/* ----------- console.c ---------- */

#include <conio.h>
#include <bios.h>
#include <dos.h>
#include "system.h"
#include "keys.h"

/* ----- table of alt keys for finding shortcut keys ----- */
char altconvert[] = {
    ALT_A,ALT_B,ALT_C,ALT_D,ALT_E,ALT_F,ALT_G,ALT_H,
    ALT_I,ALT_J,ALT_K,ALT_L,ALT_M,ALT_N,ALT_O,ALT_P,
    ALT_Q,ALT_R,ALT_S,ALT_T,ALT_U,ALT_V,ALT_W,ALT_X,
    ALT_Y,ALT_Z,ALT_0,ALT_1,ALT_2,ALT_3,ALT_4,ALT_5,
    ALT_6,ALT_7,ALT_8,ALT_9,0
};

unsigned video_mode;
unsigned video_page;

static int near cursorpos[MAXSAVES];
static int near cursorshape[MAXSAVES];
static int cs = 0;

static union REGS regs;

#ifndef POWERC
#ifndef MSC
#define ZEROFLAG 0x40
/* ---- Test for keystroke ---- */
int keyhit(void)
{
    _AH = 1;
    geninterrupt(KEYBRD);
    return (_FLAGS & ZEROFLAG) == 0;
}
#endif
#endif

/* ---- Read a keystroke ---- */
int getkey(void)
{
    int c;
    while (keyhit() == 0)
        ;
    if (((c = bioskey(0)) & 0xff) == 0)
        c = (c >> 8) | 0x80;
    return c & 0xff;
}

/* ---------- read the keyboard shift status --------- */
int getshift(void)
{
    regs.h.ah = 2;
    int86(KEYBRD, &regs, &regs);
    return regs.h.al;
}

/* ------- macro to wait one clock tick -------- */
#define wait()                     \
{                                  \
    int now = peek(0x40,0x6c);     \
    while (now == peek(0x40,0x6c)) \
        ;                          \
}

/* -------- sound a buzz tone ---------- */
void beep(void)
{
    wait();
    outp(0x43, 0xb6);               /* program the frequency */
    outp(0x42, (int) (COUNT % 256));
    outp(0x42, (int) (COUNT / 256));
    outp(0x61, inp(0x61) | 3);      /* start the sound */
    wait();
    outp(0x61, inp(0x61) & ~3);     /* stop the sound  */
}

/* -------- get the video mode and page from BIOS -------- */
void videomode(void)
{
    regs.h.ah = 15;
    int86(VIDEO, &regs, &regs);
    video_mode = regs.h.al;
    video_page = regs.x.bx;
    video_page &= 0xff00;
    video_mode &= 0x7f;
}

/* ------ position the cursor ------ */
void cursor(int x, int y)
{
    videomode();
    regs.x.dx = ((y << 8) & 0xff00) + x;
    regs.x.ax = 0x0200;
    regs.x.bx = video_page;
    int86(VIDEO, &regs, &regs);
}

/* ------ get cursor shape and position ------ */
static void near getcursor(void)
{
    videomode();
    regs.h.ah = READCURSOR;
    regs.x.bx = video_page;
    int86(VIDEO, &regs, &regs);
}

/* ------- get the current cursor position ------- */
void curr_cursor(int *x, int *y)
{
    getcursor();
    *x = regs.h.dl;
    *y = regs.h.dh;
}

/* ------ save the current cursor configuration ------ */
void savecursor(void)
{
    if (cs < MAXSAVES)    {
        getcursor();
        cursorshape[cs] = regs.x.cx;
        cursorpos[cs] = regs.x.dx;
        cs++;
    }
}

/* ---- restore the saved cursor configuration ---- */
void restorecursor(void)
{
    if (cs)    {
        --cs;
        videomode();
        regs.x.dx = cursorpos[cs];
        regs.h.ah = SETCURSOR;
         regs.x.bx = video_page;
        int86(VIDEO, &regs, &regs);
        set_cursor_type(cursorshape[cs]);
    }
}

/* ------ make a normal cursor ------ */
void normalcursor(void)
{
    set_cursor_type(0x0607);
}

/* ------ hide the cursor ------ */
void hidecursor(void)
{
    getcursor();
    regs.h.ch |= HIDECURSOR;
    regs.h.ah = SETCURSORTYPE;
    int86(VIDEO, &regs, &regs);
}

/* ------ unhide the cursor ------ */
void unhidecursor(void)
{
    getcursor();
    regs.h.ch &= ~HIDECURSOR;
    regs.h.ah = SETCURSORTYPE;
    int86(VIDEO, &regs, &regs);
}

/* ---- use BIOS to set the cursor type ---- */
void set_cursor_type(unsigned t)
{
    videomode();
    regs.h.ah = SETCURSORTYPE;
    regs.x.bx = video_page;
    regs.x.cx = t;
    int86(VIDEO, &regs, &regs);
}

/* ---- test for EGA -------- */
int isEGA(void)
{
    if (isVGA())
        return 0;
    regs.h.ah = 0x12;
    regs.h.bl = 0x10;
    int86(VIDEO, &regs, &regs);
    return regs.h.bl != 0x10;
}

/* ---- test for VGA -------- */
int isVGA(void)
{
    regs.x.ax = 0x1a00;
    int86(VIDEO, &regs, &regs);
    return regs.h.al == 0x1a && regs.h.bl > 6;
}

static void Scan350(void)
{
    regs.x.ax = 0x1201;
    regs.h.bl = 0x30;
    int86(VIDEO, &regs, &regs);
}

static void Scan400(void)
{
    regs.x.ax = 0x1202;
    regs.h.bl = 0x30;
    int86(VIDEO, &regs, &regs);
}

/* ---------- set 25 line mode ------- */
void Set25(void)
{
    if (isVGA)
        Scan400();
    regs.x.ax = 0x1114;
    regs.x.bx = 0;
    int86(VIDEO, &regs, &regs);
}

/* ---------- set 43 line mode ------- */
void Set43(void)
{
    if (isVGA)
        Scan350();
    regs.x.ax = 0x1112;
    regs.x.bx = 0;
    int86(VIDEO, &regs, &regs);
}

/* ---------- set 50 line mode ------- */
void Set50(void)
{
    if (isVGA)
        Scan400();
    regs.x.ax = 0x1112;
    regs.x.bx = 0;
    int86(VIDEO, &regs, &regs);
}