<?php

namespace EesyPHP;

use Exception;
use Smarty;
use Smarty_Security;

class Tpl {

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

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

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

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

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

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

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

  /**
   * Initialization
   * @param string $templates_dir Smarty templates directory path
   *               (optional, default: from template.directory config key)
   * @param string $templates_c_dir Smarty cache templates directory path
   *               (optional, default: from template.cache_directory config key)
   * @param bool $debug_ajax Enable/disable AJAX returned data debugging in logs
   *             (optional, default: from template.debug_ajax or debug_ajax config keys if set,
   *             false otherwise)
   * @return void
   */
  public static function init($templates_dir=null, $templates_c_dir=null, $debug_ajax=null) {
    // Check templates/templates_c directories
    if (is_null($templates_dir))
      $templates_dir = Config::get('template.directory', null, 'string');
    if (is_null($templates_c_dir))
      $templates_c_dir = Config::get('template.cache_directory', null, 'string');
    if (!$templates_dir || !is_dir($templates_dir)) {
      Log :: fatal(
        "Template directory not found (%s)",
        $templates_dir?$templates_dir:'not set');
      return;
    }
    if (!$templates_c_dir || !is_dir($templates_c_dir) || !is_writable($templates_c_dir)) {
      Log :: fatal(
        "Template cache directory not found or not writable (%s)",
        $templates_c_dir?$templates_c_dir:'not set');
      return;
    }
    self :: $smarty = new Smarty();
    self :: $smarty->setTemplateDir($templates_dir);
    self :: $smarty->setCompileDir($templates_c_dir);
    if (is_null($debug_ajax))
      $debug_ajax = Config::get('template.debug_ajax', Config::get('debug_ajax'));
    self :: $_debug_ajax = boolval($debug_ajax);
    Log :: register_fatal_error_handler(array('\\EesyPHP\\Tpl', 'fatal_error'));
  }

  /**
   * 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;
  }

  /**
   * Register CSS file(s) to load on next displayed page
   * @param array<string|array<string>> $args CSS files to load
   * @return void
   */
  public static function add_css_file(...$args) {
    foreach ($args as $files) {
      if (!is_array($files)) $files = array($files);
      foreach ($files as $file) {
        if (!in_array($file, self :: $css_files))
          self :: $css_files[] = $file;
      }
    }
  }

  /**
   * Register JS file(s) to load on next displayed page
   * @param array<string|array<string>> $args JS files to load
   * @return void
   */
  public static function add_js_file(...$args) {
    foreach ($args as $files) {
      if (!is_array($files)) $files = array($files);
      foreach ($files as $file) {
        if (!in_array($file, self :: $js_files))
          self :: $js_files[] = $file;
      }
    }
  }

  /**
   * Define common variables
   * @param string|null $pagetitle The page title
   * @return void
   */
  protected static function define_common_variables($pagetitle=null) {
    global $auth_user;
    self :: assign('pagetitle', $pagetitle);

    // Messages
    self :: assign('errors', (isset($_SESSION['errors'])?$_SESSION['errors']:array()));
    self :: assign('messages', (isset($_SESSION['messages'])?$_SESSION['messages']:array()));

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

    // Authenticated user info
    if (isset($auth_user))
      self :: assign('auth_user', $auth_user);
  }

  /**
   * 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(_("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 :: $smarty->display($template);
    }
    catch (Exception $e) {
      Log :: exception($e, "Smarty - An exception occured displaying template '$template'");
      if ($template != 'fatal_error.tpl')
        Log :: fatal(_("An error occurred while displaying this page."));
      return;
    }
    unset($_SESSION['errors']);
    unset($_SESSION['messages']);
    Hook :: trigger('after_displaying_template');
    $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);

    if (isset($_SESSION['messages']) && !empty($_SESSION['messages'])) {
      $data['messages'] = $_SESSION['messages'];
      unset($_SESSION['messages']);
    }
    if (isset($_SESSION['errors']) && !empty($_SESSION['errors'])) {
      $data['errors'] = $_SESSION['errors'];
      unset($_SESSION['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 isset(self :: $smarty);
  }

  /**
   * Get the templates directory path
   * @return string|null
   */
  public static function templates_directory() {
    return isset(self :: $templates_directory)?self :: $templates_directory:null;
  }
}