<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\HttpFoundation;

/**
 * An event generated on the server intended for streaming to the client
 * as part of the SSE streaming technique.
 *
 * @implements \IteratorAggregate<string>
 *
 * @author Yonel Ceruto <open@yceruto.dev>
 */
class ServerEvent implements \IteratorAggregate
{
    /**
     * @param string|iterable<string> $data    The event data field for the message
     * @param string|null             $type    The event type
     * @param int|null                $retry   The number of milliseconds the client should wait
     *                                         before reconnecting in case of network failure
     * @param string|null             $id      The event ID to set the EventSource object's last event ID value
     * @param string|null             $comment The event comment
     */
    public function __construct(
        private string|iterable $data,
        private ?string $type = null,
        private ?int $retry = null,
        private ?string $id = null,
        private ?string $comment = null,
    ) {
    }

    public function getData(): iterable|string
    {
        return $this->data;
    }

    /**
     * @return $this
     */
    public function setData(iterable|string $data): static
    {
        $this->data = $data;

        return $this;
    }

    public function getType(): ?string
    {
        return $this->type;
    }

    /**
     * @return $this
     */
    public function setType(string $type): static
    {
        $this->type = $type;

        return $this;
    }

    public function getRetry(): ?int
    {
        return $this->retry;
    }

    /**
     * @return $this
     */
    public function setRetry(?int $retry): static
    {
        $this->retry = $retry;

        return $this;
    }

    public function getId(): ?string
    {
        return $this->id;
    }

    /**
     * @return $this
     */
    public function setId(string $id): static
    {
        $this->id = $id;

        return $this;
    }

    public function getComment(): ?string
    {
        return $this->comment;
    }

    public function setComment(string $comment): static
    {
        $this->comment = $comment;

        return $this;
    }

    /**
     * @return \Traversable<string>
     */
    public function getIterator(): \Traversable
    {
        $head = '';
        if ($this->comment) {
            $head .= self::field(': ', $this->comment);
        }
        if ($this->id) {
            $head .= \sprintf('id: %s', self::singleLine($this->id))."\n";
        }
        if ($this->retry > 0) {
            $head .= \sprintf('retry: %s', $this->retry)."\n";
        }
        if ($this->type) {
            $head .= \sprintf('event: %s', self::singleLine($this->type))."\n";
        }
        yield $head;

        if (is_iterable($this->data)) {
            foreach ($this->data as $data) {
                yield self::field('data: ', $data);
            }
        } elseif ('' !== $this->data) {
            yield self::field('data: ', $this->data);
        }

        yield "\n";
    }

    /**
     * Renders a multi-line value as one prefixed line per line of the value.
     */
    private static function field(string $prefix, string $value): string
    {
        return $prefix.implode("\n".$prefix, preg_split("/\r\n|[\r\n]/", $value))."\n";
    }

    /**
     * Removes the line terminators that would end the field early, as the
     * SSE specification defines these fields as single-line only.
     */
    private static function singleLine(string $value): string
    {
        return str_replace(["\r", "\n"], '', $value);
    }
}
