smart-rgb/crates/borders-core/src/ui/mod.rs

//! UI/Frontend module for rendering and user interaction
//!
//! This module contains all frontend-related concerns including:
//! - Protocol definitions for frontend-backend communication
//! - Input handling
//! - Leaderboard management
//! - Platform transport abstraction

pub mod input;
pub mod leaderboard;
pub mod plugin;
pub mod protocol;
pub mod transport;

// Re-export commonly used types
pub use input::{InputEvent, InputState, KeyCode, MouseButton, TileCoord, WorldPos, tile_from_index, tile_to_index};
pub use leaderboard::{LastAttacksDigest, LastLeaderboardDigest, LeaderboardThrottle, build_attacks_update, build_leaderboard_snapshot, emit_attacks_update_system, emit_leaderboard_snapshot_system};
pub use plugin::FrontendPlugin;
pub use protocol::{AttackEntry, AttacksUpdatePayload, BackendMessage, CameraCommand, CameraStateUpdate, FrontendMessage, GameOutcome, LeaderboardEntry, LeaderboardSnapshot, MapQuery, MapQueryResponse, PaletteInit, RenderInit, RenderInputEvent, RgbColor, ShipUpdateVariant, ShipsUpdatePayload, SpawnCountdown, TerrainInit, TerrainPalette, TerrainType, TerritoryDelta, TerritorySnapshot, TileChange};
pub use transport::{FrontendTransport, RenderBridge, handle_camera_update, handle_render_input};

use crate::networking::GameView;
use bevy_ecs::prelude::*;
use std::collections::HashMap;

/// Resource to track currently highlighted nation for visual feedback
#[derive(Resource, Default, Debug)]
pub struct NationHighlightState {
    pub highlighted_nation: Option<u16>,
}

/// System that tracks hovered nation and emits highlight events
pub fn emit_nation_highlight_system(input_state: NonSend<std::sync::Arc<std::sync::Mutex<InputState>>>, game_view: Res<GameView>, mut highlight_state: ResMut<NationHighlightState>, mut backend_messages: MessageWriter<BackendMessage>) {
    let Ok(input) = input_state.lock() else {
        return;
    };

    let new_highlighted = if let Some(tile_coord) = input.cursor_tile() {
        let tile_index = tile_to_index(tile_coord, game_view.width());
        let owner_id = game_view.get_owner(tile_index as u32);

        // Water (65535) and unclaimed (65534) should clear highlight
        if owner_id >= 65534 { None } else { Some(owner_id) }
    } else {
        None
    };

    // Only emit if highlight changed
    if new_highlighted != highlight_state.highlighted_nation {
        highlight_state.highlighted_nation = new_highlighted;
        backend_messages.write(BackendMessage::HighlightNation { nation_id: new_highlighted });
    }
}

/// Resource to track previous ship states for delta updates
#[derive(Resource, Default)]
pub struct ShipStateTracker {
    /// Map of ship ID to current_path_index
    ship_indices: HashMap<u32, u32>,
}

/// System that emits ship update variants to the frontend (delta-based)
/// - Create: sent when ship first appears
/// - Move: sent only when current_path_index changes
/// - Destroy: sent when ship disappears
pub fn emit_ships_update_system(game_view: Res<GameView>, mut ship_tracker: ResMut<ShipStateTracker>, mut backend_messages: MessageWriter<BackendMessage>) {
    let current_ship_ids: std::collections::HashSet<u32> = game_view.ships.iter().map(|s| s.id).collect();

    let mut updates = Vec::new();

    // Detect destroyed ships
    for &ship_id in ship_tracker.ship_indices.keys() {
        if !current_ship_ids.contains(&ship_id) {
            updates.push(ShipUpdateVariant::Destroy { id: ship_id });
        }
    }

    // Detect new ships and moved ships
    for ship in &game_view.ships {
        match ship_tracker.ship_indices.get(&ship.id) {
            None => {
                // New ship - send Create
                updates.push(ShipUpdateVariant::Create { id: ship.id, owner_id: ship.owner_id, path: ship.path.clone(), troops: ship.troops });
                ship_tracker.ship_indices.insert(ship.id, ship.path_progress);
            }
            Some(&prev_index) if prev_index != ship.path_progress => {
                // Ship moved to next tile - send Move
                updates.push(ShipUpdateVariant::Move { id: ship.id, current_path_index: ship.path_progress });
                ship_tracker.ship_indices.insert(ship.id, ship.path_progress);
            }
            _ => {
                // No change, do nothing
            }
        }
    }

    // Clean up destroyed ships from tracker
    ship_tracker.ship_indices.retain(|id, _| current_ship_ids.contains(id));

    // Only send if there are updates
    if !updates.is_empty() {
        backend_messages.write(BackendMessage::ShipsUpdate(ShipsUpdatePayload { turn: game_view.turn_number, updates }));
    }
}