[3.0] Support Youtube embed videos with a timestamp

[jdarwood007]

Fixes #7118

Syntax:

[youtube]sF80I-TQiW0[/youtube]
[youtube start=23363]sF80I-TQiW0[/youtube]

[Sesquipedalian]

I don't think you need two versions of SMF\BBCode\YouTube. Instead, try this change in the existing YouTube class:

Find:

	/**
	 *
	 */
	public ?string $content = '<div class="videocontainer"><div><iframe frameborder="0" src="https://www.youtube.com/embed/$1?origin={hosturl}&wmode=opaque" data-youtube-id="$1" allowfullscreen loading="lazy"></iframe></div></div>';

	/**
	 *
	 */
	public ?string $disabled_content = '<a href="https://www.youtube.com/watch?v=$1" target="_blank" rel="noopener">https://www.youtube.com/watch?v=$1</a>';

Replace:

	/**
	 *
	 */
	public ?array $parameters = [
		'start' => [
			'match' => '(\d+)',
			'optional' => true,
			'default' => '0',
		],
	];

	/**
	 *
	 */
	public ?string $content = '<div class="videocontainer"><div><iframe frameborder="0" src="https://www.youtube.com/embed/$1?origin={hosturl}&wmode=opaque&start={start}" data-youtube-id="$1" allowfullscreen loading="lazy"></iframe></div></div>';

	/**
	 *
	 */
	public ?string $disabled_content = '<a href="https://www.youtube.com/watch?v=$1&t={start}s" target="_blank" rel="noopener">https://www.youtube.com/watch?v=$1&t={start}s</a>';

By making the start parameter optional and giving it a default value of 0, you can make [youtube]sF80I-TQiW0[/youtube] equivalent to [youtube start=0]sF80I-TQiW0[/youtube].

[jdarwood007]

That would have an unintended side effect of making all the fallback URLs have "t=0s" in them.

[Sesquipedalian]

That wouldn't hurt anything, as far as I can tell. 0s is the default for the t parameter in YouTube URLs anyway. But if you want to avoid it, you could add some logic to skip the URL param in the class's validate method.