<?php

namespace EesyPHP;

use Exception;
use Smarty;
use Smarty_Security;
use League\MimeTypeDetection\ExtensionMimeTypeDetector;

class Tpl {

  /**
   * Smarty object
   * @var \Smarty
   */
  public static $smarty;

  /**
   * Smarty_Security object
   * @var \Smarty_Security|null
   */
  public static $smarty_security_policy = null;

  /**
   * Core Smarty templates directory
   * @var string
   */
  public static $core_templates_directory;

  /**
   * Smarty templates directories path with their priority
   * @var array<string,int>
   */
  public static $templates_directories = array();

  /**
   * Smarty cache templates directory path
   * @var string
   */
  public static $templates_c_dir;

  /**
   * Enable/disable AJAX returned data debugging in logs
   * @var bool
   */
  public static $_debug_ajax;

  /**
   * Core static directory
   * @var string|null
   */
  public static $core_static_directory = null;

  /**
   * Static directories path with their priority
   * @var array<string,array>
   */
  private static $static_directories = array();

  /**
   * CSS files to load in next displayed page
   * @var array<string>
   */
  private static $css_files = array();

  /**
   * JavaScript files to load in next displayed page
   * @var array<string>
   */
  private static $js_files = array();

  /**
   * MIME type detector object
   * @var null|string
   */
  private static $static_root_url;

  /**
   * MIME type detector object
   * @var ExtensionMimeTypeDetector|null
   */
  private static $mime_type_detector = null;

  /**
   * Initialization
   * @param string $templates_dir Smarty templates directory path
   *               (optional, default: from templates.directory config key)
   * @param string $templates_c_dir Smarty cache templates directory path
   *               (optional, default: from templates.cache_directory config key)
   * @param bool $debug_ajax Enable/disable AJAX returned data debugging in logs
   *             (optional, default: from templates.debug_ajax or debug_ajax config keys if set,
   *             false otherwise)
   * @param bool $static_root_url Configure custom root URL path for static files
   *             (optional, default: from templates.static_root_url config key if set,
   *             '/static' otherwise. Set to False to disable)
   * @return void
   */
  public static function init($templates_dir=null, $templates_c_dir=null, $debug_ajax=null,
                              $static_root_url=null) {
    // Handle templates directories
    self :: $core_templates_directory = realpath(__DIR__."/../templates");
    self :: register_templates_directory(self :: $core_templates_directory);
    if (is_null($templates_dir))
      $templates_dir = App::get('templates.directory', null, 'string');
    if ($templates_dir) {
      if (!is_dir($templates_dir))
        Log :: fatal("Template directory not found (%s)", $templates_dir);
      self :: register_templates_directory($templates_dir);
    }

    // Handle and check templates_c directories
    if (is_null($templates_c_dir))
      $templates_c_dir = App::get('templates.cache_directory', null, 'string');
    if ($templates_c_dir) {
      if (!is_dir($templates_c_dir) || !is_writable($templates_c_dir)) {
        Log :: fatal(
          "Template cache directory not found or not writable (%s)",
          $templates_c_dir);
        return;
      }
    }
    else {
      $public_root_url = Url :: public_root_url();
      if ($public_root_url != '/') {
        $unique_name = preg_replace('#^https?://#', '', $public_root_url);
      }
      else {
        $root_directory_path = App::root_directory_path();
        if ($root_directory_path == '.') {
          Log :: fatal(
            'Fail to compute a unique templates cache directory for this application. An public '.
            'root URL or an application root directory must be set if you do not provide it at '.
            'initialization (or via config parameter).');
          return;
        }
        $unique_name = $root_directory_path;
        if (substr($unique_name, 0, 1) == '/')
          $unique_name = substr($unique_name, 1);
        if (substr($unique_name, -1) == '/')
          $unique_name = substr($unique_name, 0, -1);
      }
      $templates_c_dir = sys_get_temp_dir().'/'.str_replace(
        '/', '_', "eesyphp_templates_cache_$unique_name"
      );
      if (!is_dir($templates_c_dir) && !mkdir($templates_c_dir)) {
        Log :: fatal(
          'Fail to create application templates cache directory (%s)',
          $templates_c_dir);
        return;
      }
    }
    self :: $smarty = new Smarty();
    self :: $smarty->setTemplateDir(self :: $core_templates_directory);
    self :: $smarty->setCompileDir($templates_c_dir);
    self :: $smarty->registerResource('Tpl', new TplSmartyResource());
    if (is_null($debug_ajax))
      $debug_ajax = App::get('templates.debug_ajax', App::get('debug_ajax'));
    self :: $_debug_ajax = boolval($debug_ajax);
    Log :: register_fatal_error_handler(array('\\EesyPHP\\Tpl', 'fatal_error'));

    if (is_null($static_root_url))
      $static_root_url = App::get('templates.static_root_url', 'static/', 'string');
    if ($static_root_url) {
      if (substr($static_root_url, 0, 1) == '/')
        $static_root_url = substr($static_root_url, 1);
      if (substr($static_root_url, -1) != '/')
        $static_root_url = "$static_root_url/";
      self :: $static_root_url = $static_root_url;
      self :: $core_static_directory = realpath(__DIR__."/../static");
      self :: register_static_directory(self :: $core_static_directory, 100);
      self :: register_function('static_url', array('EesyPHP\\Tpl', 'smarty_static_url'));

      foreach(App :: get('templates.static_directories', array(), 'array') as $path)
        self :: register_static_directory($path);

      self :: register_function('var_dump', array('EesyPHP\\Tpl', 'smarty_var_dump'));
    }
  }

  /**
   * Enable security in mode to limit functions (in IF clauses) and modifiers usable from
   * template files
   * @param array<string>|null $functions List of function names granted in IF clauses
   * @param array<string>|null $modifiers List of modifier names granted
   * @return void
   */
  public static function enable_security_mode($functions=null, $modifiers=null) {
    // Define security policy
    self :: $smarty_security_policy = new Smarty_Security(self :: $smarty);

    // Allow functions in IF clauses
    if (is_array($functions))
      foreach($functions as $function)
        self :: $smarty_security_policy->php_functions[] = $function;

    // Allow modifier functions
    if (is_array($modifiers))
      foreach($modifiers as $modifier)
        self :: $smarty_security_policy->php_modifiers[] = $modifier;

    // Enable security
    self :: $smarty -> enableSecurity(self :: $smarty_security_policy);

    // Initialize errors & messages session variables
    if (!isset($_SESSION['errors']))
      $_SESSION['errors'] = array();
    if (!isset($_SESSION['messages']))
      $_SESSION['messages'] = array();
  }

  /**
   * Register a function usable from template files
   * @param string $name The function name
   * @param callable $callable The function
   * @return void
   */
  public static function register_function($name, $callable) {
    self :: $smarty -> registerPlugin("function", $name, $callable);
  }

  /**
   * Assign template variable
   * @param string $name The variable name
   * @param mixed $value The variable value
   * @return void
   */
  public static function assign($name, $value) {
    self :: $smarty -> assign($name, $value);
  }

  /**
   * Add error message
   * @param string $error The message
   * @param array $extra_args Extra arguments to use to compute error message using sprintf
   * @return void
   */
  public static function add_error($error, ...$extra_args) {
    // If extra arguments passed, format error message using sprintf
    if ($extra_args) {
      $error = call_user_func_array(
        'sprintf',
        array_merge(array($error), $extra_args)
      );
    }
    $_SESSION['errors'][] = $error;
  }

  /**
   * Add informational message
   * @param string $message The message
   * @param array $extra_args Extra arguments to use to compute message using sprintf
   * @return void
   */
  public static function add_message($message, ...$extra_args) {
    // If extra arguments passed, format message using sprintf
    if ($extra_args) {
      $message = call_user_func_array(
        'sprintf',
        array_merge(array($message), $extra_args)
      );
    }
    $_SESSION['messages'][] = $message;
  }

  /**
   * Get errors
   * @return array<string>
   */
  public static function get_errors() {
    if(isset($_SESSION['errors']) && is_array($_SESSION['errors']))
        return $_SESSION['errors'];
    return array();
  }

  /**
   * Get messages
   * @return array<string>
   */
  public static function get_messages() {
      if(isset($_SESSION['messages']) && is_array($_SESSION['messages']))
          return $_SESSION['messages'];
      return array();
  }

  /**
   * Purge messages
   * @return void
   */
  public static function purge_errors() {
      if(isset($_SESSION['errors']))
          unset($_SESSION['errors']);
  }

  /**
   * Purge messages
   * @return void
   */
  public static function purge_messages() {
      if(isset($_SESSION['messages']))
          unset($_SESSION['messages']);
  }

  /**
   * Register CSS file(s) to load on next displayed page
   * @param string|array<string> $args CSS files to load
   * @return void
   */
  public static function add_css_file(...$args) {
    // Check if the first argument is a custom static root URL
    $root_url = self :: $static_root_url;
    if (
      $args && is_string($args[0]) && array_key_exists(
        self :: clean_static_root_url($args[0]),
        self :: $static_directories
      )
    )
      $root_url = self :: clean_static_root_url(array_shift($args));
    foreach ($args as $files) {
      if (!is_array($files)) $files = array($files);
      foreach ($files as $file) {
        $path = $root_url.$file;
        if (!in_array($path, self :: $css_files))
          self :: $css_files[] = $path;
      }
    }
  }

  /**
   * Register JS file(s) to load on next displayed page
   * @param string|array<string> $args JS files to load
   * @return void
   */
  public static function add_js_file(...$args) {
    // Check if the first argument is a custom static root URL
    $root_url = self :: $static_root_url;
    if (
      $args && is_string($args[0]) && array_key_exists(
        self :: clean_static_root_url($args[0]),
        self :: $static_directories
      )
    )
      $root_url = self :: clean_static_root_url(array_shift($args));
    foreach ($args as $files) {
      if (!is_array($files)) $files = array($files);
      foreach ($files as $file) {
        $path = $root_url.$file;
        if (!in_array($path, self :: $js_files))
          self :: $js_files[] = $path;
      }
    }
  }

  /**
   * Define common variables
   * @param string|null $pagetitle The page title
   * @return void
   */
  protected static function define_common_variables($pagetitle=null) {
    self :: assign('public_root_url', Url :: public_root_url());
    self :: assign('pagetitle', $pagetitle);
    self :: assign('main_pagetitle', App::get('main_pagetitle', null, 'string'));
    self :: assign('session_key', isset($_SESSION['session_key'])?$_SESSION['session_key']:null);

    // Handle CSS & JS files included
    self :: add_css_file(App::get('templates.included_css_files', array(), 'array'));
    self :: add_js_file(App::get('templates.included_js_files', array(), 'array'));

    // Messages
    self :: assign('errors', self :: get_errors());
    self :: assign('messages', self :: get_messages());

    // Files inclusions
    self :: assign('css', self :: $css_files);
    self :: assign('js', self :: $js_files);

    // I18n text domains
    self :: assign('CORE_TEXT_DOMAIN', I18n :: CORE_TEXT_DOMAIN);
    self :: assign('TEXT_DOMAIN', I18n :: TEXT_DOMAIN);

    // Authenticated user info
    if (Auth::user())
      self :: assign('auth_user', Auth::user());

    // Webstats JS code
    Tpl :: assign(
      'webstats_js_code',
      App::get('webstats_js_code', null, 'string'));

    // Upload max size
    if (App::get('upload_max_filesize', null, 'int'))
      Tpl :: assign(
        'upload_max_filesize',
        App::get('upload_max_filesize', null, 'int'));
  }

  /**
   * Display the template
   * @param string $template The template to display
   * @param string|null $pagetitle The page title (optional)
   * @param array $extra_args Extra arguments to use to compute the page title using sprintf
   * @return void
   */
  public static function display($template, $pagetitle=null, ...$extra_args) {
    if (!$template) {
      Log :: fatal(I18n::_("No template specified."));
      return;
    }

    // If refresh parameter is present, remove it and redirect
    if (isset($_GET['refresh'])) {
      unset($_GET['refresh']);
      $url = Url :: get_current_url();
      if (!empty($_GET))
        $url .= '?'.http_build_query($_GET);
      Url :: redirect($url);
      return;
    }

    $sentry_span = new SentrySpan('smarty.display_template', "Display Smarty template");

    // If extra arguments passed, format pagetitle using sprintf
    if ($pagetitle && $extra_args) {
      $pagetitle = call_user_func_array(
        'sprintf',
        array_merge(array($pagetitle), $extra_args)
      );
    }
    try {
      Hook :: trigger('before_displaying_template');
      self :: define_common_variables($pagetitle);
      self :: $smarty->display("Tpl:$template");
    }
    catch (Exception $e) {
      Log :: exception($e, "Smarty - An exception occured displaying template '$template'");
      Hook :: trigger('after_displaying_template', array('success' => false));
      $sentry_span->finish();
      if ($template != 'fatal_error.tpl')
        Log :: fatal(I18n::_("An error occurred while displaying this page."));
      return;
    }
    self :: purge_errors();
    self :: purge_messages();
    Hook :: trigger('after_displaying_template', array('success' => true));
    $sentry_span->finish();
  }

  /**
   * Display AJAX return
   * @param array|null $data AJAX returned data (optional)
   * @param bool $pretty AJAX returned data
   *             (optional, default: true if $_REQUEST['pretty'] is set, False otherwise)
   * @return void
   */
  public static function display_ajax_return($data=null, $pretty=false) {
    if (!is_array($data))
      $data = array();
    // Adjust HTTP error code on unsuccessfull request
    elseif (isset($data['success']) && !$data['success'] && http_response_code() == 200)
      http_response_code(400);

    $data['messages'] = self :: get_messages();
    if (!$data['messages']) unset($data['messages']);
    self :: purge_messages();

    $data['errors'] = self :: get_errors();
    if (!$data['errors']) unset($data['errors']);
    self :: purge_errors();

    if (self :: $_debug_ajax)
      Log :: debug("AJAX Response : ".vardump($data));
    header('Content-Type: application/json');
    echo json_encode($data, (($pretty||isset($_REQUEST['pretty']))?JSON_PRETTY_PRINT:0));
    exit();
  }

  /**
   * Handle a fatal error
   * @param string $error The error message
   * @param array $extra_args Extra arguments to use to compute the error message using sprintf
   * @return void
   */
  public static function fatal_error($error, ...$extra_args) {
    // If extra arguments passed, format error message using sprintf
    if ($extra_args) {
      $error = call_user_func_array(
        'sprintf',
        array_merge(array($error), $extra_args)
      );
    }

    if (php_sapi_name() == "cli")
      die("FATAL ERROR : $error\n");

    // Set HTTP reponse code to 500
    http_response_code(500);

    // Handle API mode
    if (Url :: api_mode()) {
      self :: display_ajax_return(array('success' => false, 'error' => $error));
      return;
    }

    self :: assign('fatal_error', $error);
    self :: display('fatal_error.tpl');
    exit();
  }

  /**
   * Get/set AJAX debug mode
   * @param bool|null $value If boolean, the current API mode will be changed
   * @return bool Current API mode
   */
  public static function debug_ajax($value=null) {
    if (is_bool($value)) self :: $_debug_ajax = $value;
    return self :: $_debug_ajax;
  }

  /**
   * Check if initialized
   * @return bool
   */
  public static function initialized() {
    return self :: $smarty instanceof Smarty;
  }

  /**
   * Get the templates directories path
   * @return array<string>
   */
  public static function templates_directories() {
    return array_keys(self :: $templates_directories);
  }

  /**
   * Register a templates directory
   * @param string $path The templates directory path
   * @param int|null $priority The priority of this templates directory
   *                 (optional, default: prior than all other registered directories)
   * @return void
   */
  public static function register_templates_directory($path, $priority=null) {
    if (!is_dir($path)) {
      Log :: fatal(
        'register_templates_directory(%s): this templates directory does not exists',
        $path);
      return;
    }
    if (substr($path, -1) == '/')
      $path = substr($path, 0, -1);
    if (is_null($priority)) {
      $priority = (
        !empty(self :: $templates_directories)?
        max(self :: $templates_directories) + 1:
        100
      );
    }
    Log :: trace(
      'Register templates directory "%s" with priority %d',
      $path, $priority);
    self :: $templates_directories[$path] = $priority;
    arsort(self :: $templates_directories);
  }

  /**
   * Resolve templates path against registered templates directories
   * @param string $path
   * @return string|false
   */
  public static function resolve_templates_path($path) {
    foreach(array_keys(self :: $templates_directories) as $dir) {
      $fullpath = "$dir/$path";
      if (file_exists($fullpath)) {
        Log::trace('Templates file "%s" resolved as "%s"', $path, $fullpath);
        return $fullpath;
      }
    }
    Log::trace('Templates file "%s" not found', $path);
    return false;
  }

 /**
  * Return the content of a Smarty template file.
  *
  * @param string $template The template name (eg: base.tpl)
  *
  * @return string The content of the Smarty template file
  **/
  public static function get_template_source($template) {
    $path = self :: resolve_templates_path($template);
    if (!is_readable($path)) {
      // No error return with Smarty3 and highter because it's call
      // template name in lower first systematically
      return '';
    }
    return file_get_contents($path);
  }

 /**
  * Return the timestamp of the last change of a Smarty
  * template file.
  *
  * @param string $template The template name (eg: empty.tpl)
  *
  * @return int|null The timestamp of the last change of the Smarty template file
  **/
  public static function get_template_timestamp($template) {
    $path = self :: resolve_templates_path($template);
    if (is_file($path)) {
      $time = filemtime($path);
      if ($time)
        return $time;
    }
    return null;
  }

  /**
   * Clean static root URL helper
   * @param string $value
   * @return string
   */
  public static function clean_static_root_url($value) {
    if (substr($value, 0, 1) == '/')
      $value = substr($value, 1);
    if (substr($value, -1) != '/')
      $value = "$value/";
    return $value;
  }

  /**
   * Get the static directories path
   * @return array<string>
   */
  public static function static_directories() {
    $result = array();
    foreach(self :: $static_directories as $root_url => $dirs)
      foreach(array_keys($dirs) as $dir)
        if (!in_array($dir, $result))
          $result[] = $dir;
    return $result;
  }

  /**
   * Register a static directory
   * @param string $path The static directory path
   * @param int|null $priority The priority of this static directory
   *                 (optional, default: prior than all other registered directories)
   * @return void
   */
  public static function register_static_directory($path, $priority=null, $root_url=null) {
    if (is_null($root_url)) {
      if (!self :: $static_root_url)
        Log :: fatal(
          'register_static_directory(%s): no root URL provided and no default value configured',
          $path);
      $root_url = self :: $static_root_url;
    }

    if (!array_key_exists($root_url, self :: $static_directories)) {
      self :: $static_directories[$root_url] = array();
      if (is_null($priority)) $priority = 100;
      $pattern = "#^(?P<root_url>$root_url)(?P<path>.*)#";
      Log :: trace(
        'Register static file URL handler for root URL "%s" with pattern "%s" and directory '.
        '"%s" (priority: %d)', $root_url, $pattern, $path, $priority);
      Url :: add_url_handler(
        $pattern,
        array('EesyPHP\\Tpl', 'handle_static_file'),
        null,   // additionnal info
        false,  // authenticated
        false,  // override
        false,  // API mode
        array('GET')  // methods
      );
      if (is_null(self :: $mime_type_detector))
        self :: $mime_type_detector = new ExtensionMimeTypeDetector();
    }
    else {
      if (is_null($priority)) {
        $priority = max(self :: $static_directories[$root_url]);
        $priority++;
      }
      Log :: trace(
        'Register additionnal static directory "%s" for root URL "%s" (priority: %d)',
        $path, $root_url, $priority);
    }

    if (substr($path, -1) == '/')
      $path = substr($path, 0, -1);
    self :: $static_directories[$root_url][$path] = $priority;
    arsort(self :: $static_directories[$root_url]);
  }

  /**
   * Resolve static path against registered static directories
   * @param string $path
   * @return string|false
   */
  public static function resolve_static_path($root_url, $path) {
    if (!array_key_exists($root_url, self :: $static_directories)) {
      Log::error(
        'No static directory registered for root URL "%s". Can no resolve static file "%s" path.',
        $root_url, $path);
      return false;
    }
    foreach(array_keys(self :: $static_directories[$root_url]) as $dir) {
      $fullpath = "$dir/$path";
      if (file_exists($fullpath))
        return $fullpath;
    }
    Log::trace('Static file "%s%s" not found', $root_url, $path);
    return false;
  }

  /**
   * Handle URL request for static file
   * Note: this URL handler is registered in EesyPHP\Url by self::init().
   * @see self::init()
   * @param UrlRequest $request
   * @return void
   */
  public static function handle_static_file($request) {
    $path = self :: resolve_static_path($request->root_url, $request->path);
    Log::trace('Resolved static file path for "%s": "%s"', $request->path, $path);
    if (!$path)
      Url :: trigger_error_404($request);
    $mime_type = self :: $mime_type_detector->detectMimeTypeFromFile($path);
    Log::trace('MIME type detected for "%s" is "%s"', $path, $mime_type);
    dump_file($path, $mime_type);
  }

  /**
   * Function to retrieve static file URL
   * @param string $path The file path
   * @return string|false
   */
  public static function static_url($path) {
    if (self :: $static_root_url)
      return self :: $static_root_url.$path;
    return false;
  }

  /**
   * Smarty function to print static file URL
   * @param array<string,mixed> $params Parameters from template file
   * @param Smarty $smarty The smarty object
   * @return void
   */
  public static function smarty_static_url($params, $smarty) {
    if (!isset($params['path'])) return;
    $url = self :: static_url($params['path']);
    if ($url) echo $url;
  }

  /**
   * Smarty function to dump variable using var_dump()
   * @param array<string,mixed> $params Parameters from template file
   * @param Smarty $smarty The smarty object
   * @return void
   */
  public static function smarty_var_dump($params, $smarty) {
    if (!isset($params['data'])) return;
    var_dump($params['data']);
  }
}