#![allow(clippy::type_complexity)]

use std::any::TypeId;

use std::marker::PhantomData;
#[cfg(feature = "timings")]
use std::time::Instant;

use anyhow::Result;
use indexmap::IndexMap;

#[cfg(feature = "timings")]
use super::super::timings::Timings;

use crate::*;
use scene_update_macros::implement_pair_update;

macro_rules! impl_singleton_update {
    ( $name: ident, $([$var: ident]$(,)?)+ ) => {
        impl Archetype {
            paste::item! {
                pub fn [<create_ $name>]<F, Filter, $($var,)+>(f: F, filter: Filter) -> Self
                where
                    F: Fn(&mut World, Entity, $(&mut $var,)+) -> Result<()> + Send + Sync + Clone + 'static,
                    Filter: CheckFilter + 'static,
                    $(
                        $var: EntityComponent + ComponentDebug,
                    )+
                {
                    $(
                        filter.verify_dedup::<$var>();
                    )+

                    Self {
                        check_entity: Box::new({
                            move |entity| {
                                $(
                                    if !entity.components.contains::<$var>() {
                                        return false;
                                    }
                                )+

                                if !filter.check(entity) {
                                    return false;
                                }

                                true
                            }
                        }),

                        create_callback: Box::new(move |entity| {
                            $(
                                let [< $var:lower >] = UnsafeComponentStore::from(
                                    entity.get_component::<$var>()?
                                );
                            )+

                            let f = f.clone();

                            Ok(Box::new(move |e, scene_contents| {
                                unsafe { f(scene_contents, e, $([< $var:lower >].as_mut(),)+) }
                            }))
                        }),

                        entities: IndexMap::new(),
                    }
                }
            }
        }

        impl<Func, Filter, $( $var, )+> AddUpdates2<( $( $var, )+ ), Func, Filter> for Updates
        where
            $(
                $var: EntityComponent + ComponentDebug,
            )+
            Func: Fn(& mut World, Entity, $(&mut $var,)+) -> Result<()> + Send + Sync + Clone + 'static,
            Filter: CheckFilter + 'static
        {
            fn add_update(
                &mut self,
                name: &str,
                priority: u32,
                func: Func,
                filter: Filter
            ) -> Result<()> {
                paste::item! {
                    self.add(name, priority, Update::Single(Archetype::[<create_ $name>](func, filter)))
                }
            }
        }

        impl<Func, Filter, $( $var, )+> AddUpdates<( $( $var, )+ ), Func, Filter> for WorldBuilder
        where
            $(
                $var: EntityComponent + ComponentDebug,
            )+
            Func: Fn(& mut World, Entity, $(&mut $var,)+) -> Result<()> + Send + Sync + Clone + 'static,
            Filter: CheckFilter + 'static
        {
            fn add_update(
                &mut self,
                name: &str,
                priority: u32,
                func: Func,
                filter: Filter,
            ) -> Result<()> {
                self.updates.add_update(name, priority, func, filter)
            }
        }
    };
}

macro_rules! impl_pair_update {
    (
        $lhs_id: expr,
        ( $([$lhs_little: ident: $lhs_big: ident]$(,)?)+ ),
        $rhs_id: expr,
        ( $([$rhs_little: ident: $rhs_big: ident]$(,)?)+ )
    ) => {
        impl ArchetypePair {
            paste::item! {
                pub fn [<create_lhs_ $lhs_id _rhs_ $rhs_id>] <F, LeftFilter, RightFilter, $($lhs_big,)+ $($rhs_big,)+>
                    (f: F, left_filter: LeftFilter, right_filter: RightFilter) -> Self
                where
                    F: Fn(&mut World, (Entity, $(&mut $lhs_big,)+), (Entity, $(&mut $rhs_big,)+)) -> Result<()> + Send + Sync + Clone + 'static,
                    LeftFilter: CheckFilter + 'static,
                    RightFilter: CheckFilter + 'static,
                    $(
                        $rhs_big: EntityComponent + ComponentDebug,
                    )+
                    $(
                        $lhs_big: EntityComponent + ComponentDebug,
                    )+
                {
                    $(
                        left_filter.verify_dedup::<$lhs_big>();
                    )+

                    $(
                        right_filter.verify_dedup::<$rhs_big>();
                    )+

                    Self {
                        check_left_entity: Box::new({
                            move |entity| {
                                $(
                                    if !entity.components.contains::<$lhs_big>() {
                                        return false;
                                    }
                                )+

                                if !left_filter.check(entity) {
                                    return false;
                                }

                                true
                            }
                        }),
                        check_right_entity: Box::new({
                            move |entity| {
                                $(
                                    if !entity.components.contains::<$rhs_big>() {
                                        return false;
                                    }
                                )+

                                if !right_filter.check(entity) {
                                    return false;
                                }

                                true
                            }
                        }),

                        create_callback: Box::new(move |lhs_entity, rhs_entity| {
                            $(
                                let $lhs_little = UnsafeComponentStore::from(
                                    lhs_entity.get_component::<$lhs_big>()?
                                );
                            )+

                            $(
                                let $rhs_little = UnsafeComponentStore::from(
                                    rhs_entity.get_component::<$rhs_big>()?
                                );
                            )+

                            let f = f.clone();

                            Ok(Box::new(move |lhs_e, rhs_e, scene_contents| {
                                unsafe { f(scene_contents, (lhs_e, $($lhs_little.as_mut(),)+), (rhs_e, $($rhs_little.as_mut(),)+) ) }
                            }))
                        }),

                        entities: IndexMap::new(),
                    }
                }
            }
        }

        impl<Func, LhsFilter, RhsFilter, $( $lhs_big, )+ $($rhs_big,)+> AddUpdates2<( ($( $lhs_big, )+), ($($rhs_big,)+) ), Func, (LhsFilter, RhsFilter)> for Updates
        where
            $(
                $rhs_big: EntityComponent + ComponentDebug,
            )+
            $(
                $lhs_big: EntityComponent + ComponentDebug,
            )+
            Func: Fn(& mut World, (Entity, $(&mut $lhs_big,)+), (Entity, $(&mut $rhs_big,)+)) -> Result<()> + Send + Sync + Clone + 'static,
            LhsFilter: CheckFilter + 'static,
            RhsFilter: CheckFilter + 'static
        {
            fn add_update(
                &mut self,
                name: &str,
                priority: u32,
                func: Func,
                filter: (LhsFilter, RhsFilter)
            ) -> Result<()> {
                paste::item! {
                    self.add(name, priority, Update::Pair(ArchetypePair::[<create_lhs_ $lhs_id _rhs_ $rhs_id>](func, filter.0, filter.1)))?;
                }

                Ok(())
            }
        }

        impl<Func, LhsFilter, RhsFilter, $( $lhs_big, )+ $($rhs_big,)+> AddUpdates<( ($( $lhs_big, )+), ($($rhs_big,)+) ), Func, (LhsFilter, RhsFilter)> for WorldBuilder
        where
            $(
                $rhs_big: EntityComponent + ComponentDebug,
            )+
            $(
                $lhs_big: EntityComponent + ComponentDebug,
            )+
            Func: Fn(& mut World, (Entity, $(&mut $lhs_big,)+), (Entity, $(&mut $rhs_big,)+)) -> Result<()> + Send + Sync + Clone + 'static,
            LhsFilter: CheckFilter + 'static,
            RhsFilter: CheckFilter + 'static
        {
            fn add_update(
                &mut self,
                name: &str,
                priority: u32,
                func: Func,
                filter: (LhsFilter, RhsFilter),
            ) -> Result<()> {
                self.updates.add_update(name, priority, func, filter)
            }
        }
    };
}

macro_rules! impl_update_filter {
    ( $name: ident, $([$big: ident, $little: ident]$(,)?)+ ) => {
        paste::item! {
            pub struct [<$name Filter>]<$($big: EntityComponent,)+> {
                $(
                    $little: std::marker::PhantomData<$big>,
                )+
            }

            impl<$($big: EntityComponent,)+> Default for [<$name Filter>]<$($big,)+> {
                fn default() -> Self {
                    Self {
                        $(
                            $little: std::marker::PhantomData,
                        )+
                    }
                }
            }

            impl<$($big: EntityComponent,)+> CheckFilter for [<$name Filter>]<$($big,)+> {
                fn check(&self, entity: &EntityObject) -> bool {
                    $(
                        if entity.contains_component::<$big>() {
                            return false;
                        }
                    )+

                    true
                }

                fn verify_dedup<O: EntityComponent>(&self) {
                    $(
                        if TypeId::of::<O>() == TypeId::of::<$big>() {
                            panic!("Type is used as input and filter at the same time");
                        }
                    )+
                }
            }

            impl<$($big: EntityComponent,)+> Clone for [<$name Filter>]<$($big,)+> {
                fn clone(&self) -> Self {
                    Self {
                        $(
                            $little: self.$little.clone(),
                        )+
                    }
                }
            }
        }
    };
}

pub struct Query<T, F = EmptyFilter>
where
    F: CheckFilter,
{
    pub components: T,

    d: PhantomData<F>,
}

pub trait AddUpdates<T, Func, Filter> {
    fn add_update(&mut self, name: &str, priority: u32, func: Func, filter: Filter) -> Result<()>;
}

trait AddUpdates2<T, Func, Filter> {
    fn add_update(&mut self, name: &str, priority: u32, func: Func, filter: Filter) -> Result<()>;
}

pub trait CheckFilter: Send + Sync + Default + Clone {
    fn check(&self, entity: &EntityObject) -> bool;
    fn verify_dedup<O: EntityComponent>(&self);
}

#[derive(Default, Clone)]
pub struct EmptyFilter;

impl CheckFilter for EmptyFilter {
    fn check(&self, _entity: &EntityObject) -> bool {
        true
    }

    fn verify_dedup<O>(&self) {}
}

#[derive(Default, Clone, Debug)]
pub struct ArchetypeInfo {
    entities: Vec<(Entity, Option<String>)>,
}

impl ArchetypeInfo {
    pub fn new(entities: Vec<(Entity, Option<String>)>) -> Self {
        Self { entities }
    }

    pub fn entities(&self) -> &[(Entity, Option<String>)] {
        &self.entities
    }

    pub fn count(&self) -> usize {
        self.entities.len()
    }
}

pub struct Archetype {
    check_entity: Box<dyn Fn(&EntityObject) -> bool + Send + Sync>,
    create_callback: Box<
        dyn Fn(&EntityObject) -> Result<Box<dyn Fn(Entity, &mut World) -> Result<()> + Send + Sync>>
            + Send
            + Sync,
    >,

    entities: IndexMap<Entity, Box<dyn Fn(Entity, &mut World) -> Result<()> + Send + Sync>>,
}

impl Archetype {
    pub fn add_entity(&mut self, entity_object: &EntityObject) -> Result<()> {
        if (self.check_entity)(entity_object) {
            let cb = (self.create_callback)(entity_object)?;

            self.entities.insert(entity_object.as_entity(), cb);
        }

        Ok(())
    }

    pub fn remove_entity(&mut self, entity: Entity) {
        self.entities.swap_remove(&entity);
    }

    pub fn execute(&self, scene_contents: &mut World) -> Result<()> {
        for (entity, callback) in self.entities.iter() {
            callback(*entity, scene_contents)?;
        }

        Ok(())
    }

    pub fn entities(
        &self,
    ) -> &IndexMap<Entity, Box<dyn Fn(Entity, &mut World) -> Result<()> + Send + Sync>> {
        &self.entities
    }
}

pub struct ArchetypePair {
    check_left_entity: Box<dyn Fn(&EntityObject) -> bool + Send + Sync>,
    check_right_entity: Box<dyn Fn(&EntityObject) -> bool + Send + Sync>,

    create_callback: Box<
        dyn Fn(
                &EntityObject,
                &EntityObject,
            )
                -> Result<Box<dyn Fn(Entity, Entity, &mut World) -> Result<()> + Send + Sync>>
            + Send
            + Sync,
    >,

    entities: IndexMap<
        (Entity, Entity),
        Box<dyn Fn(Entity, Entity, &mut World) -> Result<()> + Send + Sync>,
    >,
}

impl ArchetypePair {
    pub(crate) fn add_entity(
        &mut self,
        entity_object: &EntityObject,
        entities: &IndexMap<Entity, EntityObject>,
    ) -> Result<()> {
        for (other_entity, other_entity_object) in entities.iter() {
            if entity_object.as_entity() == *other_entity {
                continue;
            }

            // check if the entities can be on both sides
            if (self.check_left_entity)(entity_object)
                && (self.check_right_entity)(other_entity_object)
            {
                let cb = (self.create_callback)(entity_object, other_entity_object)?;

                self.entities
                    .insert((entity_object.as_entity(), *other_entity), cb);
            }

            if (self.check_left_entity)(other_entity_object)
                && (self.check_right_entity)(entity_object)
            {
                let cb = (self.create_callback)(other_entity_object, entity_object)?;

                self.entities
                    .insert((*other_entity, entity_object.as_entity()), cb);
            }
        }

        Ok(())
    }

    pub(crate) fn remove_entity(&mut self, entity: Entity) {
        while let Some((left_entity, right_entity)) = self
            .entities
            .keys()
            .find(|(left_entity, right_entity)| *left_entity == entity || *right_entity == entity)
            .cloned()
        {
            self.entities.swap_remove(&(left_entity, right_entity));
        }
    }

    pub(crate) fn execute(&self, scene_contents: &mut World) -> Result<()> {
        for ((left_entity, right_entity), callback) in self.entities.iter() {
            callback(*left_entity, *right_entity, scene_contents)?;
        }

        Ok(())
    }
}

pub enum Update {
    Single(Archetype),
    Pair(ArchetypePair),
}

impl From<Archetype> for Update {
    fn from(archetype: Archetype) -> Self {
        Self::Single(archetype)
    }
}

impl From<ArchetypePair> for Update {
    fn from(pair: ArchetypePair) -> Self {
        Self::Pair(pair)
    }
}

pub struct Updates {
    #[cfg(feature = "timings")]
    timings: Timings,

    updates: Vec<(String, u32, Update)>,
}

impl Default for Updates {
    fn default() -> Self {
        Self {
            #[cfg(feature = "timings")]
            timings: Timings::default,

            updates: Vec::new(),
        }
    }
}

impl Updates {
    pub(crate) fn update(&mut self, world: &mut World) -> Result<()> {
        #[cfg(feature = "timings")]
        if let Some(timings) = self.timings.check_timing(world.now(), None) {
            if !timings.is_empty() {
                println!("timings: {:#?}", timings);
            }
        }

        #[cfg(feature = "timings")]
        let timings = &mut self.timings;

        self.updates
            .iter()
            .try_for_each(|(_name, _, update)| -> Result<()> {
                #[cfg(feature = "timings")]
                let before = Instant::now();

                match update {
                    Update::Single(archetype) => {
                        archetype.execute(world)?;
                    }
                    Update::Pair(archetype_pair) => {
                        archetype_pair.execute(world)?;
                    }
                }

                #[cfg(feature = "timings")]
                timings.add(_name, Instant::now().duration_since(before));

                Ok(())
            })?;

        Ok(())
    }

    pub(crate) fn add_entity(
        &mut self,
        entity_object: &EntityObject,
        entities: &IndexMap<Entity, EntityObject>,
    ) -> Result<()> {
        for (_, _, update) in self.updates.iter_mut() {
            match update {
                Update::Single(archetype) => {
                    archetype.add_entity(entity_object)?;
                }
                Update::Pair(archetype_pair) => {
                    archetype_pair.add_entity(entity_object, entities)?;
                }
            }
        }

        Ok(())
    }

    pub(crate) fn remove_entity(&mut self, entity: Entity) {
        for (_, _, update) in self.updates.iter_mut() {
            match update {
                Update::Single(archetype) => {
                    archetype.remove_entity(entity);
                }
                Update::Pair(archetype_pair) => {
                    archetype_pair.remove_entity(entity);
                }
            }
        }
    }

    // pub(crate) fn clear(&mut self) {
    //     self.updates.clear();

    //     #[cfg(feature = "timings")]
    //     self.timings.clear();
    // }

    pub(crate) fn add(&mut self, name: &str, priority: u32, update: Update) -> Result<()> {
        #[cfg(feature = "timings")]
        self.timings.add_timing_afterwards(name);

        self.updates.push((name.to_string(), priority, update));
        self.updates
            .sort_by(|(_, lhs_prio, _), (_, rhs_prio, _)| lhs_prio.cmp(rhs_prio));

        Ok(())
    }
}

// #[derive(Default)]
// pub struct Archetypes {
//     archetypes: HashMap<String, Archetype>,
// }

// impl Archetypes {
//     pub(crate) fn add_entity(&mut self, entity_object: &EntityObject) -> Result<()> {
//         for archetype in self.archetypes.values_mut() {
//             archetype.add_entity(entity_object)?;
//         }

//         Ok(())
//     }

//     pub(crate) fn remove_entity(&mut self, entity: Entity) {
//         for archetype in self.archetypes.values_mut() {
//             archetype.remove_entity(entity);
//         }
//     }

//     pub(crate) fn clear(&mut self) {
//         self.archetypes.clear();
//     }

//     pub(crate) fn insert(&mut self, name: String, archetype: Archetype) {
//         assert!(self.archetypes.insert(name, archetype).is_none());
//     }

//     pub(crate) fn get(&self, name: &String) -> Option<&Archetype> {
//         self.archetypes.get(name)
//     }

//     pub(crate) fn execute(
//         &self,
//         name: &String,
//         scene_contents: &mut SceneContents<'_>,
//     ) -> Result<()> {
//         self.archetypes[name].execute(scene_contents)
//     }
// }

#[rustfmt::skip]
impl_singleton_update!(single,      [R]);
#[rustfmt::skip]
impl_singleton_update!(double,      [R], [S]);
#[rustfmt::skip]
impl_singleton_update!(triple,      [R], [S], [T]);
#[rustfmt::skip]
impl_singleton_update!(quadruple,   [R], [S], [T], [U]);
#[rustfmt::skip]
impl_singleton_update!(quintuple,   [R], [S], [T], [U], [V]);
#[rustfmt::skip]
impl_singleton_update!(sextuple,    [R], [S], [T], [U], [V], [W]);
#[rustfmt::skip]
impl_singleton_update!(septuple,    [R], [S], [T], [U], [V], [W], [X]);
#[rustfmt::skip]
impl_singleton_update!(octuple,     [R], [S], [T], [U], [V], [W], [X], [Y]);
#[rustfmt::skip]
impl_singleton_update!(ninetuple,   [R], [S], [T], [U], [V], [W], [X], [Y], [Z]);

implement_pair_update!(impl_pair_update, 1, 10);

#[rustfmt::skip]
impl_update_filter!(Monuple,    [R, r]);
#[rustfmt::skip]
impl_update_filter!(Couple,     [R, r], [S, s]);
#[rustfmt::skip]
impl_update_filter!(Triple,     [R, r], [S, s], [T, t]);
#[rustfmt::skip]
impl_update_filter!(Quadruple,  [R, r], [S, s], [T, t], [U, u]);
#[rustfmt::skip]
impl_update_filter!(Quintuple,  [R, r], [S, s], [T, t], [U, u], [V, v]);
#[rustfmt::skip]
impl_update_filter!(Sextuple,   [R, r], [S, s], [T, t], [U, u], [V, v], [W, w]);
#[rustfmt::skip]
impl_update_filter!(Septuple,   [R, r], [S, s], [T, t], [U, u], [V, v], [W, w], [X, x]);
#[rustfmt::skip]
impl_update_filter!(Octuple,    [R, r], [S, s], [T, t], [U, u], [V, v], [W, w], [X, x], [Y, y]);
#[rustfmt::skip]
impl_update_filter!(Nonuple,    [R, r], [S, s], [T, t], [U, u], [V, v], [W, w], [X, x], [Y, y], [Z, z]);
#[rustfmt::skip]
impl_update_filter!(Decuple,    [R, r], [S, s], [T, t], [U, u], [V, v], [W, w], [X, x], [Y, y], [Z, z], [A, a]);