commit c91700a12310e845fb3ff2ae4f2fc98b9ae6cd25
Author: Mika <kontakt@donau2space.de>
Date:   Sun Mar 29 10:41:46 2026 +0000

    Add artifact_1/src/artifact_1/core.py

diff --git a/artifact_1/src/artifact_1/core.py b/artifact_1/src/artifact_1/core.py
new file mode 100644
index 0000000..f1d759f
--- /dev/null
+++ b/artifact_1/src/artifact_1/core.py
@@ -0,0 +1,83 @@
+import json
+import time
+import datetime
+import os
+from pathlib import Path
+from dataclasses import dataclass, asdict
+from typing import Any
+
+
+class ValidationError(Exception):
+    """Custom exception for invalid log data."""
+    pass
+
+
+@dataclass
+class LogEntry:
+    """Represents a single timestamp log entry."""
+    epoch_ms: int
+    monotonic_ns: int
+    tz_offset_minutes: int
+    run_id: str
+    step_id: str
+
+    def validate(self) -> None:
+        if not isinstance(self.epoch_ms, int) or self.epoch_ms < 0:
+            raise ValidationError(f"Invalid epoch_ms: {self.epoch_ms}")
+        if not isinstance(self.monotonic_ns, int) or self.monotonic_ns < 0:
+            raise ValidationError(f"Invalid monotonic_ns: {self.monotonic_ns}")
+        if not isinstance(self.tz_offset_minutes, int):
+            raise ValidationError(f"Invalid tz_offset_minutes: {self.tz_offset_minutes}")
+        if not isinstance(self.run_id, str) or not self.run_id:
+            raise ValidationError(f"Invalid run_id: {self.run_id}")
+        if not isinstance(self.step_id, str) or not self.step_id:
+            raise ValidationError(f"Invalid step_id: {self.step_id}")
+
+
+OUTPUT_PATH = Path("output/timestamps.json")
+
+
+def _ensure_output_dir(path: Path) -> None:
+    path.parent.mkdir(parents=True, exist_ok=True)
+
+
+def _save_log_entry(entry: LogEntry, path: Path) -> None:
+    _ensure_output_dir(path)
+
+    log_data = []
+    if path.exists():
+        try:
+            with open(path, "r", encoding="utf-8") as f:
+                contents = f.read().strip()
+                if contents:
+                    log_data = json.loads(contents)
+        except (json.JSONDecodeError, OSError):
+            # Reset log if file is corrupted
+            log_data = []
+
+    log_data.append(asdict(entry))
+
+    with open(path, "w", encoding="utf-8") as f:
+        json.dump(log_data, f, indent=2)
+
+
+# Public API function
+def log_timestamps(epoch_ms: int, monotonic_ns: int, tz_offset_minutes: int, run_id: str, step_id: str) -> None:
+    """Logs timestamps including epoch, monotonic, timezone offset as JSON."""
+    entry = LogEntry(
+        epoch_ms=epoch_ms,
+        monotonic_ns=monotonic_ns,
+        tz_offset_minutes=tz_offset_minutes,
+        run_id=run_id,
+        step_id=step_id,
+    )
+    entry.validate()
+    _save_log_entry(entry, OUTPUT_PATH)
+
+
+if __name__ == "__main__":
+    # For manual debugging: log current times
+    epoch_ms = int(time.time() * 1000)
+    monotonic_ns = time.monotonic_ns()
+    offset = int((datetime.datetime.now() - datetime.datetime.utcnow()).total_seconds() / 60)
+    log_timestamps(epoch_ms, monotonic_ns, offset, "manual_run", "step0")