// Simulation module - Core simulation plugin and systems
// Implements deterministic tick-based simulation (D-010 principle 4)

use bevy_app::prelude::*;
use bevy_ecs::schedule::IntoScheduleConfigs;

pub mod chunk_streaming;
// Phase sub-plugins (#843)
pub mod contraband;
pub mod dialogue;
pub mod economy;
pub mod economy_plugin;
pub mod examine;
pub mod follow;
pub mod generator;
pub mod input;
pub mod input_plugin;
pub mod interaction;
pub mod inventory;
pub mod knowledge_grant;
pub mod line_pool;
pub mod listening;
pub mod modification;
pub mod monologue;
pub mod movement;
pub mod movement_plugin;
pub mod npc_components;
pub mod npc_knowledge_transfer;
pub mod path_follow;
pub mod pathfinding;
pub mod poi;
pub mod poi_discovery;
pub mod pressure;
pub mod rng;
pub mod save_io;
pub mod save_state;
pub mod social_plugin;
pub mod sound;
pub mod spatial;
pub mod stance;
pub mod ticker;
pub mod tier;
pub mod time;
pub mod time_plugin;
pub mod triangle;
pub mod zone;

/// Core simulation plugin — shell that delegates to phase sub-plugins (#843).
///
/// Each sub-plugin owns its domain's systems, resources, and phase assignment.
/// No system registration happens here — only sub-plugin composition and
/// shared resources needed by multiple sub-plugins.
///
/// `seed` is threaded through to [`economy_plugin::EconomyPlugin`] so the
/// economy simulation uses the world seed from `StartupMessage` (#826).
pub struct SimulationPlugin {
    pub seed: u64,
}

impl Plugin for SimulationPlugin {
    fn build(&self, app: &mut App) {
        // Tier marker components (D-026) — must register before behavior systems
        app.add_plugins(tier::TierPlugin);

        // Shared resources needed by multiple sub-plugins.
        // Each sub-plugin inits its own domain-specific resources.
        app.insert_resource(rng::SimRng::new(self.seed))
            .init_resource::<save_io::SaveLoadPending>()
            .init_resource::<crate::knowledge::EntityRegistry>()
            // Triangle escalation event queue (#250) — consumed by storyteller + npc plugins
            .init_resource::<triangle::TriangleCrisisEventQueue>()
            // Cross-plugin resource safety: init resources that may be read by other plugins
            // before those plugins register. Prevents "resource not found" in standalone tests.
            .init_resource::<crate::perception::query::VisibilityGeometry>()
            .init_resource::<crate::npc::relationships::RelationshipGraph>()
            .init_resource::<crate::knowledge::KnowledgeEventQueue>();

        // Background worker pools (#843 Part C) — off-tick computation on separate cores.
        // Stub handlers for now; real implementations plug in at Phase 5+.
        app.insert_resource(crate::workers::stubs::ChunkGenWorker::new(2));
        app.insert_resource(crate::workers::stubs::NpcPrepWorker::new(1));
        app.insert_resource(crate::workers::stubs::OffscreenTickWorker::new(1));

        // Phase sub-plugins (#843) — each owns its domain
        app.add_plugins(time_plugin::TimePlugin);
        app.add_plugins(input_plugin::InputPlugin);
        app.add_plugins(movement_plugin::MovementPlugin);
        app.add_plugins(social_plugin::SocialPlugin);
        app.add_plugins(economy_plugin::EconomyPlugin { seed: self.seed });

        // Background worker tick integration (#843 Part C)
        app.add_systems(
            Update,
            crate::workers::systems::poll_worker_results
                .in_set(crate::tick_phases::TickPhase::PreInput),
        );
        app.add_systems(
            Update,
            crate::workers::systems::push_worker_requests
                .in_set(crate::tick_phases::TickPhase::PostSnapshot),
        );

        // save_load is an exclusive system (takes &mut World).
        // Exclusive systems in Bevy 0.18 cannot use .in_set() — use .before()/.after()
        // to position it within the Snapshot phase window.
        app.add_systems(
            Update,
            save_io::execute_save_load
                .before(crate::perception::observer::compute_observer_snapshot),
        );

        tracing::debug!("SimulationPlugin initialized");
    }
}