From 728e36171bebb5dc81b8dc994ca95d100c0bebde Mon Sep 17 00:00:00 2001
From: Elijah Voigt <elijah.caine.mv@gmail.com>
Date: Sat, 25 Oct 2025 22:00:49 -0700
Subject: [PATCH] Adding score and next piece preview

---
 src/bin/tetris/main.rs | 195 +++++++++++++++++++++++++++++++++--------
 1 file changed, 157 insertions(+), 38 deletions(-)

diff --git a/src/bin/tetris/main.rs b/src/bin/tetris/main.rs
index 224ffb0..4713670 100644
--- a/src/bin/tetris/main.rs
+++ b/src/bin/tetris/main.rs
@@ -8,7 +8,10 @@ use itertools::Itertools;
 mod test;
 
 // TODO: Space key: skip to end
-// TODO: When line is "full" (has 10 children) clear line and add to score
+// TODO: When piece is near wall and rotates, move it over if it fits
+// TODO: Make falling based on a timer resource ticking
+//       This allows us to tune the falling rate over time
+// TODO: Preview next batch of pieces that will drop
 
 fn main() {
     App::new()
@@ -19,35 +22,54 @@ fn main() {
             ..default()
         })
         .init_state::<GameState>()
+        .init_resource::<ShapesBuffer>()
+        .init_resource::<Score>()
         .add_systems(Startup, (init_world, init_debug_ui, init_ui))
+        // Input and basic systems
+        .add_systems(
+            Update, (
+                kb_input.run_if(on_event::<KeyboardInput>),
+                toggle_state_visibility::<GameState>.run_if(state_changed::<GameState>),
+            )
+        )
         .add_systems(
             Update,
             (
-                kb_input.run_if(on_event::<KeyboardInput>),
+                update_next_shapes.run_if(resource_changed::<ShapesBuffer>.or(resource_added::<ShapesBuffer>)),
+                add_piece.run_if(not(any_with_component::<Shape>)).after(update_next_shapes),
+                update_shape_blocks
+                    .run_if(any_component_added::<Shape>.or(any_component_changed::<Shape>)),
+
                 falling
                     .run_if(in_state(GameState::Falling))
                     .run_if(clock_cycle(1.0)),
-                update_shape_blocks
-                    .run_if(any_component_added::<Shape>.or(any_component_changed::<Shape>)),
-                sync_singleton_to_ui::<Shape>.run_if(any_component_changed::<Shape>),
-                sync_singleton_to_ui::<Orientation>.run_if(any_component_changed::<Orientation>),
                 update_position.run_if(any_component_changed::<GridPosition>),
-                add_piece.run_if(not(any_with_component::<Shape>)),
+
+                deactivate_shape.run_if(any_component_removed::<Shape>),
+
+                // Clearing lines systems
                 clear_line.run_if(any_component_changed::<LineBlocks>),
-                adjust_block_lines.run_if(any_component_changed::<Line>),
-                toggle_state_visibility::<GameState>.run_if(state_changed::<GameState>),
+                adjust_block_lines.run_if(any_component_changed::<Line>).after(clear_line),
             ),
         )
+        // UI systems
+        .add_systems(Update,
+            (
+                sync_resource_to_ui::<ShapesBuffer>.run_if(resource_changed::<ShapesBuffer>),
+                sync_resource_to_ui::<Score>.run_if(resource_changed::<Score>),
+                sync_singleton_to_ui::<Shape>.run_if(any_component_changed::<Shape>),
+                sync_singleton_to_ui::<Orientation>.run_if(any_component_changed::<Orientation>),
+            )
+        )
         .add_systems(Update, draw_grid)
-        .add_observer(deactive_shape)
         .run();
 }
 
 const SCALE: f32 = 30.0;
 
 // Declare the size of the play area
-const X_MAX: u32 = 10;
-const Y_MAX: u32 = 20;
+const X_MAX: usize = 10;
+const Y_MAX: usize = 20;
 
 // The blocks making up this shape
 #[derive(Component)]
@@ -87,8 +109,8 @@ struct Block;
 #[derive(Component, Debug, Clone, Copy, PartialEq)]
 #[require(Transform, Visibility)]
 struct GridPosition {
-    x: u32,
-    y: u32,
+    x: usize,
+    y: usize,
 }
 
 impl GridPosition {
@@ -104,8 +126,8 @@ impl GridPosition {
             Err(GameError::OutOfBoundsDown)
         } else {
             Ok(GridPosition {
-                x: x as u32,
-                y: y as u32,
+                x: x as usize,
+                y: y as usize,
             })
         }
     }
@@ -149,8 +171,8 @@ impl From<&GridPosition> for Vec3 {
     }
 }
 
-impl From<(u32, u32)> for GridPosition {
-    fn from((x, y): (u32, u32)) -> GridPosition {
+impl From<(usize, usize)> for GridPosition {
+    fn from((x, y): (usize, usize)) -> GridPosition {
         GridPosition { x, y }
     }
 }
@@ -225,6 +247,32 @@ struct Visuals {
     mesh: Handle<Mesh>,
 }
 
+#[derive(Resource, Debug, Default)]
+struct Score(usize);
+
+impl Display for Score {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}
+
+/// ShapesBuffer resource stores non-active shapes
+#[derive(Resource, Debug, Default)]
+struct ShapesBuffer {
+    /// Next stores a vector of 2N shapes that will come up in play
+    next: VecDeque<Shape>,
+}
+
+impl Display for ShapesBuffer {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        if let Some(shape) = self.next.front() {
+            write!(f, "{shape}")
+        } else {
+            write!(f, "ERR")
+        }
+    }
+}
+
 fn init_world(
     mut commands: Commands,
     mut meshes: ResMut<Assets<Mesh>>,
@@ -238,12 +286,52 @@ fn init_world(
         mesh: meshes.add(Rectangle::new(SCALE, SCALE)),
     });
 
-    (0..20).for_each(|i| {
+    (0..Y_MAX).for_each(|i| {
+        info!("Spawning line {i}");
         commands.spawn((Line(i), LineBlocks::default()));
     });
 }
 
 fn init_ui(mut commands: Commands) {
+    commands
+        .spawn((
+            Node {
+                align_self: AlignSelf::Center,
+                justify_self: JustifySelf::End,
+                flex_direction: FlexDirection::Column,
+                ..default()
+            },
+            BackgroundColor(BLACK.into()),
+        ))
+        .with_children(|parent| {
+            parent.spawn((
+                Node {
+                    flex_direction: FlexDirection::Column,
+                    align_items: AlignItems::Center,
+                    ..default()
+                },
+            )).with_children(|parent|{
+                parent.spawn(Text::new("Next:"));
+                parent.spawn((
+                    Text::new("???"),
+                    SyncResource::<ShapesBuffer>::default(),
+                ));
+            });
+            parent.spawn((
+                Node {
+                    flex_direction: FlexDirection::Column,
+                    align_items: AlignItems::Center,
+                    ..default()
+                },
+            )).with_children(|parent|{
+                parent.spawn(Text::new("Score:"));
+                parent.spawn((
+                    Text::new("???"),
+                    SyncResource::<Score>::default(),
+                ));
+            });
+        });
+
     commands
         .spawn((
             Node {
@@ -549,7 +637,7 @@ fn draw_grid(mut gizmos: Gizmos) {
     gizmos
         .grid_2d(
             Isometry2d::IDENTITY,
-            UVec2::new(X_MAX, Y_MAX),
+            UVec2::new(X_MAX as u32, Y_MAX as u32),
             Vec2::new(SCALE, SCALE),
             GREEN,
         )
@@ -577,13 +665,12 @@ fn clock_cycle(n: f32) -> impl FnMut(Res<Time>, Local<f32>) -> bool {
     }
 }
 
-fn add_piece(mut commands: Commands) {
-    // TODO: Choose a different piece
+fn add_piece(mut commands: Commands, mut shapes: ResMut<ShapesBuffer>) {
     commands
         .spawn((
             Orientation::default(),
             GridPosition::default(),
-            Shape::default(),
+            shapes.next.pop_front().unwrap(),
         ))
         .observe(movement);
 }
@@ -592,6 +679,7 @@ fn add_piece(mut commands: Commands) {
 fn clear_line(
     changed_lines: Query<Entity, Changed<LineBlocks>>,
     mut lines: Query<(Entity, &LineBlocks, &mut Line)>,
+    mut score: ResMut<Score>,
     mut commands: Commands,
 ) {
     let cleared_lines: Vec<usize> = changed_lines
@@ -600,6 +688,8 @@ fn clear_line(
         .filter_map(|(e, lb, Line(i))| {
             if lb.0.len() == 10 {
                 commands.entity(e).despawn_related::<LineBlocks>();
+                score.0 += 1;
+                info!("New score: {:?}", score.0);
                 Some(*i)
             } else {
                 None
@@ -612,11 +702,11 @@ fn clear_line(
     for (idx, cleared_line_number) in cleared_lines.into_iter().sorted().enumerate() {
         info!("Processing line {cleared_line_number} ({idx})");
         let cleared_line_number = cleared_line_number - idx;
-        lines.iter_mut().for_each(|(_, _, mut l)| {
+        lines.iter_mut().sorted_by(|(_, _, i), (_, _, j)| i.0.cmp(&j.0)).for_each(|(_, _, mut l)| {
             let dest = if l.0 > cleared_line_number {
                 l.0 - 1
             } else if l.0 == cleared_line_number {
-                (Y_MAX - (idx + 1) as u32) as usize
+                Y_MAX - 1
             } else {
                 l.0
             };
@@ -631,10 +721,21 @@ fn adjust_block_lines(
     parent: Query<&LineBlocks>,
     mut blocks: Query<&mut GridPosition>,
 ) {
+    #[cfg(debug_assertions)]
+    {
+        // Check that all line numbers are present
+        let expected_line_numbers  = 0..Y_MAX;
+        let actual_line_numbers = query.iter().map(|(_, Line(i))| i).sorted();
+        query.iter().map(|(_, Line(i))| i).sorted().for_each(|i| info!("Line #: {i}"));
+        std::iter::zip(expected_line_numbers, actual_line_numbers).for_each(|(a, b)| {
+            debug_assert_eq!(a as usize, *b);
+        });
+    }
+
     query.iter().for_each(|(e, Line(i))| {
         parent.iter_descendants(e).for_each(|block| {
             if let Ok(mut gp) = blocks.get_mut(block) {
-                gp.y = *i as u32;
+                gp.y = *i;
             }
         });
     });
@@ -719,23 +820,41 @@ fn movement(
 }
 
 // TODO: Just despawn?
-fn deactive_shape(
-    trigger: Trigger<OnRemove, Shape>,
+fn deactivate_shape(
+    mut events: RemovedComponents<Shape>,
     grid_positions: Query<&GridPosition>,
     parent: Query<&ShapeBlocks>,
     lines: Query<(Entity, &Line), With<LineBlocks>>,
     mut commands: Commands,
 ) {
-    parent.iter_descendants(trigger.target()).for_each(|block| {
-        let GridPosition { y, .. } = grid_positions.get(block).unwrap();
-        let parent_line = lines
-            .iter()
-            .find_map(|(e, Line(i))| (*y == *i as u32).then_some(e))
-            .unwrap();
-        commands
-            .entity(parent_line)
-            .add_one_related::<LineBlock>(block);
+    events.read().for_each(|target| {
+        parent.iter_descendants(target).for_each(|block| {
+            let GridPosition { y, .. } = grid_positions.get(block).unwrap();
+            let parent_line = lines
+                .iter()
+                .find_map(|(e, Line(i))| (*y == *i).then_some(e))
+                .unwrap(); // TODO: This crashed once kinda late in a game... why?
+            commands
+                .entity(parent_line)
+                .add_one_related::<LineBlock>(block);
+        });
+        commands.entity(target).despawn();
     });
-    commands.entity(trigger.target()).despawn();
 }
 
+fn update_next_shapes(mut buffer: ResMut<ShapesBuffer>) {
+    // If the buffer contains less than n+1 shapes (where n is the number of possible shapes)
+    // Ideally we have between 1n and 2n shapes in the `next` buffer
+    while buffer.next.len() < 8 {
+        // TODO: Shuffle these!
+        buffer.next.extend([
+            Shape::new_o(),
+            Shape::new_t(),
+            Shape::new_l(),
+            Shape::new_j(),
+            Shape::new_s(),
+            Shape::new_z(),
+            Shape::new_i(),
+        ]);
+    }
+}