use crate::{
    ActiveSensors, HashMap, Painter, SenseCtx, Sensor, SensorMap, Widget, WidgetId, WidgetLike,
    primitive::Primitives,
    util::{IDTracker, Id},
};
use std::{
    any::{Any, TypeId},
    ops::{Index, IndexMut},
};

pub struct Ui<Ctx> {
    ids: IDTracker,
    base: Option<WidgetId>,
    widgets: Widgets<Ctx>,
    updates: Vec<WidgetId>,
    active_sensors: ActiveSensors<Ctx>,
    sensor_map: SensorMap<Ctx>,
    primitives: Primitives,
    full_redraw: bool,
}

#[derive(Default)]
pub struct Widgets<Ctx>(HashMap<Id, Box<dyn Widget<Ctx>>>);

impl<Ctx> Ui<Ctx> {
    pub fn add<W: Widget<Ctx>, Tag>(
        &mut self,
        w: impl WidgetLike<Ctx, Tag, Widget = W>,
    ) -> WidgetId<W> {
        w.add(self)
    }

    pub fn add_widget<W: Widget<Ctx>>(&mut self, w: W) -> WidgetId<W> {
        self.push(w)
    }

    pub fn push<W: Widget<Ctx>>(&mut self, w: W) -> WidgetId<W> {
        let id = self.ids.next();
        self.widgets.insert(id.duplicate(), w);
        WidgetId::new(id, TypeId::of::<W>())
    }

    pub fn set<W: Widget<Ctx>>(&mut self, i: &WidgetId<W>, w: W) {
        self.widgets.insert(i.id.duplicate(), w);
    }

    pub fn set_base<Tag>(&mut self, w: impl WidgetLike<Ctx, Tag>) {
        self.base = Some(w.add(self).erase_type());
        self.full_redraw = true;
    }

    pub fn new() -> Self
    where
        Ctx: 'static,
    {
        Self::default()
    }

    pub fn get<W: Widget<Ctx>>(&self, id: &WidgetId<W>) -> Option<&W> {
        self.widgets.get(id)
    }

    pub fn get_mut<W: Widget<Ctx>>(&mut self, id: &WidgetId<W>) -> Option<&mut W> {
        self.widgets.get_mut(id)
    }

    pub fn id<W: Widget<Ctx>>(&mut self) -> WidgetId<W> {
        WidgetId::new(self.ids.next(), TypeId::of::<W>())
    }

    pub fn redraw_all(&mut self, ctx: &mut Ctx)
    where
        Ctx: 'static,
    {
        self.active_sensors.clear();
        let mut painter = Painter::new(
            &self.widgets,
            ctx,
            &mut self.sensor_map,
            &mut self.active_sensors,
        );
        if let Some(base) = &self.base {
            painter.draw(base);
        }
        self.primitives = painter.finish();
    }

    pub fn add_sensor<W>(&mut self, id: &WidgetId<W>, f: Sensor<Ctx>) {
        self.sensor_map
            .entry(id.id.duplicate())
            .or_default()
            .push(f);
    }

    pub fn run_sensors(&mut self, ctx: &mut Ctx)
    where
        Ctx: SenseCtx + 'static,
    {
        for sensors in self.active_sensors.clone().iter().rev() {
            for sensor in sensors {
                if ctx.active(&sensor.trigger) {
                    (sensor.f.box_clone())(self, ctx);
                }
            }
        }
    }

    pub fn update(&mut self, ctx: &mut Ctx) -> Option<&Primitives>
    where
        Ctx: 'static,
    {
        if self.full_redraw {
            self.redraw_all(ctx);
            self.full_redraw = false;
            return Some(&self.primitives);
        }
        if self.updates.is_empty() {
            return None;
        }
        self.redraw_all(ctx);
        self.updates.drain(..);
        Some(&self.primitives)
    }

    pub fn needs_redraw(&self) -> bool {
        self.full_redraw || !self.updates.is_empty()
    }
}

impl<W: Widget<Ctx>, Ctx> Index<&WidgetId<W>> for Ui<Ctx> {
    type Output = W;

    fn index(&self, id: &WidgetId<W>) -> &Self::Output {
        self.get(id).unwrap()
    }
}

impl<W: Widget<Ctx>, Ctx> IndexMut<&WidgetId<W>> for Ui<Ctx> {
    fn index_mut(&mut self, id: &WidgetId<W>) -> &mut Self::Output {
        self.updates.push(id.clone().erase_type());
        self.get_mut(id).unwrap()
    }
}

impl<Ctx> Widgets<Ctx> {
    pub fn new() -> Self {
        Self(HashMap::new())
    }

    pub fn get_dyn<W>(&self, id: &WidgetId<W>) -> &dyn Widget<Ctx> {
        self.0.get(&id.id).unwrap().as_ref()
    }

    pub fn get<W: Widget<Ctx>>(&self, id: &WidgetId<W>) -> Option<&W> {
        self.0.get(&id.id).unwrap().as_any().downcast_ref()
    }

    pub fn get_mut<W: Widget<Ctx>>(&mut self, id: &WidgetId<W>) -> Option<&mut W> {
        self.0.get_mut(&id.id).unwrap().as_any_mut().downcast_mut()
    }

    pub fn insert(&mut self, id: Id, widget: impl Widget<Ctx>) {
        self.0.insert(id, Box::new(widget));
    }

    pub fn insert_any(&mut self, id: Id, widget: Box<dyn Widget<Ctx>>) {
        self.0.insert(id, widget);
    }
}

impl<Ctx> dyn Widget<Ctx> {
    pub fn as_any(&self) -> &dyn Any {
        self
    }

    pub fn as_any_mut(&mut self) -> &mut dyn Any {
        self
    }
}

impl<Ctx: 'static> Default for Ui<Ctx> {
    fn default() -> Self {
        Self {
            ids: Default::default(),
            base: Default::default(),
            widgets: Widgets::new(),
            updates: Default::default(),
            primitives: Default::default(),
            full_redraw: false,
            active_sensors: Default::default(),
            sensor_map: Default::default(),
        }
    }
}