<?xml version="1.0" encoding="UTF-8"?>
<schema
  xmlns="http://www.w3.org/2001/XMLSchema"
  targetNamespace="urn:ietf:params:xml:ns:epp:ttl-1.0"
  xmlns:ttl="urn:ietf:params:xml:ns:epp:ttl-1.0"
  elementFormDefault="qualified">
  <annotation>
    <documentation>
      Extensible Provisioning Protocol v1.0 extension
      schema for Time-To-Live (TTL) values for domain
      and host objects.
    </documentation>
  </annotation>

  <element name="info">
    <complexType>
      <attribute name="policy" type="boolean" default="false"/>
    </complexType>
  </element>

  <!--
    <ttl> elements can appear in <create> and
    <update> commands, and <info> responses
  -->

  <element name="create" type="ttl:commandContainer">
    <unique name="uniqueRRTypeForCreate">
      <selector xpath="ttl:ttl"/>
      <field xpath="@for"/>
    </unique>
  </element>

  <element name="update" type="ttl:commandContainer">
    <unique name="uniqueRRTypeForUpdate">
      <selector xpath="ttl:ttl"/>
      <field xpath="@for"/>
    </unique>
  </element>

  <element name="infData" type="ttl:responseContainer">
    <unique name="uniqueRRTypeForInfo">
      <selector xpath="ttl:ttl"/>
      <field xpath="@for"/>
    </unique>
  </element>

  <complexType name="commandContainer">
    <sequence>
      <element
        name="ttl"
        type="ttl:commandTTLType"
        minOccurs="1"
        maxOccurs="unbounded"/>
    </sequence>
  </complexType>

  <complexType name="responseContainer">
    <sequence>
      <element
        name="ttl"
        type="ttl:responseTTLType"
        minOccurs="1"
        maxOccurs="unbounded"/>
    </sequence>
  </complexType>

  <complexType name="commandTTLType">
    <simpleContent>
      <extension base="ttl:ttlOrNull">
        <attribute
          name="for"
          type="ttl:rrType"
          use="required"/>

        <attribute
          name="custom"
          type="ttl:customRRType"/>
      </extension>
    </simpleContent>
  </complexType>

  <complexType name="responseTTLType">
    <simpleContent>
      <extension base="ttl:ttlOrNull">
        <attribute
          name="for"
          type="ttl:rrType"
          use="required"/>

        <attribute
          name="custom"
          type="ttl:customRRType"/>

        <attribute
          name="min"
          type="ttl:ttlValue"/>

        <attribute
          name="default"
          type="ttl:ttlValue"/>

        <attribute
          name="max"
          type="ttl:ttlValue"/>
      </extension>
    </simpleContent>
  </complexType>

  <!--
    union type allowing the element to either contain
    nothing or a TTL value
  -->
  <simpleType name="ttlOrNull">
    <union
      memberTypes="ttl:emptyValue ttl:ttlValue"/>
  </simpleType>

  <!-- empty value type -->
  <simpleType name="emptyValue">
    <restriction base="token">
      <length value="0"/>
    </restriction>
  </simpleType>

  <!-- TTL value type -->
  <simpleType name="ttlValue">
    <restriction base="nonNegativeInteger">
      <minInclusive value="0"/>
      <maxInclusive value="2147483647"/>
    </restriction>
  </simpleType>

  <!-- resource record mnemonic type -->
  <simpleType name="rrType">
    <restriction base="token">
      <enumeration value="NS" />
      <enumeration value="DS" />
      <enumeration value="DNAME" />
      <enumeration value="A" />
      <enumeration value="AAAA" />
      <enumeration value="custom" />
    </restriction>
  </simpleType>

  <!-- custom resource record type -->
  <simpleType name="customRRType">
    <restriction base="token">
      <pattern value="A|[A-Z][A-Z0-9\-]*[A-Z0-9]"/>
    </restriction>
  </simpleType>
</schema>
