I need new price rule depend currency.I am new at learning WooCommerce development and this feature is sample for me to learn it.

The question is simple : I have a input field which is number type under product tabs on settings page and I will enter US dollar value against Turkish Liras.

For example: 8.20

It means 1 US Dollar is equal to 8.20 Turkish Liras.

When I click save button, my custom code will change all products’ prices.If US dollar increase, also Product Price will increase or the rule exist for opposite scenerio.

The formule: ( Current Price X New Value ) / Current Value

My main problem is I cant set/change all product prices with save button.How can I do it?

Here is my code snippets about settings page from theme’s function.php:

/*------------------------------------*
*/


add_filter( 'woocommerce_get_sections_products' , 'new_price_based_currency_add_settings_tab' );

function new_price_based_currency_add_settings_tab( $settings_tab ){
     $settings_tab['new_price_based_currency_notices'] = __( 'New Price based Currency Notices' );
     return $settings_tab;
}

add_filter( 'woocommerce_get_settings_products' , 'new_price_based_currency_get_settings' , 10, 2 );

function new_price_based_currency_get_settings( $settings, $current_section ) {
    $custom_settings = array();
         if( 'new_price_based_currency_notices' == $current_section ) {

              $custom_settings =  array(

                    array(
                            'name' => __( 'New Price based Currency Notices' ),
                         'type' => 'title',
                            'desc' => __( 'When you change the currency value, your all product prices will be changed.For example, if you enter new value, new price will be calculated with "( Current Price X New Value ) / Current Value' ),
                            'id'   => 'new_price_based_currency' 
                       ),
                  array(
                'name' => __( 'US Dollar value based on Turkish Lira' ),
                          'type' => 'number',
                         'min'       => '0',
            'step'      => '0.01',
            'append'    => '$',
                'desc' => __( 'You must write US Dollar value against Turkish Lira here.For example, "8.42" . It means 8.42 Turkish Liras is equal to 1 US Dollar.'),
                'desc_tip' => true,
                'id'    => 'dollar_value'

            ),
                  array( 'type' => 'sectionend', 'id' => 'new_price_based_currency' ),

        );
            return $custom_settings;
       } else {
            return $settings;
       }
}

When I enter new value to the input field, I want to change all prices automatically depend new currency value.