<?php
namespace Fisharebest\Webtrees\Functions;

/**
 * webtrees: online genealogy
 * Copyright (C) 2015 webtrees development team
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
use Fisharebest\Webtrees\Log;

/**
 * Class FunctionsMedia - common functions
 */
class FunctionsMedia {
	/**
	 * Convert raw values from php.ini file into bytes
	 *
	 * @param string $val
	 *
	 * @return int
	 */
	public static function sizeToBytes($val) {
		if (!$val) {
			// no value was passed in, assume no limit and return -1
			$val = -1;
		}
		switch (substr($val, -1)) {
			case 'g':
			case 'G':
				return (int) $val * 1024 * 1024 * 1024;
			case 'm':
			case 'M':
				return (int) $val * 1024 * 1024;
			case 'k':
			case 'K':
				return (int) $val * 1024;
			default:
				return (int) $val;
		}
	}

	/**
	 * Determine whether there is enough memory to load a particular image.
	 *
	 * @param string $serverFilename
	 *
	 * @return bool
	 */
	public static function hasMemoryForImage($serverFilename) {
		// find out how much total memory this script can access
		$memoryAvailable = self::sizeToBytes(ini_get('memory_limit'));
		// if memory is unlimited, it will return -1 and we don’t need to worry about it
		if ($memoryAvailable == -1) {
			return true;
		}

		// find out how much memory we are already using
		$memoryUsed = memory_get_usage();

		try {
			$imgsize = getimagesize($serverFilename);
		} catch (\ErrorException $ex) {
			// Not an image, or not a valid image?
			$imgsize = false;
		}

		// find out how much memory this image needs for processing, probably only works for jpegs
		// from comments on http://www.php.net/imagecreatefromjpeg
		if ($imgsize && isset($imgsize['bits']) && (isset($imgsize['channels']))) {
			$memoryNeeded = round(($imgsize[0] * $imgsize[1] * $imgsize['bits'] * $imgsize['channels'] / 8 + Pow(2, 16)) * 1.65);
			$memorySpare  = $memoryAvailable - $memoryUsed - $memoryNeeded;
			if ($memorySpare > 0) {
				// we have enough memory to load this file
				return true;
			} else {
				// not enough memory to load this file
				$image_info = sprintf('%.2fKB, %d × %d %d bits %d channels', filesize($serverFilename) / 1024, $imgsize[0], $imgsize[1], $imgsize['bits'], $imgsize['channels']);
				Log::addMediaLog('Cannot create thumbnail ' . $serverFilename . ' (' . $image_info . ') memory avail: ' . $memoryAvailable . ' used: ' . $memoryUsed . ' needed: ' . $memoryNeeded . ' spare: ' . $memorySpare);

				return false;
			}
		} else {
			// assume there is enough memory
			// TODO find out how to check memory needs for gif and png
			return true;
		}
	}
}
