#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 <ranges>
#include <utility>

namespace kapi::platform
{
  namespace
  {
    constexpr auto candidate_flags = acpi::processor_local_apic::flags::processor_enabled  //
                                     | acpi::processor_local_apic::flags::online_capable;
  }

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

    auto bsp_found = false;
    auto core_count = 0uz;
    auto local_apic_address = madt->local_interrupt_controller_address();

    auto lapic_entries = *madt | std::views::filter([](auto const & entry) {
      return entry.type() == acpi::multiple_apic_description_table_entry::types::processor_local_apic;
    }) | std::views::transform([](auto const & entry) {
      return static_cast<acpi::processor_local_apic const &>(entry);
    }) | std::views::filter([](auto const & entry) {
      return static_cast<bool>(entry.active_flags() & candidate_flags);
    });

    for (auto const & apic : lapic_entries)
    {
      auto is_bsp = !bsp_found;
      bsp_found = true;
      auto instance = kstd::make_unique<arch::devices::local_apic>(interrupt_controller_major, core_count,
                                                                   apic.apic_id(), local_apic_address, is_bsp);
      if (kapi::platform::cpu_detected(bus, core_major, core_count, apic.processor_id(), is_bsp, std::move(instance)))
      {
        ++core_count;
      }
    }

    kstd::println("[x86_64:PLT] Found {} CPU cores", core_count);
    return core_count > 0;
  }

}  // namespace kapi::platform