Add some CLI functionality

ChangeLog.md

@@ -6,6 +6,12 @@
 
 - Added a system command for reversing the current sort order.
   ([#46](https://github.com/davep/peplum/pull/46))
+- Added `--theme` as a command line switch.
+  ([#48](https://github.com/davep/peplum/pull/48))
+- Added `--sort-by` as a command line switch.
+  ([#48](https://github.com/davep/peplum/pull/48))
+- Added support for taking a PEP number on the command line and jumping to
+  it on startup. ([#48](https://github.com/davep/peplum/pull/48))
 
 ## v0.4.2
 

src/peplum/__init__.py

@@ -1,4 +1,4 @@
-"""Peplum -- The PEP lookup manager for your terminal."""
+"""The PEP lookup manager for your terminal."""
 
 ##############################################################################
 # Python imports.

src/peplum/__main__.py

@@ -1,14 +1,97 @@
 """Main entry point for the application."""
 
+##############################################################################
+# Python imports.
+from argparse import ArgumentParser, Namespace
+from inspect import cleandoc
+from typing import get_args as get_literal_values
+
 ##############################################################################
 # Local imports.
+from . import __doc__, __version__
 from .app import Peplum
+from .app.data import SortOrder
+
+
+##############################################################################
+def get_args() -> Namespace:
+    """Get the command line arguments.
+
+    Returns:
+        The arguments.
+    """
+
+    # Build the parser.
+    parser = ArgumentParser(
+        prog="peplum",
+        description=__doc__,
+        epilog=f"v{__version__}",
+    )
+
+    # Add --version
+    parser.add_argument(
+        "-v",
+        "--version",
+        help="Show version information",
+        action="version",
+        version=f"%(prog)s v{__version__}",
+    )
+
+    # Add --license
+    parser.add_argument(
+        "--license",
+        "--licence",
+        help="Show license information",
+        action="store_true",
+    )
+
+    # Add --sort
+    parser.add_argument(
+        "-s",
+        "--sort-by",
+        help="Set the sort order for the PEPs; prefix with '~' for reverse order",
+        choices=(
+            *get_literal_values(SortOrder),
+            *(f"~{order}" for order in get_literal_values(SortOrder)),
+        ),
+    )
+
+    # Add --theme
+    parser.add_argument(
+        "-t",
+        "--theme",
+        help="Set the theme for the application (set to ? to list available themes)",
+    )
+
+    # The remainder is going to be the initial command.
+    parser.add_argument(
+        "pep",
+        help="A PEP to highlight",
+        nargs="?",
+    )
+
+    # Finally, parse the command line.
+    return parser.parse_args()
+
+
+##############################################################################
+def show_themes() -> None:
+    """Show the available themes."""
+    for theme in sorted(Peplum(Namespace(theme=None)).available_themes):
+        if theme != "textual-ansi":
+            print(theme)
 
 
 ##############################################################################
 def main() -> None:
     """Main entry point."""
-    Peplum().run()
+    args = get_args()
+    if args.license:
+        print(cleandoc(Peplum.HELP_LICENSE))
+    elif args.theme == "?":
+        show_themes()
+    else:
+        Peplum(args).run()
 
 
 ##############################################################################

src/peplum/app/data/__init__.py

@@ -17,6 +17,7 @@
     PEPCount,
     PEPs,
     PythonVersionCount,
+    SortOrder,
     StatusCount,
     TypeCount,
     WithAuthor,
@@ -44,6 +45,7 @@
     "PostHistory",
     "PythonVersionCount",
     "save_configuration",
+    "SortOrder",
     "StatusCount",
     "TypeCount",
     "update_configuration",

src/peplum/app/peplum.py

@@ -1,5 +1,9 @@
 """Provides the main application class."""
 
+##############################################################################
+# Python imports.
+from argparse import Namespace
+
 ##############################################################################
 # Textual imports.
 from textual.app import InvalidThemeError
@@ -48,13 +52,19 @@ class Peplum(EnhancedApp[None]):
 
     COMMANDS = set()
 
-    def __init__(self) -> None:
-        """Initialise the application."""
+    def __init__(self, arguments: Namespace) -> None:
+        """Initialise the application.
+
+        Args:
+            The command line arguments passed to the application.
+        """
+        self._arguments = arguments
+        """The command line arguments passed to the application."""
         super().__init__()
         configuration = load_configuration()
         if configuration.theme is not None:
             try:
-                self.theme = configuration.theme
+                self.theme = arguments.theme or configuration.theme
             except InvalidThemeError:
                 pass
 
@@ -63,9 +73,13 @@ def watch_theme(self) -> None:
         with update_configuration() as config:
             config.theme = self.theme
 
-    def on_mount(self) -> None:
-        """Display the main screen."""
-        self.push_screen(Main())
+    def get_default_screen(self) -> Main:
+        """Get the default screen for the application.
+
+        Returns:
+            The main screen.
+        """
+        return Main(self._arguments)
 
 
 ### peplum.py ends here

src/peplum/app/screens/main.py

@@ -2,6 +2,7 @@
 
 ##############################################################################
 # Python imports.
+from argparse import Namespace
 from dataclasses import dataclass
 from json import dumps, loads
 from webbrowser import open as visit_url
@@ -189,6 +190,18 @@ class Main(EnhancedScreen[None]):
     notes: var[Notes] = var(Notes)
     """The user's notes about PEPs."""
 
+    def __init__(self, arguments: Namespace) -> None:
+        """Initialise the main screen.
+
+        Args:
+            arguments: The arguments passed to the application on the command line.
+        """
+        self._arguments = arguments
+        """The arguments passed on the command line."""
+        super().__init__()
+        self._jump_to_on_load: str | None = self._arguments.pep
+        """A PEP to jump to once the display is loaded."""
+
     def compose(self) -> ComposeResult:
         """Compose the content of the main screen."""
         yield Header()
@@ -243,9 +256,31 @@ async def download_pep_data(self) -> None:
         self.notify("Fresh PEP data downloaded from the PEP API")
         self.load_pep_data()
 
+    @staticmethod
+    def _extract_pep(pep: str) -> int | None:
+        """Try and extract a PEP number from a string.
+
+        Args:
+            pep: A string that should contain a PEP number.
+
+        Returns:
+            A PEP number or [`None`][None] if one could not be found.
+
+        Notes:
+            The likes of `2342` and `PEP2342` are handled.
+        """
+        try:
+            return int(pep.strip().upper().removeprefix("PEP"))
+        except ValueError:
+            return None
+
     @on(Loaded)
     def load_fresh_peps(self, message: Loaded) -> None:
-        """React to a fresh set of PEPs being made available."""
+        """React to a fresh set of PEPs being made available.
+
+        Args:
+            message: The message letting us know we have fresh PEPs.
+        """
         if len(message.peps.authors) == 0:
             self.notify(
                 "You likely have a cached copy of the older version of the PEP data; a redownload is recommended.",
@@ -256,9 +291,20 @@ def load_fresh_peps(self, message: Loaded) -> None:
         self.all_peps = message.peps.sorted_by(config.peps_sort_order).reversed(
             config.peps_sort_reversed
         )
+        if self._jump_to_on_load is not None:
+            if (pep := self._extract_pep(self._jump_to_on_load)) is not None:
+                self.post_message(GotoPEP(pep))
+            self._jump_to_on_load = None
 
     def on_mount(self) -> None:
         """Configure the application once the DOM is mounted."""
+        # The caller has passed sorting preferences on the command line;
+        # let's get them into the configuration before anything else kicks
+        # off.
+        if self._arguments.sort_by is not None:
+            with update_configuration() as config:
+                config.peps_sort_reversed = self._arguments.sort_by[0] == "~"
+                config.peps_sort_order = self._arguments.sort_by.removeprefix("~")
         self.set_class(load_configuration().details_visble, "details-visible")
         # On startup, if we've got local PEP data...
         if pep_data().exists():