From a2ac1bcb39ce25b24115a5b82056c3aeb6bf895f Mon Sep 17 00:00:00 2001
From: Thomas Lindner <tom@dl6tom.de>
Date: Thu, 29 Dec 2022 18:56:01 +0100
Subject: [PATCH] implement MoveGenerator state machine

---
 src/blunderboard/__init__.py      |  2 +
 src/blunderboard/movegenerator.py | 84 +++++++++++++++++++++++++++++--
 2 files changed, 81 insertions(+), 5 deletions(-)

diff --git a/src/blunderboard/__init__.py b/src/blunderboard/__init__.py
index f847e90..91c05eb 100644
--- a/src/blunderboard/__init__.py
+++ b/src/blunderboard/__init__.py
@@ -8,6 +8,8 @@ def main():
     blunder_evaluator = BlunderEvaluator()
     move_generator = MoveGenerator(blunder_evaluator)
     reader = BoardReader(move_generator)
+    reader.scan()
+    reader.print()
     while True:
         reader.scan()
         sleep(0.1)
diff --git a/src/blunderboard/movegenerator.py b/src/blunderboard/movegenerator.py
index 3cb50c9..a37d6b4 100644
--- a/src/blunderboard/movegenerator.py
+++ b/src/blunderboard/movegenerator.py
@@ -1,18 +1,92 @@
 from blunderboard.blunderevaluator import BlunderEvaluator
 
 
-class MoveGenerator:
+def coords_to_field(row: int, column: int):
     columns = "abcdefgh"
+    return "%c%d" % (columns[column], row + 1)
 
+
+class MoveGenerator:
     def __init__(self, blunder_evaluator: BlunderEvaluator):
-        self.blunder_evaluator = blunder_evaluator
+        self.state: State = InitState(blunder_evaluator)
 
     def reset(self) -> None:
         print("reset")
-        self.blunder_evaluator.reset()
+        self.state = self.state.reset()
 
     def put(self, row: int, column: int) -> None:
-        print("put %c%d" % (self.columns[column], row + 1))
+        print("put %s" % coords_to_field(row, column))
+        self.state = self.state.put(row, column)
 
     def take(self, row: int, column: int) -> None:
-        print("take %c%d" % (self.columns[column], row + 1))
+        print("take %s" % coords_to_field(row, column))
+        self.state = self.state.take(row, column)
+
+
+class State:
+    def __init__(self, blunder_evaluator: BlunderEvaluator):
+        self.blunder_evaluator = blunder_evaluator
+
+    def reset(self) -> "State":
+        self.blunder_evaluator.reset()
+        return InitState(self.blunder_evaluator)
+
+    def put(self, row: int, column: int) -> "State":
+        print("ignored invalid put")
+        return self
+
+    def take(self, row: int, column: int) -> "State":
+        print("ignored invalid take")
+        return self
+
+
+class InitState(State):
+    def reset(self) -> State:
+        super().reset()
+        return self
+
+    def take(self, row: int, column: int) -> State:
+        return TakeState(self.blunder_evaluator, coords_to_field(row, column))
+
+
+class TakeState(State):
+    def __init__(self, blunder_evaluator: BlunderEvaluator, from_field: str):
+        super().__init__(blunder_evaluator)
+        self.from_field = from_field
+
+    def put(self, row: int, column: int) -> State:
+        to_field = coords_to_field(row, column)
+        if self.from_field == to_field:
+            print("ignored self-move")
+            return InitState(self.blunder_evaluator)
+        move = self.from_field + to_field
+        print("move %s" % move)
+        self.blunder_evaluator.move(move)
+        return InitState(self.blunder_evaluator)
+
+    def take(self, row: int, column: int) -> State:
+        return TakeTakeState(
+            self.blunder_evaluator, self.from_field, coords_to_field(row, column)
+        )
+
+
+class TakeTakeState(State):
+    def __init__(
+        self, blunder_evaluator: BlunderEvaluator, from_field: str, to_field: str
+    ):
+        super().__init__(blunder_evaluator)
+        self.from_field = from_field
+        self.to_field = to_field
+
+    def put(self, row: int, column: int) -> State:
+        field = coords_to_field(row, column)
+        if self.to_field == field:
+            move = self.from_field + field
+        elif self.from_field == field:
+            move = self.to_field + field
+        else:
+            print("ignored invalid put")
+            return self
+        print("move %s" % move)
+        self.blunder_evaluator.move(move)
+        return InitState(self.blunder_evaluator)