#include "multiboot.h"
#include "interrupts.h"
#include "gdt.h"
#include "scheduler.h"
#include "common.h"
#include "vfs.h"

#include <lib/print.h>
#include <lib/stream.h>
#include <lib/memory.h>

#include <memory/mm.h>

#include <drivers/iso/iso.h>
#include <drivers/ide/ide.h>
#include <drivers/pic/pic.h>
#include <drivers/ps2/ps2.h>
#include <drivers/pit/pit.h>
#include <drivers/vga/vga.h>
#include <drivers/cpio/cpio.h>

#include <stddef.h>
#include <stdint.h>

extern char __kernel_start;
extern char __kernel_end;

void parse_multiboot_modules(uint32_t mbi_vaddr) {
  // find where grub put the boot module containing initrd
  multiboot_info* mbi = (multiboot_info*)mbi_vaddr;

  uint32_t mod_count = mbi->mods_count;
  multiboot_module_t* mod = (multiboot_module_t*)((uint32_t)mbi->mods_addr + 0xC0000000);

  kprintf("found %d mods starting @ [v]0x%x\n", mod_count, (uint32_t)mod);

  for (uint32_t i = 0; i < mod_count; i++) {
    uint32_t start = mod[i].mod_start;
    uint32_t end = mod[i].mod_end;
    uint32_t cmdline = mod[i].cmdline;

    multiboot_module_info_table[i].mod_start = start + 0xC0000000;
    multiboot_module_info_table[i].mod_end = end + 0xC0000000;
    multiboot_module_info_table[i].cmdline = cmdline + 0xC0000000;
  }
}

vfs_node_t* load_initrd() {
  multiboot_module_t* initrd_module = &multiboot_module_info_table[0];
  kprintf("initrd found @ [v] 0x%x\n", initrd_module->mod_start);
  return cpio_read_fs(initrd_module->mod_start);
}

void load_origin_program() {
  vfs_node_t* vfs_root = vfs_create_root();
  vfs_node_t* initrd_root = load_initrd();
  
  if (initrd_root) {
    mount(vfs_root, initrd_root);
    kprintf("initrd read, mounted @ /\n");

    int fd = open("/origin.elf", 0);
    if (fd == -1) {
      kprintf("failed to read origin program\n");
    }

    void* buf = kalloc(512);
    int rd = read(fd, buf, 512);
    if (rd > 0) {
      kprintf("read %d bytes from origin.elf\n", rd);
    }
  }
  exit();
}

void kmain(uint32_t magic, multiboot_info* mbi)  {
  disable_interrupts();
  if (!(mbi->flags & (1 << 6))) {
    return;
  } 

  vga_init();

  uint32_t mmap_virtual_addr = mbi->mmap_addr + 0xC0000000;
  init_pmm((void*)mmap_virtual_addr, mbi->mmap_length);
  kprintf("memory detection complete. total free memory: %dMB\n", total_free_memory() / 1024 / 1024);

  init_gdt();
  init_idt();
  init_pic();
  init_pit();
  
  init_page_tables();

  parse_multiboot_modules((uint32_t)mbi);
  
  kprintf("basic initializations complete\n");

  disable_interrupts();
  init_scheduler();
  enable_interrupts();

  create_task((uint32_t)load_origin_program, fetch_cr3());
}