use super::*;
use crate::knowledge::types::KnowledgeState;
use crate::knowledge::{EntityRegistry, KnowledgeGraph};
use crate::perception::query::{ActivePerceptionMode, VisibilityGeometry};
use crate::perception::vision_cone::Facing;
use crate::simulation::monologue::MonologueBuffer;
use bevy_ecs::world::World;

/// Helper: set up a test world with resources for the two-stage observer pipeline.
fn setup_world(width: i32, height: i32) -> World {
    let mut world = World::new();
    world.insert_resource(SimulationTime::default());
    world.insert_resource(WalkabilityMap::new(width, height, 1));
    world.init_resource::<SnapshotBuffer>();
    world.init_resource::<EntityRegistry>();
    world.init_resource::<VisibilityGeometry>();
    world.init_resource::<ActivePerceptionMode>();
    world
}

/// Run the two-stage observer pipeline: geometry + snapshot.
fn run_observer_pipeline(world: &mut World) {
    let mut schedule = bevy_ecs::schedule::Schedule::default();
    schedule.add_systems((
        compute_visibility_geometry,
        compute_observer_snapshot.after(compute_visibility_geometry),
    ));
    schedule.run(world);
}

/// Run the full pipeline including interaction system.
fn run_full_pipeline(world: &mut World) {
    let mut schedule = bevy_ecs::schedule::Schedule::default();
    schedule.add_systems((
        crate::simulation::interaction::compute_nearby_interactions,
        compute_visibility_geometry,
        compute_observer_snapshot
            .after(compute_visibility_geometry)
            .after(crate::simulation::interaction::compute_nearby_interactions),
    ));
    schedule.run(world);
}

#[test]
fn player_always_visible_in_snapshot() {
    let mut world = setup_world(32, 32);
    world.spawn((
        PlayerCharacter,
        TilePosition::new(16, 16, 0),
        Facing::default(),
        KnowledgeGraph::new(),
        NearbyInteractionBuffer::default(),
        MonologueBuffer::default(),
    ));

    run_observer_pipeline(&mut world);

    let buffer = world.resource::<SnapshotBuffer>();
    let snapshot = buffer.snapshot.as_ref().expect("snapshot should exist");
    assert_eq!(snapshot.version, 6);
    assert_eq!(snapshot.entities.len(), 1);
    assert!(matches!(snapshot.entities[0].kind, EntityKind::Player));
    assert_eq!(snapshot.entities[0].observation, EntityVisibility::Visible);
}

#[test]
fn npc_in_los_visible() {
    let mut world = setup_world(32, 32);
    world.spawn((
        PlayerCharacter,
        TilePosition::new(16, 16, 0),
        Facing(FacingDirection::North),
        KnowledgeGraph::new(),
        NearbyInteractionBuffer::default(),
        MonologueBuffer::default(),
    ));
    // NPC directly north of player (in forward cone)
    world.spawn((crate::npc::Npc, TilePosition::new(16, 14, 0)));

    run_observer_pipeline(&mut world);

    let buffer = world.resource::<SnapshotBuffer>();
    let snapshot = buffer.snapshot.as_ref().unwrap();
    assert_eq!(snapshot.entities.len(), 2);
    let npc = snapshot
        .entities
        .iter()
        .find(|e| matches!(e.kind, EntityKind::Npc))
        .expect("NPC should be visible");
    assert_eq!(npc.visibility, VisibilitySector::Forward);
    assert_eq!(npc.observation, EntityVisibility::Visible);
}

#[test]
fn npc_behind_wall_not_visible() {
    let mut world = setup_world(32, 32);
    world.spawn((
        PlayerCharacter,
        TilePosition::new(16, 16, 0),
        Facing(FacingDirection::North),
        KnowledgeGraph::new(),
        NearbyInteractionBuffer::default(),
        MonologueBuffer::default(),
    ));
    // Wall between player and NPC
    let mut walkability = world.resource_mut::<WalkabilityMap>();
    walkability.set_walkable(&TilePosition::new(16, 14, 0), false);
    // NPC behind the wall
    world.spawn((crate::npc::Npc, TilePosition::new(16, 12, 0)));

    run_observer_pipeline(&mut world);

    let buffer = world.resource::<SnapshotBuffer>();
    let snapshot = buffer.snapshot.as_ref().unwrap();
    // Only player should be visible, not the NPC behind the wall
    let npcs: Vec<_> = snapshot
        .entities
        .iter()
        .filter(|e| matches!(e.kind, EntityKind::Npc))
        .collect();
    assert!(npcs.is_empty(), "NPC behind wall should not be visible");
}

#[test]
fn npc_behind_player_not_visible() {
    let mut world = setup_world(32, 32);
    world.spawn((
        PlayerCharacter,
        TilePosition::new(16, 16, 0),
        Facing(FacingDirection::North),
        KnowledgeGraph::new(),
        NearbyInteractionBuffer::default(),
        MonologueBuffer::default(),
    ));
    // NPC far behind player (south, in blind spot)
    world.spawn((crate::npc::Npc, TilePosition::new(16, 26, 0)));

    run_observer_pipeline(&mut world);

    let buffer = world.resource::<SnapshotBuffer>();
    let snapshot = buffer.snapshot.as_ref().unwrap();
    let npcs: Vec<_> = snapshot
        .entities
        .iter()
        .filter(|e| matches!(e.kind, EntityKind::Npc))
        .collect();
    assert!(npcs.is_empty(), "NPC in blind spot should not be visible");
}

#[test]
fn different_z_level_not_visible() {
    let mut world = setup_world(32, 32);
    world.spawn((
        PlayerCharacter,
        TilePosition::new(16, 16, 0),
        Facing::default(),
        KnowledgeGraph::new(),
        NearbyInteractionBuffer::default(),
        MonologueBuffer::default(),
    ));
    // NPC on different z-level
    world.spawn((crate::npc::Npc, TilePosition::new(16, 14, 1)));

    run_observer_pipeline(&mut world);

    let buffer = world.resource::<SnapshotBuffer>();
    let snapshot = buffer.snapshot.as_ref().unwrap();
    let npcs: Vec<_> = snapshot
        .entities
        .iter()
        .filter(|e| matches!(e.kind, EntityKind::Npc))
        .collect();
    assert!(npcs.is_empty(), "NPC on different z should not be visible");
}

#[test]
fn game_time_populated() {
    let mut world = setup_world(32, 32);
    let mut time = SimulationTime::default();
    time.tick = 7200; // 720 minutes = Evening
    time.tick_rate = crate::simulation::time::TickRate::Paused;
    world.insert_resource(time);
    world.spawn((
        PlayerCharacter,
        TilePosition::new(16, 16, 0),
        Facing::default(),
        KnowledgeGraph::new(),
        NearbyInteractionBuffer::default(),
        MonologueBuffer::default(),
    ));

    run_observer_pipeline(&mut world);

    let buffer = world.resource::<SnapshotBuffer>();
    let snapshot = buffer.snapshot.as_ref().unwrap();
    assert_eq!(snapshot.game_time.time_of_day, 720);
    assert_eq!(
        snapshot.game_time.day_phase,
        crate::simulation::time::DayPhase::Evening
    );
    assert_eq!(snapshot.game_time.tick_rate, crate::simulation::time::TickRate::Paused);
}

#[test]
fn visible_tiles_populated() {
    let mut world = setup_world(32, 32);
    world.spawn((
        PlayerCharacter,
        TilePosition::new(16, 16, 0),
        Facing::default(),
        KnowledgeGraph::new(),
        NearbyInteractionBuffer::default(),
        MonologueBuffer::default(),
    ));

    run_observer_pipeline(&mut world);

    let buffer = world.resource::<SnapshotBuffer>();
    let snapshot = buffer.snapshot.as_ref().unwrap();
    assert!(
        !snapshot.visible_tiles.is_empty(),
        "should have visible tiles"
    );
    // Observer's tile should be in the list
    let has_observer_tile = snapshot
        .visible_tiles
        .iter()
        .any(|t| t.x == 16 && t.y == 16 && t.z == 0);
    assert!(has_observer_tile, "observer tile should be visible");
}

#[test]
fn visible_npc_has_relationship_from_knowledge() {
    let mut world = setup_world(32, 32);
    let mut registry = EntityRegistry::new(0);

    let npc = world
        .spawn((crate::npc::Npc, TilePosition::new(16, 14, 0)))
        .id();
    let npc_sid = registry.register(npc);

    // Player knows NPC is hostile
    let mut kg = KnowledgeGraph::new();
    kg.observe_entity(npc_sid, TilePosition::new(16, 14, 0), 50);
    kg.set_relationship(&npc_sid, RelationshipState::Hostile);

    world.spawn((
        PlayerCharacter,
        TilePosition::new(16, 16, 0),
        Facing(FacingDirection::North),
        kg,
        NearbyInteractionBuffer::default(),
        MonologueBuffer::default(),
    ));

    world.insert_resource(registry);

    run_observer_pipeline(&mut world);

    let buffer = world.resource::<SnapshotBuffer>();
    let snapshot = buffer.snapshot.as_ref().unwrap();
    let npc_entity = snapshot
        .entities
        .iter()
        .find(|e| matches!(e.kind, EntityKind::Npc))
        .expect("NPC should be visible");
    assert_eq!(npc_entity.relationship, RelationshipState::Hostile);
    assert_eq!(npc_entity.observation, EntityVisibility::Visible);
}

#[test]
fn remembered_entity_appears_as_ghost() {
    let mut world = setup_world(32, 32);
    let mut registry = EntityRegistry::new(0);

    // NPC exists far behind the player (not visible)
    let npc = world
        .spawn((crate::npc::Npc, TilePosition::new(16, 30, 0)))
        .id();
    let npc_sid = registry.register(npc);

    // Player previously saw NPC at (16, 28) — behind the player (south),
    // well beyond peripheral range. The tile is NOT in the player's FOV.
    let mut kg = KnowledgeGraph::new();
    kg.observe_entity(npc_sid, TilePosition::new(16, 28, 0), 50);
    kg.observe_entity_leaving_los(&npc_sid, 60);
    kg.set_relationship(&npc_sid, RelationshipState::PersonOfInterest);

    let player = world
        .spawn((
            PlayerCharacter,
            TilePosition::new(16, 16, 0),
            Facing(FacingDirection::North),
            kg,
            NearbyInteractionBuffer::default(),
            MonologueBuffer::default(),
        ))
        .id();
    registry.register(player);
    world.insert_resource(registry);
    world.insert_resource({ let mut t = SimulationTime::default(); t.tick = 100; t });

    run_observer_pipeline(&mut world);

    let buffer = world.resource::<SnapshotBuffer>();
    let snapshot = buffer.snapshot.as_ref().unwrap();

    // Should have player (visible) + NPC (remembered)
    let remembered: Vec<_> = snapshot
        .entities
        .iter()
        .filter(|e| matches!(e.observation, EntityVisibility::Remembered { .. }))
        .collect();
    assert_eq!(remembered.len(), 1, "should have one remembered entity");
    assert_eq!(remembered[0].relationship, RelationshipState::PersonOfInterest);

    // Remembered entity at last_known_position (16, 28), not actual (16, 30)
    assert_eq!(remembered[0].x, 16.5);
    assert_eq!(remembered[0].y, 28.5);

    if let EntityVisibility::Remembered { confidence, age_ticks } = &remembered[0].observation {
        assert_eq!(*confidence, KnowledgeConfidence::KnowsDetails);
        assert_eq!(*age_ticks, 50); // tick 100 - last_observed 50
    }
}

#[test]
fn direct_confidence_not_shown_as_remembered() {
    let mut world = setup_world(32, 32);
    let mut registry = EntityRegistry::new(0);

    // NPC exists but not in LOS
    let npc = world
        .spawn((crate::npc::Npc, TilePosition::new(16, 10, 0)))
        .id();
    let npc_sid = registry.register(npc);

    // Knowledge still shows Direct (transient inconsistency)
    let mut kg = KnowledgeGraph::new();
    kg.observe_entity(npc_sid, TilePosition::new(16, 14, 0), 50);
    // Still Direct — don't show as ghost

    let player = world
        .spawn((
            PlayerCharacter,
            TilePosition::new(16, 16, 0),
            Facing(FacingDirection::North),
            kg,
            NearbyInteractionBuffer::default(),
            MonologueBuffer::default(),
        ))
        .id();
    registry.register(player);

    // Wall blocks actual NPC position
    let mut walkability = world.resource_mut::<WalkabilityMap>();
    walkability.set_walkable(&TilePosition::new(16, 12, 0), false);

    world.insert_resource(registry);

    run_observer_pipeline(&mut world);

    let buffer = world.resource::<SnapshotBuffer>();
    let snapshot = buffer.snapshot.as_ref().unwrap();

    let remembered: Vec<_> = snapshot
        .entities
        .iter()
        .filter(|e| matches!(e.observation, EntityVisibility::Remembered { .. }))
        .collect();
    assert!(
        remembered.is_empty(),
        "Direct-confidence entities should not appear as remembered ghosts"
    );
}

#[test]
fn remembered_entity_on_visible_tile_not_shown() {
    // If the player can see a tile and the entity isn't there,
    // don't show a ghost — the player knows it moved.
    let mut world = setup_world(32, 32);
    let mut registry = EntityRegistry::new(0);

    let npc = world
        .spawn((crate::npc::Npc, TilePosition::new(30, 30, 0)))
        .id();
    let npc_sid = registry.register(npc);

    // Player remembers NPC at (16, 15) — a tile the player can currently see
    let mut kg = KnowledgeGraph::new();
    kg.observe_entity(npc_sid, TilePosition::new(16, 15, 0), 50);
    kg.observe_entity_leaving_los(&npc_sid, 60);

    let player = world
        .spawn((
            PlayerCharacter,
            TilePosition::new(16, 16, 0),
            Facing(FacingDirection::North),
            kg,
            NearbyInteractionBuffer::default(),
            MonologueBuffer::default(),
        ))
        .id();
    registry.register(player);
    world.insert_resource(registry);

    run_observer_pipeline(&mut world);

    let buffer = world.resource::<SnapshotBuffer>();
    let snapshot = buffer.snapshot.as_ref().unwrap();

    let remembered: Vec<_> = snapshot
        .entities
        .iter()
        .filter(|e| matches!(e.observation, EntityVisibility::Remembered { .. }))
        .collect();
    assert!(
        remembered.is_empty(),
        "ghost should not appear on a tile the player can currently see"
    );
}

#[test]
fn remembered_entity_different_z_not_shown() {
    // Remembered entity on a different z-level should not appear
    let mut world = setup_world(32, 32);
    let mut registry = EntityRegistry::new(0);

    let npc = world
        .spawn((crate::npc::Npc, TilePosition::new(5, 5, 1)))
        .id();
    let npc_sid = registry.register(npc);

    // Player remembers NPC at z=1, but player is at z=0
    let mut kg = KnowledgeGraph::new();
    kg.observe_entity(npc_sid, TilePosition::new(5, 5, 1), 50);
    kg.observe_entity_leaving_los(&npc_sid, 60);

    let player = world
        .spawn((
            PlayerCharacter,
            TilePosition::new(16, 16, 0),
            Facing(FacingDirection::North),
            kg,
            NearbyInteractionBuffer::default(),
            MonologueBuffer::default(),
        ))
        .id();
    registry.register(player);
    world.insert_resource(registry);

    run_observer_pipeline(&mut world);

    let buffer = world.resource::<SnapshotBuffer>();
    let snapshot = buffer.snapshot.as_ref().unwrap();

    let remembered: Vec<_> = snapshot
        .entities
        .iter()
        .filter(|e| matches!(e.observation, EntityVisibility::Remembered { .. }))
        .collect();
    assert!(
        remembered.is_empty(),
        "remembered entity on different z-level should not appear in snapshot"
    );
}

#[test]
fn knowledge_without_position_not_shown() {
    // Entity known via gossip (no last_known_position) should not appear
    let mut world = setup_world(32, 32);
    let mut registry = EntityRegistry::new(0);

    let npc = world
        .spawn((crate::npc::Npc, TilePosition::new(5, 5, 0)))
        .id();
    let npc_sid = registry.register(npc);

    // Player knows about NPC but has never seen it (no position)
    let mut kg = KnowledgeGraph::new();
    // Insert knowledge manually without a position
    kg.entities.insert(npc_sid, crate::knowledge::EntityKnowledge {
        last_known_position: None,
        last_observed_tick: 0,
        last_updated_tick: 50,
        confidence: KnowledgeConfidence::KnowsOf,
        source: crate::knowledge::KnowledgeSource::Background,
        state: crate::knowledge::KnowledgeState::Active,
        relationship: RelationshipState::PersonOfInterest,
        known_attributes: std::collections::BTreeMap::new(),
    });

    let player = world
        .spawn((
            PlayerCharacter,
            TilePosition::new(16, 16, 0),
            Facing(FacingDirection::North),
            kg,
            NearbyInteractionBuffer::default(),
            MonologueBuffer::default(),
        ))
        .id();
    registry.register(player);
    world.insert_resource(registry);

    run_observer_pipeline(&mut world);

    let buffer = world.resource::<SnapshotBuffer>();
    let snapshot = buffer.snapshot.as_ref().unwrap();

    let remembered: Vec<_> = snapshot
        .entities
        .iter()
        .filter(|e| matches!(e.observation, EntityVisibility::Remembered { .. }))
        .collect();
    assert!(
        remembered.is_empty(),
        "entity without last_known_position should not appear as ghost"
    );
}

#[test]
fn multiple_npcs_in_los_all_visible() {
    let mut world = setup_world(32, 32);
    world.spawn((
        PlayerCharacter,
        TilePosition::new(16, 16, 0),
        Facing(FacingDirection::North),
        KnowledgeGraph::new(),
        NearbyInteractionBuffer::default(),
        MonologueBuffer::default(),
    ));
    // Three NPCs in front of player, no walls
    world.spawn((crate::npc::Npc, TilePosition::new(16, 14, 0)));
    world.spawn((crate::npc::Npc, TilePosition::new(14, 14, 0)));
    world.spawn((crate::npc::Npc, TilePosition::new(18, 14, 0)));

    run_observer_pipeline(&mut world);

    let buffer = world.resource::<SnapshotBuffer>();
    let snapshot = buffer.snapshot.as_ref().unwrap();
    // Player + 3 NPCs = 4 entities
    assert_eq!(snapshot.entities.len(), 4);
    let npcs: Vec<_> = snapshot
        .entities
        .iter()
        .filter(|e| matches!(e.kind, EntityKind::Npc))
        .collect();
    assert_eq!(npcs.len(), 3);
    assert!(npcs.iter().all(|n| n.observation == EntityVisibility::Visible));
}

#[test]
fn npc_behind_wall_excluded_from_multi_entity_snapshot() {
    let mut world = setup_world(32, 32);
    // Wall at (16,14)
    world
        .resource_mut::<WalkabilityMap>()
        .set_walkable(&TilePosition::new(16, 14, 0), false);

    world.spawn((
        PlayerCharacter,
        TilePosition::new(16, 16, 0),
        Facing(FacingDirection::North),
        KnowledgeGraph::new(),
        NearbyInteractionBuffer::default(),
        MonologueBuffer::default(),
    ));
    // NPC 1: behind wall (should be hidden)
    world.spawn((crate::npc::Npc, TilePosition::new(16, 13, 0)));
    // NPC 2: to the side, no wall (should be visible)
    world.spawn((crate::npc::Npc, TilePosition::new(14, 14, 0)));
    // NPC 3: also visible
    world.spawn((crate::npc::Npc, TilePosition::new(18, 15, 0)));

    run_observer_pipeline(&mut world);

    let buffer = world.resource::<SnapshotBuffer>();
    let snapshot = buffer.snapshot.as_ref().unwrap();
    // Player + 2 visible NPCs = 3 (NPC behind wall excluded)
    let npcs: Vec<_> = snapshot
        .entities
        .iter()
        .filter(|e| matches!(e.kind, EntityKind::Npc))
        .collect();
    assert_eq!(npcs.len(), 2, "NPC behind wall should be excluded");
}

#[test]
fn poi_interaction_gets_observe_first_priority() {
    let mut world = setup_world(32, 32);
    let mut registry = EntityRegistry::new(0);

    // NPC in close range, directly north of player and in LOS
    let npc = world
        .spawn((
            crate::npc::Npc,
            TilePosition::new(16, 15, 0),
            crate::simulation::interaction::Interactable,
        ))
        .id();
    let npc_sid = registry.register(npc);

    // Player knows NPC as PersonOfInterest
    let mut kg = KnowledgeGraph::new();
    kg.observe_entity(npc_sid, TilePosition::new(16, 15, 0), 50);
    kg.set_relationship(&npc_sid, RelationshipState::PersonOfInterest);

    let player = world
        .spawn((
            PlayerCharacter,
            TilePosition::new(16, 16, 0),
            Facing(FacingDirection::North),
            kg,
            NearbyInteractionBuffer::default(),
            MonologueBuffer::default(),
        ))
        .id();
    registry.register(player);
    world.insert_resource(registry);

    // Run full pipeline: interaction computes default priority,
    // then observer applies POI adjustment
    run_full_pipeline(&mut world);

    let buffer = world.resource::<SnapshotBuffer>();
    let snapshot = buffer.snapshot.as_ref().unwrap();
    assert_eq!(snapshot.nearby_interactions.len(), 1);
    let interaction = &snapshot.nearby_interactions[0];
    // POI: Observe takes priority over Talk
    assert_eq!(interaction.verbs[0].kind, VerbKind::ExamineNpc);
    assert_eq!(interaction.verbs[0].priority, 1);
    assert_eq!(interaction.verbs[1].kind, VerbKind::Talk);
    assert_eq!(interaction.verbs[1].priority, 2);
}

// -----------------------------------------------------------------------
// v6 field tests (Hoshe QA, Sprint 6 — #449)
// -----------------------------------------------------------------------

#[test]
fn snapshot_v6_fields_default_through_pipeline() {
    // Until #417 (stance) and #424 (inventory) wire up the components,
    // the observer system should produce Walk stance and empty inventory.
    let mut world = setup_world(32, 32);
    world.spawn((
        PlayerCharacter,
        TilePosition::new(16, 16, 0),
        Facing::default(),
        KnowledgeGraph::new(),
        NearbyInteractionBuffer::default(),
        MonologueBuffer::default(),
    ));

    run_observer_pipeline(&mut world);

    let buffer = world.resource::<SnapshotBuffer>();
    let snapshot = buffer.snapshot.as_ref().expect("snapshot should exist");

    assert_eq!(snapshot.version, 6, "should be protocol v6");
    assert_eq!(snapshot.player_stance, MovementStance::Walk, "default stance is Walk");
    assert!(snapshot.player_inventory.is_empty(), "default inventory is empty");
}

#[test]
fn snapshot_v6_version_is_protocol_version() {
    let mut world = setup_world(32, 32);
    world.spawn((
        PlayerCharacter,
        TilePosition::new(16, 16, 0),
        Facing::default(),
        KnowledgeGraph::new(),
        NearbyInteractionBuffer::default(),
        MonologueBuffer::default(),
    ));

    run_observer_pipeline(&mut world);

    let buffer = world.resource::<SnapshotBuffer>();
    let snapshot = buffer.snapshot.as_ref().unwrap();
    assert_eq!(
        snapshot.version,
        crate::bridge::types::PROTOCOL_VERSION,
        "snapshot version must match PROTOCOL_VERSION constant"
    );
}