script.liquid

{% if event.preview %}
  {% assign event = hash %}
  {% assign event["data"] = "customer@example.com:foobar,customer@foo:bar" | replace: ",", newline %}
  {% assign event["preview"] = true %}
{% endif %}

{% assign query_cost = 3 %}
{% assign mutation_cost = 10 %}
{% assign bucket_size = 1000 %}
{% assign buffer_factor = 2 %}

{% assign lines = event.data | strip | split: newline | uniq | sort %}
{% assign lines_and_customers = hash %}

{% assign scan_batch_size = bucket_size | times: 1.0 | divided_by: query_cost | divided_by: buffer_factor | round %}
{% assign scan_batches = lines | in_groups_of: scan_batch_size, fill_with: false %}

{% for scan_batch in scan_batches %}
  {% assign batch_lines = array %}

  {% for line in scan_batch %}
    {% if line == blank %}
      {% continue %}
    {% endif %}

    {% assign parts = line | split: ":" %}
    {% if parts.size != 2 %}
      {% log message: "Found an invalid line.", line: line %}
      {% continue %}
    {% endif %}

    {% unless parts.first contains "@" %}
      {% log message: "Found an invalid email address.", line: line %}
      {% continue %}
    {% endunless %}

    {% assign email = parts[0] | strip %}
    {% assign tag = parts[1] | strip %}

    {% assign batch_lines[batch_lines.size] = email | append: ":" | append: tag %}
  {% endfor %}

  {% if batch_lines == empty %}
    {% continue %}
  {% endif %}

  {% capture query %}
    query {
      {% for line in batch_lines %}
        {% assign email = line | split: ":" | first %}
        customer{{ forloop.index0 }}: customers(first: 1, query: {{ email | json | prepend: "email:" | json }}) {
          edges {
            node {
              id
              email
              tags
            }
          }
        }
      {% endfor %}
    }
  {% endcapture %}

  {% assign result = query | shopify %}

  {% if event.preview %}
    {% capture result_json %}
      {
        "data": {
          {% for line in batch_lines %}
            "customer{{ forloop.index0 }}": {
              "edges": [
                {
                  "node": {
                    "email": {{ line | split: ":" | first | json }},
                    "id": "gid://shopify/Customer/{{ forloop.index0 }}",
                    "tags": []
                  }
                }
              ]
            }
            {% unless forloop.last %},{% endunless %}
          {% endfor %}
        }
      }
    {% endcapture %}

    {% assign result = result_json | parse_json %}
  {% endif %}

  {% for line in batch_lines %}
    {% assign key = "customer" | append: forloop.index0 %}
    {% assign email = line | split: ":" | first %}
    {% assign tag = line | split: ":" | last %}
    {% assign customer = result.data[key].edges.first.node %}

    {% assign customer_email_downcase = customer.email | downcase %}
    {% assign email_downcase = email | downcase %}
    {% if customer_email_downcase != email_downcase %}
      {% log message: "Customer returned by Shopify somehow does not match the email address we searched for. Skipping.", line: line, customer: customer %}
      {% continue %}
    {% endif %}

    {% if customer == nil %}
      {% log message: "This customer could not be found. Skipping.", line: line %}
      {% continue %}
    {% endif %}

    {% if customer.tags contains tag %}
      {% log message: "Customer already has tag. Skipping.", line: line, tag: tag, customer: customer %}
      {% continue %}
    {% endif %}

    {% assign lines_and_customers[line] = customer %}
  {% endfor %}
{% endfor %}

{% assign taggings = array %}

{% for keyval in lines_and_customers %}
  {% assign line = keyval[0] %}
  {% assign tag = line | split: ":" | last %}
  {% assign customer = keyval[1] %}

  {% assign tagging = hash %}
  {% assign tagging["id"] = customer.id %}
  {% assign tagging["tags"] = tag %}

  {% assign taggings[taggings.size] = tagging %}
{% endfor %}

{% if taggings != empty %}
  {% assign tagging_batch_size = bucket_size | times: 1.0 | divided_by: mutation_cost | divided_by: buffer_factor | round %}
  {% assign tagging_batches = taggings | in_groups_of: tagging_batch_size, fill_with: false %}

  {% for tagging_batch in tagging_batches %}
    {% action "shopify" %}
      mutation {
        {% for tagging in tagging_batch %}
          customer{{ forloop.index0 }}: tagsAdd({{ tagging | graphql_arguments }}) {
            userErrors {
              field
              message
            }
            node {
              ... on Customer {
                id
                email
                tags
              }
            }
          }
        {% endfor %}
      }
    {% endaction %}
  {% endfor %}
{% endif %}