use std::collections::HashMap;
use std::ops::Deref;
use std::sync::Arc;

use ctx::WgpuCtx;
use tracing::{debug, error, info, trace, warn};
use wgpu::rwh::HasWindowHandle;
use winit::application::ApplicationHandler;
use winit::event::{KeyEvent, WindowEvent};
use winit::event_loop::{ActiveEventLoop, ControlFlow, EventLoop};
use winit::window::Window;
use winit::window::WindowId;

pub mod ctx;

struct WindowContext<'window> {
    window: Arc<Window>,
    ctx: WgpuCtx<'window>,
    main_window: bool,
}
impl Deref for WindowContext<'_> {
    type Target = winit::window::Window;

    fn deref(&self) -> &Self::Target {
        self.window.as_ref()
    }
}
impl WindowContext<'_> {
    pub fn is_main_window(&self) -> bool {
        self.main_window
    }
}

#[derive(Default)]
pub struct App<'window> {
    windows: HashMap<WindowId, WindowContext<'window>>,
}

impl App<'_> {
    fn create_main_window(&mut self, event_loop: &ActiveEventLoop) {
        let win_attr = Window::default_attributes().with_title("Zenyx");
        match event_loop.create_window(win_attr) {
            Ok(window) => {
                let window = Arc::new(window);
                let window_id = window.id();
                match WgpuCtx::new_blocking(window.clone()) {
                    Ok(wgpu_ctx) => {
                        self.windows.insert(
                            window_id,
                            WindowContext {
                                window,
                                ctx: wgpu_ctx,
                                main_window: true,
                            },
                        );
                        info!("Main window created: {:?}", window_id);
                    }
                    Err(e) => error!("Failed to create WGPU context: {:?}", e),
                }
            }
            Err(e) => error!("Failed to create main window: {:?}", e),
        }
    }

    fn handle_close_requested(&mut self, window_id: WindowId) {
        if self.windows.remove(&window_id).is_some() {
            debug!("Window {:?} closed", window_id);
        } else {
            warn!("Tried to close non-existent window {:?}", window_id);
        }
    }

    fn handle_keyboard_input(
        &mut self,
        event_loop: &ActiveEventLoop,
        window_id: WindowId,
        key_event: KeyEvent,
    ) {
        if !key_event.state.is_pressed() {
            return;
        }
        match key_event.physical_key {
            winit::keyboard::PhysicalKey::Code(code) => match code {
                winit::keyboard::KeyCode::Space => {
                    self.toggle_background(window_id);
                }
                winit::keyboard::KeyCode::Escape => {
                    self.spawn_child_window(event_loop);
                }
                other => error!("Unimplemented keycode: {:?}", other),
            },
            _ => debug!("Received a keyboard event with no physical key"),
        }
    }

    fn toggle_background(&mut self, window_id: WindowId) {
        if let Some(window_context) = self.windows.get_mut(&window_id) {
            let current_color = window_context.ctx.bg_color();
            let new_color = match current_color {
                wgpu::Color::WHITE => wgpu::Color::BLACK,
                wgpu::Color::BLACK => wgpu::Color::WHITE,
                _ => wgpu::Color::WHITE,
            };
            window_context.ctx.change_bg_color(new_color);
            debug!("Toggled background color for window {:?}", window_id);
        } else {
            warn!("No window context for toggling background: {:?}", window_id);
        }
    }

    fn spawn_child_window(&mut self, event_loop: &ActiveEventLoop) {
        if let Some(main_ctx) = self.windows.values().find(|ctx| ctx.is_main_window()) {
            let title = format!("Zenyx - New Window {}", self.windows.len());
            //TODO: Verify that this is safe instead of matching on it
            let win_attr = unsafe {
                let base = Window::default_attributes().with_title(title);
                match main_ctx.window_handle() {
                    Ok(handle) => base.with_parent_window(Some(handle.as_raw())),
                    Err(_) => base,
                }
            };
            match event_loop.create_window(win_attr) {
                Ok(window) => {
                    let window = Arc::new(window);
                    let window_id = window.id();
                    match WgpuCtx::new_blocking(window.clone()) {
                        Ok(wgpu_ctx) => {
                            self.windows.insert(
                                window_id,
                                WindowContext {
                                    window,
                                    ctx: wgpu_ctx,
                                    main_window: false,
                                },
                            );
                            debug!("Spawned new child window: {:?}", window_id);
                        }
                        Err(e) => error!("Failed to create WGPU context for child window: {:?}", e),
                    }
                }
                Err(e) => error!("Failed to create child window: {:?}", e),
            }
        } else {
            error!("No main window found. Cannot spawn a child window.");
        }
    }

    fn handle_redraw_requested(&mut self, window_id: WindowId) {
        if let Some(window_context) = self.windows.get_mut(&window_id) {
            window_context.ctx.draw();
            window_context.request_redraw();
            trace!(
                "Redrew window {:?} with title: {}",
                window_id,
                window_context.window.title()
            );
        } else {
            warn!("Received redraw for unknown window {:?}", window_id);
        }
    }

    fn handle_resize(&mut self, window_id: WindowId, new_size: winit::dpi::PhysicalSize<u32>) {
        if let Some(window_context) = self.windows.get_mut(&window_id) {
            window_context.ctx.resize(new_size.into());
            window_context.window.request_redraw();
            debug!(
                "Resized window {:?} to {}x{}",
                window_id, new_size.width, new_size.height
            );
        } else {
            warn!("Received resize for unknown window {:?}", window_id);
        }
    }

    fn handle_destroyed(&mut self, event_loop: &ActiveEventLoop) {
        if self.windows.is_empty() || !self.windows.iter().any(|(_, ctx)| ctx.is_main_window()) {
            self.windows.clear();
            debug!("All main windows are closed. Exiting event loop.");
            event_loop.exit();
        }
    }
}

impl ApplicationHandler for App<'_> {
    fn resumed(&mut self, event_loop: &ActiveEventLoop) {
        if self.windows.is_empty() {
            self.create_main_window(event_loop);
        }
    }

    fn window_event(
        &mut self,
        event_loop: &ActiveEventLoop,
        window_id: WindowId,
        event: WindowEvent,
    ) {
        match event {
            WindowEvent::CloseRequested => {
                self.handle_close_requested(window_id);
            }
            WindowEvent::KeyboardInput {
                event: key_event, ..
            } => {
                self.handle_keyboard_input(event_loop, window_id, key_event);
            }
            WindowEvent::RedrawRequested => {
                self.handle_redraw_requested(window_id);
            }
            WindowEvent::Resized(new_size) => {
                self.handle_resize(window_id, new_size);
            }
            WindowEvent::Destroyed => {
                self.handle_destroyed(event_loop);
            }
            _ => trace!("Unhandled window event for window {:?}", window_id),
        }
    }
}

pub fn init_renderer(event_loop: EventLoop<()>) {
    event_loop.set_control_flow(ControlFlow::Wait);
    let mut app = App::default();
    if let Err(e) = event_loop.run_app(&mut app) {
        error!("Failed to run application: {:?}", e);
    }
}