<?php
require_once($_SERVER['DOCUMENT_ROOT'] . '/config.php');
require_once($_SERVER['DOCUMENT_ROOT'] . '/api/v1/database.php');

function get_actor_or_exit($conn, string $preferred_username) {
	$actor = sql_fetch_actor($conn, $preferred_username);

	if (!$actor) {
		http_response_code(404);
		die();
	}

	return $actor;
}

function get_actor(string $preferred_username) {
	$public_key = file_get_contents(HOSTAS_PUBKEY_PATH);
	$conn = new SQLite3(HOSTAS_DATABASE_PATH);

	$actor = get_actor_or_exit($conn, $preferred_username);

	$activity_representation = array(
		'@context' => HOSTAS_CONTEXT,
		'id' => $actor['id'],
		'type' => 'Person',
		'preferredUsername' => $actor['preferredUsername'],
		'name' => $actor['name'],
		'summary' => $actor['summary'],
		'url' => $actor['url'],
		'icon' => array(
			'type' => 'Image',
			'url' => $actor['icon'],
		),
		'publicKey' => array(
			'id' => "{$actor['id']}#main-key",
			'owner' => $actor['id'],
			'publicKeyPem' => $public_key,
		),
		'inbox' => "https://" . HOSTAS_DOMAIN . "/api/v1/actor/$preferred_username/inbox",
		'outbox' => "https://" . HOSTAS_DOMAIN . "/api/v1/actor/$preferred_username/outbox",
	);

	header('Content-Type: application/activity+json');
	echo json_encode($activity_representation);

	$conn->close();
	die();
}

/** /api/v1/actor/:preferred_username/outbox?before=:before_date_iso&limit=:limit
 * Returns an OrderedCollectionPage of at most `limit` pages published before
 * `before_date_iso`.
 *
 * Parameters:
 *	before		ISO timestamp string. Only posts published before this time are included
 *	limit		Integer. Number of posts to include in the result. Default: 20. Max: HOSTAS_MAX_POSTS_PER_PAGE
 */
function get_actor_outbox_paged(string $preferred_username) {
	header('Content-Type: application/activity+json');

	$before = array_key_exists('before', $_GET) ? $_GET['before'] : date(DATE_ISO8601, time());
	$after = array_key_exists('after', $_GET) ? $_GET['after'] : date(DATE_ISO8601, 0);
	$limit = array_key_exists('limit', $_GET) ? $_GET['limit'] : 20;

	// Parameters in $_GET with a + character will get replaced with whitespace,
	// so we've got to change it back
	$before = str_replace(" ", "+", $before);
	$after = str_replace(" ", "+", $after);

	// Cap the limit at the configured maximum
	if ($limit > HOSTAS_MAX_POSTS_PER_PAGE) {
		$limit = HOSTAS_MAX_POSTS_PER_PAGE;
	}

	$conn = new SQLite3(HOSTAS_DATABASE_PATH);
	$actor = get_actor_or_exit($conn, $preferred_username);

	$sql_query = <<<'EOT'
		select object.id as object_id, object.type as object_type,
			activity.actor as activity_actor, post.id as post_id,
			post.published as post_published, post.type as post_type,
			post.content as post_content, post.published as post_published
			from object
			join activity on activity.objectId = object.id
			join object as post on activity.object = post.id
			where
				activity_actor = :actor_id
				and post_published < :before
				and post_published > :after
			order by object.published desc
			limit :limit
	EOT;

	$create_activities_result = prepare_and_execute($conn, $sql_query,
		array(
			':actor_id' => $actor['id'],
			':before' => strtotime($before),
			':after' => strtotime($after),
			':limit' => $limit
		)
	);

	$total_items = 0;
	$ordered_items = array();

	while ($entry = $create_activities_result->fetchArray()) {
		$total_items += 1;
		array_push($ordered_items, array(
			'id' => $entry['object_id'],
			'type' => $entry['object_type'],
			'actor' => $entry['activity_actor'],
			'published' => date(DATE_ISO8601, $entry['post_published']),
			'cc' => array('https://www.w3.org/ns/activitystreams#Public'),
			'object' => array(
				'id' => $entry['post_id'],
				'type'=> $entry['post_type'],
				'published' => date(DATE_ISO8601, $entry['post_published']),
				'url' => $entry['post_id'],
				'attributedTo' => $actor['id'],
				'cc' => array('https://www.w3.org/ns/activitystreams#Public'),
				'content' => $entry['post_content'],
			),
		));
	}

	$clean_uri = 'https://' . HOSTAS_DOMAIN . strtok($_SERVER['REQUEST_URI'], '?');

	$response = array(
		'@context' => HOSTAS_CONTEXT,
		'id' => 'https://' . HOSTAS_DOMAIN . $_SERVER['REQUEST_URI'],
		'type' => 'OrderedCollectionPage',
		'partOf' => 'https://' . HOSTAS_DOMAIN . $clean_uri,
		'orderedItems' => $ordered_items,
	);

	if ($total_items === 0) {
		// There may be previous items, so we can reuse the before param. We
		// need to do some pre-processing to avoid characters getting escaped
		// from the URL
		$latest_time = str_replace(" ", "+", $before);
		$response['prev'] = $clean_uri . "?after=$latest_time";
	} else {
		$earliest_time = $ordered_items[array_key_last($ordered_items)]['published'];
		$latest_time = $ordered_items[0]['published'];

		$response['prev'] = $clean_uri . "?after=$latest_time";
		$response['next'] = $clean_uri . "?before=$earliest_time";
	}

	echo json_encode($response);

	die();
}

function get_actor_outbox(string $preferred_username) {
	header('Content-Type: application/activity+json');

	$conn = new SQLite3(HOSTAS_DATABASE_PATH);
	$actor = get_actor_or_exit($conn, $preferred_username);

	$sql_query = <<<'EOT'
		select count(post.id) as post_count, min(post.published)
			from object
			join activity on activity.objectId = object.id
			join object as post on activity.object = post.id
			where activity.actor = :actor_id
	EOT;

	$items_count_result = prepare_and_execute($conn, $sql_query,
		array(':actor_id' => $actor['id'])
	);
	$items_count_row = $items_count_result->fetchArray(SQLITE3_ASSOC);
	$total_items = $items_count_row['post_count'];

	$collection_id = "https://" . HOSTAS_DOMAIN . "/api/v1/actor/$preferred_username/outbox";

	echo json_encode(array(
		'@context' => HOSTAS_CONTEXT,
		'id' => $collection_id,
		'type' => 'OrderedCollection',
		'totalItems' => $total_items,
		'first' => $collection_id . '?before=' . date(DATE_ISO8601, time()),
		'last' => $collection_id . '?after=' . date(DATE_ISO8601, 0),
	));

	die();
}

function get_actor_inbox(string $objectId) {
	die();
}

switch ($_SERVER['REQUEST_METHOD']) {
	case 'GET':
		if (sizeof(REQUEST_PATH) === 3) {
			if (REQUEST_PATH[2] === 'inbox')	get_actor_inbox(REQUEST_PATH[1]);
			else if (REQUEST_PATH[2] === 'outbox') {
				if (array_key_exists('before', $_GET) || array_key_exists('after', $_GET)) {
					get_actor_outbox_paged(REQUEST_PATH[1]);
				} else {
					get_actor_outbox(REQUEST_PATH[1]);
				}
			}
		}

		get_actor(REQUEST_PATH[1]);
		break;
	default:
		http_response_code(405);
		die();
}