use crate::core::mouse;
use crate::core::time::Instant;
use crate::core::window::Id;
use crate::core::{Point, Size};
use crate::graphics::Compositor;
use crate::program::{DefaultStyle, Program, State};

use std::collections::BTreeMap;
use std::sync::Arc;
use winit::monitor::MonitorHandle;

#[allow(missing_debug_implementations)]
pub struct WindowManager<P, C>
where
    P: Program,
    C: Compositor<Renderer = P::Renderer>,
    P::Theme: DefaultStyle,
{
    aliases: BTreeMap<winit::window::WindowId, Id>,
    entries: BTreeMap<Id, Window<P, C>>,
}

impl<P, C> WindowManager<P, C>
where
    P: Program,
    C: Compositor<Renderer = P::Renderer>,
    P::Theme: DefaultStyle,
{
    pub fn new() -> Self {
        Self {
            aliases: BTreeMap::new(),
            entries: BTreeMap::new(),
        }
    }

    pub fn insert(
        &mut self,
        id: Id,
        window: Arc<winit::window::Window>,
        application: &P,
        compositor: &mut C,
        exit_on_close_request: bool,
    ) -> &mut Window<P, C> {
        let state = State::new(application, id, &window);
        let viewport_version = state.viewport_version();
        let physical_size = state.physical_size();
        let surface = compositor.create_surface(
            window.clone(),
            physical_size.width,
            physical_size.height,
        );
        let renderer = compositor.create_renderer();

        let _ = self.aliases.insert(window.id(), id);

        let _ = self.entries.insert(
            id,
            Window {
                raw: window,
                state,
                viewport_version,
                exit_on_close_request,
                surface,
                renderer,
                mouse_interaction: mouse::Interaction::None,
                redraw_at: None,
            },
        );

        self.entries
            .get_mut(&id)
            .expect("Get window that was just inserted")
    }

    pub fn is_empty(&self) -> bool {
        self.entries.is_empty()
    }

    pub fn is_idle(&self) -> bool {
        self.entries
            .values()
            .all(|window| window.redraw_at.is_none())
    }

    pub fn redraw_at(&self) -> Option<Instant> {
        self.entries
            .values()
            .filter_map(|window| window.redraw_at)
            .min()
    }

    pub fn first(&self) -> Option<&Window<P, C>> {
        self.entries.first_key_value().map(|(_id, window)| window)
    }

    pub fn iter_mut(
        &mut self,
    ) -> impl Iterator<Item = (Id, &mut Window<P, C>)> {
        self.entries.iter_mut().map(|(k, v)| (*k, v))
    }

    pub fn get(&self, id: Id) -> Option<&Window<P, C>> {
        self.entries.get(&id)
    }

    pub fn get_mut(&mut self, id: Id) -> Option<&mut Window<P, C>> {
        self.entries.get_mut(&id)
    }

    pub fn get_mut_alias(
        &mut self,
        id: winit::window::WindowId,
    ) -> Option<(Id, &mut Window<P, C>)> {
        let id = self.aliases.get(&id).copied()?;

        Some((id, self.get_mut(id)?))
    }

    pub fn last_monitor(&self) -> Option<MonitorHandle> {
        self.entries.values().last()?.raw.current_monitor()
    }

    pub fn remove(&mut self, id: Id) -> Option<Window<P, C>> {
        let window = self.entries.remove(&id)?;
        let _ = self.aliases.remove(&window.raw.id());

        Some(window)
    }
}

impl<P, C> Default for WindowManager<P, C>
where
    P: Program,
    C: Compositor<Renderer = P::Renderer>,
    P::Theme: DefaultStyle,
{
    fn default() -> Self {
        Self::new()
    }
}

#[allow(missing_debug_implementations)]
pub struct Window<P, C>
where
    P: Program,
    C: Compositor<Renderer = P::Renderer>,
    P::Theme: DefaultStyle,
{
    pub raw: Arc<winit::window::Window>,
    pub state: State<P>,
    pub viewport_version: u64,
    pub exit_on_close_request: bool,
    pub mouse_interaction: mouse::Interaction,
    pub surface: C::Surface,
    pub renderer: P::Renderer,
    pub redraw_at: Option<Instant>,
}

impl<P, C> Window<P, C>
where
    P: Program,
    C: Compositor<Renderer = P::Renderer>,
    P::Theme: DefaultStyle,
{
    pub fn position(&self) -> Option<Point> {
        self.raw
            .inner_position()
            .ok()
            .map(|position| position.to_logical(self.raw.scale_factor()))
            .map(|position| Point {
                x: position.x,
                y: position.y,
            })
    }

    pub fn size(&self) -> Size {
        let size = self.raw.inner_size().to_logical(self.raw.scale_factor());

        Size::new(size.width, size.height)
    }
}