Sync a Product List Metafield Of Products That Share Another Common Metafield Value, with Mechanic.

mechanic/scheduler/daily
mechanic/user/trigger
mechanic/shopify/bulk_operation

{% comment %}Set up the task options{% endcomment %}
{% assign group_by_namespace = options.group_by_metafield_namespace__required %}
{% assign group_by_key = options.group_by_metafield_key__required %}
{% assign product_list_namespace = options.product_list_metafield_namespace__required %}
{% assign product_list_key = options.product_list_metafield_key__required %}
{% assign remove_out_of_stock = options.remove_out_of_stock_products__boolean %}
{% assign include_current_product = options.include_current_product__boolean %}

{% comment %}Run the bulk GraphQL query{% endcomment %}
{% if event.topic == "mechanic/user/trigger" or event.topic == "mechanic/scheduler/daily" %}
  {% capture bulk_operation_query %}
    query {
      products(query: "status:ACTIVE{% if remove_out_of_stock %} inventory_total:>0{% endif %}") {
        edges {
          node {
            __typename
            id
            title
            group: metafield(
                namespace: {{ group_by_namespace | json }}
                key: {{ group_by_key | json }}
            ) {
                value
            }
            product_list: metafield(
                namespace: {{ product_list_namespace | json }}
                key: {{ product_list_key | json }}
            ) {
                value
            }
          }
        }
      }
    }
  {% endcapture %}
  {% action "shopify" %}
    mutation {
      bulkOperationRunQuery(
        query: {{ bulk_operation_query | json }}
      ) {
        bulkOperation {
          id
          status
        }
        userErrors {
          field
          message
        }
      }
    }
  {% endaction %}
{% elsif event.topic == "mechanic/shopify/bulk_operation" %}
  {% comment %}Preview data for debugging{% endcomment %}
  {% if event.preview %}
    {% capture jsonl_string %}
      {"__typename":"Product","id":"gid:\/\/shopify\/Product\/7819883282585","title":"Sample Product 1","group":{"id":"gid:\/\/shopify\/Metafield\/39837328081049","value":"Converse"},"product_list":null}
{"__typename":"Product","id":"gid:\/\/shopify\/Product\/7819883380889","title":"Sample Product 2","group":{"value":"Converse"},"product_list":{"value":"[\"gid:\/\/shopify\/Product\/7819883282585\",\"gid:\/\/shopify\/Product\/7819883380889\",\"gid:\/\/shopify\/Product\/7819883413657\"]"}}
{"__typename":"Product","id":"gid:\/\/shopify\/Product\/7819883413657","title":"Sample Product 3","group":{"value":"Converse"},"product_list":null}
    {% endcapture %}
    {% assign bulkOperation = hash %}
    {% assign bulkOperation["objects"] = jsonl_string | parse_jsonl %}
  {% endif %}

  {% comment %}Build a hash (object) keyed by unique values from the group by field, each element is an array of product ids with a matching group by value{% endcomment %}
  {% assign products_to_process = bulkOperation.objects %}
  {% assign products_groups = hash %}
  {% for product in products_to_process %}
    {% if product.group.value %}
      {% unless products_groups[product.group.value] %}
        {% assign products_groups[product.group.value] = array %}
      {% endunless %}
      {% assign products_groups[product.group.value] = products_groups[product.group.value] | push: product.id %}
    {% endif %}
  {% endfor %}

  {% comment %}
    Procees all products
  {% endcomment %}
  {% for current_product in products_to_process %}
    {% if current_product.group.value %}
      {% assign product_list = products_groups[current_product.group.value] %}
      
      {% unless include_current_product %}
        {% comment %}
          The array we built will contain the current product too so unless a user selects the 'Include Current Product' option we rebuild it without the current product in (there's no easy function for removing an item from an array in liquid/Mechanic)
        {% endcomment %}
        {% assign product_list_less_current = array %}
        {% for product_list_item in products_groups[current_product.group.value] %}
          {% unless product_list_item == current_product.id %}
            {% assign product_list_less_current = product_list_less_current | push: product_list_item %}
          {% endunless %}
        {% endfor %}
        {% assign product_list = product_list_less_current %}
      {% endunless %}

      {% comment %}
        Check if the product list metafield value is already correct and update it if not
      {% endcomment %}
      {% assign product_list_json = product_list | json  %}
      {% if current_product.product_list.value != product_list_json %}
        {% action "shopify" %}
          mutation {
            metafieldsSet(
              metafields: [{
                ownerId: {{ current_product.id | json }},
                namespace: {{ product_list_namespace | json }},
                key: {{ product_list_key | json }},
                value: {{ product_list | json | json }},
                type: "list.product_reference"
              }]
            ) {
              metafields {
                namespace
                key
                value
              }
              userErrors {
                code
                field
                message
              }
            }
          }
        {% endaction %}
        {% log message: "Updated product:", details: current_product.title %}
      {% else %}
        {% log message: "Metafield values match, skipped updating product:", details: current_product.title %}
      {% endif %}
    {% endif %}
  {% endfor %}
{% endif %}