<?php
class Af_Lemmy extends Plugin {

	/** @var PluginHost $host */
	private $host;

	/** @var array<string> */
	private $domain_blacklist = [ "github.com" ];

	/** @var array<int, array<int, string|null>> */
	private $generated_enclosures = [];

	function about() {
		return array(null,
			"Inline images (and other content) in Lemmy.ml RSS feeds",
			"fox");
	}

	function flags() {
		return array("needs_curl" => true);
	}

	function init($host) {
		$this->host = $host;

		$host->add_hook($host::HOOK_ARTICLE_FILTER, $this);
		$host->add_hook($host::HOOK_PRE_SUBSCRIBE, $this);
	}

	function hook_pre_subscribe(&$url, $auth_login, $auth_pass) {

		// TODO

		return false;
	}

	/**
	 * @param array<string, mixed> $article
	 * @param DOMDocument $doc
	 * @param DOMXPath $xpath
	 * @return bool
	 * @throws PDOException
	 */
	private function inline_stuff(array &$article, DOMDocument &$doc, DOMXpath $xpath, string $origin_domain) : bool {

		$found = false;
		$this->generated_enclosures = [];
		$entries = $xpath->query('//a[@href]');

		foreach ($entries as $entry) {
			$entry_href = UrlHelper::rewrite_relative($article["link"], $entry->getAttribute("href"), "a");

			$matches = [];

			/* skip links going back to origin (and any other blacklisted stuff, including /u/user profiles, except for /pictrs) */
			if (!$found &&
					strpos($entry_href, "/pictrs/") === FALSE &&
					(strpos($entry_href, "/u/") !== FALSE || $this->is_blacklisted($entry_href, [$origin_domain]))) {
				Debug::log("BODY: URL $entry_href is blacklisted, skipping", Debug::LOG_EXTENDED);
				continue;
			}

			Debug::log("BODY: processing URL: " . $entry_href, Debug::LOG_VERBOSE);

			if (!$found && preg_match("/^https?:\/\/twitter.com\/(.*?)\/status\/(.*)/", $entry_href, $matches)) {
				Debug::log("handling as twitter: " . $matches[1] . " " . $matches[2], Debug::LOG_VERBOSE);

				$oembed_result = UrlHelper::fetch("https://publish.twitter.com/oembed?url=" . urlencode($entry_href));

				if ($oembed_result) {
					$oembed_result = json_decode($oembed_result, true);

					if ($oembed_result && isset($oembed_result["html"])) {

						$tmp = new DOMDocument();
						if (@$tmp->loadHTML('<?xml encoding="utf-8" ?>' . $oembed_result["html"])) {
							$p = $doc->createElement("p");

							$p->appendChild($doc->importNode(
								$tmp->getElementsByTagName("blockquote")->item(0), TRUE));

							$br = $doc->createElement('br');
							$entry->parentNode->insertBefore($p, $entry);
							$entry->parentNode->insertBefore($br, $entry);

							$found = 1;
						}
					}
				}
			}

			if (!$found && preg_match("/\.gfycat.com\/([a-z]+)?(\.[a-z]+)$/i", $entry_href, $matches)) {
				$entry->setAttribute("href", "http://www.gfycat.com/".$matches[1]);
			}

			if (!$found && preg_match("/https?:\/\/(www\.)?gfycat.com\/([a-z]+)$/i", $entry_href, $matches)) {

				Debug::log("Handling as Gfycat", Debug::LOG_VERBOSE);

				$source_stream = 'https://giant.gfycat.com/' . $matches[2] . '.mp4';
				$poster_url = 'https://thumbs.gfycat.com/' . $matches[2] . '-mobile.jpg';

				$content_type = $this->get_content_type($source_stream);

				if (strpos($content_type, "video/") !== false) {
					$this->handle_as_video($doc, $entry, $source_stream, $poster_url);
					$found = 1;
				}
			}

			// imgur .gif -> .gifv
			if (!$found && preg_match("/i\.imgur\.com\/(.*?)\.gif$/i", $entry_href)) {
				Debug::log("Handling as imgur gif (->gifv)", Debug::LOG_VERBOSE);

				$entry->setAttribute("href",
					str_replace(".gif", ".gifv", $entry_href));
			}

			if (!$found && preg_match("/\.(gifv|mp4)$/i", $entry_href)) {
				Debug::log("Handling as imgur gifv", Debug::LOG_VERBOSE);

				$source_stream = str_replace(".gifv", ".mp4", $entry_href);

				if (strpos($source_stream, "imgur.com") !== false)
					$poster_url = str_replace(".mp4", "h.jpg", $source_stream);
				else
					$poster_url = false;

				$this->handle_as_video($doc, $entry, $source_stream, $poster_url);

				$found = true;
			}

			$matches = array();
			if (!$found && $vid_id = UrlHelper::url_to_youtube_vid($entry_href)) {

				Debug::log("Handling as youtube: $vid_id", Debug::LOG_VERBOSE);

				/* normalize video URL for af_youtube_... plugins */
				$video_url = "https://www.youtube.com/v/$vid_id";

				/* push generated video URL to enclosures so that youtube embed plugins would deal with it later (if enabled) */
				$this->generated_enclosures[] = [$video_url, "text/html", null, null, '', ''];

				$found = true;
			}

			if (!$found && (preg_match("/\.(jpg|jpeg|gif|png)(\?[0-9][0-9]*)?[$\?]?/i", $entry_href) ||
				/* mb_strpos($entry_href, "i.reddituploads.com") !== false || */
				mb_strpos($this->get_content_type($entry_href), "image/") !== false)) {

				Debug::log("Handling as a picture", Debug::LOG_VERBOSE);

				$img = $doc->createElement('img');
				$img->setAttribute("src", $entry_href);

				$br = $doc->createElement('br');
				$entry->parentNode->insertBefore($img, $entry);
				$entry->parentNode->insertBefore($br, $entry);

				$found = true;
			}

			// imgur via link rel="image_src" href="..."
			if (!$found && preg_match("/imgur/", $entry_href)) {

				Debug::log("handling as imgur page/whatever", Debug::LOG_VERBOSE);

				$content_type = $this->get_content_type($entry_href);

				if ($content_type && strpos($content_type, "text/html") !== false) {

					$content = UrlHelper::fetch(["url" => $entry_href,
						"http_accept" => "text/*"]);

					if ($content) {
						$cdoc = new DOMDocument();

						if (@$cdoc->loadHTML($content)) {
							$cxpath = new DOMXPath($cdoc);

							/** @var ?DOMElement $rel_image */
							$rel_image = $cxpath->query("//link[@rel='image_src']")->item(0);

							if ($rel_image) {

								$img = $doc->createElement('img');
								$img->setAttribute("src", $rel_image->getAttribute("href"));

								$br = $doc->createElement('br');
								$entry->parentNode->insertBefore($img, $entry);
								$entry->parentNode->insertBefore($br, $entry);

								$found = true;
							}
						}
					}

				} else {
					Debug::log("skipping imgur $entry_href because of content type: $content_type", Debug::LOG_VERBOSE);
				}
			}

			// wtf is this even
			if (!$found && preg_match("/^https?:\/\/gyazo\.com\/([^\.\/]+$)/", $entry_href, $matches)) {
				$img_id = $matches[1];

				Debug::log("handling as gyazo: $img_id", Debug::LOG_VERBOSE);

				$img = $doc->createElement('img');
				$img->setAttribute("src", "https://i.gyazo.com/$img_id.jpg");

				$br = $doc->createElement('br');
				$entry->parentNode->insertBefore($img, $entry);
				$entry->parentNode->insertBefore($br, $entry);

				$found = true;
			}

			// let's try meta properties
			if (!$found) {
				Debug::log("looking for meta og:image", Debug::LOG_VERBOSE);

				$content_type = $this->get_content_type($entry_href);

				if ($content_type && strpos($content_type, "text/html") !== false) {

					$content = UrlHelper::fetch(["url" => $entry_href,
						"http_accept" => "text/*"]);

					if ($content) {
						$cdoc = new DOMDocument();

						if (@$cdoc->loadHTML($content)) {
							$cxpath = new DOMXPath($cdoc);

							/** @var ?DOMElement $og_image */
							$og_image = $cxpath->query("//meta[@property='og:image']")->item(0);

							/** @var ?DOMElement $og_video */
							$og_video = $cxpath->query("//meta[@property='og:video']")->item(0);

							if ($og_video) {

								$source_stream = $og_video->getAttribute("content");

								if ($source_stream) {

									if ($og_image) {
										$poster_url = $og_image->getAttribute("content");
									} else {
										$poster_url = false;
									}

									$this->handle_as_video($doc, $entry, $source_stream, $poster_url);
									$found = true;
								}

							} else if ($og_image) {

								$og_src = $og_image->getAttribute("content");

								if ($og_src) {
									$img = $doc->createElement('img');
									$img->setAttribute("src", $og_src);

									$br = $doc->createElement('br');
									$entry->parentNode->insertBefore($img, $entry);
									$entry->parentNode->insertBefore($br, $entry);

									$found = true;
								}
							}
						}
					}
				} else {
					Debug::log("BODY: skipping $entry_href because of content type: $content_type", Debug::LOG_VERBOSE);
				}
			}
		}

		return $found > 0;
	}

	function hook_article_filter($article) {

		if (preg_match("/lemmy.ml\/post\/[0-9]{1,}$/", $article['link']) !== false && !empty($article["content"])) {
			$doc = new DOMDocument();

			if (@$doc->loadHTML($article["content"])) {
				$xpath = new DOMXPath($doc);

				if ($this->is_blacklisted($article['link']))
					return $article;

				$origin_domain = parse_url($article["feed"]["site_url"] ?? '', PHP_URL_HOST);

				$found = $this->inline_stuff($article, $doc, $xpath, $origin_domain);
				$node = $doc->getElementsByTagName('body')->item(0);

				if ($node && $found) {
					$article["content"] = $doc->saveHTML($node);
					$article["enclosures"] = $this->generated_enclosures;
				} else {
					// $article = $this->readability($article, $content_href, $doc, $xpath);
				}
			}
		}

		return $article;
	}

	private function handle_as_image(DOMDocument $doc, DOMElement $entry, string $image_url, string $link_url = "") : void {
		$img = $doc->createElement("img");
		$img->setAttribute("src", $image_url);

		$p = $doc->createElement("p");

		if ($link_url) {
			$a = $doc->createElement("a");
			$a->setAttribute("href", $link_url);

			$a->appendChild($img);
			$p->appendChild($a);
		} else {
			$p->appendChild($img);
		}

		$entry->parentNode->insertBefore($p, $entry);
	}

	private function handle_as_video(DOMDocument $doc, DOMElement $entry, string $source_stream, string $poster_url = "") : void {

		Debug::log("handle_as_video: $source_stream", Debug::LOG_VERBOSE);

		$video = $doc->createElement('video');
		$video->setAttribute("autoplay", "1");
		$video->setAttribute("controls", "1");
		$video->setAttribute("loop", "1");

		if ($poster_url) $video->setAttribute("poster", $poster_url);

		$source = $doc->createElement('source');
		$source->setAttribute("src", $source_stream);
		$source->setAttribute("type", "video/mp4");

		$video->appendChild($source);

		$br = $doc->createElement('br');
		$entry->parentNode->insertBefore($video, $entry);
		$entry->parentNode->insertBefore($br, $entry);
	}

	/** $useragent defaults to Config::get_user_agent() */
	private function get_header(string $url, int $header, string $useragent = "") : string {
		$ret = "";

		if (function_exists("curl_init")) {
			$ch = curl_init($url);
			curl_setopt($ch, CURLOPT_TIMEOUT, 5);
			curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
			curl_setopt($ch, CURLOPT_HEADER, true);
			curl_setopt($ch, CURLOPT_NOBODY, true);
			curl_setopt($ch, CURLOPT_FOLLOWLOCATION, !ini_get("open_basedir"));
			curl_setopt($ch, CURLOPT_USERAGENT, $useragent ? $useragent : Config::get_user_agent());

			@curl_exec($ch);
			$ret = curl_getinfo($ch, $header);
		}

		return $ret;
	}

	private function get_content_type(string $url, string $useragent = "") : string {
		return $this->get_header($url, CURLINFO_CONTENT_TYPE, $useragent);
	}

	/**
	 * @param array<string,mixed> $article
	 * @param string $url
	 * @param DOMDocument $doc
	 * @param DOMXPath $xpath
	 * @param bool $debug
	 * @return array<string,mixed>
	 * @throws PDOException
	 */
	private function readability(array $article, string $url, DOMDocument $doc, DOMXpath $xpath, bool $debug = false) : array {

		if (function_exists("curl_init") && $this->host->get($this, "enable_readability") &&
			mb_strlen(strip_tags($article["content"])) <= 150) {

			// do not try to embed posts linking back to other reddit posts
			// readability.php requires PHP 5.6
			if ($url &&	strpos($url, "reddit.com") === false) {

				/* link may lead to a huge video file or whatever, we need to check content type before trying to
				parse it which p much requires curl */

				$useragent_compat = "Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.1; WOW64; Trident/6.0)";
				$content_type = $this->get_content_type($url, $useragent_compat);

				if ($content_type && strpos($content_type, "text/html") !== false) {

					$this->host->run_hooks_callback(PluginHost::HOOK_GET_FULL_TEXT,
						function ($result) use (&$article) {
							if ($result) {
								$article["content"]  = $result;
								return true;
							}
						},
						$url);
				}
			}
		}

		return $article;
	}

	/**
	 * @param string $src
	 * @param array<string> $also_blacklist
	 * @return bool
	 */
	private function is_blacklisted(string $src, array $also_blacklist = []) : bool {
		$src_domain = parse_url($src, PHP_URL_HOST);

		if ($src_domain)
		foreach ([...$this->domain_blacklist, ...$also_blacklist] as $domain) {
				if (strstr($src_domain, $domain) !== false) {
					return true;
				}
			}

		return false;
	}

	function api_version() {
		return 2;
	}

}