#pragma once

#include <brynet/base/Stack.hpp>
#include <brynet/net/SocketLibTypes.hpp>
#include <cassert>
#include <cstdlib>

#if defined BRYNET_PLATFORM_LINUX || defined BRYNET_PLATFORM_DARWIN
#include <poll.h>
#endif

#ifdef BRYNET_PLATFORM_WINDOWS
const static int CHECK_READ_FLAG = (POLLIN | POLLRDNORM | POLLRDBAND);
const static int CHECK_WRITE_FLAG = (POLLOUT | POLLWRNORM);
const static int CHECK_ERROR_FLAG = (POLLERR | POLLHUP);
#elif defined BRYNET_PLATFORM_LINUX || defined BRYNET_PLATFORM_DARWIN
const static int CHECK_READ_FLAG = (POLLIN | POLLRDNORM | POLLRDBAND | POLLPRI);
const static int CHECK_WRITE_FLAG = (POLLOUT | POLLWRNORM | POLLWRBAND);
const static int CHECK_ERROR_FLAG = (POLLERR | POLLHUP);
#endif

enum CheckType {
	ReadCheck = 0x1,
	WriteCheck = 0x2,
	ErrorCheck = 0x4,
};

struct poller_s {
	struct pollfd *pollFds;
	int nfds;
	int limitSize;
};

static void upstep_pollfd(struct poller_s *self, int upSize) {
	if (upSize <= 0) {
		return;
	}

	struct pollfd *newPollfds = (struct pollfd *)malloc(
			sizeof(struct pollfd) * (self->limitSize + upSize));
	if (newPollfds == nullptr) {
		return;
	}

	if (self->pollFds != nullptr) {
		memcpy(newPollfds, self->pollFds, sizeof(struct pollfd) * self->nfds);
		free(self->pollFds);
		self->pollFds = nullptr;
	}
	self->pollFds = newPollfds;
	self->limitSize += upSize;
}

static struct pollfd *find_pollfd(struct poller_s *self, BrynetSocketFD fd) {
	for (int i = 0; i < self->nfds; i++) {
		if (self->pollFds[i].fd == fd) {
			return self->pollFds + i;
		}
	}

	return nullptr;
}

static void try_remove_pollfd(struct poller_s *self, BrynetSocketFD fd) {
	int pos = -1;
	for (int i = 0; i < self->nfds; i++) {
		if (self->pollFds[i].fd == fd) {
			pos = i;
			break;
		}
	}

	if (pos != -1) {
		memmove(self->pollFds + pos,
				self->pollFds + pos + 1,
				sizeof(struct pollfd) * (self->nfds - pos - 1));
		self->nfds--;
		assert(self->nfds >= 0);
	}
}

static struct poller_s *poller_new(void) {
	struct poller_s *ret = (struct poller_s *)malloc(sizeof(struct poller_s));
	if (ret != nullptr) {
		ret->pollFds = NULL;
		ret->limitSize = 0;
		ret->nfds = 0;
		upstep_pollfd(ret, 1024);
	}

	return ret;
}

static void poller_delete(struct poller_s *self) {
	free(self->pollFds);
	self->pollFds = nullptr;
	self->nfds = 0;
	self->limitSize = 0;

	free(self);
	self = nullptr;
}

static void poller_add(struct poller_s *self, BrynetSocketFD fd, int type) {
	if (self->limitSize == self->nfds) {
		upstep_pollfd(self, 128);
	}

	if (self->limitSize <= self->nfds) {
		return;
	}

	struct pollfd *pf = find_pollfd(self, fd);
	if (pf == nullptr) {
		/*real add*/
		pf = self->pollFds + self->nfds;
		pf->events = 0;
		pf->fd = fd;

		self->nfds++;
	}

	if (type & ReadCheck) {
		pf->events |= CHECK_READ_FLAG;
	}

	if (type & WriteCheck) {
		pf->events |= CHECK_WRITE_FLAG;
	}

	if (type & ErrorCheck) {
		//pf->events |= CHECK_ERROR_FLAG;   TODO::on windows, not supports
	}
}

static void poller_del(struct poller_s *self, BrynetSocketFD fd, int type) {
	struct pollfd *pf = find_pollfd(self, fd);
	if (pf == nullptr) {
		return;
	}

	if (type & ReadCheck) {
		pf->events &= ~CHECK_READ_FLAG;
	}

	if (type & WriteCheck) {
		pf->events &= ~CHECK_WRITE_FLAG;
	}

	if (type & ErrorCheck) {
		pf->events &= ~CHECK_ERROR_FLAG;
	}

	if (pf->events == 0) {
		try_remove_pollfd(self, fd);
	}
}

static void poller_remove(struct poller_s *self, BrynetSocketFD fd) {
	try_remove_pollfd(self, fd);
}

static bool check_event(const struct pollfd *pf, enum CheckType type) {
	if (pf == nullptr) {
		return false;
	}

	if ((type & ReadCheck) &&
			(pf->revents & CHECK_READ_FLAG)) {
		return true;
	} else if ((type & WriteCheck) &&
			   (pf->revents & CHECK_WRITE_FLAG)) {
		return true;
	} else if ((type & ErrorCheck) &&
			   (pf->revents & CHECK_ERROR_FLAG)) {
		return true;
	} else {
		return false;
	}
}

static void poller_visitor(struct poller_s *self,
		enum CheckType type,
		struct stack_s *result) {
	for (int i = 0; i < self->nfds; i++) {
		if (check_event(self->pollFds + i, type)) {
			stack_push(result, &self->pollFds[i].fd);
		}
	}
}

static int poller_poll(struct poller_s *self, long overtime) {
#ifdef BRYNET_PLATFORM_WINDOWS
	int ret = WSAPoll(&self->pollFds[0], self->nfds, overtime);
#elif defined BRYNET_PLATFORM_LINUX || defined BRYNET_PLATFORM_DARWIN
	int ret = poll(self->pollFds, self->nfds, overtime);
#endif

	if (ret == BRYNET_SOCKET_ERROR) {
		ret = (BRYNET_ERRNO != BRYNET_EINTR) ? -1 : 0;
	}

	return ret;
}

static bool poller_check(struct poller_s *self, BrynetSocketFD fd, enum CheckType type) {
	const struct pollfd *pf = find_pollfd(self, fd);
	if (pf == NULL) {
		return false;
	}
	return check_event(pf, type);
}