1 files changed, 34 insertions, 0 deletions
diff --git a/scripts/version.py b/scripts/version.py
new file mode 100644
index 0000000..9076b93
--- /dev/null
+++ b/scripts/version.py
@@ -0,0 +1,34 @@
+import datetime
+import subprocess
+
+__all__ = ("get_version",)
+
+
+def get_version() -> str:
+    """
+    Return a version based on the HEAD commit's date.
+
+    The format is 'year.month.day.commits' and is compliant with PEP 440. 'commits' is the amount of
+    commits made on the same date as HEAD, excluding HEAD. This ensures versions are unique if
+    multiple release occur on the same date.
+    """
+    args = ["git", "show", "-s", "--format=%ct", "HEAD"]
+    stdout = subprocess.check_output(args, text=True)
+    timestamp = float(stdout.strip())
+    date = datetime.datetime.fromtimestamp(timestamp, datetime.timezone.utc)
+
+    commits = count_commits_on_date(date) - 1  # Exclude HEAD.
+
+    # Don't use strftime because it includes leading zeros, which are against PEP 440.
+    return f"{date.year}.{date.month}.{date.day}.{commits}"
+
+
+def count_commits_on_date(dt: datetime.datetime) -> int:
+    """Return the amount of commits made on the given UTC aware datetime."""
+    dt = dt.combine(dt - datetime.timedelta(days=1), dt.max.time(), dt.tzinfo)
+
+    # git log uses the committer date for this, not the author date.
+    args = ["git", "log", "--oneline", "--after", str(dt.timestamp())]
+    stdout = subprocess.check_output(args, text=True)
+
+    return stdout.strip().count("\n")