refactor(clew): configure logging at startup

src/clew/clew.py

@@ -5,6 +5,7 @@ import logging
 import os
 import shutil
 import sys
+from datetime import UTC, datetime
 from pathlib import Path
 
 from rpycdec.rpa import extract_rpa
@@ -58,7 +59,8 @@ def prepare_output(output_root: Path, overwrite: bool) -> Path:
     for name in MANAGED_DIRS:
         path = output_root / name
         if path.exists() and not overwrite:
-            raise SystemExit(f"clew: refusing to overwrite existing output path: {path}")
+            LOGGER.critical("refusing to overwrite existing output path: %s", path)
+            raise SystemExit(2)
 
     if overwrite:
         for name in MANAGED_DIRS:
@@ -78,7 +80,8 @@ def normalize_suffixes(suffixes: list[str] | None) -> list[str] | None:
     normalized = []
     for suffix in suffixes:
         if not suffix:
-            raise SystemExit("clew: suffix must not be empty")
+            LOGGER.critical("suffix must not be empty")
+            raise SystemExit(2)
         if not suffix.startswith("."):
             suffix = f".{suffix}"
         normalized.append(suffix)
@@ -109,8 +112,22 @@ def extract_archive(
     LOGGER.info("extracted archive: %s", archive_relative)
 
 
-def configure_logging() -> None:
+def configure_logging(output_root: Path) -> None:
-    logging.basicConfig(level=logging.INFO, format="%(message)s")
+    log_level = logging.INFO
+    timestamp = datetime.now(UTC).strftime("%Y%m%dT%H%M%SZ")
+    logs_dir = output_root / "logs"
+    logs_dir.mkdir(parents=True, exist_ok=True)
+    log_file = logs_dir / f"{logging.getLevelName(log_level)}-clew-{timestamp}.log"
+
+    formatter = logging.Formatter("%(message)s")
+
+    file_handler = logging.FileHandler(log_file, encoding="utf-8")
+    file_handler.setFormatter(formatter)
+
+    stream_handler = logging.StreamHandler()
+    stream_handler.setFormatter(formatter)
+
+    logging.basicConfig(level=log_level, handlers=[file_handler, stream_handler])
 
 
 def run(args: argparse.Namespace) -> None:
@@ -118,10 +135,10 @@ def run(args: argparse.Namespace) -> None:
     output_root = resolve_output_root(args.output_root)
 
     if not game_root.is_dir():
-        raise SystemExit(f"clew: game root is not a directory: {game_root}")
+        LOGGER.critical("game root is not a directory: %s", game_root)
+        raise SystemExit(2)
 
     suffixes = normalize_suffixes(args.suffix)
-    configure_logging()
     extracted_dir = prepare_output(output_root, args.overwrite)
 
     LOGGER.info("copying loose files")
@@ -138,4 +155,5 @@ def run(args: argparse.Namespace) -> None:
 
 if __name__ == "__main__":
     args = parse_args(sys.argv[1:])
+    configure_logging(resolve_output_root(args.output_root))
     run(args)