#include "vmm.h"

typedef void (*constructor)();

extern "C" {
/* .text */
uint32_t begin_text;
uint32_t end_text;

/* .rodata */
uint32_t begin_rodata;
uint32_t end_rodata;

/* .data */
uint32_t begin_constinit;
uint32_t end_constinit;
constructor begin_ctors;
constructor end_ctors;
uint32_t begin_data;
uint32_t end_data;

/* .bss */
uint32_t begin_bss;
uint32_t end_bss;

void kernel_constructors() {
  for (constructor* i = &begin_ctors; i != &end_ctors; ++i) (*i)();
}

void dump_address() {
  printk("text      begin: ", uhex{reinterpret_cast<uint32_t>(&begin_text)},
         " end: ", uhex{reinterpret_cast<uint32_t>(&end_text)}, '\n');

  printk("rodata    begin: ", uhex{reinterpret_cast<uint32_t>(&begin_rodata)},
         " end: ", uhex{reinterpret_cast<uint32_t>(&end_rodata)}, '\n');

  printk("constinit begin: ", uhex{reinterpret_cast<uint32_t>(&begin_constinit)},
         " end: ", uhex{reinterpret_cast<uint32_t>(&end_constinit)}, '\n');

  printk("ctors     begin: ", uhex{reinterpret_cast<uint32_t>(&begin_ctors)},
         " end: ", uhex{reinterpret_cast<uint32_t>(&end_ctors)}, '\n');

  printk("data      begin: ", uhex{reinterpret_cast<uint32_t>(&begin_data)},
         " end: ", uhex{reinterpret_cast<uint32_t>(&end_data)}, '\n');

  printk("bss       begin: ", uhex{reinterpret_cast<uint32_t>(&begin_bss)},
         " end: ", uhex{reinterpret_cast<uint32_t>(&end_bss)}, '\n');
}
}  // extern "C"

/* boot.S externs */
extern uint32_t kernel_pagedir;
extern uint32_t kernel_ptable0;
extern uint32_t VADDR_OFFSET;

/* vmm */
static_assert(sizeof(vmm::address) == 4);
static_assert(vmm::address(0xc03ff000) == 0xc03ff000);
static_assert(vmm::address(0xc03ff000).table_idx == 768);
static_assert(vmm::address(0xc03ff000).page_idx == 1023);
static_assert(vmm::address(0xc03ff000).offset == 0);

vmm::vmm(uint32_t* addr) : directory{(addr == nullptr) ? &kernel_pagedir : addr} {}

Result<uint32_t, vmm::Error> vmm::map(uint32_t addr, const vmm::address dest) {
  const auto phys_offset = addr % 4096;
  const auto phys_paddr = addr & 0xfffff000;

  // TODO allocate page table
  if (directory[dest.table_idx] == 0) return Result<uint32_t, vmm::Error>{vmm::TableNotAllocated};

  page_table table{directory[dest.table_idx]};

  if (table.set(dest.page_idx, phys_paddr)) {
    vmm::reload();
    return Result<uint32_t, vmm::Error>{dest + phys_offset};
  } else
    return Result<uint32_t, vmm::Error>{vmm::AddressAlreadyMapped};
}

void vmm::unmap(const address d) {
  if (directory[d.table_idx] == 0) return;
  page_table table{directory[d.table_idx]};
  table.set(d.page_idx, 0);
  vmm::reload();
}

vmm::page_table::page_table(uint32_t from) {
  // TODO get flags
  // convert physical address to a virtual address so we can read it
  from &= 0xfffff000;  // discard flags
  from += reinterpret_cast<uint32_t>(&VADDR_OFFSET);

  pages = reinterpret_cast<uint32_t*>(from);
}