refactor: simplify CLI command logic by extracting helper functions (#13)

Reviewed-on: #13
Co-authored-by: Mathias <mathias2784@web.de>

src/photools3/__init__.py

@@ -1,2 +1,5 @@
-def main() -> None:
-    print("Hello from photools3!")
+from .cli import app
+
+
+def main():
+    app()

src/photools3/__main__.py

@@ -0,0 +1,4 @@
+from .cli import app
+
+if __name__ == "__main__":
+    app()

src/photools3/cli.py

@@ -0,0 +1,68 @@
+from pathlib import Path
+from typing import Annotated, Any
+
+import typer
+
+from photools3.llm_session import LlmSessionCaptionsAndKeywords
+from photools3.photo import Photo
+
+app = typer.Typer(help="PhotoTools3: A CLI for image processing.")
+
+
+@app.callback(invoke_without_command=True)
+def main(
+    ctx: typer.Context,
+    version: bool | None = typer.Option(None, "--version", is_eager=True),
+):
+    """
+    Main entry point for PhotoTools3 CLI.
+    """
+    if version:
+        typer.echo("photools3 version 0.1.0")
+        raise typer.Exit()
+
+    if ctx.invoked_subcommand is None:
+        typer.echo(ctx.get_help())
+        raise typer.Exit()
+
+
+@app.command("keywords")
+def keywords(
+    file_path: Annotated[Path, typer.Argument(..., help="Path to the image file")],
+):
+    """Extract keywords from a single image."""
+    if not file_path.exists():
+        typer.echo(f"Error: File '{file_path}' does not exist.", err=True)
+        raise typer.Exit(code=1)
+
+    try:
+        typer.echo(f"Processing: {file_path}")
+        result = _run_keywords_extraction(file_path)
+        _print_results(result)
+    except Exception as e:  # noqa: BLE001
+        typer.echo(f"Error processing image: {e}", err=True)
+        raise typer.Exit(code=1)
+
+
+def _run_keywords_extraction(file_path: Path) -> Any:
+    """Handles the core logic of loading the photo and calling the LLM."""
+    session = LlmSessionCaptionsAndKeywords()
+    photo = Photo(file_path)
+    return session.call([photo])
+
+
+def _print_results(result: Any) -> None:
+    """Formats and prints the extraction results to the console."""
+    typer.echo("\n--- Results ---")
+    if isinstance(result, dict):
+        caption = result.get("caption", "No caption found.")
+        tags = result.get("tags", [])
+        typer.echo(f"Caption: {caption}")
+        typer.echo(f"Tags: {', '.join(tags)}")
+    else:
+        typer.echo(str(result))
+    typer.echo("---------------")
+
+
+if __name__ == "__main__":
+    app()

src/photools3/llm_session.py

@@ -129,6 +129,7 @@ class LlmSessionCaptionsAndKeywords(LlmSession):
                 "  - Do not add any other text outside of this JSON format!\n"
                 "- When writing captions, ONLY describe what is visible on the photo. Do not interpret!\n"
                 "- Only use keywords from the keyword list, appended below.\n"
+                "- Answer in German.\n"
                 "\n"
                 "## Keyword list"
                 "\n"