Change CLI tool argument parsing to click

The click library allows for more complex interactions with the CLI tool
for upcoming changes that add support for interacting with the actual
trading API.

In future the listing of day ahead prices from the entsoe API might be
moved into a separate CLI tool.

Signed-off-by: cwasicki <[email protected]>

Author: cwasicki

src/frequenz/client/electricity_trading/cli/__main__.py

@@ -3,41 +3,49 @@
 
 """CLI tool to interact with the trading API."""
 
-import argparse
 from datetime import datetime, timedelta
 from zoneinfo import ZoneInfo
 
+import click
+
 from frequenz.client.electricity_trading.cli.day_ahead import list_day_ahead_prices
 
+TZ = ZoneInfo("Europe/Berlin")
 
-def main() -> None:
-    """Run main entry point for the CLI tool."""
-    tz = ZoneInfo("Europe/Berlin")
-    midnight = datetime.combine(datetime.now(tz), datetime.min.time(), tzinfo=tz)
-    parser = argparse.ArgumentParser()
-    parser.add_argument("--entsoe_key", type=str, required=True)
-    parser.add_argument(
-        "--start",
-        type=datetime.fromisoformat,
-        required=False,
-        default=midnight,
-    )
-    parser.add_argument(
-        "--end",
-        type=datetime.fromisoformat,
-        required=False,
-        default=midnight + timedelta(days=2),
-    )
-    parser.add_argument("--country_code", type=str, required=False, default="DE_LU")
-    args = parser.parse_args()
+iso = datetime.fromisoformat
+
+
+def midnight(days: int = 0) -> str:
+    """Return today's midnight."""
+    return (
+        datetime.combine(datetime.now(TZ), datetime.min.time(), tzinfo=TZ)
+        + timedelta(days)
+    ).isoformat()
 
+
+@click.group()
+def cli() -> None:
+    """CLI tool to interact with the trading API."""
+
+
+@cli.command()
+@click.option("--entsoe-key", required=True, type=str)
+@click.option("--start", default=midnight(), type=iso)
+@click.option("--end", default=midnight(days=2), type=iso)
+@click.option("--country-code", type=str, default="DE_LU")
+def list_day_ahead(
+    entsoe_key: str, *, start: datetime, end: datetime, country_code: str
+) -> None:
+    """List day-ahead prices."""
     list_day_ahead_prices(
-        entsoe_key=args.entsoe_key,
-        start=args.start,
-        end=args.end,
-        country_code=args.country_code,
+        entsoe_key=entsoe_key, start=start, end=end, country_code=country_code
     )
 
 
+def main() -> None:
+    """Run the main Click CLI."""
+    cli()
+
+
 if __name__ == "__main__":
     main()