use std::{error::Error, fmt::Debug, hash::Hash, marker::PhantomData};

use bevy::prelude::*;
use bevy_input_actionmap::InputMap;
use bevy_rapier2d::prelude::*;
use bevy_tts::Tts;

use crate::{
    core::{Coordinates, Player, PointLike},
    error::error_handler,
    map::Map,
    pathfinding::Destination,
    visibility::{RevealedTiles, Viewshed, Visible, VisibleEntities},
};

#[derive(Component, Clone, Copy, Debug, Default, PartialEq, Reflect)]
#[reflect(Component)]
pub struct Explorable;

#[derive(Component, Clone, Copy, Debug, Default, PartialEq, Reflect)]
#[reflect(Component)]
pub struct ExplorationFocused;

#[allow(dead_code)]
#[derive(Component, Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd, Reflect)]
pub enum ExplorationType {
    Portal = 0,
    Item = 1,
    Character = 2,
    Ally = 3,
    Enemy = 4,
}

// Doesn't make sense to create from a `String`.
#[allow(clippy::from_over_into)]
impl Into<String> for ExplorationType {
    fn into(self) -> String {
        match self {
            ExplorationType::Portal => "Exit".into(),
            ExplorationType::Item => "Item".into(),
            ExplorationType::Character => "Character".into(),
            ExplorationType::Ally => "Ally".into(),
            ExplorationType::Enemy => "Enemy".into(),
        }
    }
}

// Likewise.
#[allow(clippy::from_over_into)]
impl Into<&str> for ExplorationType {
    fn into(self) -> &'static str {
        match self {
            ExplorationType::Portal => "exit",
            ExplorationType::Item => "item",
            ExplorationType::Character => "character",
            ExplorationType::Ally => "ally",
            ExplorationType::Enemy => "enemy",
        }
    }
}

#[derive(Component, Clone, Copy, Debug, Default, Deref, DerefMut, Reflect)]
#[reflect(Component)]
pub struct Exploring(pub (f32, f32));

impl_pointlike_for_tuple_component!(Exploring);

#[derive(Component, Clone, Debug, Default, Deref, DerefMut)]
pub struct FocusedExplorationType(pub Option<ExplorationType>);

#[derive(Component, Clone, Copy, Debug, Default, Reflect)]
#[reflect(Component)]
pub struct Mappable;

fn exploration_type_change<S, A: 'static>(
    config: Res<ExplorationConfig<S, A>>,
    mut tts: ResMut<Tts>,
    input: Res<InputMap<A>>,
    mut explorers: Query<(&VisibleEntities, &mut FocusedExplorationType)>,
    features: Query<&ExplorationType>,
) -> Result<(), Box<dyn Error>>
where
    S: 'static + Clone + Debug + Eq + Hash + Send + Sync,
    A: Hash + Eq + Clone + Send + Sync,
{
    if let (Some(select_next_type), Some(select_prev_type)) = (
        config.action_explore_select_next_type.clone(),
        config.action_explore_select_prev_type.clone(),
    ) {
        let changed = input.just_active(select_next_type.clone())
            || input.just_active(select_prev_type.clone());
        if !changed {
            return Ok(());
        }
        for (visible, mut focused) in explorers.iter_mut() {
            let mut types: Vec<ExplorationType> = vec![];
            for e in visible.iter() {
                if let Ok(t) = features.get(*e) {
                    types.push(*t);
                }
            }
            types.sort();
            types.dedup();
            if types.is_empty() {
                tts.speak("Nothing visible.", true)?;
            } else if input.just_active(select_prev_type.clone()) {
                if let Some(t) = &focused.0 {
                    if let Some(i) = types.iter().position(|v| *v == *t) {
                        if i == 0 {
                            focused.0 = None;
                        } else {
                            let t = &types[i - 1];
                            focused.0 = Some(*t);
                        }
                    } else {
                        let t = types.last().unwrap();
                        focused.0 = Some(*t);
                    }
                } else {
                    let t = types.last().unwrap();
                    focused.0 = Some(*t);
                }
            } else if input.just_active(select_next_type.clone()) {
                if let Some(t) = &focused.0 {
                    if let Some(i) = types.iter().position(|v| *v == *t) {
                        if i == types.len() - 1 {
                            focused.0 = None;
                        } else {
                            let t = &types[i + 1];
                            focused.0 = Some(*t);
                        }
                    } else {
                        let t = types.first().unwrap();
                        focused.0 = Some(*t);
                    }
                } else {
                    let t = types.first().unwrap();
                    focused.0 = Some(*t)
                }
            }
        }
    }
    Ok(())
}

fn exploration_type_focus<S, A: 'static>(
    mut commands: Commands,
    config: Res<ExplorationConfig<S, A>>,
    input: Res<InputMap<A>>,
    mut tts: ResMut<Tts>,
    explorers: Query<(
        Entity,
        &VisibleEntities,
        &FocusedExplorationType,
        Option<&Exploring>,
    )>,
    features: Query<(Entity, &Coordinates, &ExplorationType)>,
) -> Result<(), Box<dyn Error>>
where
    S: 'static + Clone + Debug + Eq + Hash + Send + Sync,
    A: Hash + Eq + Clone + Send + Sync,
{
    if let (Some(explore_focus_next), Some(explore_focus_prev)) = (
        config.action_explore_focus_next.clone(),
        config.action_explore_focus_prev.clone(),
    ) {
        let changed = input.just_active(explore_focus_next.clone())
            || input.just_active(explore_focus_prev.clone());
        if !changed {
            return Ok(());
        }
        for (entity, visible_entities, focused_type, exploring) in explorers.iter() {
            let mut features = features
                .iter()
                .filter(|v| visible_entities.contains(&v.0))
                .map(|v| (v.1.floor(), v.2))
                .collect::<Vec<((f32, f32), &ExplorationType)>>();
            if features.is_empty() {
                tts.speak("Nothing visible.", true)?;
                return Ok(());
            }
            features.sort_by(|(c1, _), (c2, _)| c1.partial_cmp(c2).unwrap());
            if let Some(focused) = &focused_type.0 {
                features.retain(|(_, t)| **t == *focused);
            }
            let mut target: Option<&((f32, f32), &ExplorationType)> = None;
            if input.just_active(explore_focus_next.clone()) {
                if let Some(exploring) = exploring {
                    target = features.iter().find(|(c, _)| *c > **exploring);
                    if target.is_none() {
                        target = features.first();
                    }
                } else {
                    target = features.first();
                }
            } else if input.just_active(explore_focus_prev.clone()) {
                if let Some(exploring) = exploring {
                    features.reverse();
                    target = features.iter().find(|(c, _)| *c < **exploring);
                    if target.is_none() {
                        target = features.first();
                    }
                } else {
                    target = features.last();
                }
            }
            if let Some((coordinates, _)) = target {
                commands
                    .entity(entity)
                    .insert(Exploring(coordinates.floor()));
            }
        }
    }
    Ok(())
}

fn exploration_type_changed_announcement(
    mut tts: ResMut<Tts>,
    focused: Query<
        (
            &FocusedExplorationType,
            ChangeTrackers<FocusedExplorationType>,
        ),
        Changed<FocusedExplorationType>,
    >,
) -> Result<(), Box<dyn Error>> {
    for (focused, changed) in focused.iter() {
        if changed.is_added() {
            return Ok(());
        }
        match &focused.0 {
            Some(v) => {
                let v: String = (*v).into();
                tts.speak(v, true)?;
            }
            None => {
                tts.speak("Everything", true)?;
            }
        };
    }
    Ok(())
}

fn exploration_focus<S, A: 'static, D: 'static + Clone + Default + Send + Sync>(
    mut commands: Commands,
    config: Res<ExplorationConfig<S, A>>,
    input: Res<InputMap<A>>,
    map: Query<&Map<D>>,
    explorers: Query<(Entity, &Coordinates, Option<&Exploring>), With<Player>>,
) where
    S: 'static + Clone + Debug + Eq + Hash + Send + Sync,
    A: Hash + Eq + Clone + Send + Sync,
{
    if let (
        Some(explore_forward),
        Some(explore_backward),
        Some(explore_left),
        Some(explore_right),
    ) = (
        config.action_explore_forward.clone(),
        config.action_explore_backward.clone(),
        config.action_explore_left.clone(),
        config.action_explore_right.clone(),
    ) {
        for map in map.iter() {
            if let Ok((entity, coordinates, exploring)) = explorers.get_single() {
                let coordinates = **coordinates;
                let mut exploring = if let Some(exploring) = exploring {
                    **exploring
                } else {
                    coordinates.floor()
                };
                let orig = exploring;
                if input.just_active(explore_forward.clone()) {
                    exploring.1 += 1.;
                } else if input.just_active(explore_backward.clone()) {
                    exploring.1 -= 1.;
                } else if input.just_active(explore_left.clone()) {
                    exploring.0 -= 1.;
                } else if input.just_active(explore_right.clone()) {
                    exploring.0 += 1.;
                }
                if orig != exploring
                    && exploring.0 >= 0.
                    && exploring.0 < map.width as f32
                    && exploring.1 >= 0.
                    && exploring.1 < map.height as f32
                {
                    commands.entity(entity).insert(Exploring(exploring));
                }
            }
        }
    }
}

fn navigate_to_explored<S, A: 'static, D: 'static + Clone + Default + Send + Sync>(
    mut commands: Commands,
    config: Res<ExplorationConfig<S, A>>,
    input: Res<InputMap<A>>,
    map: Query<(&Map<D>, &RevealedTiles)>,
    explorers: Query<(Entity, &Exploring)>,
) where
    S: 'static + Clone + Debug + Eq + Hash + Send + Sync,
    A: Hash + Eq + Clone + Send + Sync,
{
    if let Some(navigate_to_explored) = config.action_navigate_to_explored.clone() {
        for (entity, exploring) in explorers.iter() {
            for (map, revealed_tiles) in map.iter() {
                let point = **exploring;
                let idx = point.to_index(map.width);
                let known = revealed_tiles[idx];
                if input.just_active(navigate_to_explored.clone()) && known {
                    commands
                        .entity(entity)
                        .insert(Destination((point.x_i32(), point.y_i32())));
                }
            }
        }
    }
}

fn exploration_changed_announcement<D: 'static + Clone + Default + Send + Sync>(
    mut commands: Commands,
    mut tts: ResMut<Tts>,
    map: Query<(&Map<D>, &RevealedTiles)>,
    explorer: Query<(&Coordinates, &Exploring, &Viewshed), Changed<Exploring>>,
    focused: Query<Entity, With<ExplorationFocused>>,
    explorable: Query<Entity, Or<(With<Visible>, With<Explorable>)>>,
    names: Query<&Name>,
    types: Query<&ExplorationType>,
    mappables: Query<&Mappable>,
    rapier_context: Res<RapierContext>,
) -> Result<(), Box<dyn Error>> {
    if let Ok((coordinates, exploring, viewshed)) = explorer.get_single() {
        let coordinates = coordinates.floor();
        for (map, revealed_tiles) in map.iter() {
            let point = **exploring;
            let idx = point.to_index(map.width);
            let shape = Collider::cuboid(0.49, 0.49);
            let known = revealed_tiles[idx];
            let visible = viewshed.is_point_visible(exploring);
            let fog_of_war = known && !visible;
            let description = if known {
                let mut tokens: Vec<&str> = vec![];
                for entity in focused.iter() {
                    commands.entity(entity).remove::<ExplorationFocused>();
                }
                let exploring = Vec2::new(exploring.x(), exploring.y());
                rapier_context.intersections_with_shape(
                    exploring,
                    0.,
                    &shape,
                    InteractionGroups::all(),
                    Some(&|v| explorable.get(v).is_ok()),
                    |entity| {
                        commands.entity(entity).insert(ExplorationFocused);
                        if visible || mappables.get(entity).is_ok() {
                            if let Ok(name) = names.get(entity) {
                                tokens.push(name.as_str());
                            }
                            if tokens.is_empty() {
                                if let Ok(t) = types.get(entity) {
                                    tokens.push((*t).into());
                                }
                            }
                        }
                        true
                    },
                );
                if tokens.is_empty() {
                    let tile = map.tiles[idx];
                    if tile.is_blocked() {
                        "wall".to_string()
                    } else {
                        "floor".to_string()
                    }
                } else {
                    tokens.join(": ")
                }
            } else {
                "Unknown".to_string()
            };
            let mut tokens: Vec<String> = vec![
                description,
                coordinates.direction_and_distance(exploring, None),
            ];
            if fog_of_war {
                tokens.push("in the fog of war".into());
            }
            tts.speak(tokens.join(", ").to_string(), true)?;
        }
    }
    Ok(())
}

fn cleanup(
    mut commands: Commands,
    explorers: Query<Entity, With<Exploring>>,
    focus: Query<Entity, With<ExplorationFocused>>,
) {
    for entity in explorers.iter() {
        commands.entity(entity).remove::<Exploring>();
    }
    for entity in focus.iter() {
        commands.entity(entity).remove::<ExplorationFocused>();
    }
}

#[derive(Clone, Debug)]
pub struct ExplorationConfig<S, A> {
    pub exploration_control_states: Vec<S>,
    pub action_explore_forward: Option<A>,
    pub action_explore_backward: Option<A>,
    pub action_explore_left: Option<A>,
    pub action_explore_right: Option<A>,
    pub action_explore_focus_next: Option<A>,
    pub action_explore_focus_prev: Option<A>,
    pub action_explore_select_next_type: Option<A>,
    pub action_explore_select_prev_type: Option<A>,
    pub action_navigate_to_explored: Option<A>,
}

impl<S, A> Default for ExplorationConfig<S, A> {
    fn default() -> Self {
        Self {
            exploration_control_states: vec![],
            action_explore_forward: None,
            action_explore_backward: None,
            action_explore_left: None,
            action_explore_right: None,
            action_explore_focus_next: None,
            action_explore_focus_prev: None,
            action_explore_select_next_type: None,
            action_explore_select_prev_type: None,
            action_navigate_to_explored: None,
        }
    }
}

pub struct ExplorationPlugin<'a, S, A, D>(PhantomData<&'a S>, PhantomData<&'a A>, PhantomData<D>);

impl<'a, S, A, D> Default for ExplorationPlugin<'a, S, A, D> {
    fn default() -> Self {
        Self(PhantomData, PhantomData, PhantomData)
    }
}

impl<'a, S, A, D> Plugin for ExplorationPlugin<'a, S, A, D>
where
    S: Clone + Debug + Eq + Hash + Send + Sync,
    A: Hash + Eq + Clone + Send + Sync,
    D: 'static + Clone + Default + Send + Sync,
    'a: 'static,
{
    fn build(&self, app: &mut App) {
        if !app.world.contains_resource::<ExplorationConfig<S, A>>() {
            app.insert_resource(ExplorationConfig::<S, A>::default());
        }
        let config = app
            .world
            .get_resource::<ExplorationConfig<S, A>>()
            .unwrap()
            .clone();
        app.register_type::<ExplorationFocused>()
            .register_type::<ExplorationType>()
            .register_type::<Mappable>()
            .add_system_to_stage(
                CoreStage::PostUpdate,
                exploration_changed_announcement::<D>.chain(error_handler),
            );
        if config.exploration_control_states.is_empty() {
            app.add_system(exploration_focus::<S, A, D>)
                .add_system(exploration_type_focus::<S, A>.chain(error_handler))
                .add_system(exploration_type_change::<S, A>.chain(error_handler))
                .add_system(navigate_to_explored::<S, A, D>)
                .add_system_to_stage(
                    CoreStage::PostUpdate,
                    exploration_type_changed_announcement.chain(error_handler),
                );
        } else {
            let states = config.exploration_control_states;
            for state in states {
                app.add_system_set(
                    SystemSet::on_update(state.clone())
                        .with_system(exploration_focus::<S, A, D>)
                        .with_system(exploration_type_focus::<S, A>.chain(error_handler))
                        .with_system(exploration_type_change::<S, A>.chain(error_handler))
                        .with_system(navigate_to_explored::<S, A, D>)
                        .with_system(exploration_type_changed_announcement.chain(error_handler)),
                )
                .add_system_set(SystemSet::on_exit(state).with_system(cleanup));
            }
        }
    }
}