF)
	{
	  *s = 0;
	  return NULL;
	}
      if ((*s++ = k) == '\n')
	break;
    }
  *s = 0;
  return buf;
}

void terminate_writer (void *w)
{
  if (w != NULL)
    {
      (void) wungetc (EOF, w);
      (void) wgetc (w);
    }
}

void terminate_all_writers (int plx)
{
  WrHead *w;
  WrHead *x;
  
  if (plx >= 0 && plx < max_players)
    {
      w = players[plx].writer;
      while ((x = w) != NULL)
	{
	  w = w->previous;
	  terminate_writer (x);
	}
    }
}