#include "drivers/uart.h"
#include "kernel/pmm.h"
#include "kernel/mm.h"
#include "kernel/trap.h"

// void print_hex(uint64_t val)
// {
//     char buf[17];
//     buf[16] = 0;
//     const char *digits = "0123456789ABCDEF";
//     for (int i = 15; i >= 0; i--)
//     {
//         buf[i] = digits[val & 0xf];
//         val >>= 4;
//     }
//     Drivers::uart_puts("0x");
//     Drivers::uart_puts(buf);
// }

extern "C" void kernel_main()
{

    Drivers::uart_init();
    Drivers::uart_puts("\n[Modern DOS Kernel] Booted in S-Mode.\n");
    Drivers::uart_puts("2025 Richard Qin\n");
    Drivers::uart_puts("\n");

    Drivers::uart_puts("[Kernel] Initializing PMM...\n");
    PMM::init();
    Drivers::uart_puts("[Kernel] PMM initialized.\n");

    Drivers::uart_puts("[Kernel] Testing alloc_page...\n");
    void *p1 = PMM::alloc_page();
    void *p2 = PMM::alloc_page();

    Drivers::uart_puts("Allocated Page 1: ");
    Drivers::print_hex((uint64_t)p1);
    Drivers::uart_puts("\n");

    Drivers::uart_puts("Allocated Page 2: ");
    Drivers::print_hex((uint64_t)p2);
    Drivers::uart_puts("\n");

    Drivers::uart_puts("[Kernel] Freeing Page 1...\n");
    PMM::free_page(p1);

    void *p3 = PMM::alloc_page();
    Drivers::uart_puts("Allocated Page 3: ");
    Drivers::print_hex((uint64_t)p3);
    Drivers::uart_puts("\n");

    if (p3 == p1)
    {
        Drivers::uart_puts("[Test Passed] Reuse freed memory successfully.\n");
    }
    else
    {
        Drivers::uart_puts("[Test Failed] Memory leak or logic error.\n");
    }

    VM::kvminit();
    Drivers::uart_puts("[Boot] Kernel page table created.\n");

    VM::kvminithart();
    Drivers::uart_puts("[Boot] MMU ENABLED! We are now using virtual addresses.\n");

    Trap::init();
    Drivers::uart_puts("[Boot] Trap Handler Installed.\n");

    Drivers::uart_puts("\n[Test] Triggering Page Fault by reading 0x0...\n");
    volatile int *p = (int *)0x0;
    int crash = *p;
    (void)crash;

    Drivers::uart_puts("[Test Failed] Shuold not reach here.\n");

    Drivers::uart_puts("\n[Test] Triggering Store Fault on Text Segment...\n");
    *(int*)0x80000000 = 1234;

    while (1)
    {

    }
}