/*
 * Compiled under DJGPP
 */

#include <stdio.h>
#include <conio.h>
#include <time.h>

#define BLOCK 0xdb      //Solid block character
#define LEFT 10         //Left-most column for scanner_a
#define RIGHT 70        //Right-most column for scanner_a
#define LINER 10        //Line for scanner_a
#define TRUE 1
#define FALSE 0

/* Global variables are a good idea for programs that
   Fake multitasking. This way the variables not only are static
   but are also available to other routines  */

int block_x;            //Saves the block position for scanner_a()
int block_y;
int xpos;               //Saves cursor position for some_text()
int ypos;
int counter;            //Used in score()

/*
 * This routine displays the time in the upper left corner of the
 * screen. It's a standard, Unix-like time display routine
 */

void show_time(void)
{
    struct tm *rightnow;                //variables defined in TIME.H
    time_t rawtime;

    time(&rawtime);
    rightnow = localtime(&rawtime);
    gotoxy(1,1);
    cprintf("%s",asctime(rightnow));    //asctime() displays the time string
}

/*
 * This routine displays a block character that bounces back and forth
 * across the text screen. I called it scanner_a() because at one time
 * I also wrote a scanner_b() function. But they run too fast for anyone
 * to notice any difference.
 */

void scanner_a(void)
{
    static int direction;               //static variables are preserved
                                        //so this value is remembered
    gotoxy(block_x,block_y);            //set the cursor!
    cprintf(" ");                       //Erase the old block

    if(block_x==LEFT) direction=1;      //Check bounds and change direction
    if(block_x==RIGHT) direction=-1;    //if the block is at the end

    block_x = block_x + direction;      //move the block's location
    gotoxy(block_x,block_y);            //set the cursor
    cprintf("%c",BLOCK);                //Display the block
}

/*
 * Here is the function that processes text. First kbhit() is checked
 * to see if any keys have been pressed. If not, the function doesn't
 * run and the program doesn't sit and wait for a key to be pressed.
 */

int some_text()
{
    char c;

    if(kbhit())                 //TRUE if a key has been pressed
    {
        gotoxy(xpos,ypos);      //update cursor
        c=getch();              //read character
        cprintf("%c",c);        //dipslay character via console routine
        xpos = wherex();        //Grab cursor's new position and save it
        ypos = wherey();
        if(c == 0x0d)           //ENTER pressed?
            return(1);          //Return if so otherwise, continue
        else
            return(0);
    }
    else
        return(0);              //A normal return if no key was waiting
}

/*
 * Finally, something else to add: This is just a counter displayed
 * In the upper right corner of the screen. Consider it your "score"!!
 */

void score(void)
{
    counter++;                  //Counter is a global variable, an int.
                                //It's value will never be more than 32K
    gotoxy(70,1);               //Always display it at the same spot
    cprintf("%i",counter);      //Console output
}

/*
 * Ah! The main loop. Since the routines are listed above there's no
 * need for prototyping here. Also, notice the "int main()" format, which
 * is considered the standard for DJGPP.
 */

int main()
{
    int done;

    /* Initialize variables & such */

    clrscr();                   //Clear the screen

    block_x = LEFT;             //Preset the block's position
    block_y = LINER;

    gotoxy(1,15);               //Text prompt
    cprintf("Type some text:");
    xpos = wherex();            //Saving cursor location for text input
    ypos = wherey();

    counter = 0;                //Initialize the "score"

    /* Here is the loop that runs the show */

    done = FALSE;               //Prep for the almost-endless loop


    while(!done)                //The event loop

    {
        if(some_text())         //Check for text input

            done = TRUE;
        scanner_a();            //Move the block

        show_time();            //Display the time

        score();                //Display the score

    }

    gotoxy(1,23);               //Put cursor at the bottom of the screen

                                //for when the program ends

}