{% from "nhsuk/macros/attributes.njk" import nhsukAttributes %}

{#- Set variant for this component #}
{%- set variant = params.variant -%}

{#- Set classes for this component #}
{%- set classNames = "nhsuk-back-link" -%}

{%- if variant == "reverse" and (not params.classes or not "nhsuk-back-link--reverse" in params.classes) %}
  {% set classNames = classNames ~ " nhsuk-back-link--" ~ variant %}
{% endif %}

{%- if params.classes %}
  {% set classNames = classNames ~ " " ~ params.classes %}
{% endif %}

{#- Determine type of element to use, if not explicitly set #}
{%- if params.element %}
  {% set element = params.element | lower %}
{% else %}
  {% if params.href and not params.type %}
    {% set element = "a" %}
  {% else %}
    {% set element = "button" %}
  {% endif %}
{% endif %}

{#- Define attributes that we can use across all element types #}
{%- set attributesHtml %}
  {{- nhsukAttributes({
    class: classNames,
    id: {
      value: params.id,
      optional: true
    }
  }) -}}

  {% if element == "button" %}
    {{- nhsukAttributes({
      type: params.type | default("submit")
    }) -}}
  {% elif element == "a" %}
    {{- nhsukAttributes({
      href: params.href | default("#")
    }) -}}
  {% endif %}

  {{- nhsukAttributes(params.attributes) -}}
{% endset %}

{%- set innerHtml %}
{% if caller %}
  {{- caller() }}
{% elif params.html %}
  {{- params.html | safe }}
{% else %}
  {{- params.text | default("Back", true) }}
{% endif %}
{% endset -%}

<{{ element }} {{- attributesHtml | safe }}>
  {% if params.visuallyHiddenText %}
  <span class="nhsuk-u-visually-hidden">{{ params.visuallyHiddenText }} </span>
  {{- innerHtml | safe | trim | indent(2) }}
  {% else %}
  {{ innerHtml | safe | trim | indent(2) }}
  {% endif %}
</{{ element }}>