Change default variation value for the same product according to the category woocommerce

Question

I'm working on a way to display default variations value for the SAME product according to the category he is. For example, I sell a card with option blue & red. When the user comes by the category ONE, I want the default value is blue. If he comes by the category TWO, the value will be red.

I found a hook woocommerce_product_default_attributes, but I don't know how to use it .

Note : It seems that woocommerce recognize only one category per product even if your product is in two category.

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Example (edit):

I have a product P.
Product P is in two categories : Cat 1 & Cat 2.
Also, product P has two variables : Blue & Red

When the user comes by Cat 1, I want the default value is Blue. If he comes by Cat 2, the value will be Red.

The answer code of @LoicTheAztech (below) works, BUT:

When I go to Cat 1 or Cat 2, I can see that for Woocommerce, the product is only in Cat 1, even if we can access by both category.

So before everything, I need to solve the woocommerce issue.

Answer 1

New updated answer HERE with the replacement filter hook, as since WooCommerce 3, get_variation_default_attributes() method is replaced by get_default_attributes() and woocommerce_product_get_default_attributes is the new related filter hook to be used.

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Before WooCommerce 3, the filter hook woocommerce_product_default_attributes was located in get_variation_default_attributes() deprecated method, so it's not really the right hook to achieve what you want.

You can achieve your conditional function in woocommerce_before_add_to_cart_form action hook, for example.

Notes:

• Product Attribute taxonomy always begin by 'pa_' + the attribute slug
• You need to set in for variable products the default value for this attribute in the variation tab settings.

The code:

add_action( 'woocommerce_before_add_to_cart_form', function(){
    global $product;

    // We EXIT if it's not a variable product
    if( ! $product->is_type('variable') ) return;

    ## DEFINE HERE the desired product attribute taxonomy
    $pa_attribute = 'pa_color';
    $default_attribute_for_variation = $product->get_variation_default_attribute( $pa_attribute );

    // We EXIT if Product Attribute Color is not set as variation usage
    if( empty( $default_attribute_for_variation ) ) return;

    // Get the array of default attributes
    $default_attributes = $product->get_default_attributes();

    // For product category 'ONE => Attribute "blue" slug value
    if( has_term( 'clothing', 'product_cat', $product->get_id() ) )
        $default_attributes[$pa_attribute] = 'blue';

    // For product category 'TWO' => Attribute "blue" slug value
    elseif( has_term( 'TWO', 'product_cat', $product->get_id() ) )
        $default_attributes[$pa_attribute] = 'red';

    else return; // If no product categories match we exit

    // If a product category match we set the default attribute
    $product->set_default_attributes( $default_attributes );
}, 80, 0 );

Code goes in function.php file of your active child theme (or theme) or also in any plugin file.

This code is tested and works.