Initial Commit

unshackle/core/tracks/chapter.py

@@ -0,0 +1,77 @@
+from __future__ import annotations
+
+import re
+from typing import Optional, Union
+from zlib import crc32
+
+TIMESTAMP_FORMAT = re.compile(r"^(?P<hour>\d{2}):(?P<minute>\d{2}):(?P<second>\d{2})(?P<ms>.\d{3}|)$")
+
+
+class Chapter:
+    def __init__(self, timestamp: Union[str, int, float], name: Optional[str] = None):
+        """
+        Create a new Chapter with a Timestamp and optional name.
+
+        The timestamp may be in the following formats:
+        - "HH:MM:SS" string, e.g., `25:05:23`.
+        - "HH:MM:SS.mss" string, e.g., `25:05:23.120`.
+        - a timecode integer in milliseconds, e.g., `90323120` is `25:05:23.120`.
+        - a timecode float in seconds, e.g., `90323.12` is `25:05:23.120`.
+
+        If you have a timecode integer in seconds, just multiply it by 1000.
+        If you have a timecode float in milliseconds (no decimal value), just convert
+        it to an integer.
+        """
+        if timestamp is None:
+            raise ValueError("The timestamp must be provided.")
+
+        if not isinstance(timestamp, (str, int, float)):
+            raise TypeError(f"Expected timestamp to be {str}, {int} or {float}, not {type(timestamp)}")
+        if not isinstance(name, (str, type(None))):
+            raise TypeError(f"Expected name to be {str}, not {type(name)}")
+
+        if not isinstance(timestamp, str):
+            if isinstance(timestamp, int):  # ms
+                hours, remainder = divmod(timestamp, 1000 * 60 * 60)
+                minutes, remainder = divmod(remainder, 1000 * 60)
+                seconds, ms = divmod(remainder, 1000)
+            elif isinstance(timestamp, float):  # seconds.ms
+                hours, remainder = divmod(timestamp, 60 * 60)
+                minutes, remainder = divmod(remainder, 60)
+                seconds, ms = divmod(int(remainder * 1000), 1000)
+            else:
+                raise TypeError
+            timestamp = f"{int(hours):02}:{int(minutes):02}:{int(seconds):02}.{str(ms).zfill(3)[:3]}"
+
+        timestamp_m = TIMESTAMP_FORMAT.match(timestamp)
+        if not timestamp_m:
+            raise ValueError(f"The timestamp format is invalid: {timestamp}")
+
+        hour, minute, second, ms = timestamp_m.groups()
+        if not ms:
+            timestamp += ".000"
+
+        self.timestamp = timestamp
+        self.name = name
+
+    def __repr__(self) -> str:
+        return "{name}({items})".format(
+            name=self.__class__.__name__, items=", ".join([f"{k}={repr(v)}" for k, v in self.__dict__.items()])
+        )
+
+    def __str__(self) -> str:
+        return " | ".join(filter(bool, ["CHP", self.timestamp, self.name]))
+
+    @property
+    def id(self) -> str:
+        """Compute an ID from the Chapter data."""
+        checksum = crc32(str(self).encode("utf8"))
+        return hex(checksum)
+
+    @property
+    def named(self) -> bool:
+        """Check if Chapter is named."""
+        return bool(self.name)
+
+
+__all__ = ("Chapter",)