added better builder for executor

src/executor/builder.rs

@@ -0,0 +1,57 @@
+use std::time::Duration;
+
+use crate::{labyrinth::generator::MazeGenerator, Maze};
+
+pub trait MazeState {}
+pub trait BuildableMazeState: MazeState {
+    fn get(self) -> Maze;
+}
+
+pub struct Unprovided;
+
+impl MazeState for Unprovided {}
+
+struct Provided {
+    maze: Maze,
+}
+
+impl MazeState for Provided {}
+impl BuildableMazeState for Provided {
+    fn get(self) -> Maze {
+        self.maze
+    }
+}
+
+struct Generated {
+    generator: Box<dyn MazeGenerator>,
+}
+
+impl MazeState for Generated {}
+impl BuildableMazeState for Generated {
+    fn get(mut self) -> Maze {
+        self.generator.generate()
+    }
+}
+
+pub struct ExecutorBuilder<MS>
+where
+    MS: MazeState,
+{
+    maze_state: MS,
+    delay: Duration,
+}
+
+pub fn new_builder() -> ExecutorBuilder<Unprovided> {
+    ExecutorBuilder {
+        maze_state: Unprovided,
+        delay: Duration::from_millis(100),
+    }
+}
+
+impl<MS: BuildableMazeState> ExecutorBuilder<MS> {
+    pub fn build(self) -> (Maze, Duration) {
+        let maze = self.maze_state.get();
+        let delay = self.delay;
+        (maze, delay)
+    }
+}