#include <kapi/interrupts.hpp>

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

#include <algorithm>
#include <cstdint>
#include <utility>

namespace kapi::interrupts
{

  namespace
  {
    auto constinit handlers = kstd::flat_map<std::uint32_t, kstd::vector<std::pair<handler *, kstd::weak_ptr<void>>>>{};
  }  // namespace

  auto register_handler(std::uint32_t irq_number, handler & handler, kstd::weak_ptr<void> context) -> void
  {
    if (handlers.contains(irq_number))
    {
      auto & handler_list = handlers.at(irq_number);
      handler_list.push_back(std::pair{&handler, context});
    }
    else
    {
      handlers.emplace(irq_number, kstd::vector{
                                     std::pair{&handler, context}
      });
    }
  }

  auto unregister_handler(std::uint32_t irq_number, handler & handler) -> void
  {
    auto & handler_list = handlers.at(irq_number);
    auto [first, last] =
        std::ranges::remove_if(handler_list, [&](auto const & entry) { return entry.first == &handler; });
    handler_list.erase(first, last);
  }

  auto dispatch(std::uint32_t irq_number) -> status
  {
    if (!handlers.contains(irq_number))
    {
      kstd::println(kstd::print_sink::stderr, "[OS:interrupts] No handler for IRQ{}", irq_number);
      return status::unhandled;
    }

    auto & handler_list = handlers.at(irq_number);

    if (handler_list.empty())
    {
      kstd::println(kstd::print_sink::stderr, "[OS:interrupts] No handler for IRQ{}", irq_number);
      return status::unhandled;
    }

    for (auto const & [handler, context] : handler_list)
    {
      if (handler && handler->handle_interrupt(irq_number, context) == status::handled)
      {
        return status::handled;
      }
    }

    return status::unhandled;
  }

}  // namespace kapi::interrupts