/*
 * Utility routines which interact with the user.
 */

#include <curses.h>
#include <stdarg.h>
#include <setjmp.h>
#include <strings.h>

#include "pline.h"
#include "debug.h"
#include "structs.h"
#include "signals.h"
#include "display.h"

#include "disputil.h"

/*
 * Display a prompt and accept an input string.  prompt is, of course,
 *  the prompt.  buf and buflen describe the buffer available for the
 *  input string.  flags is a bitmask, containing zero or more of
 *
 *	PRF_NOSTD
 *		Don't handle the standard characters; pass _all_ typed
 *		input to the approval function.
 *
 *  approval is a function which decides what to do in response to each
 *  typed character.  Its return value is one of
 *
 *	CHOK_OK
 *		Accept this character and add it to the string;
 *		continue reading.
 *	CHOK_BAD
 *  		Don't accept this character, but do continue reading.
 *	CHOK_TERM
 *		Accept this character, add it to the string, but also
 *		terminate the read operation.
 *	CHOK_TERMNS
 *		Don't add this character to the string, but do
 *		terminate the read with the string so far.
 *	CHOK_ABORT
 *		Abort the read operation.
 *	CHOK_DEL
 *		Delete the previous character, if any.  (Like termios's
 *		ERASE character.)
 *	CHOK_CLEAR
 *		Delete the entire string-so-far.  (Like termios's KILL
 *		character.)
 *
 * PRF_NOSTD is implemented by using an internal approval function
 *  which handles the standard characters and, for other characters,
 *  calls the provided approval function.
 *
 * A SIGINT received during this produces an abort condition, as if it
 *  had been a CHOK_ABORT character.
 *
 * There is no line editing beyond CHOK_DEL and CHOK_CLEAR.
 *
 * The standard characters are
 *
 *	ESC		CHOK_ABORT
 *	CR (^M)		CHOK_TERMNS
 *	LF/NL (^J)	CHOK_TERMNS
 *	DEL		CHOK_DEL
 *	BS (^H)		CHOK_DEL
 *	CAN (^X)	CHOK_CLEAR
 *	NAK (^U)	CHOK_CLEAR
 *
 * Note that a terminating NUL is always provided on successful
 *  returns, so the maximum string length accepted is buflen-1.
 *
 * The return value is one of
 *
 *	PR_OK
 *		Everything went fine and a string was entered and
 *		terminated normally.
 *	PR_ABORTED
 *		Something happened to abort the read: a SIGINT or a
 *		CHOK_ABORT character.
 */
PRSTAT prompt_and_read(const char *prompt, char *buf, int buflen, unsigned int flags, CHOK (*approval)(char))
{
 CHOK (*app)(char);
 int len;
 int c;
 CHOK ok;
 JMP j;

 CHOK defapp(char ch)
  { switch (ch)
     { case '\33': return(CHOK_ABORT); break;
       case '\r': case '\n': return(CHOK_TERMNS); break;
       case '\177': case '\b': return(CHOK_DEL); break;
       case '\030': case '\025': return(CHOK_CLEAR); break;
     }
    return((*approval)(ch));
  }

 if (setjmp(j.b))
  { pop_sigint_throw();
    move(LINES-1,0);
    clrtoeol();
    return(PR_ABORTED);
  }
 app = (flags & PRF_NOSTD) ? approval : &defapp;
 len = 0;
 while (1)
  { mvaddstr(LINES-1,0,prompt);
    addnstr(buf,len);
    clrtoeol();
    push_sigint_throw(&j);
    c = tget();
    pop_sigint_throw();
    ok = (*app)(c);
    switch (ok)
     { case CHOK_OK:
	  if (len >= buflen-1)
	   { beep();
	     break;
	   }
	  buf[len++] = c;
	  break;
       case CHOK_BAD:
	  beep();
	  break;
       case CHOK_TERM:
	  if (len >= buflen-1)
	   { beep();
	     break;
	   }
	  buf[len++] = c;
	  /* fall through */
       case CHOK_TERMNS:
	  buf[len] = '\0';
	  move(LINES-1,0);
	  clrtoeol();
	  return(PR_OK);
	  break;
       case CHOK_ABORT:
	  move(LINES-1,0);
	  clrtoeol();
	  return(PR_ABORTED);
	  break;
       case CHOK_DEL:
	  if (len > 0) len --;
	  break;
       case CHOK_CLEAR:
	  len = 0;
	  break;
       default:
	  panic("bad return %d from approval function in prompt_and_read",(int)ok);
	  break;
     }
  }
}

/*
 * Ask the user to choose one of a small number of choices, internal
 *  version.
 *
 * This version takes a prompt and a list of string choices.  The
 *  return value is the index into the choice list, or -1 if aborted.
 *
 * It is an error if there are more choices than will fit on the
 *  display or more choices than 26 (letters available), or if any
 *  single choice string is longer than 70 characters.
 *
 * SIGINT also aborts the choice, like ESC.
 *
 * If the argument list does not contain at least one choice - ie, if
 *  str1 is nil - then the operation returns the abort value
 *  immediately, without any user interaction.
 */
static int choose_one_internal(const char *prompt, const char * const *svec, int vecn)
{
 int i;
 int maxl;
 int l;
 JMP j;

 maxl = 0;
 for (i=0;i<vecn;i++)
  { l = strlen(svec[i]);
    if (l > maxl) maxl = l;
  }
 if (vecn < 1) return(-1);
 if (vecn >= LINES) panic("choose_one: too many choices");
 if (vecn >= 26) panic("choose_one: too many choices");
 if (maxl > 70) panic("choose_one: choice too long");
 if (setjmp(j.b))
  { pop_sigint_throw();
    move(LINES-1,0);
    clrtoeol();
    return(-1);
  }
 if (vecn == 1)
  { mvprintw(0,0,"a) %s ",svec[0]);
  }
 else
  { for (i=0;i<vecn;i++) mvprintw(i,0,"%c) %-*s|",'a'+i,maxl,svec[i]);
  }
 while (1)
  { mvprintw(LINES-1,0,"%s",prompt);
    clrtoeol();
    push_sigint_throw(&j);
    i = tget();
    pop_sigint_throw();
    move(LINES-1,0);
    clrtoeol();
    if (i == '\33') return(-1);
    i -= 'a';
    if ((i >= 0) && (i < vecn))
     { clear();
       showdisp();
       return(i);
     }
    beep();
  }
}

/*
 * Ask the user to choose one of a small number of choices.
 *
 * The calling pattern is
 *
 * choose_one(prompt,str1,ret1,str2,ret2,...,strN,retN,(char *)0,retE)
 *
 * If str1 is chosen, ret1 is returned; if str2 is chosen, ret2 is
 *  returned, etc.  If ESC is entered, cancelling the choice, retE is
 *  returned.
 *
 * It is an error if there are more choices than will fit on the
 *  display or more choices than 26 (letters available), or if any
 *  single choice string is longer than 70 characters.
 *
 * SIGINT also aborts the choice, like ESC.
 *
 * If the argument list does not contain at least one choice - ie, if
 *  str1 is nil - then the operation returns the abort value
 *  immediately, without any user interaction.
 */
int choose_one(const char *prompt, ...)
{
 int n;
 va_list ap;
 const char *s;
 int val;
 int i;
 int abortval;

 va_start(ap,prompt);
 n = 0;
 while (1)
  { s = va_arg(ap,const char *);
    val = va_arg(ap,int);
    if (! s) break;
    n ++;
  }
 abortval = val;
 va_end(ap);
 if (n < 1) return(abortval);
  { const char *strings[n];
    int vals[n];
    va_start(ap,prompt);
    for (i=0;i<n;i++)
     { s = va_arg(ap,const char *);
       strings[i] = s;
       vals[i] = va_arg(ap,int);
     }
    va_end(ap);
    i = choose_one_internal(prompt,&strings[0],n);
    move(LINES-1,0);
    clrtoeol();
    i = (i < 0) ? abortval : vals[i];
  }
 return(i);
}

/*
 * Ask the user to choose one of a small number of choices.
 *
 * This is just like choose_one except that the list of choices is
 *  passed as a const char * const * vector and a count, instead of
 *  multiple arguments, and the ret values are indices into that vector
 *  (with -1 as the abort value).
 */
int choose_one_v(const char *prompt, const char * const *vec, int vecn)
{
 return(choose_one_internal(prompt,vec,vecn));
}

/*
 * Ask for yes/no confirmation of some action.  ESC and SIGINT are
 *  equivalent to N; keep this in mind when writing the prompt.
 *
 * One space is appended to the prompt, but nothing more; the prompt
 *  string should be worded so as to make it clear what is being asked
 *  and what meanings `yes' and `no' have.
 */
int confirm(const char *prompt)
{
 int c;
 JMP j;

 if (setjmp(j.b))
  { pop_sigint_throw();
    move(LINES-1,0);
    clrtoeol();
    return(0);
  }
 while (1)
  { mvprintw(LINES-1,0,"%s ",prompt);
    clrtoeol();
    push_sigint_throw(&j);
    c = tget();
    pop_sigint_throw();
    move(LINES-1,0);
    clrtoeol();
    switch (c)
     { case 'y': case 'Y':
	  return(1);
	  break;
       case 'n': case 'N': case '\33':
	  return(0);
	  break;
     }
    beep();
  }
}