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

use bevy::prelude::*;
use bevy_rapier2d::prelude::*;
use bevy_tts::Tts;
use leafwing_input_manager::prelude::*;

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

#[derive(Actionlike, PartialEq, Eq, Clone, Copy, Hash, Debug)]
pub enum ExplorationAction {
    Forward,
    Backward,
    Left,
    Right,
    FocusNext,
    FocusPrev,
    SelectNextType,
    SelectPrevType,
    NavigateTo,
}

#[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;

#[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<T>(pub Option<T>)
where
    T: Component + Default;

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

fn exploration_type_change<ExplorationType, State>(
    mut tts: ResMut<Tts>,
    mut explorers: Query<(
        &ActionState<ExplorationAction>,
        &VisibleEntities,
        &mut FocusedExplorationType<ExplorationType>,
    )>,
    features: Query<&ExplorationType>,
) -> Result<(), Box<dyn Error>>
where
    ExplorationType: Component + Default + Copy + Ord,
    State: 'static + Clone + Debug + Eq + Hash + Send + Sync,
{
    for (actions, 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 actions.just_pressed(ExplorationAction::SelectPrevType) {
            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 actions.just_pressed(ExplorationAction::SelectNextType) {
            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<ExplorationType, State>(
    mut commands: Commands,
    mut tts: ResMut<Tts>,
    explorers: Query<(
        Entity,
        &ActionState<ExplorationAction>,
        &VisibleEntities,
        &FocusedExplorationType<ExplorationType>,
        Option<&Exploring>,
    )>,
    features: Query<(Entity, &Transform, &ExplorationType)>,
) -> Result<(), Box<dyn Error>>
where
    ExplorationType: Component + Default + PartialEq,
    State: 'static + Clone + Debug + Eq + Hash + Send + Sync,
{
    for (entity, actions, visible_entities, focused_type, exploring) in explorers.iter() {
        let mut features = features
            .iter()
            .filter(|v| visible_entities.contains(&v.0))
            .map(|v| (v.1.trunc(), 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 actions.just_pressed(ExplorationAction::FocusNext) {
            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 actions.just_pressed(ExplorationAction::FocusPrev) {
            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.trunc()));
        }
    }
    Ok(())
}

fn exploration_type_changed_announcement<ExplorationType>(
    mut tts: ResMut<Tts>,
    focused: Query<
        (
            &FocusedExplorationType<ExplorationType>,
            Ref<FocusedExplorationType<ExplorationType>>,
        ),
        Changed<FocusedExplorationType<ExplorationType>>,
    >,
) -> Result<(), Box<dyn Error>>
where
    ExplorationType: Component + Default + Copy + Into<String>,
{
    for (focused, changed) in &focused {
        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<State, MapData>(
    mut commands: Commands,
    map: Query<&Map<MapData>>,
    explorers: Query<
        (
            Entity,
            &ActionState<ExplorationAction>,
            &Transform,
            Option<&Exploring>,
        ),
        With<Player>,
    >,
) where
    State: 'static + Clone + Debug + Eq + Hash + Send + Sync,
    MapData: 'static + Clone + Default + Send + Sync,
{
    for (entity, actions, transform, exploring) in explorers.iter() {
        let coordinates = transform.translation;
        let mut exploring = if let Some(exploring) = exploring {
            **exploring
        } else {
            let floor = coordinates.floor();
            (floor.x, floor.y)
        };
        let orig = exploring;
        if actions.just_pressed(ExplorationAction::Forward) {
            exploring.1 += 1.;
        } else if actions.just_pressed(ExplorationAction::Backward) {
            exploring.1 -= 1.;
        } else if actions.just_pressed(ExplorationAction::Left) {
            exploring.0 -= 1.;
        } else if actions.just_pressed(ExplorationAction::Right) {
            exploring.0 += 1.;
        }
        let dimensions = if let Ok(map) = map.get_single() {
            Some((map.width as f32, map.height as f32))
        } else {
            None
        };
        if let Some((width, height)) = dimensions {
            if exploring.0 >= width || exploring.1 >= height {
                return;
            }
        }
        if orig != exploring && exploring.0 >= 0. && exploring.1 >= 0. {
            commands.entity(entity).insert(Exploring(exploring));
        }
    }
}

fn navigate_to_explored<State, MapData>(
    mut commands: Commands,
    map: Query<(&Map<MapData>, &RevealedTiles)>,
    explorers: Query<(Entity, &ActionState<ExplorationAction>, &Exploring)>,
) where
    State: 'static + Clone + Debug + Eq + Hash + Send + Sync,
    MapData: 'static + Clone + Default + Send + Sync,
{
    for (entity, actions, 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 actions.just_pressed(ExplorationAction::NavigateTo) && known {
                commands
                    .entity(entity)
                    .insert(Destination((point.x_i32(), point.y_i32())));
            }
        }
    }
}

fn exploration_changed_announcement<ExplorationType, MapData>(
    mut commands: Commands,
    mut tts: ResMut<Tts>,
    map: Query<(&Map<MapData>, &RevealedTiles)>,
    explorer: Query<(&Transform, &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>>
where
    ExplorationType: Component + Copy + Into<String>,
    MapData: 'static + Clone + Default + Send + Sync,
{
    if let Ok((coordinates, exploring, viewshed)) = explorer.get_single() {
        let coordinates = coordinates.trunc();
        let point = **exploring;
        let shape = Collider::cuboid(0.5 - f32::EPSILON, 0.5 - f32::EPSILON);
        let (known, idx) = if let Ok((map, revealed_tiles)) = map.get_single() {
            let idx = point.to_index(map.width);
            (revealed_tiles[idx], Some(idx))
        } else {
            (false, None)
        };
        let visible = viewshed.is_point_visible(exploring);
        let fog_of_war = !visible && known;
        let description: String = if known || visible {
            let mut tokens: Vec<String> = 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,
                QueryFilter::new().predicate(&|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.to_string());
                        }
                        if tokens.is_empty() {
                            if let Ok(t) = types.get(entity) {
                                tokens.push((*t).into());
                            }
                        }
                    }
                    true
                },
            );
            if tokens.is_empty() {
                if let Some(idx) = idx {
                    if let Ok((map, _)) = map.get_single() {
                        let tile = map.tiles[idx];
                        if tile.is_blocked() {
                            tokens.push("wall".to_string());
                        } else {
                            tokens.push("floor".to_string());
                        }
                    }
                }
                tokens.first().cloned().unwrap_or_default()
            } else {
                tokens.join(": ")
            }
        } else {
            "Unknown".to_string()
        };
        let mut tokens = vec![
            description,
            coordinates.direction_and_distance(exploring, None),
        ];
        if fog_of_war {
            tokens.push("in the fog of war".to_string());
        }
        tts.speak(tokens.join(", "), 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(Resource, Clone, Debug, Default)]
struct ExplorationConfig<State> {
    states: Vec<State>,
}

#[derive(Resource, Clone, Default)]
pub struct ExplorationPlugin<ExplorationType, State, MapData> {
    pub states: Vec<State>,
    pub exploration_type: PhantomData<ExplorationType>,
    pub map_data: PhantomData<MapData>,
}

impl<ExplorationType, State, MapData> Plugin for ExplorationPlugin<ExplorationType, State, MapData>
where
    ExplorationType: 'static + Component + Default + Copy + Ord + PartialEq + Into<String>,
    State: States,
    MapData: 'static + Clone + Default + Send + Sync,
{
    fn build(&self, app: &mut App) {
        let config = ExplorationConfig {
            states: self.states.clone(),
        };
        app.insert_resource(config.clone())
            .register_type::<ExplorationFocused>()
            .register_type::<Mappable>()
            .register_type::<Explorable>()
            .add_plugin(InputManagerPlugin::<ExplorationAction>::default())
            .add_system(
                exploration_changed_announcement::<ExplorationType, MapData>.pipe(error_handler),
            );
        if config.states.is_empty() {
            app.add_systems((
                exploration_focus::<State, MapData>,
                exploration_type_focus::<ExplorationType, State>.pipe(error_handler),
                exploration_type_change::<ExplorationType, State>.pipe(error_handler),
                navigate_to_explored::<State, MapData>,
            ))
            .add_system(
                exploration_type_changed_announcement::<ExplorationType>
                    .pipe(error_handler)
                    .in_base_set(CoreSet::PostUpdate),
            );
        } else {
            let states = config.states;
            for state in states {
                app.add_systems(
                    (
                        exploration_focus::<State, MapData>,
                        exploration_type_focus::<ExplorationType, State>.pipe(error_handler),
                        exploration_type_change::<ExplorationType, State>.pipe(error_handler),
                        navigate_to_explored::<State, MapData>,
                        exploration_type_changed_announcement::<ExplorationType>
                            .pipe(error_handler),
                    )
                        .in_set(OnUpdate(state.clone())),
                )
                .add_system(cleanup.in_schedule(OnExit(state)));
            }
        }
    }
}