use itertools::Itertools;

use crate::{Fill, Filter, Object, ObjectSizes, Point, Region, Toggleable};
use std::{collections::HashMap, fmt::Display};

#[derive(Debug, Clone, Default)]
// #[wasm_bindgen(getter_with_clone)]
pub struct Layer {
    pub object_sizes: ObjectSizes,
    pub objects: HashMap<String, Object>,
    pub name: String,
    pub hidden: bool,
}

impl Layer {
    pub fn new(name: impl Display) -> Self {
        Layer {
            object_sizes: ObjectSizes::default(),
            objects: HashMap::new(),
            name: format!("{}", name),
            hidden: false,
        }
    }

    pub fn hide(&mut self) {
        self.hidden = true;
    }

    pub fn show(&mut self) {
        self.hidden = false;
    }

    pub fn toggle(&mut self) {
        self.hidden.toggle();
    }

    pub fn object(&mut self, name: &str) -> &mut Object {
        self.safe_object(name).unwrap()
    }

    pub fn safe_object(&mut self, name: &str) -> Option<&mut Object> {
        self.objects.get_mut(name)
    }

    pub fn objects_sorted_owned(
        &self,
    ) -> impl Iterator<Item = (String, Object)> + '_ {
        self.objects
            .iter()
            .sorted_by_cached_key(|&(id, _)| id.clone())
            .map(|(id, obj)| (id.clone(), obj.clone()))
    }

    // Useful to be able to guarantee a stable order when rendering.
    pub fn objects_sorted(&self) -> impl Iterator<Item = (&String, &Object)> {
        self.objects
            .iter()
            .sorted_by_cached_key(|&(id, _)| id.clone())
    }

    // Useful to be able to guarantee a stable order when rendering.
    pub fn objects_sorted_mut(
        &mut self,
    ) -> impl Iterator<Item = (&String, &mut Object)> {
        self.objects
            .iter_mut()
            .sorted_by_cached_key(|&(id, _)| id.clone())
    }

    pub fn objects_in(
        &mut self,
        region: Region,
    ) -> impl Iterator<Item = (&String, &mut Object)> {
        self.objects
            .iter_mut()
            .filter(move |(_, obj)| obj.shape.region().within(&region))
    }

    pub fn object_at(&mut self, point: Point) -> Option<&mut Object> {
        self.find_object_mut(|o| o.position() == point.as_corner())
    }

    pub fn has_object_that(&self, pred: impl Fn(&Object) -> bool) -> bool {
        self.objects.values().any(|obj| pred(obj))
    }

    pub fn find_object_mut(
        &mut self,
        pred: impl Fn(&Object) -> bool,
    ) -> Option<&mut Object> {
        self.objects.values_mut().find(|obj| pred(obj))
    }

    pub fn find_object(&self, pred: impl Fn(&Object) -> bool) -> Option<&Object> {
        self.objects.values().find(|obj| pred(obj))
    }

    // Remove all objects.
    pub fn clear(&mut self) {
        self.objects.clear();
    }

    pub fn replace(&mut self, with: Layer) {
        self.objects.clone_from(&with.objects);
    }

    pub fn remove_all_objects_in(&mut self, region: &Region) {
        self.objects.retain(|_, Object { shape: object, .. }| {
            !object.region().within(region)
        })
    }

    pub fn paint_all_objects(&mut self, fill: Fill) {
        for obj in self.objects.values_mut() {
            obj.fill = Some(fill);
        }
    }

    pub fn filter_all_objects(&mut self, filter: Filter) {
        for obj in self.objects.values_mut() {
            obj.filters.push(filter)
        }
    }

    pub fn move_all_objects(&mut self, dx: i32, dy: i32) {
        self.objects
            .iter_mut()
            .for_each(|(_, Object { shape: object, .. })| {
                object.translate(dx, dy)
            });
    }

    pub fn add(&mut self, name: impl Display, object: impl Into<Object>) {
        let name_str = format!("{}", name);

        if self.objects.contains_key(&name_str) {
            panic!("object {} already exists in layer {}", name_str, self.name);
        }

        self.set(name_str, object);
    }

    pub fn add_anon(&mut self, object: impl Into<Object>) {
        self.add(format!("anon-{}", self.objects.len()), object);
    }

    pub fn add_many(
        &mut self,
        objects: impl IntoIterator<Item = (impl Display, Object)>,
    ) {
        for (name, obj) in objects {
            self.add(name, obj);
        }
    }

    pub fn add_many_anon(&mut self, objects: impl IntoIterator<Item = Object>) {
        for obj in objects {
            self.add_anon(obj);
        }
    }

    pub fn set(&mut self, name: impl Display, object: impl Into<Object>) {
        let name_str = format!("{}", name);

        self.objects.insert(name_str, object.into());
    }

    pub fn filter_object(
        &mut self,
        name: &str,
        filter: Filter,
    ) -> Result<(), String> {
        self.objects
            .get_mut(name)
            .ok_or(format!("Object '{}' not found", name))?
            .filters
            .push(filter);

        Ok(())
    }

    pub fn remove_object(&mut self, name: &str) {
        self.objects.remove(name);
    }

    pub fn replace_object(&mut self, name: &str, object: Object) {
        self.remove_object(name);
        self.add(name, object);
    }

    pub fn add_objects(&mut self, objects: impl IntoIterator<Item = Object>) {
        for obj in objects {
            self.add_anon(obj);
        }
    }

    pub fn objects_with_tag(
        &mut self,
        tag: impl Display,
    ) -> impl Iterator<Item = (&String, &mut Object)> {
        let tag_str = format!("{}", tag);
        self.objects
            .iter_mut()
            .filter(move |(_, obj)| obj.has_tag(&tag_str))
    }

    pub fn tag_objects(
        &mut self,
        tag: impl Display,
        objects: impl Fn(&String, &Object) -> bool,
    ) {
        let tag_str = format!("{}", tag);
        for (_, obj) in
            self.objects.iter_mut().filter(|(id, obj)| objects(id, obj))
        {
            obj.tag(&tag_str);
        }
    }

    /// Returns the effective region the layer occupies, by merging all its objects' regions.
    pub fn region(&self) -> Region {
        self.objects
            .values()
            .map(|object| object.region())
            .fold(Region::default(), |acc, region| acc.merge(&region))
    }
}

impl Object {
    pub fn add_to(self, layer: &mut Layer) {
        layer.add_anon(self);
    }

    pub fn set_in(self, layer: &mut Layer, name: impl Display) {
        layer.set(name, self);
    }
}