use std::collections::HashMap;
use std::path::PathBuf;
use std::time::Instant;

use canary::{PanelId, ScriptAbiImpl, ScriptInstance, WasmtimeRuntime, WasmtimeScript};
use glium::backend::glutin::DisplayCreationError;
use glium::{glutin, Surface};
use glutin::event::{Event, WindowEvent};
use glutin::event_loop::{ControlFlow, EventLoop, EventLoopProxy, EventLoopWindowTarget};
use glutin::window::WindowId;

use crate::gl::Graphics;
use crate::ipc::{IpcMessage, IpcMessageSender};

pub enum WindowMessage {
    OpenWindow { id: usize, script: PathBuf },
    CloseWindow { id: usize },
    Quit,
}

pub type WindowMessageSender = EventLoopProxy<WindowMessage>;

pub struct Window {
    pub graphics: Graphics,
    pub script: WasmtimeScript<ScriptAbiImpl>,
    pub panel: PanelId,
    pub last_update: Instant,
}

impl Window {
    pub fn new(
        script: WasmtimeScript<ScriptAbiImpl>,
        panel: PanelId,
        event_loop: &EventLoopWindowTarget<WindowMessage>,
    ) -> Result<Self, DisplayCreationError> {
        let wb = glutin::window::WindowBuilder::new();
        let cb = glutin::ContextBuilder::new();
        let display = glium::Display::new(wb, cb, &event_loop)?;
        let graphics = Graphics::new(display);
        let last_update = Instant::now();
        Ok(Self {
            graphics,
            script,
            panel,
            last_update,
        })
    }

    pub fn get_id(&self) -> WindowId {
        self.graphics.display.gl_window().window().id()
    }

    pub fn request_redraw(&mut self) {
        self.graphics.display.gl_window().window().request_redraw();
    }
    
    pub fn update(&mut self) {
        let now = Instant::now();
        let dt = now.duration_since(self.last_update).as_secs_f32();
        self.script.update(self.panel, dt);
    }

    pub fn draw(&mut self) {
        self.script.draw(self.panel, |commands| {
            self.graphics.draw(commands);
        });
    }
}

pub struct WindowStore {
    pub ipc_sender: IpcMessageSender,
    pub ipc_to_window: HashMap<usize, WindowId>,
    pub windows: HashMap<WindowId, Window>,
    pub runtime: WasmtimeRuntime,
}

impl WindowStore {
    pub fn new(ipc_sender: IpcMessageSender) -> Self {
        Self {
            ipc_sender,
            ipc_to_window: Default::default(),
            windows: Default::default(),
            runtime: WasmtimeRuntime::new().unwrap(),
        }
    }

    pub fn run(mut self, event_loop: EventLoop<WindowMessage>) -> ! {
        event_loop.run(move |event, event_loop, control_flow| match event {
            Event::WindowEvent { window_id, event } => {
                if let Some(window) = self.windows.get_mut(&window_id) {
                    match event {
                        WindowEvent::Resized(_) => window.request_redraw(),
                        _ => {}
                    }
                }
            }
            Event::RedrawRequested(id) => {
                if let Some(window) = self.windows.get_mut(&id) {
                    window.draw();
                }
            }
            Event::MainEventsCleared => {
                for (_id, window) in self.windows.iter_mut() {
                    window.update();
                    window.request_redraw();
                }
            }
            Event::UserEvent(event) => match event {
                WindowMessage::OpenWindow { id, script } => {
                    println!("Opening window {} with script {:?}", id, script);
                    let abi = Default::default();
                    let module = std::fs::read(script).unwrap();
                    let mut script = self.runtime.load_module(abi, &module).unwrap();
                    let panel = script.bind_panel(vec![]);
                    let window = Window::new(script, panel, &event_loop).unwrap();
                    let window_id = window.get_id();
                    self.windows.insert(window_id, window);
                    self.ipc_to_window.insert(id, window_id);
                }
                WindowMessage::CloseWindow { id } => {
                    if let Some(window_id) = self.ipc_to_window.remove(&id) {
                        self.windows.remove(&window_id);
                    }
                }
                WindowMessage::Quit => *control_flow = ControlFlow::Exit,
            },
            _ => {}
        });
    }
}