Implement signature processing into argparser

Create Invoke method which parses a list of args and invokes the function

morpheus/exts/command.py

@@ -0,0 +1,81 @@
+import inspect
+from argparse import ArgumentParser
+from typing import Optional
+
+
+class Command:
+    def __init__(self, function: callable, extension: str = None):
+        if not callable(function):
+            raise RuntimeError('The function to make a command from must be a callable')
+
+        # if not inspect.isawaitable(function):
+        #     raise RuntimeError('The function to make a command from must be a coroutine')
+
+        self.extension = extension
+        self.signature = inspect.signature(function)
+        self.parser: ArgumentParser = self.process_parameters(self.signature.parameters)
+        self.function: callable = function
+
+    def process_parameters(self, params: dict) -> ArgumentParser:
+        iterator = iter(params.items())
+
+        if self.extension:
+            try:
+                next(iterator)
+            except StopIteration:
+                raise RuntimeError('self is missing from signature')
+
+        try:
+            next(iterator)  # the next param should be ctx
+        except StopIteration:
+            raise RuntimeError('ctx is missing from signature')
+
+        parser = ArgumentParser()
+        for name, param in iterator:
+            param: inspect.Parameter
+            if param.kind == param.VAR_POSITIONAL:
+                nargs = '+'
+            else:
+                nargs = 1
+
+            if param.annotation == param.empty:
+                param_type = str
+            else:
+                param_type = param.annotation
+
+            if param.kind == param.KEYWORD_ONLY:
+                name = '--' + name
+
+            if param.default == param.empty:
+                parser.add_argument(name, nargs=nargs, type=param_type)
+            else:
+                parser.add_argument(name, nargs=nargs, type=param_type, default=param.default)
+
+        return parser
+
+    def invoke(self, ctx, args_list):
+        iterator = iter(self.signature.parameters.items())
+
+        if self.extension:
+            try:
+                next(iterator)
+            except StopIteration:
+                raise RuntimeError('self is missing from signature')
+
+        try:
+            next(iterator)  # the next param should be ctx
+        except StopIteration:
+            raise RuntimeError('ctx is missing from signature')
+
+        args = []
+        kwargs = {}
+        params = self.parser.parse_args(args_list)
+
+        for key, value in iterator:
+            value: inspect.Parameter
+            if value.kind == value.VAR_POSITIONAL or value.kind == value.POSITIONAL_OR_KEYWORD:
+                args.extend(params.__dict__[key])
+            else:
+                kwargs[key] = params.__dict__[key]
+
+        self.function(ctx, *args, **kwargs)