Rework input buffer to match HDR closer (#79)

## Summary

- Preserve distinct same-action bindings in rollback input frames.
- Add independent command lifetimes with tap and state-scoped hold buffering.
- Detect second shield bindings and consume shield commands for air dodge.
- Fix duplicate keyboard mappings being overwritten.

Reviewed-on: #79
Co-authored-by: Álex Román Núñez <eirexe@eirteam.moe>

src/input/buffer.rs

@@ -1,8 +1,4 @@
-//! Per-fighter input state: the current and previous frame, plus the buffered
-//! commands (smash inputs and friends) that states query when deciding whether
-//! to interrupt.
-
-use std::ops::{Index, IndexMut};
+//! Rollback-safe input history and command buffering.
 
 use bevy::prelude::*;
 use bevy_ggrs::{PlayerInputs, Rollback};
@@ -12,14 +8,15 @@ use strum_macros::EnumIter;
 use crate::fighter::FighterFacingDirection;
 use crate::fighter::attack::AttackKind;
 use crate::game_settings::GameSettings;
-use crate::input::FighterInputFrame;
+use crate::input::{DigitalAction, FighterInputFrame};
 use crate::netcode::GGRSCfg;
 use crate::player::Player;
 
-#[derive(Clone, Copy, EnumIter, Debug)]
+#[derive(Clone, Copy, EnumIter, Debug, PartialEq, Eq, Hash)]
 pub enum FighterCommands {
     Jump,
     Shield,
+    GuardHold,
     Attack,
     SmashMoveUp,
     SmashMoveDown,
@@ -27,7 +24,31 @@ pub enum FighterCommands {
     SmashMoveRight,
 }
 
-#[derive(Default, Clone, Hash, Copy)]
+pub(crate) fn second_binding_pressed(
+    current: crate::input::ActionBindingMask,
+    previous: crate::input::ActionBindingMask,
+) -> bool {
+    current.count() >= 2 && current.pressed_since(previous).0 != 0
+}
+
+impl FighterCommands {
+    pub const COUNT: usize = 8;
+
+    pub const fn index(self) -> usize {
+        match self {
+            Self::Jump => 0,
+            Self::Shield => 1,
+            Self::GuardHold => 2,
+            Self::Attack => 3,
+            Self::SmashMoveUp => 4,
+            Self::SmashMoveDown => 5,
+            Self::SmashMoveLeft => 6,
+            Self::SmashMoveRight => 7,
+        }
+    }
+}
+
+#[derive(Default, Clone, Hash, Copy, Debug)]
 pub enum FighterAttackCommandType {
     #[default]
     Neutral,
@@ -44,86 +65,140 @@ pub enum FighterAttackCommandType {
 impl FighterAttackCommandType {
     pub fn to_attack_kind_grounded(&self) -> AttackKind {
         match self {
-            FighterAttackCommandType::Neutral => AttackKind::Jab,
-            FighterAttackCommandType::SmashAttackUp => AttackKind::UpSmash,
-            FighterAttackCommandType::SmashAttackDown => AttackKind::DownSmash,
-            FighterAttackCommandType::SmashAttackLeft => AttackKind::ForwardSmash,
-            FighterAttackCommandType::SmashAttackRight => AttackKind::ForwardSmash,
-            FighterAttackCommandType::TiltAttackUp => AttackKind::UpTilt,
-            FighterAttackCommandType::TiltAttackDown => AttackKind::DownTilt,
-            FighterAttackCommandType::TiltAttackLeft => AttackKind::ForwardTilt,
-            FighterAttackCommandType::TiltAttackRight => AttackKind::ForwardTilt,
+            Self::Neutral => AttackKind::Jab,
+            Self::SmashAttackUp => AttackKind::UpSmash,
+            Self::SmashAttackDown => AttackKind::DownSmash,
+            Self::SmashAttackLeft | Self::SmashAttackRight => AttackKind::ForwardSmash,
+            Self::TiltAttackUp => AttackKind::UpTilt,
+            Self::TiltAttackDown => AttackKind::DownTilt,
+            Self::TiltAttackLeft | Self::TiltAttackRight => AttackKind::ForwardTilt,
         }
     }
+
     pub fn to_attack_kind_airborne(&self, facing_direction: &FighterFacingDirection) -> AttackKind {
         match self {
-            FighterAttackCommandType::Neutral => AttackKind::NeutralAir,
-            FighterAttackCommandType::SmashAttackUp | FighterAttackCommandType::TiltAttackUp => AttackKind::UpAir,
-            FighterAttackCommandType::SmashAttackDown | FighterAttackCommandType::TiltAttackDown => AttackKind::DownAir,
-            
-            FighterAttackCommandType::SmashAttackLeft | FighterAttackCommandType::TiltAttackLeft => {
-                match facing_direction {
-                    FighterFacingDirection::Left => AttackKind::ForwardAir,
-                    FighterFacingDirection::Right => AttackKind::BackAir,
-                }
+            Self::Neutral => AttackKind::NeutralAir,
+            Self::SmashAttackUp | Self::TiltAttackUp => AttackKind::UpAir,
+            Self::SmashAttackDown | Self::TiltAttackDown => AttackKind::DownAir,
+            Self::SmashAttackLeft | Self::TiltAttackLeft => match facing_direction {
+                FighterFacingDirection::Left => AttackKind::ForwardAir,
+                FighterFacingDirection::Right => AttackKind::BackAir,
             },
-            FighterAttackCommandType::SmashAttackRight | FighterAttackCommandType::TiltAttackRight => {
-                match facing_direction {
-                    FighterFacingDirection::Left => AttackKind::BackAir,
-                    FighterFacingDirection::Right => AttackKind::ForwardAir,
-                }
+            Self::SmashAttackRight | Self::TiltAttackRight => match facing_direction {
+                FighterFacingDirection::Left => AttackKind::BackAir,
+                FighterFacingDirection::Right => AttackKind::ForwardAir,
             },
         }
     }
 }
 
-/// Frames of life remaining for each buffered command. Indexed by
-/// [`FighterCommands`] so adding a command is a two-line change here.
-#[derive(Default, Clone, Copy, Hash)]
-pub struct FighterCommandLifetimes {
-    smash_move_left: u8,
-    smash_move_right: u8,
-    smash_move_down: u8,
-    smash_move_up: u8,
-    jump: u8,
-    shield: u8,
-    attack: u8,
+#[derive(Clone, Copy, Debug, Hash)]
+struct CommandSlot {
+    lifetime: u8,
+    age: u16,
+    hold_remaining: HoldLimit,
+    consumed: bool,
 }
 
-impl Index<FighterCommands> for FighterCommandLifetimes {
-    type Output = u8;
-
-    fn index(&self, command: FighterCommands) -> &Self::Output {
-        match command {
-            FighterCommands::SmashMoveLeft => &self.smash_move_left,
-            FighterCommands::SmashMoveRight => &self.smash_move_right,
-            FighterCommands::SmashMoveDown => &self.smash_move_down,
-            FighterCommands::SmashMoveUp => &self.smash_move_up,
-            FighterCommands::Jump => &self.jump,
-            FighterCommands::Shield => &self.shield,
-            FighterCommands::Attack => &self.attack,
+impl Default for CommandSlot {
+    fn default() -> Self {
+        Self {
+            lifetime: 0,
+            age: 0,
+            hold_remaining: HoldLimit::Disabled,
+            consumed: false,
         }
     }
 }
 
-impl IndexMut<FighterCommands> for FighterCommandLifetimes {
-    fn index_mut(&mut self, command: FighterCommands) -> &mut Self::Output {
-        match command {
-            FighterCommands::SmashMoveLeft => &mut self.smash_move_left,
-            FighterCommands::SmashMoveRight => &mut self.smash_move_right,
-            FighterCommands::SmashMoveDown => &mut self.smash_move_down,
-            FighterCommands::SmashMoveUp => &mut self.smash_move_up,
-            FighterCommands::Jump => &mut self.jump,
-            FighterCommands::Shield => &mut self.shield,
-            FighterCommands::Attack => &mut self.attack,
+#[derive(Clone, Copy, Debug, Default, Hash, PartialEq, Eq)]
+enum HoldLimit {
+    #[default]
+    Disabled,
+    Frames(u16),
+    Infinite,
+}
+
+#[derive(Clone, Copy, Debug, Default, Hash, PartialEq, Eq)]
+enum HoldOverride {
+    #[default]
+    Inherit,
+    Disabled,
+    Frames(u16),
+    Infinite,
+}
+
+impl HoldOverride {
+    fn from_max_frames(max_frames: u16) -> Self {
+        if max_frames == 0 {
+            Self::Infinite
+        } else {
+            Self::Frames(max_frames)
         }
     }
 }
 
-#[derive(Component, Default, Clone, Copy, Hash)]
+impl HoldLimit {
+    fn from_max_frames(max_frames: u16) -> Self {
+        if max_frames == 0 {
+            Self::Infinite
+        } else {
+            Self::Frames(max_frames)
+        }
+    }
+}
+
+#[derive(Clone, Copy, Debug, Hash)]
+struct ButtonHistory {
+    trigger_age: u16,
+    release_age: u16,
+    held_frames: u16,
+    secondary_trigger_age: u16,
+}
+
+impl Default for ButtonHistory {
+    fn default() -> Self {
+        Self {
+            trigger_age: u16::MAX,
+            release_age: u16::MAX,
+            held_frames: 0,
+            secondary_trigger_age: u16::MAX,
+        }
+    }
+}
+
+impl ButtonHistory {
+    fn update(&mut self, current: u16, previous: u16) {
+        let pressed = current & !previous;
+        let released = previous & !current;
+        self.trigger_age = self.trigger_age.saturating_add(1);
+        self.release_age = self.release_age.saturating_add(1);
+        self.secondary_trigger_age = self.secondary_trigger_age.saturating_add(1);
+        if pressed != 0 {
+            self.trigger_age = 0;
+        }
+        if released != 0 {
+            self.release_age = 0;
+        }
+        if current != 0 {
+            self.held_frames = self.held_frames.saturating_add(1);
+        } else {
+            self.held_frames = 0;
+        }
+        if current.count_ones() >= 2 && (pressed != 0 || previous.count_ones() < 2) {
+            self.secondary_trigger_age = 0;
+        }
+    }
+}
+
+/// Per-fighter input state. Every field is deterministic rollback state.
+#[derive(Component, Clone, Copy, Hash)]
 #[require(Rollback)]
 pub struct FighterInput {
-    command_lifetimes: FighterCommandLifetimes,
+    command_slots: [CommandSlot; FighterCommands::COUNT],
+    hold_limits: [HoldOverride; FighterCommands::COUNT],
+    hold_all: HoldLimit,
+    button_history: [ButtonHistory; 3],
     prev_frame: FighterInputFrame,
     current_frame: FighterInputFrame,
     frames_in_x_flick_deadzone: u8,
@@ -131,6 +206,22 @@ pub struct FighterInput {
     attack_command: FighterAttackCommandType,
 }
 
+impl Default for FighterInput {
+    fn default() -> Self {
+        Self {
+            command_slots: [CommandSlot::default(); FighterCommands::COUNT],
+            hold_limits: [HoldOverride::default(); FighterCommands::COUNT],
+            hold_all: HoldLimit::default(),
+            button_history: [ButtonHistory::default(); 3],
+            prev_frame: FighterInputFrame::default(),
+            current_frame: FighterInputFrame::default(),
+            frames_in_x_flick_deadzone: 0xFE,
+            frames_in_y_flick_deadzone: 0xFE,
+            attack_command: FighterAttackCommandType::Neutral,
+        }
+    }
+}
+
 impl FighterInput {
     pub fn get_last_frame(&self) -> FighterInputFrame {
         self.current_frame
@@ -142,40 +233,188 @@ impl FighterInput {
     }
 
     pub fn clear_buffer(&mut self) {
-        self.command_lifetimes = FighterCommandLifetimes::default()
+        self.command_slots = [CommandSlot::default(); FighterCommands::COUNT];
     }
 
     pub fn clear_command(&mut self, command: FighterCommands) {
-        self.command_lifetimes[command] = 0;
+        let slot = &mut self.command_slots[command.index()];
+        slot.lifetime = 0;
+        slot.hold_remaining = HoldLimit::Disabled;
+        slot.consumed = true;
+    }
+
+    pub fn consume_command(&mut self, command: FighterCommands) -> bool {
+        if self.has_command(command) {
+            self.clear_command(command);
+            true
+        } else {
+            false
+        }
     }
 
     pub fn set_lifetime(&mut self, command: FighterCommands, lifetime: u8) {
-        self.command_lifetimes[command] = lifetime;
+        let slot = &mut self.command_slots[command.index()];
+        slot.lifetime = lifetime;
+        slot.age = 0;
+        slot.hold_remaining = HoldLimit::Disabled;
+        slot.consumed = false;
+        self.latch_if_hold_enabled(command);
     }
 
     pub fn has_command(&self, command: FighterCommands) -> bool {
-        self.command_lifetimes[command] > 0
+        self.command_slots[command.index()].lifetime > 0
     }
 
     pub fn reduce_command_lifetime(&mut self, command: FighterCommands) {
-        self.command_lifetimes[command] = self.command_lifetimes[command].saturating_sub(1);
+        self.command_slots[command.index()].lifetime = self.command_slots[command.index()]
+            .lifetime
+            .saturating_sub(1);
+    }
+
+    /// Holds all inputs for n frames
+    pub fn enable_hold_all(&mut self, max_frames: u16) {
+        self.hold_all = HoldLimit::from_max_frames(max_frames);
+        self.latch_active_commands();
+    }
+
+    pub fn disable_hold_all(&mut self) {
+        self.hold_all = HoldLimit::Disabled;
+    }
+
+    /// Stops global enrollment and immediately cancels every latched command.
+    pub fn cancel_hold_all(&mut self) {
+        self.disable_hold_all();
+        for slot in &mut self.command_slots {
+            slot.hold_remaining = HoldLimit::Disabled;
+        }
+    }
+
+    pub fn enable_hold(&mut self, command: FighterCommands, max_frames: u16) {
+        self.hold_limits[command.index()] = HoldOverride::from_max_frames(max_frames);
+        if self.has_command(command) {
+            self.latch_if_hold_enabled(command);
+        }
+    }
+
+    /// Explicitly prevents this command from using either command-specific or
+    /// global hold buffering, while preserving an existing latch.
+    pub fn disable_hold(&mut self, command: FighterCommands) {
+        self.hold_limits[command.index()] = HoldOverride::Disabled;
+    }
+
+    /// Removes the command-specific policy so this command inherits the
+    /// global policy again.
+    pub fn reset_hold_override(&mut self, command: FighterCommands) {
+        self.hold_limits[command.index()] = HoldOverride::Inherit;
+    }
+
+    /// Stops enrollment and immediately cancels this command's hold lifetime.
+    pub fn cancel_hold(&mut self, command: FighterCommands) {
+        self.disable_hold(command);
+        self.command_slots[command.index()].hold_remaining = HoldLimit::Disabled;
+    }
+
+    fn latch_if_hold_enabled(&mut self, command: FighterCommands) {
+        let limit = self.hold_limit(command);
+        let slot = &mut self.command_slots[command.index()];
+        slot.hold_remaining = match limit {
+            HoldLimit::Disabled => return,
+            HoldLimit::Infinite => HoldLimit::Infinite,
+            // The limit includes tap-buffer frames already elapsed.
+            HoldLimit::Frames(max_frames) => {
+                let remaining = max_frames.saturating_sub(slot.age);
+                if remaining == 0 {
+                    return;
+                }
+                HoldLimit::Frames(remaining)
+            }
+        };
+    }
+
+    fn latch_active_commands(&mut self) {
+        for command in FighterCommands::iter() {
+            if self.has_command(command) {
+                self.latch_if_hold_enabled(command);
+            }
+        }
+    }
+
+    pub fn is_pressed(&self, action: DigitalAction) -> bool {
+        self.current_frame
+            .bindings_for(action)
+            .pressed_since(self.prev_frame.bindings_for(action))
+            .0
+            != 0
+    }
+
+    pub fn is_released(&self, action: DigitalAction) -> bool {
+        self.current_frame
+            .bindings_for(action)
+            .released_since(self.prev_frame.bindings_for(action))
+            .0
+            != 0
+    }
+
+    pub fn pressed_bindings(&self, action: DigitalAction) -> u16 {
+        self.current_frame
+            .bindings_for(action)
+            .pressed_since(self.prev_frame.bindings_for(action))
+            .0
+    }
+
+    pub fn binding_count(&self, action: DigitalAction) -> u32 {
+        self.current_frame.bindings_for(action).count()
     }
 
     pub fn get_frames_in_smash_move_deadzone(&self) -> u8 {
         self.frames_in_x_flick_deadzone
     }
-
     pub fn set_attack_command_type(&mut self, command: FighterAttackCommandType) {
         self.attack_command = command;
     }
-
     pub fn get_attack_command_type(&self) -> FighterAttackCommandType {
         self.attack_command
     }
+
+    fn hold_limit(&self, command: FighterCommands) -> HoldLimit {
+        let specific = self.hold_limits[command.index()];
+        match specific {
+            HoldOverride::Inherit => self.hold_all,
+            HoldOverride::Disabled => HoldLimit::Disabled,
+            HoldOverride::Frames(frames) => HoldLimit::Frames(frames),
+            HoldOverride::Infinite => HoldLimit::Infinite,
+        }
+    }
+
+    fn update_hold(&mut self, command: FighterCommands) {
+        let index = command.index();
+        let slot = &mut self.command_slots[index];
+        slot.age = slot.age.saturating_add(1);
+        match slot.hold_remaining {
+            HoldLimit::Disabled => {}
+            HoldLimit::Infinite => {
+                if slot.lifetime == 0 {
+                    slot.lifetime = 1;
+                }
+            }
+            HoldLimit::Frames(remaining) => {
+                // This tick consumes one of the total persistent frames, but
+                // the command remains active for the tick that consumes the
+                // final frame.
+                let remaining = remaining.saturating_sub(1);
+                slot.hold_remaining = if remaining == 0 {
+                    HoldLimit::Disabled
+                } else {
+                    HoldLimit::Frames(remaining)
+                };
+                if slot.lifetime == 0 {
+                    slot.lifetime = 1;
+                }
+            }
+        }
+    }
 }
 
-/// Turns this frame's rolled-back inputs into per-fighter [`FighterInput`]
-/// state. Runs in `GameplaySet::Input`, before any state looks at it.
 pub fn postprocess_input(
     query: Query<(&mut FighterInput, &Player)>,
     inputs: Res<PlayerInputs<GGRSCfg>>,
@@ -187,95 +426,95 @@ pub fn postprocess_input(
         }
 
         input.push_input_frame(inputs[player.handle].0);
+        let current_bindings = input.current_frame.bindings;
+        let previous_bindings = input.prev_frame.bindings;
+        for (history, action) in input.button_history.iter_mut().zip([
+            DigitalAction::Jump,
+            DigitalAction::Shield,
+            DigitalAction::Attack,
+        ]) {
+            history.update(
+                current_bindings.get(action).0,
+                previous_bindings.get(action).0,
+            );
+        }
 
-        // Directional smash detection
         let x_abs = input.current_frame.movement.x.abs();
         let y_abs = input.current_frame.movement.y.abs();
-
         let reset_deadzone = game_settings.input_common.smash_input_reset_axis_threshold;
         let axis_threshold = game_settings.input_common.smash_input_axis_threshold;
         let frame_threshold = game_settings.input_common.smash_input_frame_threshold;
 
         if x_abs < reset_deadzone {
             input.frames_in_x_flick_deadzone = 0xFE;
+        } else if input.prev_frame.movement.x.abs() < reset_deadzone
+            || input.prev_frame.movement.x.signum() != input.current_frame.movement.x.signum()
+        {
+            input.frames_in_x_flick_deadzone = 1;
         } else {
-            let prev_x_abs = input.prev_frame.movement.x.abs();
-            if prev_x_abs < reset_deadzone
-                || input.prev_frame.movement.x.signum() != input.current_frame.movement.x.signum()
-            {
-                input.frames_in_x_flick_deadzone = 1;
-            } else {
-                input.frames_in_x_flick_deadzone =
-                    input.frames_in_x_flick_deadzone.saturating_add(1);
-            }
+            input.frames_in_x_flick_deadzone = input.frames_in_x_flick_deadzone.saturating_add(1);
         }
 
         if y_abs < reset_deadzone {
             input.frames_in_y_flick_deadzone = 0xFE;
+        } else if input.prev_frame.movement.y.abs() < reset_deadzone
+            || input.prev_frame.movement.y.signum() != input.current_frame.movement.y.signum()
+        {
+            input.frames_in_y_flick_deadzone = 1;
         } else {
-            let prev_y_abs = input.prev_frame.movement.y.abs();
-            if prev_y_abs < reset_deadzone
-                || input.prev_frame.movement.y.signum() != input.current_frame.movement.y.signum()
-            {
-                input.frames_in_y_flick_deadzone = 1;
-            } else {
-                input.frames_in_y_flick_deadzone =
-                    input.frames_in_y_flick_deadzone.saturating_add(1);
-            }
+            input.frames_in_y_flick_deadzone = input.frames_in_y_flick_deadzone.saturating_add(1);
         }
 
-        if !input.prev_frame.jump && input.current_frame.jump {
-            input.set_lifetime(
-                FighterCommands::Jump,
-                game_settings.input_common.input_buffer_size,
-            );
+        let tap = game_settings.input_common.input_buffer_size;
+        let jump_pressed = input.is_pressed(DigitalAction::Jump);
+        let shield_pressed = input.is_pressed(DigitalAction::Shield);
+        let attack_pressed = input.is_pressed(DigitalAction::Attack);
+        if jump_pressed {
+            input.set_lifetime(FighterCommands::Jump, tap);
+        }
+        if shield_pressed {
+            input.set_lifetime(FighterCommands::Shield, tap);
         }
 
-        if !input.prev_frame.shield && input.current_frame.shield {
-            input.set_lifetime(
-                FighterCommands::Shield,
-                game_settings.input_common.input_buffer_size,
-            );
-        }
-
-        if !input.prev_frame.attack && input.current_frame.attack {
-            input.set_lifetime(
-                FighterCommands::Attack,
-                game_settings.input_common.input_buffer_size,
-            );
+        let shield_now = input.current_frame.bindings_for(DigitalAction::Shield);
+        let shield_previous = input.prev_frame.bindings_for(DigitalAction::Shield);
+        let second_shield_pressed = second_binding_pressed(shield_now, shield_previous);
+        if second_shield_pressed {
+            input.set_lifetime(FighterCommands::GuardHold, tap);
         }
 
         let mut y_flick_detected =
             y_abs >= axis_threshold && input.frames_in_y_flick_deadzone <= frame_threshold;
         let mut x_flick_detected =
             x_abs >= axis_threshold && input.frames_in_x_flick_deadzone <= frame_threshold;
-
         if y_flick_detected {
             input.clear_command(FighterCommands::SmashMoveUp);
             input.clear_command(FighterCommands::SmashMoveDown);
-
             input.frames_in_y_flick_deadzone = 0xFF;
-
-            let command_to_set = if input.current_frame.movement.y > 0.0 {
+            let command = if input.current_frame.movement.y > 0.0 {
                 FighterCommands::SmashMoveUp
             } else {
                 FighterCommands::SmashMoveDown
             };
-
-            input.set_lifetime(command_to_set, game_settings.input_common.input_buffer_size);
+            input.set_lifetime(command, tap);
+        }
+        if x_flick_detected {
+            input.clear_command(FighterCommands::SmashMoveLeft);
+            input.clear_command(FighterCommands::SmashMoveRight);
+            input.frames_in_x_flick_deadzone = 0xFF;
+            let command = if input.current_frame.movement.x > 0.0 {
+                FighterCommands::SmashMoveRight
+            } else {
+                FighterCommands::SmashMoveLeft
+            };
+            input.set_lifetime(command, tap);
         }
-
-        // if both flicks are detected, only one wins
-
         if x_flick_detected && y_flick_detected {
             x_flick_detected = x_abs > y_abs;
             y_flick_detected = !x_flick_detected;
         }
 
-        let attack_detected = input.current_frame.attack && !input.prev_frame.attack;
-
-        // Tilt/smash up/down
-        if attack_detected {
+        if attack_pressed {
             let attack_type = if y_flick_detected {
                 if input.current_frame.movement.y > 0.0 {
                     FighterAttackCommandType::SmashAttackUp
@@ -303,25 +542,142 @@ pub fn postprocess_input(
             } else {
                 FighterAttackCommandType::Neutral
             };
-
-            input.set_lifetime(
-                FighterCommands::Attack,
-                game_settings.input_common.input_buffer_size,
-            );
+            input.set_lifetime(FighterCommands::Attack, tap);
             input.set_attack_command_type(attack_type);
         }
 
-        if x_flick_detected {
-            input.clear_command(FighterCommands::SmashMoveLeft);
-            input.clear_command(FighterCommands::SmashMoveRight);
-
-            let command_to_set = if input.current_frame.movement.x > 0.0 {
-                FighterCommands::SmashMoveRight
-            } else {
-                FighterCommands::SmashMoveLeft
-            };
-
-            input.set_lifetime(command_to_set, game_settings.input_common.input_buffer_size);
+        for command in FighterCommands::iter() {
+            input.update_hold(command);
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::input::ActionBindingMask;
+
+    fn advance_command(input: &mut FighterInput, command: FighterCommands) {
+        input.reduce_command_lifetime(command);
+        input.update_hold(command);
+    }
+
+    #[test]
+    fn second_binding_is_an_edge_not_a_level() {
+        let first = ActionBindingMask(0b0001);
+        let both = ActionBindingMask(0b0011);
+        assert!(second_binding_pressed(both, first));
+        assert!(!second_binding_pressed(both, both));
+    }
+
+    #[test]
+    fn replacing_a_binding_still_triggers_the_combination() {
+        let previous = ActionBindingMask(0b0011);
+        let current = ActionBindingMask(0b0101);
+        assert!(second_binding_pressed(current, previous));
+    }
+
+    #[test]
+    fn command_can_be_consumed_without_erasing_raw_input() {
+        let mut input = FighterInput::default();
+        input.set_lifetime(FighterCommands::GuardHold, 3);
+        assert!(input.consume_command(FighterCommands::GuardHold));
+        assert!(!input.has_command(FighterCommands::GuardHold));
+        assert_eq!(input.get_last_frame(), FighterInputFrame::default());
+    }
+
+    #[test]
+    fn hold_extension_does_not_resurrect_consumed_commands() {
+        let mut input = FighterInput::default();
+        input.enable_hold(FighterCommands::Shield, 10);
+        input.set_lifetime(FighterCommands::Shield, 1);
+        input.update_hold(FighterCommands::Shield);
+        input.reduce_command_lifetime(FighterCommands::Shield);
+        input.update_hold(FighterCommands::Shield);
+        assert!(input.has_command(FighterCommands::Shield));
+        input.consume_command(FighterCommands::Shield);
+        input.update_hold(FighterCommands::Shield);
+        assert!(!input.has_command(FighterCommands::Shield));
+    }
+
+    #[test]
+    fn hold_buffer_keeps_released_attack_through_jump_squat() {
+        let mut input = FighterInput::default();
+        input.set_lifetime(FighterCommands::Attack, 3);
+        // Recognition happened before jump squat enabled persistence.
+        input.update_hold(FighterCommands::Attack);
+        input.enable_hold_all(10);
+
+        // Five simulation ticks cover the test fighter's jump squat. The
+        // physical attack binding is released, but persistence belongs to the
+        // recognized command rather than the binding's held state.
+        for _ in 0..5 {
+            advance_command(&mut input, FighterCommands::Attack);
+        }
+
+        assert!(input.has_command(FighterCommands::Attack));
+        // Jump-squat exit stops enrollment. The latch crosses into Jump and
+        // remains visible on its first airborne interrupt frame.
+        input.disable_hold_all();
+        advance_command(&mut input, FighterCommands::Attack);
+        assert!(input.has_command(FighterCommands::Attack));
+        assert!(input.consume_command(FighterCommands::Attack));
+        assert!(!input.has_command(FighterCommands::Attack));
+    }
+
+    #[test]
+    fn finite_hold_limit_includes_elapsed_tap_frames() {
+        let mut input = FighterInput::default();
+        input.set_lifetime(FighterCommands::Attack, 3);
+        // The recognition frame has already elapsed when jump squat starts.
+        input.update_hold(FighterCommands::Attack);
+        input.enable_hold_all(10);
+
+        for _ in 0..9 {
+            advance_command(&mut input, FighterCommands::Attack);
+            assert!(input.has_command(FighterCommands::Attack));
+        }
+        advance_command(&mut input, FighterCommands::Attack);
+        assert!(!input.has_command(FighterCommands::Attack));
+    }
+
+    #[test]
+    fn stopping_enrollment_and_cancelling_latches_are_distinct() {
+        let mut input = FighterInput::default();
+        input.enable_hold_all(10);
+        input.set_lifetime(FighterCommands::Shield, 1);
+        input.disable_hold_all();
+        advance_command(&mut input, FighterCommands::Shield);
+        assert!(input.has_command(FighterCommands::Shield));
+
+        input.cancel_hold_all();
+        advance_command(&mut input, FighterCommands::Shield);
+        assert!(!input.has_command(FighterCommands::Shield));
+    }
+
+    #[test]
+    fn command_override_can_disable_global_hold() {
+        let mut input = FighterInput::default();
+        input.enable_hold_all(10);
+        input.disable_hold(FighterCommands::Attack);
+        input.set_lifetime(FighterCommands::Attack, 1);
+        advance_command(&mut input, FighterCommands::Attack);
+        assert!(!input.has_command(FighterCommands::Attack));
+
+        input.reset_hold_override(FighterCommands::Attack);
+        input.set_lifetime(FighterCommands::Attack, 1);
+        advance_command(&mut input, FighterCommands::Attack);
+        assert!(input.has_command(FighterCommands::Attack));
+    }
+
+    #[test]
+    fn infinite_hold_uses_an_explicit_state() {
+        let mut input = FighterInput::default();
+        input.enable_hold(FighterCommands::Shield, 0);
+        input.set_lifetime(FighterCommands::Shield, 1);
+        for _ in 0..u16::MAX as usize + 1 {
+            advance_command(&mut input, FighterCommands::Shield);
+        }
+        assert!(input.has_command(FighterCommands::Shield));
+    }
+}