<?php

/**
 * ImageTools Class
 * Thumbnail aide, mostly
 */
class ImageTools {
	/**
	 * Store processed links to avoid repetition
	 * @var array 'URL' => 'Parsed URL'
	 */
	private static $Storage = array();

	/**
	 * We use true as an extra property to make the domain an array key
	 * @var array $Hosts Array of image hosts
	 */
	private static $Hosts = array(
		'whatimg.com' => true,
		'imgur.com' => true
	);

	/**
	 * Blacklisted sites
	 * @var array $Blacklist Array of blacklisted hosts
	 */
	private static $Blacklist = array(
		'tinypic.com'
	);

	/**
	 * Array of image hosts that provide thumbnailing
	 * @var array $Thumbs
	 */
	private static $Thumbs = array(
		'i.imgur.com' => true,
		'whatimg.com' => true
	);

	/**
	 * Array of extensions
	 * @var array $Extensions
	 */
	private static $Extensions = array(
		'jpg' => true,
		'jpeg' => true,
		'png' => true,
		'gif' => true
	);

	/**
	 * Checks from our list of valid hosts
	 * @param string $Host Domain/host to check
	 * @return boolean
	 */
	public static function valid_host($Host) {
		return !empty(self::$Hosts[$Host]) && self::$Hosts[$Host] === true;
	}

	/**
	 * Checks if a link's host is (not) good, otherwise displays an error.
	 * @param string $Url Link to an image
	 * @return boolean
	 */
	public static function blacklisted($Url, $ShowError = true) {
		foreach (self::$Blacklist as &$Value) {
			if (stripos($Url, $Value)) {
				$ParsedUrl = parse_url($Url);
				if ($ShowError) {
					error($ParsedUrl['host'] . ' is not an allowed image host. Please use a different host.');
				}
				return true;
			}
		}
		return false;
	}

	/**
	 * Checks to see if a link has a thumbnail
	 * @param string $Url Link to an image
	 * @return string|false Matched host or false
	 */
	private static function thumbnailable($Url) {
		$ParsedUrl = parse_url($Url);
		return !empty(self::$Thumbs[$ParsedUrl['host']]);
	}

	/**
	 * Checks an extension
	 * @param string $Ext Extension to check
	 * @return boolean
	 */
	private static function valid_extension($Ext) {
//		return @self::$Extensions[$Ext] === true;
		return !empty(self::$Extensions[$Ext]) && self::$Extensions[$Ext] === true;
	}

	/**
	 * Stores a link with a (thumbnail) link
	 * @param type $Link
	 * @param type $Processed
	 */
	private static function store($Link, $Processed) {
		self::$Storage[$Link] = $Processed;
	}

	/**
	 * Retrieves an entry from our storage
	 * @param type $Link
	 * @return boolean|string Returns false if no match
	 */
	private static function get_stored($Link) {
		if (isset(self::$Storage[$Link])) {
			return self::$Storage[$Link];
		}
		return false;
	}

	/**
	 * Checks if URL points to a whatimg thumbnail.
	 */
	private static function has_whatimg_thumb($Url) {
		return (strpos($Url, '_thumb') !== false);
	}

	/**
	 * Cleans up imgur URL if it already has a modifier attached to the end of it.
	 */
	private static function clean_imgur_url($Url) {
		$Extension = pathinfo($Url, PATHINFO_EXTENSION);
		$Full = preg_replace('/\.[^.]*$/', '', $Url);
		$Base = substr($Full, 0, strrpos($Full, '/'));
		$Path = substr($Full, strrpos($Full, '/') + 1);
		if (strlen($Path) == 6) {
			$Last = $Path[strlen($Path) - 1];
			if ($Last == 'm' || $Last == 'l' || $Last == 's' || $Last == 'h' || $Last == 'b') {
				$Path = substr($Path, 0, -1);
			}
		}
		return "$Base/$Path.$Extension";
	}

	/**
	 * Replaces the extension.
	 */
	private static function replace_extension($String, $Extension) {
		return preg_replace('/\.[^.]*$/', $Extension, $String);
	}

	/**
	 * Create image proxy URL
	 * @param string $Url image URL
	 * @return image proxy URL
	 */
	public static function proxy_url($Url) {
		global $SSL;
		return ($SSL ? 'https' : 'http') . '://' . SITE_URL . '/image.php?c=1&amp;i=' . urlencode($Url);
	}

	/**
	 * Determine the image URL. This takes care of the image proxy and thumbnailing.
	 * @param string $Url
	 * @param bool $Thumb
	 * @return string
	 */
	public static function process($Url, $Thumb = false) {
		if (empty($Url)) {
			return '';
		}
		if (($Found = self::get_stored($Url . ($Thumb ? '_thumb' : '')))) {
			return $Found;
		}

		$ProcessedUrl = $Url;
		if ($Thumb) {
			$Extension = pathinfo($Url, PATHINFO_EXTENSION);
			if (self::thumbnailable($Url) && self::valid_extension($Extension)) {
				if (strpos($Url, 'whatimg') !== false && !self::has_whatimg_thumb($Url)) {
					$ProcessedUrl = self::replace_extension($Url, '_thumb.' . $Extension);
				} elseif (strpos($Url, 'imgur') !== false) {
					$ProcessedUrl = self::replace_extension(self::clean_imgur_url($Url), 'm.' . $Extension);
				}
			}
		}

		if (check_perms('site_proxy_images')) {
			$ProcessedUrl = self::proxy_url($ProcessedUrl);
		}

		self::store($Url . ($Thumb ? '_thumb' : ''), $ProcessedUrl);
		return $ProcessedUrl;
	}

	/**
	 * Cover art thumbnail in browse, on artist pages etc.
	 * @global array $CategoryIcons
	 * @param string $Url
	 * @param int $CategoryID
	 */
	public static function cover_thumb($Url, $CategoryID) {
		global $CategoryIcons;
		if ($Url) {
			$Src = self::process($Url, true);
			$Lightbox = self::process($Url);
		} else {
			$Src = STATIC_SERVER . 'common/noartwork/' . $CategoryIcons[$CategoryID - 1];
			$Lightbox = $Src;
		}
?>
		<img src="<?=$Src?>" width="90" height="90" alt="Cover" onclick="lightbox.init('<?=$Lightbox?>', 90)" />
<?
	}
}