Settings_Page::update_settings()

	private function update_settings(){
		$defaults = $this->options_obj()->get_defaults();

		foreach( $defaults as $key => $val ){
			if( is_numeric( $val ) ){
				if( isset( $_POST[ $key ] ) ){
					$defaults[ $key ] = (int)$_POST[ $key ];
				}
				continue;
			}
			if( is_bool( $val ) ){
				$defaults[ $key ] = isset( $_POST[ $key ] );
				continue;
			}

			// trim strings
			if( isset( $_POST[ $key ] ) ){
				$defaults[ $key ] = trim( $_POST[ $key ] );
			}
		}

		// rewrite
		$plugin_settings = $this->options_obj()->get_options();
		$flush_rules = false;
		if( isset( $_POST['post_slug'] ) ){
			$post_slug = sanitize_title( $_POST['post_slug'] );
			if( !empty( $_POST['post_slug'] ) && $plugin_settings['post_slug'] !== $post_slug ){
				$defaults['post_slug'] = $post_slug;
				$flush_rules = true;
			}else{
				$defaults['post_slug'] = $plugin_settings['post_slug'];
			}
		}

		if( isset( $_POST['taxonomy_slug'] ) ){
			$tax_slug = sanitize_title( $_POST['taxonomy_slug'] );
			/**
			 * Check that taxonomy slug is not empty, is updated and is not the same as the post slug
			 */
			if( !empty( $_POST['taxonomy_slug'] ) && $plugin_settings['taxonomy_slug'] !== $tax_slug && $_POST['taxonomy_slug'] != $defaults['post_slug'] ){
				$defaults['taxonomy_slug'] = $tax_slug;
				$flush_rules = true;
			}else{
				$defaults['taxonomy_slug'] = $plugin_settings['taxonomy_slug'];
			}
		}

		if( isset( $_POST['tag_slug'] ) ){
			$tag_slug = sanitize_title( $_POST['tag_slug'] );
			if( !empty( $_POST['tag_slug'] ) && $plugin_settings['tag_slug'] !== $tag_slug && $_POST['tag_slug'] != $defaults['post_slug'] && $_POST['tag_slug'] != $defaults['taxonomy_slug'] ){
				$defaults['tag_slug'] = $tag_slug;
				$flush_rules = true;
			}else{
				$defaults['tag_slug'] = $plugin_settings['tag_slug'];
			}
		}

		// reset OAuth if user changes the keys
		if( isset( $_POST['vimeo_consumer_key'] ) && isset( $_POST['vimeo_secret_key'] ) ){
			if(
				($_POST['vimeo_consumer_key'] != $plugin_settings['vimeo_consumer_key']) ||
				($_POST['vimeo_secret_key'] != $plugin_settings['vimeo_secret_key'] )
			){
				$defaults['oauth_token'] = '';
				$defaults['oauth_secret'] = '';
			}
		}else{
			// if the consumer keys are not sent by POST, set the old values
			$defaults['vimeo_consumer_key'] = $plugin_settings['vimeo_consumer_key'];
			$defaults['vimeo_secret_key'] = $plugin_settings['vimeo_secret_key'];
			$defaults['oauth_token'] = $plugin_settings['oauth_token'];
		}

		$this->options_obj()->update_options( $defaults );

		if( $flush_rules ){
			// create rewrite ( soft )
			// register custom post
			Plugin::instance()->get_cpt()->register_post();
			flush_rewrite_rules();
		}

		return $defaults;
	}