#include "kapi/platform.hpp"

#include "kapi/acpi.hpp"
#include "kapi/devices.hpp"

#include "arch/devices/local_apic.hpp"

#include <kstd/memory>
#include <kstd/print>

#include <cstddef>
#include <utility>

namespace kapi::platform
{

  auto discover_cpu_topology(kapi::devices::bus & bus) -> bool
  {
    auto static const core_major = kapi::devices::allocate_major_number();
    auto static const interrupt_controller_major = kapi::devices::allocate_major_number();
    auto static core_index = 0uz;

    auto madt = kapi::acpi::get_table("APIC");
    if (!madt)
    {
      kstd::println("[x86_64:PLT] Failed to find ACPI APIC table");
      return false;
    }

    auto real_madt = static_cast<acpi::madt_header const *>(madt.get());
    auto current = reinterpret_cast<std::byte const *>(madt.get()) + sizeof(kapi::acpi::madt_header);
    auto end = reinterpret_cast<std::byte const *>(madt.get()) + madt->length();

    auto bsp_found = false;
    auto core_count = 0uz;

    while (current < end)
    {
      auto const * sub_table = reinterpret_cast<kapi::acpi::madt_subtable_header const *>(current);
      if (sub_table->type() == 0)
      {
        auto const * local_apic = reinterpret_cast<kapi::acpi::madt_local_apic const *>(sub_table);
        if (local_apic->flags() & 0b11)
        {
          auto is_bsp = !bsp_found;
          bsp_found = true;
          auto lapic = kstd::make_unique<arch::devices::local_apic>(interrupt_controller_major, core_index,
                                                                    local_apic->apic_id(),
                                                                    real_madt->local_interrupt_controller_address());
          if (kapi::platform::cpu_detected(bus, core_major, core_index, local_apic->processor_id(), is_bsp,
                                           std::move(lapic)))
          {
            ++core_count;
          }
        }
      }

      current += sub_table->length();
    }

    kstd::println("[x86_64:PLT] Found {} CPU cores", core_count);

    return core_count > 0;
  }

}  // namespace kapi::platform