1 files changed, 118 insertions, 0 deletions
diff --git a/functions/audio.py b/functions/audio.py
new file mode 100644
index 0000000..d0e599d
--- /dev/null
+++ b/functions/audio.py
@@ -0,0 +1,118 @@
+"""Audio function module.
+
+Contains the definition of the Audio, the audio primitive. 
+"""
+
+import xml.etree.ElementTree as et
+
+from .function import Function
+
+from ..constants import AUDIO, BXW
+from ..exceptions import LoadError
+
+class Audio(Function):
+    """Class representing an audio cue. 
+
+    This is the primitive for audio, and all sound cues must be based in some manner off of 
+    Audio. This function merely plays a single audio file once, starting at t=0. 
+
+    The duration of the audio is automatically determined and is zero if the file does not 
+    exist or is unsupported by ffmpeg. 
+    """
+    scope = ()
+    audio_scope = frozenset()
+    actual_duration = 0
+
+    def __init__(self, w, id_ = None, name = None, fade_in = 0, fade_out = 0,
+                 filename: str = None):
+        super().__init__(w=w, type_=AUDIO, id_=id_, name=name, duration=0, 
+                         fade_in=fade_in, fade_out=fade_out)
+
+        self._filename = filename
+
+        if filename is not None:
+            self.duration = self.w.get_audio_length(filename)
+            self.audio_scope = frozenset(((filename,),))
+        else:
+            self.duration = 0
+            self.audio_scope = frozenset()
+
+        self.actual_duration = self.duration
+
+    def get_data(self):
+        return None
+
+    def copy_data(self, data):
+        return None
+
+    def render(self, t, data = None):
+        return ((), 
+                ((self.id, self._filename, 0, self.fade_in, self.duration, self.fade_out),),
+                None)
+
+    @property
+    def filename(self):
+        """Return the current audio filename."""
+        return self._filename
+
+    @filename.setter 
+    def filename(self, value: str):
+        """Set the current audio filename, updating the duration."""
+        if value is not None:
+            self.duration = self.w.get_audio_length(value)
+            self.audio_scope = frozenset(((value,),))
+        else:
+            self.duration = 0
+            self.audio_scope = frozenset()
+
+        self._filename = value
+        self.w.function_changed(self)
+
+    def serialize(self) -> et.Element:
+        e = et.Element(BXW+"function")
+        e.set("type", self.type)
+        e.set("id", str(self.id))
+        e.set("name", self.name)
+        e.set("fade-in", str(self.fade_in))
+        e.set("fade-out", str(self.fade_out))
+        if self.filename is not None:
+            filename = et.SubElement(e, BXW+"filename")
+            filename.text = self.filename
+
+        return e
+
+    @classmethod
+    def deserialize(cls, w, e):
+        if e.tag != BXW+"function":
+            raise LoadError("Invalid function tag")
+        elif e.get("type") != AUDIO:
+            raise LoadError("Load delegated to wrong class (this is a bug)")
+        
+        id_ = cls.int_or_none(e.get("id"))
+        if id_ is None:
+            raise LoadError("Function tag has invalid/missing ID")
+
+        name = e.get("name")
+
+        fade_in = e.get("fade-in")
+        try:
+            fade_in = int(fade_in) if fade_in else 0
+        except ValueError:
+            raise LoadError("Invalid fade in")
+
+        fade_out = e.get("fade-out")
+        try:
+            fade_out = int(fade_out) if fade_out else 0
+        except ValueError:
+            raise LoadError("Invalid fade out")
+
+        if len(e) > 1:
+            raise LoadError("Audio tag can have at most one filename")
+        elif len(e) == 1:
+            filename, = e
+            filename = filename.text
+        else:
+            filename = None
+
+        return cls(w=w, id_=id_, name=name, filename=filename, fade_in=fade_in,
+                   fade_out=fade_out)