#include <stdarg.h>
#ifdef USE_OS_RANDOM
#include <stdlib.h>
#endif

#include "glk.h"

#include "miscfort.h"
#include "commons.h"
#include "funcs.h"

/* This file contains various functions which help the Dungeon code work
    with Glk. */

/* Random number functions. If your OS has random() and srandom(), you can
    define USE_OS_RANDOM. Otherwise, substitutes are provided. */
#ifndef USE_OS_RANDOM
    static glui32 lo_random(void);
    static void lo_seed_random(glui32 seed);
    static glui32 rand_table[55]; /* State for the RNG. */
    static int rand_index1, rand_index2;
#endif /* USE_OS_RANDOM */

static winid_t mainwin = 0;    /* The story window. */
static winid_t statuswin = 0;  /* The status window. */

void glk_main()
{
    /* Open the main window. */
    mainwin = glk_window_open(0, 0, 0, wintype_TextBuffer, 1);
    if (!mainwin) {
        /* It's possible that the main window failed to open. There's
            nothing we can do without it, so exit. */
        return; 
    }
    
    /* Open the status window, a one-line textgrid. */
    statuswin = glk_window_open(mainwin, winmethod_Above | winmethod_Fixed, 
        1, wintype_TextGrid, 0);
    /* It's possible that the status window failed to open. If so, statuswin
        is zero; we'll check that later, in redraw_statusline(). */
    
    /* Set the current output stream to print to the main window. This will
        be true for the rest of the game, unless noted otherwise. */
    glk_set_window(mainwin);
    
    /* Run the game. */
    dungeon_main();
}

/* These are the random-number functions called by the game source. If
    USE_OS_RANDOM is defined, they call random() and srandom(). If not,
    they call some substitutes supplied below. */

integer rnd_(integer *val)
{
    int ix;
#ifdef USE_OS_RANDOM
    ix = random();
#else /* USE_OS_RANDOM */
    ix = lo_random();
#endif /* USE_OS_RANDOM */
    if (ix < 0)
        ix = (-ix);
    return ix % (*val);
}

int inirnd_(integer *v1, integer *v2)
{
#ifdef USE_OS_RANDOM
    srandom(((*v1) << 16) | (*v2));
#else /* USE_OS_RANDOM */
    lo_seed_random(((*v1) << 16) | (*v2));
#endif /* USE_OS_RANDOM */
    return 0;
}

/* These functions are called by the game source to determine the date and
    time; they're used to seed the RNG, and also for the "time" command
    (which prints how long you've been playing.) They don't work very
    well at all, I'm afraid. I plan to add clock-time functions to Glk in
    the future, as an optional capability, but they're not there yet. */

int idate_(integer *year, integer *month, integer *day)
{
    *year = 1998;
    *month = 1;
    *day = 1;
    return 0; 
}

int itime_(integer *hour, integer *min, integer *sec)
{
    *hour = 12;
    *min = 0;
    *sec = 0;
    return 0;
}

/* Print a string and wait for a key to be hit. */
void s_paus(char *prompt, int len)
{
    glk_put_char('\n');
    glk_put_buffer(prompt, len);
    getchar_();
    glk_put_char('\n');
    glk_put_char('\n');
}

/* Redraw the status window. This is called before every key or line input,
    and again whenever there's an evtype_Arrange event. */
static void redraw_statusline(void)
{
    integer ix, as;
    glui32 width;
    
    /* If there's no status window, forget it. */
    if (!statuswin)
        return;
        
    glk_set_window(statuswin);
    glk_window_clear(statuswin);
    
    glk_window_get_size(statuswin, &width, NULL);

    /* We copy the code from the "rname" verb, which prints the room name.
        See verbs.c V67. */
    ix = rooms_1.rdesc2 - play_1.here;
    if (ix > 0) {
        ix = rmsg_1.rtext[ix - 1];
    }
    ix = abs(ix);
    if (ix) {
        glk_window_move_cursor(statuswin, 1, 0);
        printdb(ix - 1, -1, -1, FALSE_);
    }

    /* Now we print the score and number of moves. Allow 20 characters. If
        the screen is too narrow, this stomps on the room name -- sorry about 
        that. */
    glk_window_move_cursor(statuswin, (width - 20), 0);

    as = advs_1.ascore[play_1.winner - 1];
    weeprintf("Score: %d / %d",
        as, play_1.moves);

    glk_set_window(mainwin); /* Set the output stream back to the main window. */
}

/* Read a null-terminated line of text. */
int getline_null_(char *buf, int buflen)
{
    int len = getline_(buf, buflen);
    if (len >= buflen)
        buf[buflen - 1] = '\0';
    else
        buf[len] = '\0';
    return len;
}

/* Read a line of text. This runs the usual Glk event loop. */
int getline_(char *buf, int buflen)
{
    event_t ev;
    
    redraw_statusline();
    
    /* Request input... */
    glk_request_line_event(mainwin, buf, buflen, 0);

    while (1) {
        glk_select(&ev);
        switch (ev.type) {
            case evtype_LineInput:
                /* Got some. */
                return ev.val1;
            case evtype_Arrange:
                /* The window changed size, so we have to redo the
                    status line. */
                redraw_statusline();
                break;
        }
    }
}

/* Read a single keystroke. This runs the usual Glk event loop. */
int getchar_()
{
    event_t ev;
    
    redraw_statusline();
    
    /* Request input... */
    glk_request_char_event(mainwin);

    while (1) {
        glk_select(&ev);
        switch (ev.type) {
            case evtype_CharInput:
                /* Got some. */
                return ev.val1;
            case evtype_Arrange:
                /* The window changed size, so we have to redo the
                    status line. */
                redraw_statusline();
                break;
        }
    }
}

/* Shut down the program. It's the library's job to put up a "hit any key
    to exit" message. (Which is important, because there may be some closing
    text printed just before this call, and the player ought to have time
    to read it.) */
int s_stop(char *s, ftnlen n)
{
    glk_exit();
    return 0;
}

/* Read an array of integers from a file, 4 bytes each, big-endian. */
int f_get_ints(strid_t fl, integer *ptr, integer num)
{
  int ix, jx;
  int ch;
  glsi32 val;

  for (ix=0; ix<num; ix++, ptr++) {
    val = 0;
    for (jx=0; jx<4; jx++) {
      ch = glk_get_char_stream(fl);
      if (ch == -1) {
        glk_exit();      
      }
      val = (val << 8) | (ch & 0xff);
    }
    *ptr = val;
  }
  
  return TRUE_;
}

/* Read an array of logicals from a file, 4 bytes each, big-endian. */
int f_get_llogicals(strid_t fl, logical *ptr, integer num)
{
  int ix, jx;
  int ch;
  glsi32 val;

  for (ix=0; ix<num; ix++, ptr++) {
    val = 0;
    for (jx=0; jx<4; jx++) {
      ch = glk_get_char_stream(fl);
      if (ch == -1) {
        glk_exit();      
      }
      val = (val << 8) | (ch & 0xff);
    }
    *ptr = val;
  }
  
  return TRUE_;
}

/* Read an array of logicals from a file, 1 byte each. */
int f_get_logicals(strid_t fl, logical *ptr, integer num)
{
  int ix;
  int ch;

  for (ix=0; ix<num; ix++, ptr++) {
    ch = glk_get_char_stream(fl);
    if (ch == -1) {
      glk_exit();      
    }
    if (ch)
      *ptr = TRUE_;
    else
      *ptr = FALSE_;
  }

  return TRUE_;
}

/* Write an array of integers to a file, 4 bytes each, big-endian. */
int f_put_ints(strid_t fl, integer *ptr, integer num)
{
  int ix;
  glsi32 val;

  for (ix=0; ix<num; ix++, ptr++) {
    val = *ptr;
    glk_put_char_stream(fl, (val >> 24) & 0xff);
    glk_put_char_stream(fl, (val >> 16) & 0xff);
    glk_put_char_stream(fl, (val >> 8) & 0xff);
    glk_put_char_stream(fl, (val) & 0xff);
  }

  return TRUE_;
}

/* Write an array of logicals to a file, 1 byte each. */
int f_put_logicals(strid_t fl, logical *ptr, integer num)
{
  int ix;

  for (ix=0; ix<num; ix++, ptr++) {
    if (*ptr) {
      glk_put_char_stream(fl, 1);
    }
    else {
      glk_put_char_stream(fl, 0);
    }
  }

  return TRUE_;
}

/* A simple number reader. */
int str_to_num(char *buf)
{
    int negative = 0;
    int val = 0;
    
    for (; *buf; buf++) {
        if (*buf == '-') {
            negative = 1;
        }
        else if (*buf >= '0' && *buf <= '9') {
            val = val * 10 + (*buf - '0');
        }
    }
    
    if (negative)
        return -val;
    else
        return val;
}

/* A simple number printer. */
static void num_to_str(char *buf, int num)
{
    int ix;
    int size = 0;
    char tmpc;
    
    if (num == 0) {
        buf[0] = '0';
        buf[1] = '\0';
        return;
    }
    
    if (num < 0) {
        buf[0] = '-';
        buf++;
        num = -num;
    }
    
    while (num) {
        buf[size] = '0' + (num % 10);
        size++;
        num /= 10;
    }
    for (ix=0; ix<size/2; ix++) {
        tmpc = buf[ix];
        buf[ix] = buf[size-ix-1];
        buf[size-ix-1] = tmpc;
    }
    buf[size] = '\0';
}

/* A simplified printf() substitute, which prints to the current Glk
    output stream. The only format codes it understands are %c, %d, %s. */
void weeprintf(char *fmt, ...)
{
    va_list argptr;
    glsi32 val;
    char numbuf[32];
    char *cx;
    
    va_start(argptr, fmt);
    for (; *fmt; fmt++) {
        if (*fmt == '%' && *(fmt+1)) {
            fmt++;
            switch (*fmt) {
                case 'c':
                    val = va_arg(argptr, glsi32);
                    glk_put_char(val & 0xff);
                    break;
                case 'd':
                    val = va_arg(argptr, glsi32);
                    num_to_str(numbuf, val);
                    for (cx=numbuf; *cx; cx++)
                        glk_put_char(*cx);
                    break;
                case 's':
                    cx = va_arg(argptr, char *);
                    for (; *cx; cx++)
                        glk_put_char(*cx);
                    break;
                default:
                    glk_put_char('%');
                    glk_put_char(*fmt);
                    break;
            }
        }
        else {
            glk_put_char(*fmt);
        }
    }
    va_end(argptr);
}

/* Read some text from the Dungeon data file and print it. This prints message
    number msgnum. If msgsub1 (and possibly msgsub2) are >= 0, it also reads 
    those messages, and substitutes them for the first one (two) '#' characters
    in the text. If newline is true, it follows everything up with a newline. 
   This allows a certain amount of formatting in the text it reads in, also.
    A tab character ('\011') is turned into four spaces. 
    Ctrl-A ('\001') means to turn on fixed-width formatting.
    Ctrl-B ('\002') means to turn off fixed-width formatting. (It's okay 
        to skip the closing ctrl-B; this code will automatically turn off the
        fixed-width after the final newline.)
    An escape character ('\033') means to skip the final newline, even if one
        was requested. This is used in a few places to glue messages together
        on the same line.
    No other control characters, except the newline (ctrl-J, '\012'), are legal.
    */
void printdb(int msgnum, int msgsub1, int msgsub2, int newline)
{
    int ix, count;
    glsi32 fpos;
    char subbufa[80], subbufb[80];
    char *sub1=NULL, *sub2=NULL;
    int suppressnewline = FALSE_;
    int insub;
    int fixedmode;
    
    if (msgsub1 >= 0) {
        fpos = datafile_strings + datafile_strindex[msgsub1];
        if (fpos < 0) {
            weeprintf("Internal error: Tried to print nonexistent message %d.\n",
                msgsub1);
            return;
        }
        glk_stream_set_position(datafile, fpos, seekmode_Start);
        for (ix=0; ix<79; ix++) {
            subbufa[ix] = glk_get_char_stream(datafile);
            subbufa[ix] ^= (msgsub1 + ix + 3) & 0xff;
            if (subbufa[ix] == '\004')
                break;
        }
        subbufa[ix] = '\0';
        sub1 = subbufa;
    }
    
    if (msgsub2 >= 0) {
        fpos = datafile_strings + datafile_strindex[msgsub2];
        if (fpos < 0) {
            weeprintf("Internal error: Tried to print nonexistent message %d.\n",
                msgsub2);
            return;
        }
        glk_stream_set_position(datafile, fpos, seekmode_Start);
        for (ix=0; ix<79; ix++) {
            subbufb[ix] = glk_get_char_stream(datafile);
            subbufb[ix] ^= (msgsub2 + ix + 3) & 0xff;
            if (subbufb[ix] == '\004')
                break;
        }
        subbufb[ix] = '\0';
        sub2 = subbufb;
    }

    fpos = datafile_strings + datafile_strindex[msgnum];
    if (fpos < 0) {
        weeprintf("Internal error: Tried to print nonexistent message %d.\n",
            msgnum);
        return;
    }
    glk_stream_set_position(datafile, fpos, seekmode_Start);

    /* Print out. */
    fixedmode = FALSE_;
    insub = FALSE_;
    count = 0;
    while (TRUE_) {
        unsigned char ch;
        if (!insub) {
            ch = glk_get_char_stream(datafile);
            ch ^= (msgnum + count + 3) & 0xff;
            count++;
            if (ch == '\004')
                break;
        }
        else {
            ch = *sub1;
            if (ch == '\0') {
                insub = FALSE_;
                sub1 = sub2;
                sub2 = NULL;
                continue;
            }
            sub1++;
        }
        
        switch (ch) {
            case '#':
                if (!insub && sub1) {
                    insub = TRUE_;
                }
                else {
                    glk_put_char(ch);
                }
                break;
            case '\011':
                glk_put_string("    ");
                break;
            case '\033':
                suppressnewline = TRUE_;
                break;
            case '\001':
                if (!fixedmode) {
                    fixedmode = TRUE_;
                    glk_set_style(style_Preformatted);
                }
                break;
            case '\002':
                if (fixedmode) {
                    fixedmode = FALSE_;
                    glk_set_style(style_Normal);
                }
                break;
            default:
                glk_put_char(ch);
                break;
        }
    }

    if (newline && !suppressnewline)
        glk_put_char('\n');
        
    if (fixedmode) {
        fixedmode = FALSE_;
        glk_set_style(style_Normal);
    }
}

#ifndef USE_OS_RANDOM
/* Here is a pretty standard random-number generator and seed function. */

static glui32 lo_random()
{
    rand_index1 = (rand_index1 + 1) % 55;
    rand_index2 = (rand_index2 + 1) % 55;
    rand_table[rand_index1] = rand_table[rand_index1] - rand_table[rand_index2];
    return rand_table[rand_index1];
}

static void lo_seed_random(glui32 seed)
{
    glui32 k = 1;
    int i, loop;

    rand_table[54] = seed;
    rand_index1 = 0;
    rand_index2 = 31;
    
    for (i = 0; i < 55; i++) {
        int ii = (21 * i) % 55;
        rand_table[ii] = k;
        k = seed - k;
        seed = rand_table[ii];
    }
    for (loop = 0; loop < 4; loop++) {
        for (i = 0; i < 55; i++)
            rand_table[i] = rand_table[i] - rand_table[ (1 + i + 30) % 55];
    }
}

#endif /* USE_OS_RANDOM */