Template.class.php

<?php

/**
 * Simple template engine
 */
class Template {

    private static $templatesPath = 'templates/';
    private static $cache = array();
    
    /**
     * @param string $name filename without extension
     * @return self
     */
    public static function from($name) {
        return self::fromPath(self::$templatesPath, $name);
    }

   /**
     * @param string $path path to directory of template files
     * @param string $name filename without extension
     * @return self
     */
    public static function fromPath($path, $name) {
        return new Template($path, $name);
    }
    
    /**
     * Merge templates to one string
     * @param Template[] $templates
     * @param string $separator
     * @return string
     */
    public static function merge(array $templates, $separator = "\n") {
        $output = '';
        foreach ($templates as $template) {
            $output .= $template->render() . $separator;
        }
        return $output;
    }

    /**
     * @param string $templatesPath
     */
    public static function setTemplatesPath($templatesPath) {
        self::$templatesPath = $templatesPath;
    }

    /**
     * @return string
     */
    public static function getTemplatesPath() {
        return self::$templatesPath;
    }
    
    protected $file;
    protected $values;
    protected $excludeFromCache;
    
    private function __construct($templatesPath, $file) {
        $this->file = $templatesPath . $file . '.tpl';
        $this->values = array();
        $this->excludeFromCache = false;
    }
    
    /**
     * Add data to view
     * @param string|array $key
     * @param mixed $value
     * @return $this
     */
    public function with($key, $value) {
        if (is_array($key)) {
            $this->values = array_merge($this->values, $key);
        } else {
            $this->values[$key] = $value;
        }
        return $this;
    }

    public function excludeFromCache() {
        $this->excludeFromCache = true;
        return $this;
    }
    
    /**
     * Render template
     * @return string
     */
    public function render() {
        // Get template content from storage or cache
        if (array_key_exists($this->file, self::$cache)) {
            $output = self::$cache[$this->file];
        } else {
            $output = file_get_contents($this->file);
            if (!$this->excludeFromCache) {
                self::$cache[$this->file] = $output;
            }
        }
        // {|key|} - multilanguage key
        $output = preg_replace_callback('#\{\|(.*?)\|\}#u', function($key) {
            global $lang;
            return $lang->get($key[1]); 
        }, $output);

        // {?key?} - if key doesn't exists - clear value
        $output = preg_replace_callback('#\{\?(.*?)\?\}#u', function($key) {
            if (array_key_exists($key[1], $this->values)) {
                return $this->values[$key[1]];
            }
            return '';
        }, $output);

        // {key} - normal replace if exists
        foreach ($this->values as $key => $value) {
            $output = str_replace('{'.$key.'}', $value, $output);
        }
        return $output;
    }
    
    public function __toString() {
        return $this->render();
    }
}