#include <stddef.h>
#include <stdint.h>
#include "bitmap/bitmap.h"
#include "spinlock/spinlock.h"
#include "bootinfo/bootinfo.h"
#include "vmm.h"
#include "kprintf.h"
#include "util/util.h"
#include "hal/hal.h"
#include "pmm/pmm.h"
#include "paging/paging.h"

#define POS_ENSURE 0x40000000

#define PAGE_SIZE 0x1000

VirtMem VIRT_MEM;

void vmm_init(void) {
  spinlock_init(&VIRT_MEM.spinlock);
  BitMap *bm = &VIRT_MEM.self;

  size_t targetpos = _DIV_ROUNDUP(BOOT_INFO.hhdm_off - BOOT_INFO.memmap_total - POS_ENSURE, PAGE_SIZE) * PAGE_SIZE;
  bm->init = false;

  bm->mem_start = targetpos;
  bm->nblocks = _DIV_ROUNDUP(BOOT_INFO.memmap_total, BITMAP_BLOCK_SIZE);
  bm->nbytes = _DIV_ROUNDUP(bm->nblocks, 8);

  uint64_t pagesrequired = _DIV_ROUNDUP(bm->nbytes, BITMAP_BLOCK_SIZE);
  bm->map = (uint8_t *)vmm_alloc(pagesrequired);
  hal_memset(bm->map, 0, bm->nbytes);

  bm->init = true;
}

void *vmm_alloc(size_t pages) {
  size_t phys = (size_t)pmm_alloc(pages);
  uint64_t out = phys + BOOT_INFO.hhdm_off;
  return (void *)out;
}


void vmm_free(void *ptr, size_t pages) {
  size_t phys = paging_virt2phys((size_t)ptr);
  if (!phys) {
    ERR("vmm", "could not find phys addr for %p\n", ptr);
    hal_hang();
  }
  pmm_free(phys, pages);
}