#include "exception.h"
#include "gdt.h"
#include "idt.h"
#include "interrupt.h"
#include "io.h"
#include "irq.h"
#include "klibc.h"
#include "mem.h"
#include "multiboot.h"
#include "paging.h"
#include "pit.h"
#include "serial.h"
#include "stdarg.h"
#ifdef RUN_TEST
#include "test.h"
#endif
#include "types.h"
#include "vga.h"

#define CHECK_FLAG(flags, bit) ((flags) & (1 << (bit)))
void cpuid(int code, uint32_t *a, uint32_t *d)
{
    asm volatile("cpuid" : "=a"(*a), "=d"(*d) : "0"(code) : "ebx", "ecx");
}

// Multiboot information available here :
// https://www.gnu.org/software/grub/manual/multiboot/multiboot.html#kernel_002ec
void kmain(unsigned long magic, unsigned long addr)
{
    unsigned long upper_mem = 0;
    VGASetup(BLACK, GREEN);

    printf("Setting up Interruptions\n");
    gdtSetup();
    idtSetup();
    irqSetup();
    pitSetup(100);

    if (magic == MULTIBOOT_BOOTLOADER_MAGIC) { // Get loaded by Grub wuth mutliboot version 1
        multiboot_info_t *mbi = (multiboot_info_t *)addr;
        /* Are mem_* valid? */
        if (CHECK_FLAG(mbi->flags, 0)) {
            printf("mem_lower = %dKB mem_upper %dKB\n", mbi->mem_lower, mbi->mem_upper);
            upper_mem = mbi->mem_upper;
        }

        /* Is boot_device valid? */
        if (CHECK_FLAG(mbi->flags, 1)) {
            printf("boot_device = %d\n", mbi->boot_device);
        }

        /* Is the command line passed? */
        if (CHECK_FLAG(mbi->flags, 2)) {
            printf("cmdline = %s\n", (char *)mbi->cmdline);
        }
    }

    if (upper_mem == 0) {
        printf("Cannot get upper phy mem bound. Using default value 32MB\n");
        upper_mem = 32 * 1024;
    }

    printf("Setting up Pagination\n");
    paddr_t lastUserByMem;
    memSetup(upper_mem, &lastUserByMem);
#ifdef RUN_TEST
    testPhymem();
#endif
    pagingSetup(lastUserByMem);

    printf("Setting up IRQ handlers\n");
    irqSetRoutine(IRQ_KEYBOARD, keyboard_handler);

    printf("Enabling HW interrupts\n");
    exceptionSetRoutine(EXCEPTION_DOUBLE_FAULT, print_handler);
    exceptionSetRoutine(EXCEPTION_PAGE_FAULT, pagefault_handler);
    // Enabling the HW interrupts
    asm volatile("sti\n");

    printf("Setting up Serial link (115200)\n");
    serialSetup(115200);
#ifdef RUN_TEST
    run_test();
#endif

    int count = 0;
    while (1) {
        printIntDetails(count++, GREEN, BLACK, 0, VGA_HEIGHT - 1);
    }
    printf("exiting\n");
}