Support writing to pyproject.toml

Many Python projects support a pyproject.toml file, so its
important to support it as a special output file.

If pyproject.toml is passed, precli-init will update the file
with a tool.precli section and its configuration options.

This change also prompts to overwrite existing files. In addition
the enabled vs. disabled rules is now part of a list rather than
option on each rule section. This makes it easier to customize
since most users would prefer to maintain a list rather than
updating each section.

Signed-off-by: Eric Brown <[email protected]>

precli/cli/init.py

@@ -1,9 +1,14 @@
 # Copyright 2024 Secure Sauce LLC
 # SPDX-License-Identifier: BUSL-1.1
 import argparse
+import pathlib
 import sys
 from argparse import Namespace
 
+if sys.version_info >= (3, 11):
+    import tomllib
+else:
+    import tomli as tomllib
 import tomli_w
 
 from precli.core import loader
@@ -24,26 +29,32 @@ def setup_arg_parser() -> Namespace:
         help="output the config to given file",
     )
 
-    args = parser.parse_args()
-
-    return args
+    return parser.parse_args()
 
 
 def get_config() -> dict:
     parsers = loader.load_extension(group="precli.parsers")
     rules = [r for p in parsers.values() for r in p.rules.values()]
 
     config = {"rule": {}}
+    enabled = []
+    disabled = []
 
     for rule in rules:
         config["rule"][rule.id] = {
-            "enabled": rule.config.enabled,
             "level": rule.config.level,
         }
+        if rule.config.enabled:
+            enabled.append(rule.id)
+        else:
+            disabled.append(rule.id)
         if rule.config.parameters:
             for parameter, value in rule.config.parameters.items():
                 config["rule"][rule.id][parameter] = value
 
+    config["enabled"] = enabled
+    config["disabled"] = disabled
+
     return config
 
 
@@ -56,9 +67,34 @@ def main():
 
     # Write to the given file
     try:
-        # TODO: check if file already exists and prompt to overwrite
-        with open(args.output, "wb") as f:
-            tomli_w.dump(config, f)
+        path = pathlib.Path(args.output)
+
+        # Check if the file already exists and prompt for overwrite
+        if path.exists():
+            overwrite = input(
+                f"The file '{args.output}' already exists. Overwrite? (y/N): "
+            )
+            if overwrite.lower() != "y":
+                print("Operation cancelled.")
+                return 1
+
+        # Check if the target file is pyproject.toml and prepare the structure
+        if path.name == "pyproject.toml":
+            if path.exists():
+                with open(path, "rb") as f:
+                    doc = tomllib.load(f)
+                doc.setdefault("tool", {}).setdefault("precli", {}).update(
+                    config
+                )
+            else:
+                doc = {"tool": {"precli": config}}
+        else:
+            doc = config
+
+        # Write the configuration to the specified file
+        with open(path, "wb") as f:
+            tomli_w.dump(doc, f)
+
     except OSError:
         print(f"Error writing to file: {args.output}")
         return 1