#include <kapi/devices.hpp>

#include <kernel/devices/root_bus.hpp>
#include <kernel/drivers/init.hpp>

#include <kapi/system.hpp>
#include <kapi/test_support/devices.hpp>

#include <kstd/flat_map.hpp>
#include <kstd/memory.hpp>
#include <kstd/print.hpp>
#include <kstd/string.hpp>
#include <kstd/vector.hpp>

#include <string_view>
#include <utility>

namespace kapi::devices
{
  namespace
  {
    auto constinit root_bus = kstd::shared_ptr<kernel::devices::root_bus>{};
    auto constinit device_tree = kstd::flat_map<kstd::string, kstd::weak_ptr<device>>{};
  }  // namespace

  auto init() -> void
  {
    if (root_bus)
    {
      kapi::system::panic("[OS:DEV] The device subsystem has already been initialized");
    }

    interface_registry::init();
    kernel::drivers::init();

    root_bus = kstd::make_shared<kernel::devices::root_bus>();
    register_device(root_bus);
  }

  auto get_root_bus() -> kstd::shared_ptr<bus>
  {
    if (!root_bus)
    {
      kapi::system::panic("[OS:DEV] Root bus not initialized!");
    }
    return root_bus;
  }

  auto register_device(kstd::shared_ptr<device> device) -> bool
  {
    if (!device)
    {
      return false;
    }

    kstd::println("[OS:DEV] Registering device {}", device->name());

    auto found = device_tree.find(device->name());
    if (found != device_tree.end())
    {
      if (!found->second.expired())
      {
        return false;
      }

      found->second = device;
      return true;
    }

    return device_tree.emplace(device->name(), device).second;
  }

  auto unregister_device(device &) -> bool
  {
    kstd::println("[OS:DEV] TODO: implement device deregistration");
    return false;
  }

  auto find_device(std::string_view name) -> kstd::shared_ptr<device>
  {
    auto found = device_tree.find(kstd::string{name});
    if (found == device_tree.end())
    {
      return nullptr;
    }

    return found->second.lock();
  }

  auto all() -> kstd::vector<kstd::shared_ptr<device>>
  {
    auto result = kstd::vector<kstd::shared_ptr<device>>{};

    for (auto const & [name, weak_device] : device_tree)
    {
      if (auto device = weak_device.lock())
      {
        result.push_back(std::move(device));
      }
    }

    return result;
  }

}  // namespace kapi::devices

namespace kapi::test_support::devices
{
  auto deinit() -> void
  {
    deinit_interface_registry();
    deinit_driver_registry();

    kapi::devices::root_bus.reset();
  }
}  // namespace kapi::test_support::devices