//! Stub worker resources (#843 Part C).
//!
//! Each worker type is a Bevy Resource wrapping a typed `BackgroundWorkerPool`.
//! The actual computation logic is a no-op placeholder — implementations
//! plug in when the phases that need them arrive (Phase 5+).
//!
//! The infrastructure (channels, threads, push/poll) is real and tested.

use bevy_ecs::prelude::*;

use super::pool::BackgroundWorkerPool;

// ---------------------------------------------------------------------------
// ChunkGen — terrain, buildings, props, navmesh for a world chunk
// ---------------------------------------------------------------------------

/// Request to generate a chunk at the given coordinates.
#[derive(Debug, Clone)]
pub struct ChunkGenRequest {
    pub chunk_x: i32,
    pub chunk_y: i32,
    pub chunk_z: i32,
    pub world_seed: u64,
}

/// Generated chunk data (placeholder — real struct will hold terrain, props, navmesh).
#[derive(Debug)]
pub struct ChunkGenResult {
    pub chunk_x: i32,
    pub chunk_y: i32,
    pub chunk_z: i32,
    /// Placeholder: real result holds terrain heightfield, building list, prop list, navmesh.
    pub generated: bool,
}

/// Bevy resource for the chunk generation worker pool.
#[derive(Resource)]
pub struct ChunkGenWorker {
    pub pool: BackgroundWorkerPool<ChunkGenRequest, ChunkGenResult>,
}

impl ChunkGenWorker {
    pub fn new(thread_count: usize) -> Self {
        Self {
            pool: BackgroundWorkerPool::spawn(thread_count, |req: ChunkGenRequest| {
                // Stub: real implementation generates terrain from seed + coordinates
                ChunkGenResult {
                    chunk_x: req.chunk_x,
                    chunk_y: req.chunk_y,
                    chunk_z: req.chunk_z,
                    generated: true,
                }
            }),
        }
    }
}

// ---------------------------------------------------------------------------
// NpcPrep — pre-compute NPC state for areas about to become visible
// ---------------------------------------------------------------------------

/// Request to prepare NPCs for an area.
#[derive(Debug, Clone)]
pub struct NpcPrepRequest {
    pub area_id: String,
    pub world_seed: u64,
}

/// Prepared NPC state (placeholder).
#[derive(Debug)]
pub struct NpcPrepResult {
    pub area_id: String,
    pub npc_count: usize,
}

/// Bevy resource for the NPC preparation worker pool.
#[derive(Resource)]
pub struct NpcPrepWorker {
    pub pool: BackgroundWorkerPool<NpcPrepRequest, NpcPrepResult>,
}

impl NpcPrepWorker {
    pub fn new(thread_count: usize) -> Self {
        Self {
            pool: BackgroundWorkerPool::spawn(thread_count, |req: NpcPrepRequest| {
                // Stub: real implementation pre-generates NPC appearance, inventory, mood
                NpcPrepResult {
                    area_id: req.area_id,
                    npc_count: 0,
                }
            }),
        }
    }
}

// ---------------------------------------------------------------------------
// OffscreenTick — advance NPC state for entities outside the active tier
// ---------------------------------------------------------------------------

/// Request to advance off-screen NPCs by a specific number of ticks.
#[derive(Debug, Clone)]
pub struct OffscreenTickRequest {
    pub area_id: String,
    /// Exact number of simulation ticks to advance. Deterministic.
    pub ticks_to_advance: u64,
    pub world_seed: u64,
}

/// Updated NPC state after off-screen ticking (placeholder).
#[derive(Debug)]
pub struct OffscreenTickResult {
    pub area_id: String,
    pub ticks_advanced: u64,
}

/// Bevy resource for the off-screen tick worker pool.
#[derive(Resource)]
pub struct OffscreenTickWorker {
    pub pool: BackgroundWorkerPool<OffscreenTickRequest, OffscreenTickResult>,
}

impl OffscreenTickWorker {
    pub fn new(thread_count: usize) -> Self {
        Self {
            pool: BackgroundWorkerPool::spawn(thread_count, |req: OffscreenTickRequest| {
                // Stub: real implementation snapshots NPC state, advances N ticks
                OffscreenTickResult {
                    area_id: req.area_id,
                    ticks_advanced: req.ticks_to_advance,
                }
            }),
        }
    }
}