<?php
/**
 * Copyright (c) 2013-2017
 *
 * @category  Library
 * @package   Dwoo\Template
 * @author    Jordi Boggiano <j.boggiano@seld.be>
 * @author    David Sanchez <david38sanchez@gmail.com>
 * @copyright 2008-2013 Jordi Boggiano
 * @copyright 2013-2017 David Sanchez
 * @license   http://dwoo.org/LICENSE LGPLv3
 * @version   1.4.0
 * @date      2017-03-16
 * @link      http://dwoo.org/
 */

namespace Dwoo\Template;

use Dwoo\Core;
use Dwoo\Compiler;
use Dwoo\ITemplate;
use Dwoo\ICompiler;
use Dwoo\Exception;

/**
 * Represents a Dwoo template contained in a string.
 * This software is provided 'as-is', without any express or implied warranty.
 * In no event will the authors be held liable for any damages arising from the use of this software.
 */
class Str implements ITemplate
{
    /**
     * Template name.
     *
     * @var string
     */
    protected $name;

    /**
     * Template compilation id.
     *
     * @var string
     */
    protected $compileId;

    /**
     * Template cache id, if not provided in the constructor, it is set to
     * the md4 hash of the request_uri. it is however highly recommended to
     * provide one that will fit your needs.
     * in all cases, the compilation id is prepended to the cache id to separate
     * templates with similar cache ids from one another
     *
     * @var string
     */
    protected $cacheId;

    /**
     * Validity duration of the generated cache file (in seconds).
     * set to -1 for infinite cache, 0 to disable and null to inherit the Dwoo instance's cache time
     *
     * @var int
     */
    protected $cacheTime;

    /**
     * Boolean flag that defines whether the compilation should be enforced (once) or
     * not use this if you have issues with the compiled templates not being updated
     * but if you do need this it's most likely that you should file a bug report.
     *
     * @var bool
     */
    protected $compilationEnforced;

    /**
     * Caches the results of the file checks to save some time when the same
     * templates is rendered several times.
     *
     * @var array
     */
    protected static $cache = array(
        'cached'   => array(),
        'compiled' => array()
    );

    /**
     * Holds the compiler that built this template.
     *
     * @var ICompiler
     */
    protected $compiler;

    /**
     * Chmod value for all files written (cached or compiled ones).
     * set to null if you don't want any chmod operation to happen
     *
     * @var int
     */
    protected $chmod = 0777;

    /**
     * Containing template string.
     *
     * @var string
     */
    protected $template;

    /**
     * Creates a template from a string.
     *
     * @param string $templateString the template to use
     * @param int    $cacheTime      duration of the cache validity for this template,
     *                               if null it defaults to the Dwoo instance that will
     *                               render this template, set to -1 for infinite cache or 0 to disable
     * @param string $cacheId        the unique cache identifier of this page or anything else that
     *                               makes this template's content unique, if null it defaults
     *                               to the current url
     * @param string $compileId      the unique compiled identifier, which is used to distinguish this
     *                               template from others, if null it defaults to the md4 hash of the template
     */
    public function __construct($templateString, $cacheTime = null, $cacheId = null, $compileId = null)
    {
        $this->template  = $templateString;
        $this->name      = hash('md4', $templateString);
        $this->cacheTime = $cacheTime;

        if ($compileId !== null) {
            $this->compileId = str_replace('../', '__', strtr($compileId, '\\%?=!:;' . PATH_SEPARATOR, '/-------'));
        } else {
            $this->compileId = $templateString;
        }

        if ($cacheId !== null) {
            $this->cacheId = str_replace('../', '__', strtr($cacheId, '\\%?=!:;' . PATH_SEPARATOR, '/-------'));
        }
    }

    /**
     * Returns the cache duration for this template.
     * defaults to null if it was not provided
     *
     * @return int|null
     */
    public function getCacheTime()
    {
        return $this->cacheTime;
    }

    /**
     * Sets the cache duration for this template.
     * can be used to set it after the object is created if you did not provide
     * it in the constructor
     *
     * @param int $seconds duration of the cache validity for this template, if
     *                     null it defaults to the Dwoo instance's cache time. 0 = disable and
     *                     -1 = infinite cache
     */
    public function setCacheTime($seconds = null)
    {
        $this->cacheTime = $seconds;
    }

    /**
     * Returns the chmod value for all files written (cached or compiled ones).
     * defaults to 0777
     *
     * @return int|null
     */
    public function getChmod()
    {
        return $this->chmod;
    }

    /**
     * Set the chmod value for all files written (cached or compiled ones).
     * set to null if you don't want to do any chmod() operation
     *
     * @param int $mask new bitmask to use for all files
     */
    public function setChmod($mask = null)
    {
        $this->chmod = $mask;
    }

    /**
     * Returns the template name.
     *
     * @return string
     */
    public function getName()
    {
        return $this->name;
    }

    /**
     * Returns the resource name for this template class.
     *
     * @return string
     */
    public function getResourceName()
    {
        return 'string';
    }

    /**
     * Returns the resource identifier for this template, false here as strings don't have identifiers.
     *
     * @return false
     */
    public function getResourceIdentifier()
    {
        return false;
    }

    /**
     * Returns the template source of this template.
     *
     * @return string
     */
    public function getSource()
    {
        return $this->template;
    }

    /**
     * Returns an unique value identifying the current version of this template,
     * in this case it's the md4 hash of the content.
     *
     * @return string
     */
    public function getUid()
    {
        return $this->name;
    }

    /**
     * Returns the compiler used by this template, if it was just compiled, or null.
     *
     * @return ICompiler
     */
    public function getCompiler()
    {
        return $this->compiler;
    }

    /**
     * Marks this template as compile-forced, which means it will be recompiled even if it
     * was already saved and wasn't modified since the last compilation. do not use this in production,
     * it's only meant to be used in development (and the development of dwoo particularly).
     */
    public function forceCompilation()
    {
        $this->compilationEnforced = true;
    }

    /**
     * Returns the cached template output file name, true if it's cache-able but not cached
     * or false if it's not cached.
     *
     * @param Core $core the dwoo instance that requests it
     *
     * @return string|bool
     */
    public function getCachedTemplate(Core $core)
    {
        $cacheLength = $core->getCacheTime();
        if ($this->cacheTime !== null) {
            $cacheLength = $this->cacheTime;
        }

        // file is not cacheable
        if ($cacheLength == 0) {
            return false;
        }

        $cachedFile = $this->getCacheFilename($core);

        if (isset(self::$cache['cached'][$this->cacheId]) === true && file_exists($cachedFile)) {
            // already checked, return cache file
            return $cachedFile;
        } elseif ($this->compilationEnforced !== true && file_exists($cachedFile) && ($cacheLength === - 1 || filemtime($cachedFile) > ($_SERVER['REQUEST_TIME'] - $cacheLength)) && $this->isValidCompiledFile($this->getCompiledFilename($core))) {
            // cache is still valid and can be loaded
            self::$cache['cached'][$this->cacheId] = true;

            return $cachedFile;
        }

        // file is cacheable
        return true;
    }

    /**
     * Caches the provided output into the cache file.
     *
     * @param Core   $core   the dwoo instance that requests it
     * @param string $output the template output
     *
     * @return mixed full path of the cached file or false upon failure
     */
    public function cache(Core $core, $output)
    {
        $cacheDir   = $core->getCacheDir();
        $cachedFile = $this->getCacheFilename($core);

        // the code below is courtesy of Rasmus Schultz,
        // thanks for his help on avoiding concurency issues
        $temp = tempnam($cacheDir, 'temp');
        if (!($file = @fopen($temp, 'wb'))) {
            $temp = $cacheDir . uniqid('temp');
            if (!($file = @fopen($temp, 'wb'))) {
                trigger_error('Error writing temporary file \'' . $temp . '\'', E_USER_WARNING);

                return false;
            }
        }

        fwrite($file, $output);
        fclose($file);

        $this->makeDirectory(dirname($cachedFile), $cacheDir);
        if (!@rename($temp, $cachedFile)) {
            @unlink($cachedFile);
            @rename($temp, $cachedFile);
        }

        if ($this->chmod !== null) {
            chmod($cachedFile, $this->chmod);
        }

        self::$cache['cached'][$this->cacheId] = true;

        return $cachedFile;
    }

    /**
     * Clears the cached template if it's older than the given time.
     *
     * @param Core $core      the dwoo instance that was used to cache that template
     * @param int  $olderThan minimum time (in seconds) required for the cache to be cleared
     *
     * @return bool true if the cache was not present or if it was deleted, false if it remains there
     */
    public function clearCache(Core $core, $olderThan = - 1)
    {
        $cachedFile = $this->getCacheFilename($core);

        return !file_exists($cachedFile) || (filectime($cachedFile) < (time() - $olderThan) && unlink($cachedFile));
    }

    /**
     * Returns the compiled template file name.
     *
     * @param Core      $core     the dwoo instance that requests it
     * @param ICompiler $compiler the compiler that must be used
     *
     * @return string
     */
    public function getCompiledTemplate(Core $core, ICompiler $compiler = null)
    {
        $compiledFile = $this->getCompiledFilename($core);

        if ($this->compilationEnforced !== true && isset(self::$cache['compiled'][$this->compileId]) === true) {
            // already checked, return compiled file
        } elseif ($this->compilationEnforced !== true && $this->isValidCompiledFile($compiledFile)) {
            // template is compiled
            self::$cache['compiled'][$this->compileId] = true;
        } else {
            // compiles the template
            $this->compilationEnforced = false;

            if ($compiler === null) {
                $compiler = $core->getDefaultCompilerFactory($this->getResourceName());

                if ($compiler === null || $compiler === array('Dwoo\Compiler', 'compilerFactory')) {
                    $compiler = Compiler::compilerFactory();
                } else {
                    $compiler = call_user_func($compiler);
                }
            }

            $this->compiler = $compiler;

            $compiler->setCustomPlugins($core->getCustomPlugins());
            $compiler->setSecurityPolicy($core->getSecurityPolicy());
            $this->makeDirectory(dirname($compiledFile), $core->getCompileDir());
            file_put_contents($compiledFile, $compiler->compile($core, $this));
            if ($this->chmod !== null) {
                chmod($compiledFile, $this->chmod);
            }

            if (extension_loaded('Zend OPcache')) {
                opcache_invalidate($compiledFile);
            } elseif (extension_loaded('apc') && ini_get('apc.enabled')) {
                apc_delete_file($compiledFile);
            }

            self::$cache['compiled'][$this->compileId] = true;
        }

        return $compiledFile;
    }

    /**
     * Checks if compiled file is valid (it exists).
     *
     * @param string $file
     *
     * @return bool True cache file existence
     */
    protected function isValidCompiledFile($file)
    {
        return file_exists($file);
    }

    /**
     * Returns a new template string object with the resource id being the template source code.
     *
     * @param Core      $core           the dwoo instance requiring it
     * @param mixed     $resourceId     the filename (relative to this template's dir) of the template to include
     * @param int       $cacheTime      duration of the cache validity for this template, if null it defaults to the
     *                                  Dwoo instance that will render this template if null it defaults to the Dwoo
     *                                  instance that will render this template
     * @param string    $cacheId        the unique cache identifier of this page or anything else that makes this
     *                                  template's content unique, if null it defaults to the current url makes this
     *                                  template's content unique, if null it defaults to the current url
     * @param string    $compileId      the unique compiled identifier, which is used to distinguish this template from
     *                                  others, if null it defaults to the filename+bits of the path template from
     *                                  others, if null it defaults to the filename+bits of the path
     * @param ITemplate $parentTemplate the template that is requesting a new template object (through an include,
     *                                  extends or any other plugin) an include, extends or any other plugin)
     *
     * @return $this
     */
    public static function templateFactory(Core $core, $resourceId, $cacheTime = null, $cacheId = null,
                                           $compileId = null, ITemplate $parentTemplate = null)
    {
        return new self($resourceId, $cacheTime, $cacheId, $compileId);
    }

    /**
     * Returns the full compiled file name and assigns a default value to it if
     * required.
     *
     * @param Core $core the Core instance that requests the file name
     *
     * @return string the full path to the compiled file
     */
    protected function getCompiledFilename(Core $core)
    {
        return $core->getCompileDir() . hash('md4', $this->compileId) . '.d' . Core::RELEASE_TAG . '.php';
    }

    /**
     * Returns the full cached file name and assigns a default value to it if
     * required.
     *
     * @param Core $core the dwoo instance that requests the file name
     *
     * @return string the full path to the cached file
     */
    protected function getCacheFilename(Core $core)
    {
        // no cache id provided, use request_uri as default
        if ($this->cacheId === null) {
            if (isset($_SERVER['REQUEST_URI']) === true) {
                $cacheId = $_SERVER['REQUEST_URI'];
            } elseif (isset($_SERVER['SCRIPT_FILENAME']) && isset($_SERVER['argv'])) {
                $cacheId = $_SERVER['SCRIPT_FILENAME'] . '-' . implode('-', $_SERVER['argv']);
            } else {
                $cacheId = '';
            }
            // force compiled id generation
            $this->getCompiledFilename($core);

            $this->cacheId = str_replace('../', '__',
                $this->compileId . strtr($cacheId, '\\%?=!:;' . PATH_SEPARATOR, '/-------'));
        }

        return $core->getCacheDir() . $this->cacheId . '.html';
    }

    /**
     * Returns some php code that will check if this template has been modified or not.
     * if the function returns null, the template will be instanciated and then the Uid checked
     *
     * @return string
     */
    public function getIsModifiedCode()
    {
        return null;
    }

    /**
     * Ensures the given path exists.
     *
     * @param string $path    any path
     * @param string $baseDir the base directory where the directory is created
     *                        ($path must still contain the full path, $baseDir
     *                        is only used for unix permissions)
     *
     * @throws Exception
     */
    protected function makeDirectory($path, $baseDir = null)
    {
        if (is_dir($path) === true) {
            return;
        }

        if ($this->chmod === null) {
            $chmod = 0777;
        } else {
            $chmod = $this->chmod;
        }

        $retries = 3;
        while ($retries --) {
            @mkdir($path, $chmod, true);
            if (is_dir($path)) {
                break;
            }
            usleep(20);
        }

        // enforce the correct mode for all directories created
        if (strpos(PHP_OS, 'WIN') !== 0 && $baseDir !== null) {
            $path    = strtr(str_replace($baseDir, '', $path), '\\', '/');
            $folders = explode('/', trim($path, '/'));
            foreach ($folders as $folder) {
                $baseDir .= $folder . DIRECTORY_SEPARATOR;
                if (!chmod($baseDir, $chmod)) {
                    throw new Exception('Unable to chmod ' . "$baseDir to $chmod: " . print_r(error_get_last(), true));
                }
            }
        }
    }
}