<?php

namespace App\Net;

use App\Chat\Frame;
use App\Chat\Session;

/** One TCP client: what it sent and is not a whole line yet, what waits to be written. */
final class TcpSession implements Session
{
    public const MAX_OUTPUT = 1_048_576;

    public string $buffer = '';
    private string $output = '';
    private bool $closed = false;

    /** @param resource $stream */
    public function __construct(public $stream, private readonly string $peer)
    {
    }

    public function send(string $code, array $fields = []): void
    {
        if ($this->closed) {
            return;
        }
        $this->output .= Frame::encode($code, $fields);
        if (strlen($this->output) > self::MAX_OUTPUT) {
            $this->close(); // a client that does not read any more
            return;
        }
        $this->flush();
    }

    public function hasOutput(): bool
    {
        return $this->output !== '' && !$this->closed;
    }

    public function flush(): void
    {
        if ($this->closed || $this->output === '') {
            return;
        }
        $written = @fwrite($this->stream, $this->output);
        if ($written === false) {
            $this->close();
            return;
        }
        $this->output = (string)substr($this->output, $written);
    }

    public function close(): void
    {
        if ($this->closed) {
            return;
        }
        $this->flush();
        $this->closed = true;
        if (is_resource($this->stream)) {
            @fclose($this->stream);
        }
    }

    public function isClosed(): bool
    {
        return $this->closed;
    }

    public function address(): string
    {
        return $this->peer;
    }

    public function ip(): string
    {
        return ClientIp::host($this->peer);
    }
}