<?php


// FILEPATH URL --> RELATIVE_PATH
// SIDE-EFFECT: Written redirect PHP to filepath
//	Create a simple PHP redirection file at $filepath to $url;
//	return the relative path to it.
function write_alias($filepath, $url)
{
	$file_p = fopen($filepath, 'w');
	$redirect_string = "<?php header('Location: " . $url . "'); ?>\n";

	if (fwrite($file_p, $redirect_string)) {
		fclose($file_p);
		return $filepath;
	}
	else {
		return 0;
	}
}


// FILEPATH SOURCE_STRING --> RELATIVE_PATH
// SIDE-EFFECT: Written metadata TXT at $filepath.txt
//	Create a metadata file for set path;
//	return the relative path to it.
function write_metadata($filepath, $source)
{
	if (empty($source)) {
		$source = "[citation needed]";
	}

	$file_p = fopen($filepath . ".txt", 'w');
	$source_string = "Source:\n"
		. prefix_text(set_line_length($source, 50),
				"          ");

	if (fwrite($file_p, $source_string)) {
		fclose($file_p);
		return $source_string;
	}
	else {
		return 0;
	}
}


// FILENAME --> FILE_EXTENSION
//	Return the file-extension of a filename.
function file_extension($file_name)
{
	return strtolower(pathinfo($file_name, PATHINFO_EXTENSION));
}

// FILENAME --> BOOLEAN
//	Return whether or not a filename has an 'image' file-extension
function is_image($file_name)
{
	$file_ext = file_extension($file_name);

	if (in_array(($file_ext), array("jpg", "jpeg", "jpg", "png"))) {
		return 1;
	} else {
		return 0;
	}
}


?>