<?php

require_once( dirname(__FILE__).'/Version.php');

/**
* Utility for handling the generation and caching of css files
*
* @package Less
* @subpackage cache
*
*/
class Less_Cache{

// directory less.php can use for storing data
public static $cache_dir = false;

// prefix for the storing data
public static $prefix = 'lessphp_';

// prefix for the storing vars
public static $prefix_vars = 'lessphpvars_';

// specifies the number of seconds after which data created by less.php will be seen as 'garbage' and potentially cleaned up
public static $gc_lifetime = 604800;


/**
* Save and reuse the results of compiled less files.
* The first call to Get() will generate css and save it.
* Subsequent calls to Get() with the same arguments will return the same css filename
*
* @param array $less_files Array of .less files to compile
* @param array $parser_options Array of compiler options
* @param array $modify_vars Array of variables
* @return string Name of the css file
*/
public static function Get( $less_files, $parser_options = array(), $modify_vars = array() ){


//check $cache_dir
if( isset($parser_options['cache_dir']) ){
Less_Cache::$cache_dir = $parser_options['cache_dir'];
}

if( empty(Less_Cache::$cache_dir) ){
throw new Exception('cache_dir not set');
}

if( isset($parser_options['prefix']) ){
Less_Cache::$prefix = $parser_options['prefix'];
}

if( empty(Less_Cache::$prefix) ){
throw new Exception('prefix not set');
}

if( isset($parser_options['prefix_vars']) ){
Less_Cache::$prefix_vars = $parser_options['prefix_vars'];
}

if( empty(Less_Cache::$prefix_vars) ){
throw new Exception('prefix_vars not set');
}

self::CheckCacheDir();
$less_files = (array)$less_files;


//create a file for variables
if( !empty($modify_vars) ){
$lessvars = Less_Parser::serializeVars($modify_vars);
$vars_file = Less_Cache::$cache_dir . Less_Cache::$prefix_vars . sha1($lessvars) . '.less';

if( !file_exists($vars_file) ){
file_put_contents($vars_file, $lessvars);
}

$less_files += array($vars_file => '/');
}


// generate name for compiled css file
$hash = md5(json_encode($less_files));
$list_file = Less_Cache::$cache_dir . Less_Cache::$prefix . $hash . '.list';

// check cached content
if( !isset($parser_options['use_cache']) || $parser_options['use_cache'] === true ){
if( file_exists($list_file) ){

self::ListFiles($list_file, $list, $cached_name);
$compiled_name = self::CompiledName($list, $hash);

// if $cached_name is the same as the $compiled name, don't regenerate
if( !$cached_name || $cached_name === $compiled_name ){

$output_file = self::OutputFile($compiled_name, $parser_options );

if( $output_file && file_exists($output_file) ){
@touch($list_file);
return basename($output_file); // for backwards compatibility, we just return the name of the file
}
}
}
}

$compiled = self::Cache( $less_files, $parser_options );
if( !$compiled ){
return false;
}

$compiled_name = self::CompiledName( $less_files, $hash );
$output_file = self::OutputFile($compiled_name, $parser_options );


//save the file list
$list = $less_files;
$list[] = $compiled_name;
$cache = implode("\n",$list);
file_put_contents( $list_file, $cache );


//save the css
file_put_contents( $output_file, $compiled );


//clean up
self::CleanCache();

return basename($output_file);
}

/**
* Force the compiler to regenerate the cached css file
*
* @param array $less_files Array of .less files to compile
* @param array $parser_options Array of compiler options
* @param array $modify_vars Array of variables
* @return string Name of the css file
*/
public static function Regen( $less_files, $parser_options = array(), $modify_vars = array() ){
$parser_options['use_cache'] = false;
return self::Get( $less_files, $parser_options, $modify_vars );
}

public static function Cache( &$less_files, $parser_options = array() ){


// get less.php if it exists
$file = dirname(__FILE__) . '/Less.php';
if( file_exists($file) && !class_exists('Less_Parser') ){
require_once($file);
}

$parser_options['cache_dir'] = Less_Cache::$cache_dir;
$parser = new Less_Parser($parser_options);


// combine files
foreach($less_files as $file_path => $uri_or_less ){

//treat as less markup if there are newline characters
if( strpos($uri_or_less,"\n") !== false ){
$parser->Parse( $uri_or_less );
continue;
}

$parser->ParseFile( $file_path, $uri_or_less );
}

$compiled = $parser->getCss();


$less_files = $parser->allParsedFiles();

return $compiled;
}


private static function OutputFile( $compiled_name, $parser_options ){

//custom output file
if( !empty($parser_options['output']) ){

//relative to cache directory?
if( preg_match('#[\\\\/]#',$parser_options['output']) ){
return $parser_options['output'];
}

return Less_Cache::$cache_dir.$parser_options['output'];
}

return Less_Cache::$cache_dir.$compiled_name;
}


private static function CompiledName( $files, $extrahash ){

//save the file list
$temp = array(Less_Version::cache_version);
foreach($files as $file){
$temp[] = filemtime($file)."\t".filesize($file)."\t".$file;
}

return Less_Cache::$prefix.sha1(json_encode($temp).$extrahash).'.css';
}


public static function SetCacheDir( $dir ){
Less_Cache::$cache_dir = $dir;
self::CheckCacheDir();
}

public static function CheckCacheDir(){

Less_Cache::$cache_dir = str_replace('\\','/',Less_Cache::$cache_dir);
Less_Cache::$cache_dir = rtrim(Less_Cache::$cache_dir,'/').'/';

if( !file_exists(Less_Cache::$cache_dir) ){
if( !mkdir(Less_Cache::$cache_dir) ){
throw new Less_Exception_Parser('Less.php cache directory couldn\'t be created: '.Less_Cache::$cache_dir);
}

}elseif( !is_dir(Less_Cache::$cache_dir) ){
throw new Less_Exception_Parser('Less.php cache directory doesn\'t exist: '.Less_Cache::$cache_dir);

}elseif( !is_writable(Less_Cache::$cache_dir) ){
throw new Less_Exception_Parser('Less.php cache directory isn\'t writable: '.Less_Cache::$cache_dir);

}

}


/**
* Delete unused less.php files
*
*/
public static function CleanCache(){
static $clean = false;


if( $clean || empty(Less_Cache::$cache_dir) ){
return;
}

$clean = true;

// only remove files with extensions created by less.php
// css files removed based on the list files
$remove_types = array('lesscache'=>1,'list'=>1,'less'=>1,'map'=>1);

$files = scandir(Less_Cache::$cache_dir);
if( !$files ){
return;
}

$check_time = time() - self::$gc_lifetime;
foreach($files as $file){


// don't delete if the file wasn't created with less.php
if( strpos($file,Less_Cache::$prefix) !== 0 ){
continue;
}

$parts = explode('.',$file);
$type = array_pop($parts);


if( !isset($remove_types[$type]) ){
continue;
}

$full_path = Less_Cache::$cache_dir . $file;
$mtime = filemtime($full_path);

// don't delete if it's a relatively new file
if( $mtime > $check_time ){
continue;
}


// delete the list file and associated css file
if( $type === 'list' ){
self::ListFiles($full_path, $list, $css_file_name);
if( $css_file_name ){
$css_file = Less_Cache::$cache_dir . $css_file_name;
if( file_exists($css_file) ){
unlink($css_file);
}
}
}

unlink($full_path);
}


}


/**
* Get the list of less files and generated css file from a list file
*
*/
static function ListFiles($list_file, &$list, &$css_file_name ){

$list = explode("\n",file_get_contents($list_file));

//pop the cached name that should match $compiled_name
$css_file_name = array_pop($list);

if( !preg_match('/^' . Less_Cache::$prefix . '[a-f0-9]+\.css$/',$css_file_name) ){
$list[] = $css_file_name;
$css_file_name = false;
}

}

}