feat: pathfinding for ghosts, add debug rendering of paths

tests/pathfinding.rs

@@ -0,0 +1,117 @@
+use pacman::entity::direction::Direction;
+use pacman::entity::ghost::{Ghost, GhostType};
+use pacman::entity::graph::{Graph, Node};
+use pacman::texture::sprite::{AtlasMapper, MapperFrame, SpriteAtlas};
+use std::collections::HashMap;
+
+fn create_test_atlas() -> SpriteAtlas {
+    let mut frames = HashMap::new();
+    let directions = ["up", "down", "left", "right"];
+    let ghost_types = ["blinky", "pinky", "inky", "clyde"];
+
+    for ghost_type in &ghost_types {
+        for (i, dir) in directions.iter().enumerate() {
+            frames.insert(
+                format!("ghost/{}/{}_{}.png", ghost_type, dir, "a"),
+                MapperFrame {
+                    x: i as u16 * 16,
+                    y: 0,
+                    width: 16,
+                    height: 16,
+                },
+            );
+            frames.insert(
+                format!("ghost/{}/{}_{}.png", ghost_type, dir, "b"),
+                MapperFrame {
+                    x: i as u16 * 16,
+                    y: 16,
+                    width: 16,
+                    height: 16,
+                },
+            );
+        }
+    }
+
+    let mapper = AtlasMapper { frames };
+    let dummy_texture = unsafe { std::mem::zeroed() };
+    SpriteAtlas::new(dummy_texture, mapper)
+}
+
+#[test]
+fn test_ghost_pathfinding() {
+    // Create a simple test graph
+    let mut graph = Graph::new();
+
+    // Add nodes in a simple line: 0 -> 1 -> 2
+    let node0 = graph.add_node(Node {
+        position: glam::Vec2::new(0.0, 0.0),
+    });
+    let node1 = graph.add_node(Node {
+        position: glam::Vec2::new(10.0, 0.0),
+    });
+    let node2 = graph.add_node(Node {
+        position: glam::Vec2::new(20.0, 0.0),
+    });
+
+    // Connect the nodes
+    graph.connect(node0, node1, false, None, Direction::Right).unwrap();
+    graph.connect(node1, node2, false, None, Direction::Right).unwrap();
+
+    // Create a test atlas for the ghost
+    let atlas = create_test_atlas();
+
+    // Create a ghost at node 0
+    let ghost = Ghost::new(&graph, node0, GhostType::Blinky, &atlas);
+
+    // Test pathfinding from node 0 to node 2
+    let path = ghost.calculate_path_to_target(&graph, node2);
+
+    assert!(path.is_some());
+    let path = path.unwrap();
+    assert_eq!(path, vec![node0, node1, node2]);
+}
+
+#[test]
+fn test_ghost_pathfinding_no_path() {
+    // Create a test graph with disconnected components
+    let mut graph = Graph::new();
+
+    let node0 = graph.add_node(Node {
+        position: glam::Vec2::new(0.0, 0.0),
+    });
+    let node1 = graph.add_node(Node {
+        position: glam::Vec2::new(10.0, 0.0),
+    });
+
+    // Don't connect the nodes
+    let atlas = create_test_atlas();
+    let ghost = Ghost::new(&graph, node0, GhostType::Blinky, &atlas);
+
+    // Test pathfinding when no path exists
+    let path = ghost.calculate_path_to_target(&graph, node1);
+
+    assert!(path.is_none());
+}
+
+#[test]
+fn test_ghost_debug_colors() {
+    let atlas = create_test_atlas();
+    let mut graph = Graph::new();
+    let node = graph.add_node(Node {
+        position: glam::Vec2::new(0.0, 0.0),
+    });
+
+    let blinky = Ghost::new(&graph, node, GhostType::Blinky, &atlas);
+    let pinky = Ghost::new(&graph, node, GhostType::Pinky, &atlas);
+    let inky = Ghost::new(&graph, node, GhostType::Inky, &atlas);
+    let clyde = Ghost::new(&graph, node, GhostType::Clyde, &atlas);
+
+    // Test that each ghost has a different debug color
+    let colors = std::collections::HashSet::from([
+        blinky.debug_color(),
+        pinky.debug_color(),
+        inky.debug_color(),
+        clyde.debug_color(),
+    ]);
+    assert_eq!(colors.len(), 4, "All ghost colors should be unique");
+}