/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   Epoll.hpp                                          :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: acossari <acossari@student.codam.nl>       +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2026/08/26 11:34:23 by acossari          #+#    #+#             */
/*   Updated: 2026/08/26 11:34:25 by acossari         ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#pragma once

#include <sys/epoll.h>

#include <array>
#include <cstddef>
#include <cstdint>
#include <exception>
#include <span>
#include <string>

#include "net/FileDescriptor.hpp"

namespace webserv {

class Epoll final {
  public:
    class Error : public std::exception {
      public:
        explicit Error(std::string message);
        const char* what() const noexcept override;

      private:
        std::string msg_;
    };

    // wait() returns at most this many ready events per call. Smaller batches
    // require more calls, while larger batches delay the next loop iteration.
    // The value is a middle ground. Excess events remain for later calls.
    static constexpr std::size_t EVENT_BATCH_CAPACITY = 256;

    Epoll();

    void add(int fd, std::uint32_t events, std::uint64_t token);
    void modify(int fd, std::uint32_t events, std::uint64_t token);
    void remove(int fd) noexcept;

    std::span<const epoll_event> wait(int timeoutMillis);

  private:
    FileDescriptor fd_;
    std::array<epoll_event, EVENT_BATCH_CAPACITY> events_{};
};

}  // namespace webserv