<?php
/**
 * ZAP factory
 */
class ZAPZap {
	private $tpl = '';
	private $folder;
	private $height;
	private $width;
	private $words;

	public function __construct() {
		ob_start();
		if (!isset($_SESSION['collages']) || $_SESSION['collages'] <= 0) {
			$this->destroySession();
			$this->tpl .= ob_get_clean();
			return;
		}

		$this->width = $_SESSION['width'];
		$this->height = $_SESSION['height'];
		$this->folder = $_SESSION['folder'];
		$this->words = $_SESSION['words'];

		if (!empty($this->words)) {
			// Still downloading source images for the words.
			$this->showFoundImage();
		} elseif (empty($_SESSION['images'])) {
			// Start a new collage.
			$this->buildNextCollage();
		} else {
			// Add another source image to the current collage.
			$imgName = array_shift($_SESSION['images']);
			$image = $this->createImage($_SESSION['collageNr']);
			$image->addToCanvas($imgName);
		}
		$this->tpl .= ob_get_clean();
	}

	/**
	 * Build the next collage if any remain, otherwise finish.
	 */
	private function buildNextCollage() {
		if ($_SESSION['collages'] <= 0) {
			$this->destroySession();
			return;
		}

		// On the very first collage, load the downloaded source images.
		// On later collages, reuse the original list.
		if (!isset($_SESSION['imgOriginal'])) {
			$_SESSION['images'] = ImgTools::convertGifsToPng($this->retrieveImages());
			$_SESSION['imgOriginal'] = $_SESSION['images'];
		} else {
			$_SESSION['images'] = $_SESSION['imgOriginal'];
			shuffle($_SESSION['images']);
		}

		if (empty($_SESSION['images'])) {
			$this->destroySession();
			return;
		}

		// Track the current collage number separately so addToCanvas always
		// reads/writes the same file while this collage is being built.
		$_SESSION['collageNr'] = $_SESSION['collages'];
		$_SESSION['collages']--;

		$firstIm = array_shift($_SESSION['images']);
		$image = $this->createImage($_SESSION['collageNr']);
		$image->createBasicCanvas($firstIm);
	}

	private function createImage($collages) {
		return new ImgProcess($this->folder, $this->width, $this->height, $collages);
	}

	private function destroySession() {
		if (Session::destroy()) {
			$this->tpl .= "<p>" . ERROR_PREFIX . "Image ready</p>";
		} else {
			$this->tpl .= "<p>" . ERROR_PREFIX . "Strange... Could not end PHP session";
		}
		return;
	}

	private function setSessionVar($key, $value) {
		$_SESSION[$key] = $value;
	}

	private function showFoundImage() {
		$keyWord = array_shift($this->words);
		$search = new ImgSearch($this->folder, $keyWord);
		$imageUrl = $search->getImage();

		if ($imageUrl) {
			ImgIOTools::urlOnScreen($imageUrl);
		} else {
			ImgIOTools::urlOnScreen(ZAP_APP_BASE_DIR . DIRECTORY_SEPARATOR
								. ZAP_WEB_DIR . DIRECTORY_SEPARATOR
								. 'images' . DIRECTORY_SEPARATOR . 'error_noHit.png');
		}
		$this->setSessionVar('words', $this->words);
	}

	private function retrieveImages() {
		$img_ar = glob('{'  . $this->folder . DIRECTORY_SEPARATOR .'*.jpg,'
							. $this->folder . DIRECTORY_SEPARATOR .'*.png,'
							. $this->folder . DIRECTORY_SEPARATOR .'*.jpeg,'
							. $this->folder . DIRECTORY_SEPARATOR .'*.JPG,'
							. $this->folder . DIRECTORY_SEPARATOR .'*.gif'
							. '}', GLOB_BRACE);
		shuffle($img_ar);
		return $img_ar;
	}

	public function getContent() {
		return $this->tpl;
	}
}
?>