// Input processing system
// Timestamped player input events for deterministic simulation (D-010 principle 4)
// PlayerInput: semantic actions (MoveNorth, Interact, UsePerceptionMode, ToggleStance)
//
// This module owns the queue and the dispatch table only. Per-domain handler
// bodies live in their owning modules (T-1062): movement, inventory, dialogue,
// examine, follow, interaction, stance, save_io, settings, economy, bookmark,
// bridge::debug, perception::vision_cone, and test_world (reset, teleport).

use crate::bookmark::{
    handle_confirm_bookmark, handle_request_bookmark_catalog, BookmarkInputParams,
};
use crate::bridge::debug::{queue_debug_command, DebugCommandBuffer};
use crate::bridge::types::{ObjectType, PlayerAction, PlayerInput};
use crate::knowledge::EntityRegistry;
use crate::perception::vision_cone::handle_set_facing;
use crate::settings::{queue_settings_command, SettingsCommand, SettingsCommandBuffer};
use crate::simulation::dialogue::{handle_confront, handle_dialogue_response, handle_talk};
use crate::simulation::economy::{queue_econ_state_query, EconQueryBuffer};
use crate::simulation::examine::handle_examine;
use crate::simulation::follow::handle_follow;
use crate::simulation::interaction::{handle_door_interact, handle_terminal_interact, DoorState};
use crate::simulation::inventory::{handle_place, handle_take, CarriedBy, InventorySlot, ItemName};
use crate::simulation::movement::{apply_move, PlayerCharacter, TilePosition};
use crate::simulation::save_io::{queue_save_load, SaveLoadCommand, SaveLoadPending};
use crate::simulation::stance::{handle_toggle_stance, PlayerMoveCooldown, Stance};
use crate::simulation::time::{PauseParams, TickRate};
use crate::test_world::reset::{handle_reset, RoomResetTrigger, RoomSnapshots};
use crate::test_world::teleport::handle_teleport_to_hub;
use bevy_ecs::prelude::*;
use std::collections::VecDeque;

/// Maximum number of inputs the queue will hold before dropping oldest.
/// Prevents unbounded memory growth from input flooding.
pub const INPUT_QUEUE_CAPACITY: usize = 1000;

/// Player query shared by the dispatch and the per-domain input handlers.
/// One alias instead of nine per-handler `clippy::type_complexity` allows (T-1062).
pub type PlayerInputQuery<'w, 's> = Query<
    'w,
    's,
    (
        Entity,
        &'static TilePosition,
        Option<&'static mut Stance>,
        Option<&'static mut PlayerMoveCooldown>,
    ),
    With<PlayerCharacter>,
>;

/// Queue of pending player inputs, ordered by tick
#[derive(Resource, Debug, Default)]
pub struct InputQueue {
    queue: VecDeque<PlayerInput>,
}

impl InputQueue {
    /// Add a new input to the queue.
    /// Inputs must be pushed in tick order for deterministic processing.
    /// Panics in debug builds if tick ordering is violated.
    /// Drops oldest inputs when capacity is exceeded.
    pub fn push(&mut self, input: PlayerInput) {
        debug_assert!(
            self.queue.back().is_none_or(|last| last.tick <= input.tick),
            "InputQueue: tick ordering violated (last={}, new={})",
            self.queue.back().map_or(0, |last| last.tick),
            input.tick,
        );
        if self.queue.len() >= INPUT_QUEUE_CAPACITY {
            let dropped = self.queue.pop_front();
            tracing::warn!(
                "InputQueue at capacity ({}), dropping oldest input (tick={})",
                INPUT_QUEUE_CAPACITY,
                dropped.map_or(0, |d| d.tick),
            );
        }
        self.queue.push_back(input);
    }

    /// Drain all inputs for ticks <= the given tick
    /// Returns inputs in FIFO order
    pub fn drain_for_tick(&mut self, tick: u64) -> Vec<PlayerInput> {
        let mut result = Vec::new();
        while let Some(front) = self.queue.front() {
            if front.tick <= tick {
                result.push(self.queue.pop_front().unwrap());
            } else {
                break;
            }
        }
        result
    }

    /// Get the current queue length
    pub fn len(&self) -> usize {
        self.queue.len()
    }

    /// Check if the queue is empty
    pub fn is_empty(&self) -> bool {
        self.queue.is_empty()
    }
}

/// Drains InputQueue for the current tick, converts PlayerActions to ECS components.
/// Handles stance toggling (D-053), movement cooldown, Take/Place verbs (#424),
/// and save/load commands (#553).
#[allow(clippy::too_many_arguments)]
pub fn process_player_input(
    mut input_queue: ResMut<InputQueue>,
    mut pause: PauseParams,
    mut commands: Commands,
    registry: Res<EntityRegistry>,
    mut player_query: PlayerInputQuery,
    inventory_items: Query<(Entity, &CarriedBy, &ItemName, &InventorySlot)>,
    all_positions: Query<&TilePosition>,
    reset_triggers: Query<&RoomResetTrigger>,
    mut room_snapshots: Option<ResMut<RoomSnapshots>>,
    mut save_load: Option<ResMut<SaveLoadPending>>,
    mut debug_cmd_buffer: Option<ResMut<DebugCommandBuffer>>,
    mut settings_cmd_buffer: Option<ResMut<SettingsCommandBuffer>>,
    mut econ_query_buf: Option<ResMut<EconQueryBuffer>>,
    door_states: Query<&DoorState>,
    object_types: Query<&ObjectType>,
    mut bookmark: BookmarkInputParams<'_>,
) {
    let current_tick = pause.time.tick;
    let paused = pause.time.paused();
    let inputs = input_queue.drain_for_tick(current_tick);

    // Track whether any movement was attempted this tick (for cooldown tick advance)
    let mut move_attempted = false;

    for input in inputs {
        // Discard all gameplay actions while paused (D-052, R2-OQ-01).
        // SaveGame/LoadGame are also exempted — saving while paused is valid (#553).
        // AutoPause/AutoResume (T-970) are whitelisted for the same reason as
        // Pause/Unpause: AutoResume MUST reach the match arm while paused (that's
        // the entire point — resuming from a paused state), and AutoPause is
        // included for symmetry even though its handler is a no-op whenever the
        // sim isn't already TickRate::Full.
        if paused
            && !matches!(
                input.action,
                PlayerAction::Pause
                    | PlayerAction::Unpause
                    | PlayerAction::AutoPause
                    | PlayerAction::AutoResume
                    | PlayerAction::TeleportToHub
                    | PlayerAction::SaveGame { .. }
                    | PlayerAction::LoadGame { .. }
                    | PlayerAction::DebugCommand(_)
                    | PlayerAction::ChangeSetting { .. }
                    | PlayerAction::RequestAllSettings
                    | PlayerAction::DeleteSetting { .. }
                    | PlayerAction::EconStateQuery { .. }
                    | PlayerAction::RequestBookmarkCatalog
                    | PlayerAction::ConfirmBookmark { .. }
            )
        {
            continue;
        }
        match input.action {
            PlayerAction::MoveNorth => {
                move_attempted = true;
                apply_move(&mut player_query, &mut commands, 0, -1);
            }
            PlayerAction::MoveSouth => {
                move_attempted = true;
                apply_move(&mut player_query, &mut commands, 0, 1);
            }
            PlayerAction::MoveEast => {
                move_attempted = true;
                apply_move(&mut player_query, &mut commands, 1, 0);
            }
            PlayerAction::MoveWest => {
                move_attempted = true;
                apply_move(&mut player_query, &mut commands, -1, 0);
            }
            PlayerAction::MoveNortheast => {
                move_attempted = true;
                apply_move(&mut player_query, &mut commands, 1, -1);
            }
            PlayerAction::MoveNorthwest => {
                move_attempted = true;
                apply_move(&mut player_query, &mut commands, -1, -1);
            }
            PlayerAction::MoveSoutheast => {
                move_attempted = true;
                apply_move(&mut player_query, &mut commands, 1, 1);
            }
            PlayerAction::MoveSouthwest => {
                move_attempted = true;
                apply_move(&mut player_query, &mut commands, -1, 1);
            }
            PlayerAction::ToggleStanceUp => {
                handle_toggle_stance(&mut player_query, true);
            }
            PlayerAction::ToggleStanceDown => {
                handle_toggle_stance(&mut player_query, false);
            }
            PlayerAction::Pause => {
                pause.time.tick_rate = TickRate::Paused;
                tracing::debug!("Simulation paused by player input");
            }
            PlayerAction::Unpause => {
                pause.time.tick_rate = TickRate::Full;
                tracing::debug!("Simulation unpaused by player input");
            }
            PlayerAction::AutoPause => {
                // T-970 (D-226 layer 1, Option A): only take effect when the sim
                // is currently fully running. A pre-existing manual pause or Half
                // rate (D-088) is left completely untouched — no previous-rate
                // stack, so if auto-pause didn't cause the pause, auto-resume
                // must not clear it either (see AutoResume below).
                if pause.time.tick_rate == TickRate::Full {
                    pause.time.tick_rate = TickRate::Paused;
                    if let Some(auto_pause) = pause.auto_pause.as_deref_mut() {
                        auto_pause.active = true;
                    }
                    tracing::debug!("Simulation auto-paused (implant fullscreen)");
                }
            }
            PlayerAction::AutoResume => {
                // T-970: only resume — and only clear the flag — if OUR OWN
                // auto-pause is what caused the current pause. A prior manual
                // pause or Half rate survives the implant close untouched.
                let should_resume = pause.auto_pause.as_deref().is_some_and(|a| a.active);
                if should_resume {
                    pause.time.tick_rate = TickRate::Full;
                    if let Some(auto_pause) = pause.auto_pause.as_deref_mut() {
                        auto_pause.active = false;
                    }
                    tracing::debug!("Simulation auto-resumed (implant closed)");
                }
            }
            PlayerAction::SetTickRate(rate) => {
                pause.time.tick_rate = rate;
                tracing::debug!("Tick rate set to {:?} by player input", rate);
            }
            PlayerAction::Interact {
                target_entity_id,
                ref verb,
            } => {
                // Cancel follow when player uses any non-Follow verb (#241).
                if verb.as_deref() != Some("Follow") {
                    if let Ok((player_entity, _, _, _)) = player_query.single() {
                        commands
                            .entity(player_entity)
                            .remove::<crate::simulation::follow::FollowTarget>();
                    }
                }
                match verb.as_deref() {
                    Some("Take") => {
                        handle_take(
                            &mut commands,
                            &registry,
                            &player_query,
                            &inventory_items,
                            target_entity_id,
                        );
                    }
                    Some("Place") => {
                        handle_place(&mut commands, &registry, &player_query, target_entity_id);
                    }
                    Some("Talk") => {
                        handle_talk(
                            &mut commands,
                            &registry,
                            &player_query,
                            &all_positions,
                            target_entity_id,
                        );
                    }
                    Some("Follow") => {
                        handle_follow(
                            &mut commands,
                            &registry,
                            &player_query,
                            &all_positions,
                            target_entity_id,
                            current_tick,
                        );
                    }
                    Some("Examine NPC")
                    | Some("ExamineNpc")
                    | Some("Examine Object")
                    | Some("ExamineObject")
                    | Some("Observe") => {
                        handle_examine(
                            &mut commands,
                            &registry,
                            &player_query,
                            &all_positions,
                            target_entity_id,
                        );
                    }
                    Some("Confront") => {
                        handle_confront(
                            &mut commands,
                            &registry,
                            &player_query,
                            &all_positions,
                            target_entity_id,
                        );
                    }
                    Some("Reset") => {
                        handle_reset(
                            &mut commands,
                            &registry,
                            &reset_triggers,
                            &mut room_snapshots,
                            target_entity_id,
                            current_tick,
                        );
                    }
                    // #246: Door and Terminal behavior
                    Some("Open") | Some("Close") => {
                        handle_door_interact(
                            &mut commands,
                            &registry,
                            &player_query,
                            &door_states,
                            target_entity_id,
                        );
                    }
                    Some("Use") => {
                        handle_terminal_interact(
                            &mut commands,
                            &registry,
                            &player_query,
                            &object_types,
                            target_entity_id,
                        );
                    }
                    _ => {
                        tracing::info!(
                            "Interact: target={:?}, verb={:?} — logged only",
                            target_entity_id,
                            verb,
                        );
                    }
                }
            }
            PlayerAction::WalkAway => {
                if let Ok((player_entity, _, _, _)) = player_query.single() {
                    commands
                        .entity(player_entity)
                        .insert(crate::simulation::dialogue::WalkAwayRequest);
                    tracing::debug!("WalkAway: marker set on player");
                }
            }
            PlayerAction::SetFacing { ref facing } => {
                handle_set_facing(&mut player_query, &mut commands, facing);
            }
            PlayerAction::TeleportToHub => {
                handle_teleport_to_hub(&mut player_query, &mut commands);
            }
            PlayerAction::DialogueResponse {
                target_entity_id,
                ref response_id,
            } => {
                handle_dialogue_response(
                    &mut commands,
                    &registry,
                    &player_query,
                    &all_positions,
                    target_entity_id,
                    response_id,
                );
            }
            PlayerAction::UsePerceptionMode(ref mode) => {
                tracing::trace!("UsePerceptionMode({}) — no-op for Sprint 1", mode);
            }
            PlayerAction::SaveGame { ref path } => {
                queue_save_load(
                    save_load.as_deref_mut(),
                    SaveLoadCommand::Save {
                        path: std::path::PathBuf::from(path),
                    },
                );
            }
            PlayerAction::LoadGame { ref path } => {
                queue_save_load(
                    save_load.as_deref_mut(),
                    SaveLoadCommand::Load {
                        path: std::path::PathBuf::from(path),
                    },
                );
            }
            PlayerAction::DebugCommand(cmd) => {
                queue_debug_command(debug_cmd_buffer.as_deref_mut(), cmd);
            }
            PlayerAction::ChangeSetting { key, value } => {
                queue_settings_command(
                    settings_cmd_buffer.as_deref_mut(),
                    SettingsCommand::Change { key, value },
                );
            }
            PlayerAction::RequestAllSettings => {
                queue_settings_command(
                    settings_cmd_buffer.as_deref_mut(),
                    SettingsCommand::RequestAll,
                );
            }
            PlayerAction::DeleteSetting { key } => {
                queue_settings_command(
                    settings_cmd_buffer.as_deref_mut(),
                    SettingsCommand::Delete { key },
                );
            }
            PlayerAction::EconStateQuery { system_id } => {
                queue_econ_state_query(econ_query_buf.as_deref_mut(), system_id);
            }
            PlayerAction::RequestBookmarkCatalog => {
                handle_request_bookmark_catalog(&mut bookmark);
            }
            PlayerAction::ConfirmBookmark {
                bookmark_id,
                starting_location_id,
            } => {
                handle_confirm_bookmark(
                    bookmark_id,
                    starting_location_id,
                    &bookmark.registry,
                    &mut bookmark.selected,
                    &mut bookmark.sim_error_buf,
                    current_tick,
                );
            }
        }
    }

    // If no movement was attempted this tick, still advance cooldown counter
    if !move_attempted {
        if let Ok((_, _, _, Some(mut cooldown))) = player_query.single_mut() {
            cooldown.tick();
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::bridge::types::MovementStance;
    use crate::simulation::movement::MoveIntent;
    use crate::simulation::time::{AutoPauseState, SimulationTime};

    #[test]
    fn drain_returns_inputs_up_to_tick() {
        let mut queue = InputQueue::default();
        queue.push(PlayerInput {
            tick: 1,
            action: PlayerAction::MoveNorth,
        });
        queue.push(PlayerInput {
            tick: 2,
            action: PlayerAction::MoveSouth,
        });
        queue.push(PlayerInput {
            tick: 5,
            action: PlayerAction::Interact {
                target_entity_id: None,
                verb: None,
            },
        });
        let inputs = queue.drain_for_tick(3);
        assert_eq!(inputs.len(), 2);
        assert_eq!(queue.len(), 1);
    }

    #[test]
    fn drain_empty_queue_returns_empty() {
        let mut queue = InputQueue::default();
        let inputs = queue.drain_for_tick(10);
        assert!(inputs.is_empty());
    }

    #[test]
    #[should_panic(expected = "tick ordering violated")]
    fn push_rejects_out_of_order_in_debug() {
        let mut queue = InputQueue::default();
        queue.push(PlayerInput {
            tick: 5,
            action: PlayerAction::MoveNorth,
        });
        queue.push(PlayerInput {
            tick: 2,
            action: PlayerAction::MoveSouth,
        });
    }

    #[test]
    fn process_input_move_creates_intent() {
        let mut world = bevy_ecs::world::World::new();
        world.insert_resource(InputQueue::default());
        world.insert_resource(SimulationTime::default());
        world.init_resource::<crate::knowledge::EntityRegistry>();

        let player = world
            .spawn((PlayerCharacter, TilePosition::new(5, 5, 0)))
            .id();

        world.resource_mut::<InputQueue>().push(PlayerInput {
            tick: 0,
            action: PlayerAction::MoveNorth,
        });

        let mut schedule = bevy_ecs::schedule::Schedule::default();
        schedule.add_systems(process_player_input);
        schedule.run(&mut world);

        let intent = world.get::<MoveIntent>(player).unwrap();
        assert_eq!(intent.target, TilePosition::new(5, 4, 0));
    }

    #[test]
    fn process_input_pause_sets_paused() {
        let mut world = bevy_ecs::world::World::new();
        world.insert_resource(InputQueue::default());
        world.insert_resource(SimulationTime::default());
        world.init_resource::<crate::knowledge::EntityRegistry>();

        world.resource_mut::<InputQueue>().push(PlayerInput {
            tick: 0,
            action: PlayerAction::Pause,
        });

        let mut schedule = bevy_ecs::schedule::Schedule::default();
        schedule.add_systems(process_player_input);
        schedule.run(&mut world);

        assert_eq!(
            world.resource::<SimulationTime>().tick_rate,
            TickRate::Paused
        );
    }

    #[test]
    fn process_input_set_tick_rate() {
        let mut world = bevy_ecs::world::World::new();
        world.insert_resource(InputQueue::default());
        world.insert_resource(SimulationTime::default());
        world.init_resource::<crate::knowledge::EntityRegistry>();

        world.resource_mut::<InputQueue>().push(PlayerInput {
            tick: 0,
            action: PlayerAction::SetTickRate(TickRate::Half),
        });

        let mut schedule = bevy_ecs::schedule::Schedule::default();
        schedule.add_systems(process_player_input);
        schedule.run(&mut world);

        assert_eq!(world.resource::<SimulationTime>().tick_rate, TickRate::Half);
    }

    #[test]
    #[should_panic(expected = "PlayerCharacter entity must exist")]
    fn process_input_no_player_panics() {
        let mut world = bevy_ecs::world::World::new();
        world.insert_resource(InputQueue::default());
        world.insert_resource(SimulationTime::default());
        world.init_resource::<crate::knowledge::EntityRegistry>();

        world.resource_mut::<InputQueue>().push(PlayerInput {
            tick: 0,
            action: PlayerAction::MoveNorth,
        });

        let mut schedule = bevy_ecs::schedule::Schedule::default();
        schedule.add_systems(process_player_input);
        schedule.run(&mut world);
    }

    #[test]
    fn process_input_future_tick_ignored() {
        let mut world = bevy_ecs::world::World::new();
        world.insert_resource(InputQueue::default());
        world.insert_resource(SimulationTime::default());
        world.init_resource::<crate::knowledge::EntityRegistry>();

        let player = world
            .spawn((PlayerCharacter, TilePosition::new(5, 5, 0)))
            .id();

        world.resource_mut::<InputQueue>().push(PlayerInput {
            tick: 5,
            action: PlayerAction::MoveNorth,
        });

        let mut schedule = bevy_ecs::schedule::Schedule::default();
        schedule.add_systems(process_player_input);
        schedule.run(&mut world);

        // No MoveIntent should be created (input for future tick)
        assert!(world.get::<MoveIntent>(player).is_none());
    }

    // === Pause Guard Tests (#461, #462, #463) ===
    // Prevent Bug #3 recurrence: player movement while paused.
    // The pause guard at process_player_input discards movement inputs
    // when SimulationTime.tick_rate == TickRate::Paused (D-052).

    #[test]
    fn movement_discarded_while_paused() {
        // #461: Movement input rejected while paused — prevents Bug #3 recurrence.
        let mut world = bevy_ecs::world::World::new();
        world.insert_resource(InputQueue::default());
        let mut time = SimulationTime::default();
        time.tick_rate = TickRate::Paused;
        world.insert_resource(time);
        world.init_resource::<crate::knowledge::EntityRegistry>();

        let player = world
            .spawn((PlayerCharacter, TilePosition::new(5, 5, 0)))
            .id();

        world.resource_mut::<InputQueue>().push(PlayerInput {
            tick: 0,
            action: PlayerAction::MoveNorth,
        });

        let mut schedule = bevy_ecs::schedule::Schedule::default();
        schedule.add_systems(process_player_input);
        schedule.run(&mut world);

        // Movement must be discarded — no MoveIntent created
        assert!(
            world.get::<MoveIntent>(player).is_none(),
            "MoveNorth must be discarded while paused (Bug #3 guard)"
        );
    }

    #[test]
    fn unpause_accepted_while_paused() {
        // #462: Unpause command is the one control action allowed while paused.
        let mut world = bevy_ecs::world::World::new();
        world.insert_resource(InputQueue::default());
        let mut time = SimulationTime::default();
        time.tick_rate = TickRate::Paused;
        world.insert_resource(time);
        world.init_resource::<crate::knowledge::EntityRegistry>();

        // Player entity required for process_player_input (even if no movement)
        world.spawn((PlayerCharacter, TilePosition::new(5, 5, 0)));

        world.resource_mut::<InputQueue>().push(PlayerInput {
            tick: 0,
            action: PlayerAction::Unpause,
        });

        let mut schedule = bevy_ecs::schedule::Schedule::default();
        schedule.add_systems(process_player_input);
        schedule.run(&mut world);

        assert_eq!(
            world.resource::<SimulationTime>().tick_rate,
            TickRate::Full,
            "Unpause must be accepted while paused"
        );
    }

    #[test]
    fn pause_unpause_roundtrip_with_movement() {
        // #463: Full cycle — pause -> move (rejected) -> unpause -> move (accepted).
        let mut world = bevy_ecs::world::World::new();
        world.insert_resource(InputQueue::default());
        world.insert_resource(SimulationTime::default());
        world.init_resource::<crate::knowledge::EntityRegistry>();

        let player = world
            .spawn((PlayerCharacter, TilePosition::new(5, 5, 0)))
            .id();

        let mut schedule = bevy_ecs::schedule::Schedule::default();
        schedule.add_systems(process_player_input);

        // Step 1: Pause
        world.resource_mut::<InputQueue>().push(PlayerInput {
            tick: 0,
            action: PlayerAction::Pause,
        });
        schedule.run(&mut world);
        assert_eq!(
            world.resource::<SimulationTime>().tick_rate,
            TickRate::Paused,
            "Step 1: game should be paused"
        );

        // Step 2: Move while paused — must be rejected
        world.resource_mut::<InputQueue>().push(PlayerInput {
            tick: 0,
            action: PlayerAction::MoveNorth,
        });
        schedule.run(&mut world);
        assert!(
            world.get::<MoveIntent>(player).is_none(),
            "Step 2: movement must be rejected while paused"
        );

        // Step 3: Unpause
        world.resource_mut::<InputQueue>().push(PlayerInput {
            tick: 0,
            action: PlayerAction::Unpause,
        });
        schedule.run(&mut world);
        assert_eq!(
            world.resource::<SimulationTime>().tick_rate,
            TickRate::Full,
            "Step 3: game should be unpaused"
        );

        // Step 4: Move after unpause — must succeed
        world.resource_mut::<InputQueue>().push(PlayerInput {
            tick: 0,
            action: PlayerAction::MoveNorth,
        });
        schedule.run(&mut world);
        assert!(
            world.get::<MoveIntent>(player).is_some(),
            "Step 4: movement must succeed after unpause"
        );
    }

    // === Remaining Pause Guard Tests (#468) ===
    // Edge cases: stance, interact, batch discard, and SetTickRate while paused.

    #[test]
    fn stance_toggle_rejected_while_paused() {
        // #468: Stance toggle rejected while paused.
        let mut world = bevy_ecs::world::World::new();
        world.insert_resource(InputQueue::default());
        let mut time = SimulationTime::default();
        time.tick_rate = TickRate::Paused;
        world.insert_resource(time);
        world.init_resource::<crate::knowledge::EntityRegistry>();

        world.spawn((
            PlayerCharacter,
            TilePosition::new(5, 5, 0),
            Stance::default(), // Walk
            PlayerMoveCooldown::default(),
        ));

        world.resource_mut::<InputQueue>().push(PlayerInput {
            tick: 0,
            action: PlayerAction::ToggleStanceUp,
        });

        let mut schedule = bevy_ecs::schedule::Schedule::default();
        schedule.add_systems(process_player_input);
        schedule.run(&mut world);

        let mut query = world.query::<&Stance>();
        let stance = query.single(&world).unwrap();
        assert_eq!(
            stance.0,
            MovementStance::Walk,
            "Stance toggle must be rejected while paused"
        );
    }

    #[test]
    fn interact_rejected_while_paused() {
        // #468: Interact rejected while paused.
        // This test verifies no panic and no side effects — interact is a no-op while paused.
        let mut world = bevy_ecs::world::World::new();
        world.insert_resource(InputQueue::default());
        let mut time = SimulationTime::default();
        time.tick_rate = TickRate::Paused;
        world.insert_resource(time);
        world.init_resource::<crate::knowledge::EntityRegistry>();

        let player = world
            .spawn((PlayerCharacter, TilePosition::new(5, 5, 0)))
            .id();
        world
            .resource_mut::<crate::knowledge::EntityRegistry>()
            .register(player);

        // Spawn item on the ground
        let item = world
            .spawn((TilePosition::new(5, 4, 0), ItemName("Manifest Copy".into())))
            .id();
        let item_sid = world
            .resource_mut::<crate::knowledge::EntityRegistry>()
            .register(item);

        world.resource_mut::<InputQueue>().push(PlayerInput {
            tick: 0,
            action: PlayerAction::Interact {
                target_entity_id: Some(item_sid.0),
                verb: Some("Take".into()),
            },
        });

        let mut schedule = bevy_ecs::schedule::Schedule::default();
        schedule.add_systems(process_player_input);
        schedule.run(&mut world);

        // Item must remain on ground — Take rejected while paused
        assert!(
            world.get::<TilePosition>(item).is_some(),
            "Item must stay on ground — interact rejected while paused"
        );
        assert!(
            world.get::<CarriedBy>(item).is_none(),
            "Item must not be picked up while paused"
        );
    }

    #[test]
    fn batch_discard_while_paused() {
        // #468: All inputs in a batch discarded while paused (except Pause/Unpause).
        let mut world = bevy_ecs::world::World::new();
        world.insert_resource(InputQueue::default());
        let mut time = SimulationTime::default();
        time.tick_rate = TickRate::Paused;
        world.insert_resource(time);
        world.init_resource::<crate::knowledge::EntityRegistry>();

        let player = world
            .spawn((
                PlayerCharacter,
                TilePosition::new(5, 5, 0),
                Stance::default(),
                PlayerMoveCooldown::default(),
            ))
            .id();

        // Push a batch of mixed inputs — all should be discarded except Unpause
        let queue = &mut world.resource_mut::<InputQueue>();
        queue.push(PlayerInput {
            tick: 0,
            action: PlayerAction::MoveNorth,
        });
        queue.push(PlayerInput {
            tick: 0,
            action: PlayerAction::ToggleStanceUp,
        });
        queue.push(PlayerInput {
            tick: 0,
            action: PlayerAction::SetTickRate(TickRate::Half),
        });

        let mut schedule = bevy_ecs::schedule::Schedule::default();
        schedule.add_systems(process_player_input);
        schedule.run(&mut world);

        // All gameplay actions discarded
        assert!(
            world.get::<MoveIntent>(player).is_none(),
            "Movement discarded in batch"
        );
        let mut query = world.query::<&Stance>();
        let stance = query.single(&world).unwrap();
        assert_eq!(stance.0, MovementStance::Walk, "Stance unchanged in batch");
        assert_eq!(
            world.resource::<SimulationTime>().tick_rate,
            TickRate::Paused,
            "SetTickRate discarded in batch — still paused"
        );
    }

    #[test]
    fn set_tick_rate_rejected_while_paused() {
        // #468 / R2-OQ-01: SetTickRate(Half) while paused is a bug — must be rejected.
        let mut world = bevy_ecs::world::World::new();
        world.insert_resource(InputQueue::default());
        let mut time = SimulationTime::default();
        time.tick_rate = TickRate::Paused;
        world.insert_resource(time);
        world.init_resource::<crate::knowledge::EntityRegistry>();

        world.spawn((PlayerCharacter, TilePosition::new(5, 5, 0)));

        world.resource_mut::<InputQueue>().push(PlayerInput {
            tick: 0,
            action: PlayerAction::SetTickRate(TickRate::Half),
        });

        let mut schedule = bevy_ecs::schedule::Schedule::default();
        schedule.add_systems(process_player_input);
        schedule.run(&mut world);

        assert_eq!(
            world.resource::<SimulationTime>().tick_rate,
            TickRate::Paused,
            "SetTickRate must be rejected while paused (R2-OQ-01)"
        );
    }

    // === Auto-Pause Reconciliation Tests (T-970, D-226 layer 1) ===
    // Option A (lead ruling, no previous-rate stack): AutoPause only takes
    // effect from TickRate::Full; AutoResume only fires when AutoPauseState
    // says auto-pause itself caused the current pause. Manual pause and Half
    // rate (D-088) must survive an implant open/close cycle untouched.

    #[test]
    fn auto_pause_alone_then_auto_resume_unpauses() {
        // No manual pause / Half rate in play — AutoPause causes the pause, so
        // AutoResume (implant closing) must actually resume it.
        let mut world = bevy_ecs::world::World::new();
        world.insert_resource(InputQueue::default());
        world.insert_resource(SimulationTime::default());
        world.init_resource::<crate::knowledge::EntityRegistry>();
        world.init_resource::<AutoPauseState>();

        world.spawn((PlayerCharacter, TilePosition::new(5, 5, 0)));

        let mut schedule = bevy_ecs::schedule::Schedule::default();
        schedule.add_systems(process_player_input);

        world.resource_mut::<InputQueue>().push(PlayerInput {
            tick: 0,
            action: PlayerAction::AutoPause,
        });
        schedule.run(&mut world);
        assert_eq!(
            world.resource::<SimulationTime>().tick_rate,
            TickRate::Paused,
            "AutoPause must pause from Full"
        );
        assert!(
            world.resource::<AutoPauseState>().active,
            "auto_pause_active must be set — this pause was auto-triggered"
        );

        world.resource_mut::<InputQueue>().push(PlayerInput {
            tick: 0,
            action: PlayerAction::AutoResume,
        });
        schedule.run(&mut world);
        assert_eq!(
            world.resource::<SimulationTime>().tick_rate,
            TickRate::Full,
            "auto-pause-alone -> auto-resume must actually resume"
        );
        assert!(
            !world.resource::<AutoPauseState>().active,
            "flag must clear on auto-resume"
        );
    }

    #[test]
    fn manual_pause_survives_auto_pause_and_auto_resume() {
        // A prior MANUAL pause must survive the implant open/close cycle
        // untouched — auto-resume must NOT fire since auto-pause wasn't the trigger.
        let mut world = bevy_ecs::world::World::new();
        world.insert_resource(InputQueue::default());
        world.insert_resource(SimulationTime::default());
        world.init_resource::<crate::knowledge::EntityRegistry>();
        world.init_resource::<AutoPauseState>();

        world.spawn((PlayerCharacter, TilePosition::new(5, 5, 0)));

        let mut schedule = bevy_ecs::schedule::Schedule::default();
        schedule.add_systems(process_player_input);

        // Step 1: manual pause (Space bar).
        world.resource_mut::<InputQueue>().push(PlayerInput {
            tick: 0,
            action: PlayerAction::Pause,
        });
        schedule.run(&mut world);
        assert_eq!(
            world.resource::<SimulationTime>().tick_rate,
            TickRate::Paused
        );

        // Step 2: implant opens — AutoPause fires. Already paused (not Full),
        // so it must no-op and leave the flag false.
        world.resource_mut::<InputQueue>().push(PlayerInput {
            tick: 0,
            action: PlayerAction::AutoPause,
        });
        schedule.run(&mut world);
        assert_eq!(
            world.resource::<SimulationTime>().tick_rate,
            TickRate::Paused
        );
        assert!(
            !world.resource::<AutoPauseState>().active,
            "manual pause was not caused by auto-pause"
        );

        // Step 3: implant closes — AutoResume fires. Flag is false, so it must
        // NOT unpause.
        world.resource_mut::<InputQueue>().push(PlayerInput {
            tick: 0,
            action: PlayerAction::AutoResume,
        });
        schedule.run(&mut world);
        assert_eq!(
            world.resource::<SimulationTime>().tick_rate,
            TickRate::Paused,
            "manual pause -> auto-pause -> auto-resume must leave the sim still paused"
        );
    }

    #[test]
    fn half_rate_survives_auto_pause_and_auto_resume_untouched() {
        // D-088 Half rate is untouched by auto-pause/auto-resume — AutoPause
        // only takes effect from Full, so Half stays Half through an implant
        // open/close cycle (no previous-rate stack, "keep it simple").
        let mut world = bevy_ecs::world::World::new();
        world.insert_resource(InputQueue::default());
        let mut time = SimulationTime::default();
        time.tick_rate = TickRate::Half;
        world.insert_resource(time);
        world.init_resource::<crate::knowledge::EntityRegistry>();
        world.init_resource::<AutoPauseState>();

        world.spawn((PlayerCharacter, TilePosition::new(5, 5, 0)));

        let mut schedule = bevy_ecs::schedule::Schedule::default();
        schedule.add_systems(process_player_input);

        world.resource_mut::<InputQueue>().push(PlayerInput {
            tick: 0,
            action: PlayerAction::AutoPause,
        });
        schedule.run(&mut world);
        assert_eq!(
            world.resource::<SimulationTime>().tick_rate,
            TickRate::Half,
            "AutoPause must not touch Half rate"
        );
        assert!(!world.resource::<AutoPauseState>().active);

        world.resource_mut::<InputQueue>().push(PlayerInput {
            tick: 0,
            action: PlayerAction::AutoResume,
        });
        schedule.run(&mut world);
        assert_eq!(
            world.resource::<SimulationTime>().tick_rate,
            TickRate::Half,
            "AutoResume must not touch Half rate either"
        );
    }
}