//! Integration tests for basic environmental interaction (#246).
//!
//! Covers the acceptance criteria from the sprint briefing:
//! - Door toggle: player interacts with a Door, walkability flips; interacts again, flips back.
//! - Readable examine: Examine on a Readable entity returns non-empty text.
//! - Terminal interaction: Use on a Terminal emits TerminalInteracted event.
//! - DoorState persists in SaveStateV1.open_doors.

use bevy_ecs::{prelude::*, schedule::Schedule, world::World};
use settled_reach_server::knowledge::KnowledgeGraph;
use settled_reach_server::simulation::triangle::TemplateReferenceMap;
use settled_reach_server::{
    knowledge::{registry::EntityRegistry, registry::StableEntityId, types::StableId},
    npc::relationships::RelationshipGraph,
    simulation::{
        examine::{process_examine_interaction, ExamineRequest, ExamineResultBuffer, ExamineText},
        interaction::{
            process_door_interaction, process_terminal_interaction, DoorInteractRequest, DoorState,
            Interactable, ObjectType, TerminalInteractRequest, TerminalInteractedQueue,
        },
        movement::{PlayerCharacter, TilePosition, WalkabilityMap},
        save_state::{SaveStateV1, SAVE_FORMAT_VERSION},
        time::{SimulationTime, TickRate},
    },
};

// ---------------------------------------------------------------------------
// Helpers
// ---------------------------------------------------------------------------

fn make_world_with_walkability(width: i32, height: i32) -> World {
    let mut world = World::new();
    world.insert_resource(WalkabilityMap::new(width, height, 1));
    world.init_resource::<EntityRegistry>();
    world
}

fn spawn_player(world: &mut World, x: i32, y: i32) -> Entity {
    world
        .spawn((PlayerCharacter, TilePosition::new(x, y, 0)))
        .id()
}

fn spawn_door(world: &mut World, x: i32, y: i32, blocking_x: i32, blocking_y: i32) -> Entity {
    world
        .spawn((
            TilePosition::new(x, y, 0),
            Interactable,
            ObjectType::Door,
            DoorState::new(TilePosition::new(blocking_x, blocking_y, 0)),
        ))
        .id()
}

// ---------------------------------------------------------------------------
// Door behavior tests
// ---------------------------------------------------------------------------

/// Acceptance: player interacts with Door, walkability flips; interacts again, flips back.
#[test]
fn door_toggle_flips_walkability_both_ways() {
    let mut world = make_world_with_walkability(20, 20);

    // Block the door tile initially
    world
        .resource_mut::<WalkabilityMap>()
        .set_walkable(&TilePosition::new(10, 5, 0), false);

    let player = spawn_player(&mut world, 10, 6);
    let door = spawn_door(&mut world, 10, 6, 10, 5); // door tile at (10,5)

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

    // First interaction: open the door
    world
        .entity_mut(player)
        .insert(DoorInteractRequest { door_entity: door });

    schedule.run(&mut world);

    assert!(
        world
            .resource::<WalkabilityMap>()
            .can_move_to(&TilePosition::new(10, 5, 0)),
        "after Open: blocking tile must become walkable"
    );
    assert!(
        world.get::<DoorState>(door).unwrap().is_open,
        "DoorState.is_open must be true after opening"
    );
    // Request should be consumed
    assert!(
        world.get::<DoorInteractRequest>(player).is_none(),
        "DoorInteractRequest must be removed after processing"
    );

    // Second interaction: close the door
    world
        .entity_mut(player)
        .insert(DoorInteractRequest { door_entity: door });

    schedule.run(&mut world);

    assert!(
        !world
            .resource::<WalkabilityMap>()
            .can_move_to(&TilePosition::new(10, 5, 0)),
        "after Close: blocking tile must be impassable again"
    );
    assert!(
        !world.get::<DoorState>(door).unwrap().is_open,
        "DoorState.is_open must be false after closing"
    );
}

/// Door starts open: toggling closes it (walkability → blocked).
#[test]
fn door_starts_open_toggle_closes_it() {
    let mut world = make_world_with_walkability(20, 20);

    // Start with door open (tile walkable, is_open = true)
    let player = spawn_player(&mut world, 10, 6);
    let door = world
        .spawn((
            TilePosition::new(10, 6, 0),
            Interactable,
            ObjectType::Door,
            DoorState {
                is_open: true,
                blocking_tile: TilePosition::new(10, 5, 0),
            },
        ))
        .id();

    // Tile starts walkable (default map is all walkable)
    assert!(
        world
            .resource::<WalkabilityMap>()
            .can_move_to(&TilePosition::new(10, 5, 0)),
        "precondition: tile is walkable when door starts open"
    );

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

    world
        .entity_mut(player)
        .insert(DoorInteractRequest { door_entity: door });

    schedule.run(&mut world);

    assert!(
        !world
            .resource::<WalkabilityMap>()
            .can_move_to(&TilePosition::new(10, 5, 0)),
        "toggling an open door must block the tile"
    );
    assert!(
        !world.get::<DoorState>(door).unwrap().is_open,
        "DoorState.is_open must be false after closing an open door"
    );
}

/// Missing DoorState on target: system logs warning and removes request without panic.
#[test]
fn door_interact_without_door_state_does_not_panic() {
    let mut world = make_world_with_walkability(10, 10);
    let player = spawn_player(&mut world, 5, 5);
    let not_a_door = world.spawn(TilePosition::new(5, 6, 0)).id();

    world.entity_mut(player).insert(DoorInteractRequest {
        door_entity: not_a_door,
    });

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

    // Should not panic; request removed
    assert!(
        world.get::<DoorInteractRequest>(player).is_none(),
        "DoorInteractRequest must be consumed even when target lacks DoorState"
    );
}

// ---------------------------------------------------------------------------
// Readable examine tests
// ---------------------------------------------------------------------------

/// Acceptance: Examine on a Readable entity with ExamineText returns non-empty text.
#[test]
fn examine_readable_returns_authored_text() {
    use settled_reach_server::knowledge::events::KnowledgeEventQueue;

    let mut world = World::new();
    world.init_resource::<KnowledgeEventQueue>();
    world.init_resource::<EntityRegistry>();
    world.init_resource::<SimulationTime>();

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

    let readable = world
        .spawn((
            TilePosition::new(5, 6, 0),
            Interactable,
            ObjectType::Readable,
            ExamineText(
                "A logistics manifest. Freight records dating back three cycles.".to_string(),
            ),
        ))
        .id();

    world
        .entity_mut(player)
        .insert(ExamineRequest { target: readable });

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

    let event = world.get_mut::<ExamineResultBuffer>(player).unwrap().take();
    assert!(
        event.is_some(),
        "ExamineResultBuffer must contain a result after examining a Readable"
    );
    let text = event.unwrap().text;
    assert!(
        !text.is_empty(),
        "examine result text must be non-empty for a Readable entity"
    );
    assert!(
        text.contains("manifest") || text.contains("Freight") || text.contains("records"),
        "text should match the authored ExamineText, got: '{text}'"
    );
}

/// Examine on a Readable entity WITHOUT ExamineText returns a generic non-empty fallback.
#[test]
fn examine_readable_without_examine_text_returns_fallback() {
    use settled_reach_server::knowledge::events::KnowledgeEventQueue;

    let mut world = World::new();
    world.init_resource::<KnowledgeEventQueue>();
    world.init_resource::<EntityRegistry>();
    world.init_resource::<SimulationTime>();

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

    // Readable but no ExamineText component
    let readable = world
        .spawn((
            TilePosition::new(5, 6, 0),
            Interactable,
            ObjectType::Readable,
        ))
        .id();

    world
        .entity_mut(player)
        .insert(ExamineRequest { target: readable });

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

    let event = world.get_mut::<ExamineResultBuffer>(player).unwrap().take();
    assert!(
        event.is_some(),
        "ExamineResultBuffer must contain a result even without ExamineText"
    );
    let text = event.unwrap().text;
    assert!(
        !text.is_empty(),
        "fallback text must be non-empty, got: '{text}'"
    );
}

/// Examine out of range returns no result.
#[test]
fn examine_readable_out_of_range_returns_no_result() {
    use settled_reach_server::knowledge::events::KnowledgeEventQueue;

    let mut world = World::new();
    world.init_resource::<KnowledgeEventQueue>();
    world.init_resource::<EntityRegistry>();
    world.init_resource::<SimulationTime>();

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

    // Distance 8 > CLOSE_RANGE (2)
    let readable = world
        .spawn((
            TilePosition::new(5, 13, 0),
            Interactable,
            ObjectType::Readable,
            ExamineText("Out of range text".to_string()),
        ))
        .id();

    world
        .entity_mut(player)
        .insert(ExamineRequest { target: readable });

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

    let event = world.get_mut::<ExamineResultBuffer>(player).unwrap().take();
    assert!(
        event.is_none(),
        "examining an out-of-range Readable must not produce a result"
    );
}

// ---------------------------------------------------------------------------
// Terminal interaction tests
// ---------------------------------------------------------------------------

/// Use on a Terminal emits TerminalInteracted event.
#[test]
fn terminal_use_emits_terminal_interacted_event() {
    let mut world = World::new();
    world.init_resource::<TerminalInteractedQueue>();
    world.init_resource::<EntityRegistry>();
    world.init_resource::<SimulationTime>();

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

    let terminal = world
        .spawn((
            TilePosition::new(5, 6, 0),
            Interactable,
            ObjectType::Terminal,
        ))
        .id();

    // Register terminal in EntityRegistry so stable ID resolves
    let terminal_sid = StableId(42);
    world
        .entity_mut(terminal)
        .insert(StableEntityId(terminal_sid));
    world
        .resource_mut::<EntityRegistry>()
        .register_existing(terminal, terminal_sid);

    world.entity_mut(player).insert(TerminalInteractRequest {
        terminal_entity: terminal,
    });

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

    let queue = world.resource::<TerminalInteractedQueue>();
    assert_eq!(
        queue.events.len(),
        1,
        "one TerminalInteracted event must be emitted"
    );
    assert_eq!(
        queue.events[0].terminal_id, terminal_sid,
        "terminal_id must match the interacted terminal"
    );
}

/// TerminalInteractRequest is removed after processing.
#[test]
fn terminal_interact_request_consumed_after_processing() {
    let mut world = World::new();
    world.init_resource::<TerminalInteractedQueue>();
    world.init_resource::<EntityRegistry>();
    world.init_resource::<SimulationTime>();

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

    let terminal = world.spawn(TilePosition::new(5, 6, 0)).id();

    world.entity_mut(player).insert(TerminalInteractRequest {
        terminal_entity: terminal,
    });

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

    assert!(
        world.get::<TerminalInteractRequest>(player).is_none(),
        "TerminalInteractRequest must be removed after processing"
    );
}

// ---------------------------------------------------------------------------
// SaveStateV1.open_doors field
// ---------------------------------------------------------------------------

fn minimal_save() -> SaveStateV1 {
    SaveStateV1 {
        format_version: SAVE_FORMAT_VERSION,
        tick: 0,
        tick_rate: TickRate::Full,
        seed: 42,
        player_knowledge: KnowledgeGraph::new(),
        relationship_graph: RelationshipGraph::new(),
        npc_states: vec![],
        template_references: TemplateReferenceMap::default(),
        triangle_states: vec![],
        open_doors: vec![],
        modifications: vec![],
        contamination_active: false,
        activated_count: 0,
        last_activation_tick: None,
        selected_bookmark: settled_reach_server::bookmark::SelectedBookmark::default(),
    }
}

/// SaveStateV1.open_doors round-trips through MessagePack serialization.
#[test]
fn save_state_open_doors_roundtrip() {
    let mut save = minimal_save();
    save.open_doors = vec![StableId(10), StableId(20), StableId(30)];

    let bytes = save.to_bytes().expect("serialize");
    let recovered = SaveStateV1::from_bytes(&bytes).expect("deserialize");

    assert_eq!(
        recovered.open_doors,
        vec![StableId(10), StableId(20), StableId(30)],
        "open_doors must round-trip through MessagePack"
    );
}

/// Older save files (no open_doors field) deserialize without error.
/// The field defaults to empty vec via #[serde(default)].
#[test]
fn save_state_open_doors_defaults_to_empty_on_old_saves() {
    let save = minimal_save();
    assert!(
        save.open_doors.is_empty(),
        "open_doors must default to empty vec (backward compat with older saves)"
    );
}