From 7746abbbb7700fa918450101bbc6d29ed9b4b608 Mon Sep 17 00:00:00 2001
From: Andrew Godwin
Date: Wed, 9 Nov 2022 22:29:33 -0700
Subject: Most of the way through the stator refactor

---
 stator/graph.py | 47 ++++++++++++++++++++++++++++++-----------------
 1 file changed, 30 insertions(+), 17 deletions(-)

(limited to 'stator/graph.py')

diff --git a/stator/graph.py b/stator/graph.py
index b06ffb8..7fc23f7 100644
--- a/stator/graph.py
+++ b/stator/graph.py
@@ -1,9 +1,16 @@
-import datetime
-from functools import wraps
-from typing import Callable, ClassVar, Dict, List, Optional, Set, Tuple, Union
-
-from django.db import models
-from django.utils import timezone
+from typing import (
+    Any,
+    Callable,
+    ClassVar,
+    Dict,
+    List,
+    Optional,
+    Set,
+    Tuple,
+    Type,
+    Union,
+    cast,
+)
 
 
 class StateGraph:
@@ -13,7 +20,7 @@ class StateGraph:
     """
 
     states: ClassVar[Dict[str, "State"]]
-    choices: ClassVar[List[Tuple[str, str]]]
+    choices: ClassVar[List[Tuple[object, str]]]
     initial_state: ClassVar["State"]
     terminal_states: ClassVar[Set["State"]]
 
@@ -50,7 +57,7 @@ class StateGraph:
         cls.initial_state = initial_state
         cls.terminal_states = terminal_states
         # Generate choices
-        cls.choices = [(name, name) for name in cls.states.keys()]
+        cls.choices = [(state, name) for name, state in cls.states.items()]
 
 
 class State:
@@ -63,7 +70,7 @@ class State:
         self.parents: Set["State"] = set()
         self.children: Dict["State", "Transition"] = {}
 
-    def _add_to_graph(self, graph: StateGraph, name: str):
+    def _add_to_graph(self, graph: Type[StateGraph], name: str):
         self.graph = graph
         self.name = name
         self.graph.states[name] = self
@@ -71,13 +78,19 @@ class State:
     def __repr__(self):
         return f"<State {self.name}>"
 
+    def __str__(self):
+        return self.name
+
+    def __len__(self):
+        return len(self.name)
+
     def add_transition(
         self,
         other: "State",
-        handler: Optional[Union[str, Callable]] = None,
+        handler: Optional[Callable] = None,
         priority: int = 0,
     ) -> Callable:
-        def decorator(handler: Union[str, Callable]):
+        def decorator(handler: Callable[[Any], bool]):
             self.children[other] = Transition(
                 self,
                 other,
@@ -85,9 +98,7 @@ class State:
                 priority=priority,
             )
             other.parents.add(self)
-            # All handlers should be class methods, so do that automatically.
-            if callable(handler):
-                return classmethod(handler)
+            return handler
 
         # If we're not being called as a decorator, invoke it immediately
         if handler is not None:
@@ -113,7 +124,7 @@ class State:
         if automatic_only:
             transitions = [t for t in self.children.values() if t.automatic]
         else:
-            transitions = self.children.values()
+            transitions = list(self.children.values())
         return sorted(transitions, key=lambda t: t.priority, reverse=True)
 
 
@@ -141,7 +152,10 @@ class Transition:
         """
         if isinstance(self.handler, str):
             self.handler = getattr(self.from_state.graph, self.handler)
-        return self.handler
+        return cast(Callable, self.handler)
+
+    def __repr__(self):
+        return f"<Transition {self.from_state} -> {self.to_state}>"
 
 
 class ManualTransition(Transition):
@@ -157,6 +171,5 @@ class ManualTransition(Transition):
     ):
         self.from_state = from_state
         self.to_state = to_state
-        self.handler = None
         self.priority = 0
         self.automatic = False
-- 
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