<?php

namespace Coroutine\Server;

class Transport
{
	/**
	 * @var array<int, Struct>
	 */
	private array $clients = [];

	/**
	 * @var array<int, int>
	 */
	private array $userIdByFd = [];

	public function add(int $userId, Struct $data): ?Struct
	{
		$previous = $this->clients[$userId] ?? null;

		$this->clients[$userId] = $data;
		if ($data->fd > 0) {
			$this->userIdByFd[$data->fd] = $userId;
		}

		if ($previous && $previous->fd !== $data->fd) {
			unset($this->userIdByFd[$previous->fd]);
			@$previous->ws->close();
		}

		return $previous;
	}

	public function sendUserId(int $userId, mixed $data): void
	{
		$struct = $this->clients[$userId] ?? null;
		if ($struct === null) {
			return;
		}

		$struct->touch();
		@$struct->ws->push($this->normalizePayload($data));
	}

	public function sendFd(int $fd, mixed $data): void
	{
		$struct = $this->getClientId($fd);
		if ($struct === null) {
			return;
		}

		$struct->touch();
		@$struct->ws->push($this->normalizePayload($data));
	}

	public function close(int $userId): void
	{
		$struct = $this->clients[$userId] ?? null;
		if ($struct === null) {
			return;
		}

		@$struct->ws->close();
	}

	public function remove(int $userId, ?int $fd = null): void
	{
		$struct = $this->clients[$userId] ?? null;
		if ($struct === null) {
			return;
		}

		if ($fd !== null && $struct->fd !== $fd) {
			return;
		}

		unset($this->clients[$userId]);
		unset($this->userIdByFd[$struct->fd]);

		@$struct->ws->close();
	}

	public function getClientId(int $fd): ?Struct
	{
		$userId = $this->userIdByFd[$fd] ?? null;
		if ($userId === null) {
			return null;
		}

		return $this->clients[$userId] ?? null;
	}

	public function getUserId(int $userId): ?Struct
	{
		return $this->clients[$userId] ?? null;
	}

	public function has(int $userId): bool
	{
		return isset($this->clients[$userId]);
	}

	public function touch(int $userId, ?int $fd = null): void
	{
		$struct = $this->clients[$userId] ?? null;
		if ($struct === null) {
			return;
		}

		if ($fd !== null && $struct->fd !== $fd) {
			return;
		}

		$struct->touch();
	}

	public function getLists(): array
	{
		$array = [];
		foreach ($this->clients as $userId => $client) {
			$array[] = [
				'userId' => $userId,
				'fd' => $client->fd,
				'nickname' => $client->user->getNickname(),
				'connectedAt' => $client->connectedAt,
				'lastSeenAt' => $client->lastSeenAt,
			];
		}

		return $array;
	}

	public function size(): int
	{
		return count($this->clients);
	}

	private function normalizePayload(mixed $data): string
	{
		if (is_string($data)) {
			return $data;
		}

		if (is_scalar($data) || $data === null) {
			return (string)$data;
		}

		$payload = json_encode($data, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
		return $payload === false ? '' : $payload;
	}
}