/* Check if the compiler thinks you are targeting the wrong operating system. */
#if defined(__linux__)
#error "You are not using a cross-compiler"
#endif

/* This tutorial will only work for the 32-bit ix86 targets. */
#if !defined(__i386__)
#error "This tutorial needs to be compiled with a ix86-elf compiler"
#endif

#include <stdlib.h>
#include <types.h>
#include "allocator.h"
#include "cga.h"
#include "cpu/cpu.h"
#include "gdt.h"
#include "idt.h"
#include "keyboard.h"
#include "scheduler.h"
#include "serial.h"
#include "vmm.h"

/* hardware */
vmm kvmm;
#include "hardware.h"

char buffer[4096];

uint32_t check_multiboot(uint32_t, uint32_t);

extern "C" {
void dump_multiboot(uint32_t mb_magic, uint32_t mb_addr);
void dump_gdt();

[[noreturn]] void kernel_main(uint32_t mb_magic, const uint32_t mb_addr) {
#ifdef HAS_SERIAL0
  if constexpr (serial0_console)
    if (serial0.self_check()) Console::set(&serial0);
#endif

#ifdef HAS_VIDEO0
  if (const auto cga_buffer_r = kvmm.map(0xb8000, 0xc03f3000)) {
    video0.set_buffer(cga_buffer_r.value());
    if constexpr (video0_console) Console::set(&video0);
  }
#endif

  printk("Hello, kernel World!\n");
  CPU core0;
  printk("cpuid: ", core0.manufacturer(), " family ", core0.family(), " model ", core0.model(), " stepping ",
         core0.stepping(), '\n');
  runtime_assert(core0.features().fpu, "CPU lacks fpu");
  runtime_assert(core0.features().cx8, "CPU lacks cx8");

  dump_address();
   dump_gdt();

  {
    printk("Multiboot2 header at ", uhex{mb_addr}, '\n');

    const auto mb_addr_r = kvmm.map(mb_addr, {768, 1020});
    runtime_assert(mb_addr_r, "Failed to map mb_addr");

    const auto mb_addr_ = mb_addr_r.value();
    const auto mb_size = check_multiboot(mb_magic, mb_addr_);
    runtime_assert((mb_size != 0), "Invalid multiboot header");

    const auto mb_addr_re = [mb_addr, mb_size]() -> Result<uint32_t, vmm::Error> {
      if (mb_addr % 4096 + mb_size >= 4096) return kvmm.map((mb_addr % 4096 + 4096), {768, 1021});
      return {};
    }();

    printk("Multiboot2 header mounted at ", uhex{mb_addr}, " size: ", mb_size, '\n');

    dump_multiboot(mb_magic, mb_addr_);

    if (mb_addr_r) kvmm.unmap(mb_addr_r.value());
    if (mb_addr_re) kvmm.unmap(mb_addr_re.value());
  }

  GDT gdt;
  IDT idt{gdt.descriptor(GDT::kcode)};
  // Scheduler s{gdt.descriptor(GDT::kcode)};
  Keyboard kb;

  MemoryAllocator ma(reinterpret_cast<uint32_t>(buffer), sizeof(buffer));
  printk("memory free: ", ma.free_space(), '\n');

  idt.enable();

  while (true) asm volatile("hlt");
}
}  // extern "C"