#include "src/kernel/fs.h"
#include "src/kernel/gdt.h"
#include "src/kernel/idt.h"
#include "src/kernel/keyboard.h"
#include "src/kernel/panic.h"
#include "src/kernel/path.h"
#include "src/kernel/pic.h"
#include "src/kernel/process.h"
#include "src/kernel/syscall.h"
#include "src/kernel/tss.h"
#include "src/kernel/util.h"
#include "src/kernel/vga.h"
#include "src/lib/layout.h"
#include "src/lib/memory.h"

__attribute__((interrupt)) void isr_divide_by_zero(__attribute__((unused)) struct interrupt_frame *frame) {
  vga_set_string(VGA_HEIGHT - 1, 0, "EXCEPTION: divide by zero", 0x4F);
  while (1)
    ;
}

__attribute__((interrupt)) void isr_page_fault(__attribute__((unused)) struct interrupt_frame *frame) {
  vga_set_string(VGA_HEIGHT - 1, 0, "EXCEPTION: page fault", 0x4F);
  while (1)
    ;
}

__attribute__((interrupt)) void isr_general_violation(__attribute__((unused)) struct interrupt_frame *frame) {
  vga_set_string(VGA_HEIGHT - 1, 0, "EXCEPTION: general violation", 0x4F);
  while (1)
    ;
}

__attribute__((interrupt)) void isr_ata_primary(__attribute__((unused)) struct interrupt_frame *frame) {
  outb(0x20, 0x20);
  outb(0xA0, 0x20);
}

void kernel_main() {
  pic_init();
  idt_init();
  outb(0x21, inb(0x21) | 0x01); // mask out timer interrupt
  idt_set_entry(0, isr_divide_by_zero, 0x8E);
  idt_set_entry(0x0E, isr_page_fault, 0x8E);
  idt_set_entry(0x0D, isr_general_violation, 0x8E);
  idt_set_entry(46, isr_ata_primary, 0x8E);
  __asm__ volatile("sti");

  gdt_init();
  syscall_init();

  process_t *kernel = memory_allocate(sizeof(process_t));
  kernel->pml4 = (void *)KERNEL_VIRTUAL_PML4;
  kernel->root = fs_mount();
  kernel->cwd = memory_allocate(sizeof(path_t));
  kernel->stdin = keyboard_init();
  kernel->stdout = vga_init();

  fs_node_t *bin = path_open_file(kernel->root, kernel->cwd, "bin/terminal");

  ASSERT(bin, "kernel: terminal not found");

  uint8_t *code = memory_allocate(bin->size);
  fs_read(bin, 0, bin->size, code);

  process_t *terminal = process_create(kernel, code, bin->size);

  memory_free(code);
  fs_close(bin);

  __asm__ volatile("mov %0, %%cr3" : : "r"((uint64_t)VIRT_TO_PHYS((void *)KERNEL_VIRTUAL_PML4)) : "memory");

  uint8_t *stack = (uint8_t *)terminal->user_stack;

  stack -= sizeof(uint64_t);
  *(uint64_t *)stack = 0;

  terminal->user_rsp = (void *)(USER_VIRTUAL_STACK_TOP - ((uint64_t)terminal->user_stack - (uint64_t)stack));

  current_process = terminal;
  tss.rsp0 = (uint64_t)current_process->kernel_stack;
  process_switch_to(&kernel->kernel_rsp, terminal->kernel_rsp, VIRT_TO_PHYS(terminal->pml4));

  fs_unmount((fs_node_t *)kernel->root);

  outw(0x604, 0x2000); // TODO: parse ACPI tables for real hardware
  __asm__ volatile("cli; hlt");
}