From 1e92dc70571fc599c0caa60acdf76bcc33e26999 Mon Sep 17 00:00:00 2001
From: Paul Natsuo Kishimoto <mail@paul.kishimoto.name>
Date: Tue, 5 May 2020 19:55:38 +0200
Subject: [PATCH] Extend writer.xml for hierarchical ItemSchemes, Annotations

---
 sdmx/model.py                 | 13 ++++--
 sdmx/tests/writer/conftest.py | 13 +++++-
 sdmx/writer/xml.py            | 74 +++++++++++++++++++++++++++--------
 3 files changed, 79 insertions(+), 21 deletions(-)

diff --git a/sdmx/model.py b/sdmx/model.py
index 5c95c7a7e..71ca9b4d3 100644
--- a/sdmx/model.py
+++ b/sdmx/model.py
@@ -141,7 +141,7 @@ def __add__(self, other):
         result.localizations.update(other.localizations)
         return result
 
-    def localized_default(self, locale):
+    def localized_default(self, locale=None):
         """Return the string in *locale*, or else the first defined."""
         try:
             return self.localizations[locale]
@@ -311,12 +311,12 @@ def __init__(self, *args, **kwargs):
 
         # Add this Item as a child of its parent
         parent = kwargs.get('parent', None)
-        if parent and self not in parent.child:
-            parent.child.append(self)
+        if parent:
+            parent.append_child(self)
 
         # Add this Item as a parent of its children
         for c in kwargs.get('child', []):
-            c.parent = self
+            self.append_child(c)
 
     def __contains__(self, item):
         """Recursive containment."""
@@ -324,6 +324,11 @@ def __contains__(self, item):
             if item == c or item in c:
                 return True
 
+    def append_child(self, other):
+        if other not in self.child:
+            self.child.append(other)
+        other.parent = self
+
     def get_child(self, id):
         """Return the child with the given *id*."""
         for c in self.child:
diff --git a/sdmx/tests/writer/conftest.py b/sdmx/tests/writer/conftest.py
index 84ddee643..e415056d4 100644
--- a/sdmx/tests/writer/conftest.py
+++ b/sdmx/tests/writer/conftest.py
@@ -1,6 +1,6 @@
 import pytest
 from sdmx.message import StructureMessage
-from sdmx.model import Agency, Code, Codelist
+from sdmx.model import Agency, Annotation, Code, Codelist
 
 
 @pytest.fixture
@@ -25,6 +25,17 @@ def codelist():
         id='B',
         name={'en': 'Beginning of period'},
     )
+    cl.items['B1'] = Code(
+        id='B1',
+        name={'en': 'Child code of B'},
+    )
+    cl.items['B'].append_child(cl.items['B1'])
+
+    cl.items['A'].annotations.append(Annotation(
+        id='A1',
+        type='NOTE',
+        text={'en': 'Text annotation on Code A.'},
+    ))
 
     return cl
 
diff --git a/sdmx/writer/xml.py b/sdmx/writer/xml.py
index 9e9f791fd..1a06f9c3d 100644
--- a/sdmx/writer/xml.py
+++ b/sdmx/writer/xml.py
@@ -11,7 +11,9 @@
 
 
 def Element(name, *args, **kwargs):
-    return _element_maker(qname(*name.split(':')), *args, **kwargs)
+    name = name.split(':')
+    name = qname(*name) if len(name) == 2 else name[0]
+    return _element_maker(name, *args, **kwargs)
 
 
 Writer = BaseWriter('XML')
@@ -37,20 +39,50 @@ def write(obj, **kwargs):
 
 # Utility functions
 
-def nameable(obj, elem):
-    for locale, label in obj.name.localizations.items():
-        child = Element('com:Name', label)
+def i11lstring(obj, name):
+    """InternationalString.
+
+    Returns a list of elements with name `name`.
+    """
+    elems = []
+
+    for locale, label in obj.localizations.items():
+        child = Element(name, label)
         child.set(qname('xml', 'lang'), locale)
-        elem.append(child)
+        elems.append(child)
+
+    return elems
 
 
-def maintainable(obj):
-    urn = sdmx.urn.make(obj)
-    elem = Element(f'str:{obj.__class__.__name__}', urn=urn)
-    nameable(obj, elem)
+def annotable(obj, name, *args, **kwargs):
+    elem = Element(name, *args, **kwargs)
+
+    if len(obj.annotations):
+        e_anno = Element('com:Annotations')
+        e_anno.extend(Writer.recurse(a) for a in obj.annotations)
+        elem.append(e_anno)
+
     return elem
 
 
+def identifiable(obj, name, *args, **kwargs):
+    return annotable(obj, name, *args, id=obj.id, **kwargs)
+
+
+def nameable(obj, name, *args, **kwargs):
+    elem = identifiable(obj, name, *args, **kwargs)
+    elem.extend(i11lstring(obj.name, 'com:Name'))
+    return elem
+
+
+def maintainable(obj, parent=None):
+    return nameable(
+        obj,
+        f'str:{obj.__class__.__name__}',
+        urn=sdmx.urn.make(obj, parent),
+    )
+
+
 @Writer.register
 def _(obj: message.StructureMessage):
     msg = Element('mes:Structure')
@@ -77,11 +109,21 @@ def _(obj: model.ItemScheme):
 
 @Writer.register
 def _(obj: model.Item, parent):
-    # NB this isn't correct: produces .Codelist instead of .Code
-    elem = Element(
-        f'str:{obj.__class__.__name__}',
-        id=obj.id,
-        urn=sdmx.urn.make(obj, parent),
-    )
-    nameable(obj, elem)
+    elem = maintainable(obj, parent=parent)
+
+    if obj.parent:
+        # Reference to parent code
+        e_parent = Element('str:Parent')
+        e_parent.append(Element('Ref', id=obj.parent.id))
+        elem.append(e_parent)
+
+    return elem
+
+
+@Writer.register
+def _(obj: model.Annotation):
+    elem = Element('com:Annotation')
+    if obj.id:
+        elem.attrib['id'] = obj.id
+    elem.extend(i11lstring(obj.text, 'com:AnnotationText'))
     return elem