#include "multiboot.h"
#include "vga.h"

/*
static inline void outb(unsigned int port, unsigned char val) {
  asm volatile ("outb %0, %1" : : "a"(val), "Nd"(port) : "memory");
}
*/

char* itoa(int value, int base) {
    char* result;

    // check that the base if valid
    if (base < 2 || base > 36) { *result = '\0'; return result; }

    char* ptr = result, *ptr1 = result, tmp_char;
    int tmp_value;

    do {
        tmp_value = value;
        value /= base;
        *ptr++ = "zyxwvutsrqponmlkjihgfedcba9876543210123456789abcdefghijklmnopqrstuvwxyz" [35 + (tmp_value - value * base)];
    } while ( value );

    // Apply negative sign
    if (tmp_value < 0) *ptr++ = '-';
    *ptr-- = '\0';
    while(ptr1 < ptr) {
        tmp_char = *ptr;
        *ptr--= *ptr1;
        *ptr1++ = tmp_char;
    }
    return result;
}

void kmain (unsigned int mbootmagick, multiboot_info_t* mbootinfo) {

    // Cursor disabling
    // TODO: outb function
    //outb(0x3D4, 0x0A);
    //outb(0x3D5, 0x20);

    //cls();
    vga_init(VGA_COLOR_GREY, VGA_COLOR_BLACK);

    vga_write_line("=== KoalemOS ===");
    vga_write("Checking multiboot loader: ");

    // Check multiboot header
    if (mbootmagick != MULTIBOOT_BOOTLOADER_MAGIC) {
        vga_write_color("INVALID MAGIC", VGA_COLOR_BLACK, VGA_COLOR_RED);
        return;
    }
    vga_write((char *)mbootinfo->boot_loader_name);

    // Check videomode
    vga_write("\nVideomode: 0x");
    vga_write(itoa(mbootinfo->vbe_mode, 16));
    vga_write(": ");
    switch (mbootinfo->vbe_mode) {
        case MULTIBOOT_FRAMEBUFFER_TYPE_INDEXED:
            vga_write("Indexed");
            break;
        case MULTIBOOT_FRAMEBUFFER_TYPE_RGB:
            vga_write("RGB");
            break;
        case MULTIBOOT_FRAMEBUFFER_TYPE_EGA_TEXT:
            vga_write("EGA TEXT");
            break;
        default:
            vga_write_color("UNKNOWN", VGA_COLOR_BLACK, VGA_COLOR_RED);
            return;
    }

    vga_write_line("\nExecution finished, halting...");
}