<?php 

namespace app\controllers\cms;

use Registry;
use Render;
use app\controllers\Auth;
use app\models\cms\Course_model;
use app\extends\Cache_service;

class Course {


    /** PERMITION
     * -------------------------------------------------------------------------
     */


    /** is admin or permited
     * 
     * shortcut method for checking access authorization
     * 
     * returns true if user belogns to the admin group
     * OR has the specified permition/privilege
     * 
     * @param $privilege_id (int)
     * 
     * NOTE:
     * unlike the other authorization methods ...
     * $privilege_id is NOT an array but a single privilege id
     * 
     * @return true|false
     */
    private static function is_admin_or_permited( $privilege_id )
    {
        return (
            Auth::in_admin_group()
            || Auth::hasPermition([ $privilege_id ])
        );
    }


    /** FILES
     * -------------------------------------------------------------------------
     */

    /** serve file by file_path
     * (request is valid only for admin users)
     * 
     * @param $file_path (string): relative file path
     * GET @param type (string) : media-type of file
     */
    public static function serve_file($file_path)
    {
        $file = self::get_file_attributes($file_path);

        // if user is authorized
        if (self::is_admin_or_permited($file['privilege_id'])) {

            $media_type = Registry::get('REQUEST')->GET['type'];    // get media-type
            $real_path = MEDIA_STORAGE_ROOT . $file_path;           // construct real path

            if (!file_exists($real_path)) {
                Render::view('error/404');

            } else {
                Render::file($real_path, $media_type);
            }

        }
    }


    /** get_file_attributes
     * 
     * returns attributes of a file
     * (medias are proxied for speed optimization)
     * 
     * @param $path (string) : file path
     * @return $file attributes --or-- false
     */
    private static function get_file_attributes($path)
    {
        $medias = Cache_service::files_attributes();

        foreach($medias as $key => $medi) {
            if ($medi['path'] == $path) {
                return $medi;
            }
        }

        return false;
    }


    /** COURSES
     * -------------------------------------------------------------------------
     */

    /** course
     * prepare and render the course view
     * 
     * @param $id : course id
     */
    public static function course($id)
    {
        $id = intval($id);      // course id

        // collect all data needed for course view
        // --- -- -- - - -
        $cache = Cache_service::courses_struct();
        $tree = $cache['tree'];
        $breadcrumbs = $cache['breadcrumbs'];
        $lessons = Course_model::lessons_of_course(intval($id));

        // find parent_ids of current category (to open the menu tree)
        // ---
        $course_path = [];
        foreach($breadcrumbs[$id]['parents'] as $key => $parent) {
            $course_path[] = intval($parent['id']);
        }
        $course_path[] = $id;

         // then Render
        // --- -- -- - - -
        Render::view('templates/course', [
            'id' => $id,
            'title' => $breadcrumbs[ $id ]['rec']['label'],
            'categories' => $tree,
            'breadcrumbs' => $breadcrumbs,
            'lessons' => $lessons,
            'course_path' => $course_path
        ]);
    }


    /** LESSONS
     * ------------------------------------------------------------------------
     */


    /** lesson
     * 
     * check if user is authorized to view the content;
     * if so, prepare and render the lesson view
     * 
     * @param $id : lesson id
     */
    public static function lesson($id)
    {
        $id = intval($id);     // lesson id

        $lesson = Course_model::lesson($id);  // get lesson
        $course_id = $lesson['course_id'];     // get course id
        $pri_id = $lesson['privilege_id'];     // privilege needed


        if (self::is_admin_or_permited($pri_id)) {

            // collect all data needed for course view
            // --- -- -- - - -
            $cache = Cache_service::courses_struct();
            $tree = $cache['tree'];
            $breadcrumbs = $cache['breadcrumbs'];

            // find parent_ids of current category (to open the menu tree)
            // ---
            $course_path = [];
            foreach($breadcrumbs[$course_id]['parents'] as $key => $parent) {
                $course_path[] = intval($parent['id']);
            }
            $course_path[] = intval($course_id);

            // then Render
            // --- -- -- - - -
            Render::view('templates/lesson', [
                    // main content
                'id' => $id,
                'course_id' => $course_id,
                'title' => $lesson['title'],
                'lesson' => $lesson,
                    // needed for side panel and breadcrunbs
                'categories' => $tree,
                'breadcrumbs' => $breadcrumbs,
                'course_path' => $course_path
            ]);

        } else {    // user is not authorized
            Render::view('error/general', [
                'title' => 'Δεν έχετε πρόσβαση',
                'message' => 'Θα πρέπει να αγοράσετε το πακέτο πρόσβασης '
                    . $pri_id
                    .' για να δείτε το περιεχόμενο!
                    <br><br>
                    Αγόρασε τώρα το <button class="btn">πακέτο πρόσβασης '. $pri_id .'</button>'
            ]);
        }

    }


}