#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include <conio.h>
#include <graph.h>
#include <io.h>

unsigned int buffer[2000];

void printgoodbye() {
    _setbkcolor(0);
    _settextcolor(7);
    _settextcursor(0x0607);
    _clearscreen(_GCLEARSCREEN);
    _outtext("\n C'est fi-ni!\n");
}

void printslide(int handle, int n, int nmax) {
    int i;
    unsigned int *p = buffer;
    char s[10];

    __segment screen;
    unsigned int __based(void) *scrptr;

    screen = 0xB800;
    scrptr = 0;

    lseek(handle, 0, SEEK_SET);
    for (i = 0; i < n; i++) lseek(handle, 4000, SEEK_CUR);
    read(handle, buffer, 4000);
    for (i = 0; i < 2000; i++) *(screen:>scrptr + i) = buffer[i];

    _settextcursor(0x2000);
    _setbkcolor((buffer[1998]>>12)&0xF);
    _settextcolor((buffer[1998]>>8)&0xF);
    sprintf(s, "%d / %d", n + 1, nmax);
    _settextposition(25, (80-strlen(s))/2);
    _outtext(s);
}

int main(int argc, char **argv) {
    int i;
    int slide, nslides;
    int handle;
    int c;


    if (argc != 2) {
	printf("Usage: %s <file>\n", argv[0]);
	exit(1);
    }
    handle = open(argv[1], O_RDONLY);
    if (handle < 0) {
	printf("Cannot open %s...\n", argv[1]);
	exit(1);
    }

    nslides = filelength(handle) / 4000;

    slide = 0;
    while (1) {
	if (slide == nslides) {
	    printgoodbye();
	} else {
	    printslide(handle, slide, nslides);
	}
	c = getch();
	if (c == 27 || c == 'q') break;
	if (c == 'j') slide++;
	if (c == 'k') slide--;
	if (c == 'h') slide -= 5;
	if (c == 'l') slide += 5;
	if (c == 'z') slide = nslides - 1;
	if (c == 'a') slide = 0;
	if (slide < 0) slide = 0;
	if (slide > nslides) slide = nslides;
    }
    printgoodbye();


    close(handle);
    
    return 0;
}