autonomous.contact/public/tabs/forum/new_post.html

<div class="new-post-container">
	<label>
		<input type="checkbox" collapse-toggle />
		<i class="icon plus" style="display: inline-block; margin-right: 0.5rem"></i>
		<span>New Post</span>
	</label>
	<form
		data-smart="true"
		data-requires-permission="topics.posts.create"
		method="POST"
		class="post-creation-form collapsible"
		style="
			margin-top: 1rem
			width: 100%;
			transition: all 0.5s;
		"
		url="/api/topics/${ document.body.dataset.topic }/events"
		on_reply="async (event) => { await document.getElementById( 'posts-list' ).__render(event); document.getElementById(event.id)?.classList.remove('sending'); }"
		on_parsed="async (event) => { await document.getElementById( 'posts-list' ).__render(event); document.getElementById(event.id)?.classList.add('sending'); }"
	>
		<input type="hidden" name="type" value="post" />

		<input
			type="hidden"
			name="id"
			generator="(_input, form) => 'TEMP-' + form.__submitted_at.toISOString()"
			reset-on-submit
		/>
		<input
			type="hidden"
			name="meta.temp_id"
			generator="(_input, form) => 'TEMP-' + form.__submitted_at.toISOString()"
			reset-on-submit
		/>

		<input
			type="hidden"
			name="creator_id"
			generator="() => { return APP.user?.id; }"
		/>

		<input
			type="hidden"
			name="timestamps.created"
			generator="(_input, form) => form.__submitted_at.toISOString()"
			reset-on-submit
		/>
		<input
			type="hidden"
			name="timestamps.updated"
			generator="(_input, form) => form.__submitted_at.toISOString()"
			reset-on-submit
		/>

		<input
			type="hidden"
			name="parent_id"
			generator="(_input, form) => { const parent_post = form.closest( '.post-container' ); return parent_post?.dataset?.post_id; }"
		/>

		<input
			class="new-post-subject"
			type="text"
			name="data.subject"
			value=""
			placeholder="Post subject..."
			style="margin-bottom: 1rem"
			reset-on-submit
		/>
		<label>
			<input
				aria-label="Upload and share file"
				type="file"
				multiple
				data-smartforms-save-to-home="true"
				name="data.media"
				reset-on-submit
			/>
			<div class="icon attachment"></div>
		</label>
		<textarea
			type="text"
			name="data.content"
			value=""
			placeholder=" ... "
			reset-on-submit
		></textarea>
		<input type="submit" value="Post" />
	</form>
</div>