feat(dlplus): ODR-PadEnc output (#21)

.github/workflows/lint-and-test.yaml

@@ -33,4 +33,4 @@ jobs:
 
       - run: pip install -r requirements-dev.txt
 
-      - run: pytest --pylint --cov=nowplaypadgen --cov-fail-under=100 tests
+      - run: pytest --cov-fail-under=100

README.md

@@ -46,6 +46,32 @@ Later on you might want to generate DL+ that deletes an item tag.
 
 ```
 
+Finally, you can render it as an [ODR-PadEnc](https://github.com/opendigitalradio/ODR-PadEnc) style string.
+
+```python
+>>> from nowplaypadgen.dlplus import *
+>>> message = DLPlusMessage()
+>>> message.add_dlp_object(DLPlusObject("ITEM.TITLE", "Radio Bern"))
+>>> message.add_dlp_object(DLPlusObject("STATIONNAME.SHORT", "RaBe"))
+>>> message.add_dlp_object(DLPlusObject("STATIONNAME.LONG", "Radio Bern RaBe"))
+>>> message.build("{o[STATIONNAME.LONG]}")
+>>> from nowplaypadgen.renderer.odr import ODRPadEncRenderer
+>>> renderer = ODRPadEncRenderer(message)
+
+```
+
+This will generate the following ODR-PadEnc style DLS string when rendered with `print(renderer)`:
+
+```
+##### parameters { #####
+DL_PLUS=1
+DL_PLUS_TAG=1 0 10
+DL_PLUS_TAG=31 11 4
+DL_PLUS_TAG=32 0 15
+##### parameters } #####
+Radio Bern RaBe
+```
+
 ## Release Management
 
 The CI/CD setup uses semantic commit messages following the [conventional commits standard](https://www.conventionalcommits.org/en/v1.0.0/).

nowplaypadgen/renderer/odr.py

@@ -0,0 +1,79 @@
+"""Convert to ODR-padenc style string prepresentation of Dynamic Label Plus strings.
+
+This module generates a string/file that may be used with odr-padenc. odr-padenc
+expects ether a simple DLS string or a string prefixed with a DLS header that
+specifies the dynamic segments to be encoded into the mux.
+
+More documentation on the odr-padenc format is available from <TODO>.
+"""
+
+from nowplaypadgen.dlplus import DLPlusMessage
+
+
+class ODRPadEncRenderer:
+    """Manage ODR-padenc format."""
+
+    def __init__(self, message: DLPlusMessage):
+        """Create :class:`ODRPadEncRenderer` instance."""
+        self._message = message
+        super().__init__()
+
+    @property
+    def message(self):
+        """Return messsage.
+
+        :returns: `DLPlusMessage`
+        """
+        return self._message
+
+    def __str__(self):
+        """Render :class:`ODRPadEncRenderer` as a odr-padenc style string.
+
+        @TODO ensure this matches what odr-padenc expects.
+
+        Simple non labeled strings are output as is.
+
+        >>> from nowplaypadgen.dlplus import DLPlusMessage, DLPlusObject
+        >>> message = DLPlusMessage()
+        >>> message.build("I am a message!")
+        >>> odr = ODRPadEncRenderer(message)
+        >>> str(odr)
+        'I am a message!'
+
+        If you add labels they are added in a odr-padenc style parameters frontmatter.
+
+        >>> message.add_dlp_object(DLPlusObject("STATIONNAME.LONG", "Radio RaBe"))
+        >>> message.add_dlp_object(DLPlusObject("STATIONNAME.SHORT", "RaBe"))
+        >>> message.build("{o[STATIONNAME.LONG]}")
+        >>> string = str(odr)
+        >>> "##### parameters { #####" in string
+        True
+        >>> "DL_PLUS=1" in string
+        True
+        >>> "DL_PLUS_TAG=31 6 4" in string
+        True
+        >>> "DL_PLUS_TAG=32 0 10" in string
+        True
+        >>> "##### parameters } #####" in string
+        True
+        >>> "Radio RaBe" in string
+        True
+
+        :returns: String DLPlusMessage formatted for input to odr-dabenc.
+        """
+        dlp_tags = ""
+        if self.message.get_dlp_tags():
+            dlp_tags = "".join(
+                (
+                    "##### parameters { #####\n",
+                    "DL_PLUS=1\n",
+                    "".join(
+                        {
+                            f"DL_PLUS_TAG={tag.code} {tag.start} {tag.length}\n"
+                            for (_, tag) in self.message.get_dlp_tags().items()
+                        }
+                    ),
+                    "##### parameters } #####\n",
+                )
+            )
+        return f"{dlp_tags}{self.message.message}"

tests/test_render_odr.py

@@ -0,0 +1,24 @@
+from nowplaypadgen.dlplus import DLPlusMessage, DLPlusObject
+from nowplaypadgen.renderer.odr import ODRPadEncRenderer
+
+
+def test_render_odr():
+    """Test the rendering of a DL Pluss message."""
+
+    message = DLPlusMessage()
+    message.add_dlp_object(DLPlusObject("ITEM.TITLE", "Radio Bern"))
+    message.add_dlp_object(DLPlusObject("STATIONNAME.SHORT", "RaBe"))
+    message.add_dlp_object(DLPlusObject("STATIONNAME.LONG", "Radio Bern RaBe"))
+    message.build("{o[STATIONNAME.LONG]}")
+
+    renderer = ODRPadEncRenderer(message)
+    output = str(renderer)
+
+    assert output.split("\n")[0] == "##### parameters { #####"
+    assert output.split("\n")[1] == "DL_PLUS=1"
+    assert output.split("\n")[5] == "##### parameters } #####"
+    assert output.split("\n")[6] == "Radio Bern RaBe"
+
+    assert "DL_PLUS_TAG=1 0 10" in output
+    assert "DL_PLUS_TAG=31 11 4" in output
+    assert "DL_PLUS_TAG=32 0 15" in output