script.liquid

{% assign out_of_stock_inventory_quantity = options.out_of_stock_inventory_quantity__number_required %}
{% assign search_query = options.only_monitor_products_matching_this_search_query | default: "" %}

{% assign metafield_key
  = task.id
  | append: search_query
  | append: out_of_stock_inventory_quantity
  | sha256
  | slice: 0, 7
  | append: "-out-of-stock"
%}

{% if event.topic contains "shopify/inventory_levels/" %}
  {% capture query %}
    query {
      inventoryLevel(
        id: {{ inventory_level.admin_graphql_api_id | json }}
      ) {
        item {
          variant {
            product {
              legacyResourceId
            }
          }
        }
      }
    }
  {% endcapture %}

  {% assign result = query | shopify %}

  {% comment %}
    -- send the product ID through the paginated query so any configured search query can be applied to it
  {% endcomment %}

  {%- capture search_query -%}
    {{ search_query }} id:{{ result.data.inventoryLevel.item.variant.product.legacyResourceId }}
  {%- endcapture -%}
{% endif %}

{% assign back_in_stock_email_list = array %}
{% assign newly_back_in_stock_email_product_title = nil %}
{% assign newly_back_in_stock_product_ids = array %}
{% assign newly_out_of_stock_product_ids = array %}
{% assign out_of_stock_email_list = array %}
{% assign out_of_stock_email_product_title = nil %}

{% assign cursor = nil %}

{% for n in (0..100) %}
  {% capture query %}
    query {
      products(
        first: 250
        query: {{ search_query | json }}
        after: {{ cursor | json }}
      ) {
        pageInfo {
          hasNextPage
          endCursor
        }
        nodes {
          id
          legacyResourceId
          title
          totalInventory
          metafield(
            namespace: "mechanic"
            key: {{ metafield_key | json }}
          ) {
            id
          }
        }
      }
    }
  {% endcapture %}

  {% assign result = query | shopify %}

  {% for product in result.data.products.nodes %}
    {% if product.totalInventory <= out_of_stock_inventory_quantity %}
      {% if product.metafield == blank or event.topic == "mechanic/user/trigger" %}
        {% log %}
          "{{ product.title }} is out of stock."
        {% endlog %}

        {% assign out_of_stock_email_product_title = product.title %}

        {% if product.metafield == blank %}
          {% comment %}
            For a manual run, we always send an email about out-of-stock products. But, we
            don't need to consider these products *newly* out of stock.
          {% endcomment %}
          {% assign newly_out_of_stock_product_ids[newly_out_of_stock_product_ids.size] = product.id %}
        {% endif %}

        {%- capture list_item -%}
          <li><a href="{{ shop.admin_url }}/products/{{ product.legacyResourceId }}">{{ product.title }}</a></li>
        {%- endcapture -%}

        {% assign out_of_stock_email_list = out_of_stock_email_list | push: list_item %}
      {% endif %}

    {% else %}
      {% if product.metafield %}
        {% log %}
          "{{ product.title }} is back in stock."
        {% endlog %}

        {% assign newly_back_in_stock_email_product_title = product.title %}
        {% assign newly_back_in_stock_product_ids[newly_back_in_stock_product_ids.size] = product.id %}

        {%- capture list_item -%}
          <li><a href="{{ shop.admin_url }}/products/{{ product.legacyResourceId }}">{{ product.title }}</a></li>
        {%- endcapture -%}

        {% assign back_in_stock_email_list = back_in_stock_email_list | push: list_item %}
      {% endif %}
    {% endif %}
  {% endfor %}

  {% if result.products.pageInfo.hasNextPage %}
    {% assign cursor = result.data.products.pageInfo.endCursor %}
  {% else %}
    {% break %}
  {% endif %}
{% endfor %}

{% if event.preview %}
  {% assign out_of_stock_email_list[back_in_stock_email_list.size] = '<li><a>Premium T-Shirt</a></li>' %}
  {% assign newly_out_of_stock_product_ids[newly_out_of_stock_product_ids.size] = 'gid://shopify/Product/1234567890' %}
  {% assign out_of_stock_email_product_title = 'Premium T-Shirt' %}
{% endif %}

{% log
  newly_out_of_stock_product_count: newly_out_of_stock_product_ids.size,
  newly_back_in_stock_product_count: newly_back_in_stock_product_ids.size
%}

{% comment %}
  -- save mutation inputs for setting and deleting metafields
{% endcomment %}

{% assign metafields_to_set = array %}
{% assign metafields_to_delete = array %}

{% for product_id in newly_out_of_stock_product_ids %}
  {% assign metafield_to_set = hash %}
  {% assign metafield_to_set["ownerId"] = product_id %}
  {% assign metafield_to_set["namespace"] = "mechanic" %}
  {% assign metafield_to_set["key"] = metafield_key %}
  {% assign metafield_to_set["type"] = "number_integer" %}
  {% assign metafield_to_set["value"] = "1" %}
  {% assign metafields_to_set = metafields_to_set | push: metafield_to_set %}
{% endfor %}

{% for product_id in newly_back_in_stock_product_ids %}
  {% assign metafield_to_delete = hash %}
  {% assign metafield_to_delete["ownerId"] = product_id %}
  {% assign metafield_to_delete["namespace"] = "mechanic" %}
  {% assign metafield_to_delete["key"] = metafield_key %}
  {% assign metafields_to_delete = metafields_to_delete | push: metafield_to_delete %}
{% endfor %}

{% if options.send_email_for_out_of_stock_products__boolean != true %}
  {% assign out_of_stock_email_list = array %}
{% endif %}

{% if options.send_email_for_back_in_stock_products__boolean != true %}
  {% assign back_in_stock_email_list = array %}
{% endif %}

{% if out_of_stock_email_list.size > 0 or back_in_stock_email_list.size > 0 %}
  {% capture email_subject %}
    {% if out_of_stock_email_list.size == 1 and back_in_stock_email_list.size == 0 %}
      Out of stock: {{ out_of_stock_email_product_title }}
    {% elsif back_in_stock_email_list.size == 1 and out_of_stock_email_list.size == 0 %}
      Back in stock: {{ newly_back_in_stock_email_product_title }}
    {% elsif out_of_stock_email_list.size > 1 and back_in_stock_email_list.size == 0 %}
      Out of stock: {{ out_of_stock_email_list.size }} products
    {% elsif back_in_stock_email_list.size > 1 and out_of_stock_email_list.size == 0 %}
      Back in stock: {{ out_of_stock_email_list.size }} products
    {% else %}
      Stock update: {{ out_of_stock_email_list.size }} out of stock, {{ back_in_stock_email_list.size }} back in stock
    {% endif %}
  {% endcapture %}

  {% capture email_body %}
    Hi there,
    <br><br>

    {% if out_of_stock_email_list.size > 0 %}
      We found <b>{{ out_of_stock_email_list.size }} out of stock {{ out_of_stock_email_list.size | pluralize: 'product', 'products' }}</b>:
      <br>
      <ul>{{ out_of_stock_email_list | join: "" }}</ul>
      <br>
    {% endif %}

    {% if back_in_stock_email_list.size > 0 %}
      We found <b>{{ back_in_stock_email_list.size }} back in stock {{ back_in_stock_email_list.size | pluralize: 'product', 'products' }}</b>:
      <br>
      <ul>{{ back_in_stock_email_list | join: "" }}</ul>
      <br>
    {% endif %}

    Thanks,
    <br>Mechanic (for {{ shop.name }})
  {% endcapture %}

  {% action "email" %}
    {
      "to": {{ options.stock_update_email_recipients__email_array_required | join: ", " | json }},
      "subject": {{ email_subject | strip | json }},
      "body": {{ email_body | unindent | strip | json }},
      "reply_to": {{ shop.customer_email | json }},
      "from_display_name": {{ shop.name | json }}
    }
  {% endaction %}
{% endif %}

{% comment %}
  -- metafields may be set 25 at a time
{% endcomment %}

{% if metafields_to_set != blank %}
  {% assign groups_of_metafields_to_set = metafields_to_set | in_groups_of: 25, fill_with: false %}

  {% for group_of_metafields_to_set in groups_of_metafields_to_set %}
    {% action "shopify" %}
      mutation {
        metafieldsSet(
          metafields: {{ group_of_metafields_to_set | graphql_arguments }}
        ) {
          metafields {
            id
            namespace
            key
            type
            value
            owner {
              ... on Product {
                id
              }
            }
          }
          userErrors {
            code
            field
            message
          }
        }
      }
    {% endaction %}
  {% endfor %}
{% endif %}

{% comment %}
  -- metafields may be deleted in batches of 250
{% endcomment %}

{% if metafields_to_delete != blank %}
  {% assign groups_of_metafields_to_delete = metafields_to_delete | in_groups_of: 250, fill_with: false %}

  {% for group_of_metafields_to_delete in groups_of_metafields_to_delete %}
    {% action "shopify" %}
      mutation {
        metafieldsDelete(
          metafields: {{ group_of_metafields_to_delete | graphql_arguments }}
        ) {
          deletedMetafields {
            ownerId
            namespace
            key
          }
          userErrors {
            field
            message
          }
        }
      }
    {% endaction %}
  {% endfor %}
{% endif %}