shadowengine2d 2.0.0

/*
 * MIT License
 * 
 * Copyright (c) 2025 ShadowEngine2D
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

use crate::EngineResult;
use winit::{
    application::ApplicationHandler,
    event::{DeviceEvent, DeviceId, StartCause, WindowEvent},
    event_loop::{ActiveEventLoop, EventLoop},
    window::{WindowId, WindowAttributes, Window as WinitWindow},
};
use std::sync::Arc;

#[derive(Debug, Clone)]
pub struct WindowConfig {
    pub title: String,
    pub width: u32,
    pub height: u32,
    pub resizable: bool,
}

impl Default for WindowConfig {
    fn default() -> Self {
        Self {
            title: "ShadowEngine2D".to_string(),
            width: 800,
            height: 600,
            resizable: true,
        }
    }
}

pub struct Window {
    pub window: Arc<WinitWindow>,
    pub config: WindowConfig,
}

impl Window {
    pub fn new(window: WinitWindow, config: WindowConfig) -> Self {
        Self {
            window: Arc::new(window),
            config,
        }
    }

    pub fn inner_size(&self) -> (u32, u32) {
        let size = self.window.inner_size();
        (size.width, size.height)
    }

    pub fn set_title(&self, title: &str) {
        self.window.set_title(title);
    }
}

pub trait AppHandler {
    fn on_init(&mut self, window: &Window) -> EngineResult<()> {
        Ok(())
    }
    
    fn on_update(&mut self, window: &Window, delta_time: f32) -> EngineResult<()>;
    
    fn on_render(&mut self, window: &Window) -> EngineResult<()>;
    
    fn on_window_event(&mut self, window: &Window, event: &WindowEvent) -> EngineResult<()> {
        Ok(())
    }
    
    fn on_exit(&mut self) {}
}

pub struct EventLoopHandler {
    window: Option<Window>,
    config: WindowConfig,
    app_handler: Box<dyn AppHandler>,
    last_frame: std::time::Instant,
}

impl EventLoopHandler {
    pub fn new(config: WindowConfig, app_handler: Box<dyn AppHandler>) -> Self {
        Self {
            window: None,
            config,
            app_handler,
            last_frame: std::time::Instant::now(),
        }
    }
}

impl ApplicationHandler for EventLoopHandler {
    fn resumed(&mut self, event_loop: &ActiveEventLoop) {
        if self.window.is_none() {
            let window_attrs = WindowAttributes::default()
                .with_title(&self.config.title)
                .with_inner_size(winit::dpi::LogicalSize::new(
                    self.config.width, 
                    self.config.height
                ))
                .with_resizable(self.config.resizable);

            match event_loop.create_window(window_attrs) {
                Ok(winit_window) => {
                    let window = Window::new(winit_window, self.config.clone());
                    if let Err(e) = self.app_handler.on_init(&window) {
                        eprintln!("Initialization error: {}", e);
                        event_loop.exit();
                        return;
                    }
                    self.window = Some(window);
                },
                Err(e) => {
                    eprintln!("Failed to create window: {}", e);
                    event_loop.exit();
                }
            }
        }
    }

    fn new_events(&mut self, _event_loop: &ActiveEventLoop, _cause: StartCause) {
        if let Some(window) = &self.window {
            let now = std::time::Instant::now();
            let delta_time = now.duration_since(self.last_frame).as_secs_f32();
            self.last_frame = now;

            if let Err(e) = self.app_handler.on_update(window, delta_time) {
                eprintln!("Update error: {}", e);
            }

            if let Err(e) = self.app_handler.on_render(window) {
                eprintln!("Render error: {}", e);
            }
            
            window.window.request_redraw();
        }
    }

    fn window_event(
        &mut self,
        event_loop: &ActiveEventLoop,
        _window_id: WindowId,
        event: WindowEvent,
    ) {
        if let Some(window) = &self.window {
            match &event {
                WindowEvent::CloseRequested => {
                    self.app_handler.on_exit();
                    event_loop.exit();
                },
                _ => {
                    if let Err(e) = self.app_handler.on_window_event(window, &event) {
                        eprintln!("Window event error: {}", e);
                    }
                }
            }
        }
    }

    fn device_event(
        &mut self,
        _event_loop: &ActiveEventLoop,
        _device_id: DeviceId,
        _event: DeviceEvent,
    ) {

    }
}

pub fn run_window(config: WindowConfig, app_handler: Box<dyn AppHandler>) -> EngineResult<()> {
    let event_loop = EventLoop::new()?;
    event_loop.set_control_flow(winit::event_loop::ControlFlow::Poll);
    
    let mut handler = EventLoopHandler::new(config, app_handler);
    event_loop.run_app(&mut handler)?;
    
    Ok(())
}