{# One labelled control, in the four shapes the configuration forms need, plus
   one button that belongs to a box rather than to a form.

   Macros rather than includes so a caller cannot forget to set the variable one
   reads, and so the distinction that matters here is structural: ``field`` and
   ``choice`` take a value and put it back, ``secret`` and ``secret_lines`` have
   no value parameter at all. A credential cannot be echoed into a page by
   somebody passing the wrong argument, because there is no argument to pass.

     {% from "partials/field.html" import field, secret, choice, generate %}
     {{ field("name", "Display name", value=fields.name, hint="Defaults to the spec's title.") }}
     {{ secret("token", "Token", error=errors.get("token")) }}
     {{ choice("auth_type", "Authentication", auth_options, fields.auth_type) }}

   **Every conditional attribute below starts with a space, and has to.** The
   environment renders with ``trim_blocks`` and ``lstrip_blocks`` (web/shell.py),
   which take the newline after a block tag and the indentation before one — so
   two conditional attributes on consecutive lines are emitted with nothing
   between them. ``checked`` beside ``data-reveal`` came out as one attribute
   called ``checkeddata-reveal``, which a browser accepts and silently leaves the
   box unticked; ``placeholder`` beside ``aria-invalid`` did the same to a
   rejected number field. The space inside the block is what separates them, and
   an extra one where the attribute is absent costs nothing (task 125).
#}

{% macro _messages(name, hint, error) -%}
{% if hint %}<span class="field__hint">{{ hint }}</span>{% endif %}
{% if error %}<span class="field__error" id="{{ name }}-error" role="alert">{{ error }}</span>{% endif %}
{%- endmacro %}

{% macro field(name, label, value="", hint=none, error=none, type="text", required=false,
               placeholder=none) -%}
<label class="field{% if error %} field--invalid{% endif %}">
  <span class="field__label">{{ label }}</span>
  <input
    class="field__input"
    type="{{ type }}"
    name="{{ name }}"
    value="{{ value }}"
    {# What the box means when it is left empty, said where it is left empty. #}
    {% if placeholder is not none %} placeholder="{{ placeholder }}"{% endif %}
    autocomplete="off"
    spellcheck="false"
    {% if required %} required{% endif %}
    {% if error %} aria-invalid="true" aria-describedby="{{ name }}-error"{% endif %}
  />
  {{ _messages(name, hint, error) }}
</label>
{%- endmacro %}

{# A credential field. Never carries a value, in any circumstance: what the
   operator typed last time is either already stored or was wrong. #}
{% macro secret(name, label, hint=none, error=none) -%}
<label class="field{% if error %} field--invalid{% endif %}">
  <span class="field__label">{{ label }}</span>
  <input
    class="field__input"
    type="password"
    name="{{ name }}"
    autocomplete="new-password"
    spellcheck="false"
    {% if error %} aria-invalid="true" aria-describedby="{{ name }}-error"{% endif %}
  />
  {{ _messages(name, hint, error) }}
</label>
{%- endmacro %}

{# The same promise, for a credential that is more than one line. #}
{% macro secret_lines(name, label, hint=none, error=none, rows=4) -%}
<label class="field{% if error %} field--invalid{% endif %}">
  <span class="field__label">{{ label }}</span>
  <textarea
    class="field__input"
    name="{{ name }}"
    rows="{{ rows }}"
    autocomplete="off"
    spellcheck="false"
    {% if error %} aria-invalid="true" aria-describedby="{{ name }}-error"{% endif %}
  ></textarea>
  {{ _messages(name, hint, error) }}
</label>
{%- endmacro %}

{# A checkbox, which is the one control whose value is its presence: unticked,
   it is simply not in the submitted form. ``reveal`` works on it exactly as it
   does on a select — see static/js/forms.js — which is how "Replace the
   credential" opens the panel holding the credential. #}
{% macro switch(name, label, checked=false, hint=none, error=none, reveal=none) -%}
<label class="switch{% if error %} switch--invalid{% endif %}">
  <input
    class="switch__input"
    type="checkbox"
    name="{{ name }}"
    value="true"
    {% if checked %} checked{% endif %}
    {% if reveal %} data-reveal="{{ reveal }}"{% endif %}
    {% if error %} aria-invalid="true" aria-describedby="{{ name }}-error"{% endif %}
  />
  <span class="switch__label">{{ label }}</span>
  {{ _messages(name, hint, error) }}
</label>
{%- endmacro %}

{# ``options`` is a list of (value, label) pairs. ``reveal`` names the group of
   panels this control shows and hides; see static/js/forms.js. #}
{% macro choice(name, label, options, value="", hint=none, error=none, reveal=none) -%}
<label class="field{% if error %} field--invalid{% endif %}">
  <span class="field__label">{{ label }}</span>
  <select
    class="field__select"
    name="{{ name }}"
    {% if reveal %} data-reveal="{{ reveal }}"{% endif %}
    {% if error %} aria-invalid="true" aria-describedby="{{ name }}-error"{% endif %}
  >
    {% for option, text in options %}
    <option value="{{ option }}"{% if option == value %} selected{% endif %}>{{ text }}</option>
    {% endfor %}
  </select>
  {{ _messages(name, hint, error) }}
</label>
{%- endmacro %}

{# A button that fills the box named by ``field`` with a freshly generated
   secret, for a value the operator has to invent rather than be given: the MCP
   bearer token, so far (task 126).

   Hidden here and unhidden by static/js/forms.js. Everything else in this file
   works without a script and this cannot — a button that fills a box needs
   something to fill it with — and a control that does nothing when clicked is
   worse than one that was never offered. The hint beside the box says how to
   make a token at a shell instead.

   The value is generated in the browser, never on the server. It would
   otherwise have to come back through the flash cookie, which is signed,
   written to the browser's disk and sent again on the next request, or the
   route would have to stop redirecting after a POST. Generated here it only
   ever travels the direction it has to travel anyway. #}
{% macro generate(field, label="Generate one") -%}
<button class="button button--quiet field__aside" type="button"
        data-generate="{{ field }}" hidden>{{ label }}</button>
{%- endmacro %}