#pragma once

#include <BAN/CircularQueue.h>
#include <BAN/HashMap.h>
#include <BAN/HashSet.h>
#include <kernel/FS/Inode.h>

#include <sys/epoll.h>

namespace Kernel
{

	class Epoll final : public Inode
	{
	public:
		static BAN::ErrorOr<BAN::RefPtr<Epoll>> create();
		~Epoll();

		BAN::ErrorOr<void> ctl(int op, BAN::RefPtr<Inode> inode, epoll_event event);
		BAN::ErrorOr<size_t> wait(BAN::Span<epoll_event> events, uint64_t waketime_ns);

		void notify(BAN::RefPtr<Inode> inode, uint32_t event);

	private:
		Epoll() = default;

	public:
		ino_t ino() const override         { return 0; }
		Mode mode() const override         { return { Mode::IRUSR | Mode::IWUSR }; }
		nlink_t nlink() const override     { return 0; }
		uid_t uid() const override         { return 0; }
		gid_t gid() const override         { return 0; }
		off_t size() const override        { return 0; }
		timespec atime() const override    { return {}; }
		timespec mtime() const override    { return {}; }
		timespec ctime() const override    { return {}; }
		blksize_t blksize() const override { return PAGE_SIZE; }
		blkcnt_t blocks() const override   { return 0; }
		dev_t dev() const override         { return 0; }
		dev_t rdev() const override        { return 0; }

		bool is_epoll() const override { return true; }

		const FileSystem* filesystem() const override { return nullptr; }

		bool can_read_impl() const override { return false; }
		bool can_write_impl() const override { return false; }
		bool has_error_impl() const override { return false; }
		bool has_hangup_impl() const override { return false; }

		BAN::ErrorOr<void> fsync_impl() override { return {}; }

	private:
		struct InodeRefPtrHash
		{
			BAN::hash_t operator()(const BAN::RefPtr<Inode>& inode)
			{
				return BAN::hash<const Inode*>()(inode.ptr());
			}
		};

	private:
		ThreadBlocker m_thread_blocker;
		BAN::HashMap<BAN::RefPtr<Inode>, uint32_t,    InodeRefPtrHash> m_ready_events;
		BAN::HashMap<BAN::RefPtr<Inode>, epoll_event, InodeRefPtrHash> m_listening_events;
	};

}