use crate::shared::player::*;
use crate::shared::projectile::*;
use crate::shared::*;
use bevy::ecs::system::*;
use bevy::utils::Duration;
use std::ops::*;

#[derive(Copy, Clone, PartialEq, Debug, Deserialize, Serialize)]
pub enum Ability {
    Activated(ActivatedAbility),
    Directional(DirectionalAbility),
    Targeted(TargetedAbility),
}

#[derive(Copy, Clone, PartialEq, Debug, Deserialize, Serialize)]
pub enum TargetedAbility {
    MeeleAttack,
    RangedAttack,
}

impl TargetedAbility {
    pub fn to_projectile(
        self,
        source_player: PlayerId,
        position: Vec2,
        target_player: PlayerId,
    ) -> Projectile {
        match self {
            TargetedAbility::MeeleAttack => Projectile {
                type_: ProjectileType::Instant(InstantProjectile { target_player }),
                source_player,
                damage: 5.,
            },
            TargetedAbility::RangedAttack => Projectile {
                type_: ProjectileType::Targeted(TargetedProjectile {
                    target_player,
                    position,
                }),
                source_player,
                damage: 6.,
            },
        }
    }
}

#[derive(Copy, Clone, PartialEq, Debug, Deserialize, Serialize)]
pub enum ActivatedAbility {
    Speed,
}

#[derive(Copy, Clone, PartialEq, Debug, Deserialize, Serialize)]
pub enum DirectionalAbility {
    Dash,
    Spear,
}

pub struct DirectionalAbilityActivation(
    pub fn(commands: &mut Commands, source_player: PlayerId, direction: Vec2) -> (),
);

impl DirectionalAbility {
    pub fn activate(self) -> DirectionalAbilityActivation {
        match self {
            DirectionalAbility::Dash => DirectionalAbilityActivation(dash_activation),
            DirectionalAbility::Spear => DirectionalAbilityActivation(spear_activation),
        }
    }
}

fn dash_activation(commands: &mut Commands, source_player: PlayerId, direction: Vec2) {
    commands.add(move |world: &mut World| {
        world.run_system_once(
            move |players: Query<(Entity, &PlayerId)>,
                  mut set: ParamSet<(
                Query<&mut PlayerPosition>,
                Query<(&PlayerId, &PlayerPosition)>,
            )>| {
                let Some(source_entity) = ({
                    let mut source_entity = None;
                    for (entity, player_id) in players.iter() {
                        if *player_id != source_player {
                            continue;
                        }
                        source_entity = Some(entity);
                        break;
                    }
                    source_entity
                }) else {
                    return;
                };

                let Some(source_position) = ({
                    let positions = set.p0();
                    if let Ok(position) = positions.get(source_entity) {
                        Some(*position)
                    } else {
                        None
                    }
                }) else {
                    return;
                };

                let dash_end = {
                    let dash_targets = set.p1();
                    dash_collision(
                        source_player,
                        source_position.0,
                        direction,
                        150.,
                        &dash_targets,
                    )
                };

                let mut positions = set.p0();
                if let Ok(mut position) = positions.get_mut(source_entity) {
                    position.0 = dash_end;
                }
            },
        )
    });
}

pub fn dash_collision(
    source_id: PlayerId,
    dash_start: Vec2,
    dash_direction: Vec2,
    dash_max_distance: f32,
    player_positions: &Query<(&PlayerId, &PlayerPosition)>,
) -> Vec2 {
    let mut dash_collision = dash_max_distance * dash_direction;
    let mut collision = false;
    for (player_id, position) in player_positions.iter() {
        if *player_id == source_id {
            continue;
        }

        let player_position = position.0 - dash_start;
        let player_projection = player_position.project_onto(dash_collision);
        let player_rejection = player_position - player_projection;
        let scalar_factor = player_projection.dot(dash_collision).signum()
            * player_projection.length()
            / dash_collision.length();

        if scalar_factor < 0. || scalar_factor > 1.0 {
            continue;
        }

        if player_rejection.length() < 2. * PLAYER_RADIUS {
            collision = true;
            dash_collision = player_projection;
        }
    }

    if collision {
        dash_start
            + (dash_collision.length() - 2. * PLAYER_RADIUS) * dash_collision.normalize_or_zero()
    } else {
        dash_start + dash_max_distance * dash_direction
    }
}

fn spear_activation(commands: &mut Commands, source_player: PlayerId, direction: Vec2) {
    commands.add(move |world: &mut World| {
        world.run_system_once(
            move |mut commands: Commands, players: Query<(&PlayerId, &PlayerPosition)>| {
                for (id, position) in players.iter() {
                    if *id != source_player {
                        continue;
                    }
                    commands.spawn(ProjectileBundle::new(Projectile {
                        type_: ProjectileType::Free(FreeProjectile {
                            position: position.0,
                            direction,
                            starting_position: position.0,
                        }),
                        source_player,
                        damage: 15.,
                    }));
                }
            },
        )
    });
}

#[derive(Debug, Serialize, Deserialize, Clone, Copy, PartialEq, Eq)]
pub enum AbilitySlot {
    A,
    Q,
    W,
    E,
    R,
    F,
    G,
}

impl AbilitySlot {
    pub fn to_label(self) -> &'static str {
        match self {
            AbilitySlot::A => "A",
            AbilitySlot::Q => "Q",
            AbilitySlot::W => "W",
            AbilitySlot::E => "E",
            AbilitySlot::R => "R",
            AbilitySlot::F => "F",
            AbilitySlot::G => "G",
        }
    }

    pub fn all() -> Vec<Self> {
        vec![
            AbilitySlot::A,
            AbilitySlot::Q,
            AbilitySlot::W,
            AbilitySlot::E,
            AbilitySlot::R,
            AbilitySlot::F,
            AbilitySlot::G,
        ]
    }
}

impl Index<AbilitySlot> for [Duration; 7] {
    type Output = Duration;

    fn index(&self, ability_slot: AbilitySlot) -> &Self::Output {
        &self[ability_slot as usize]
    }
}

impl IndexMut<AbilitySlot> for [Duration; 7] {
    fn index_mut(&mut self, ability_slot: AbilitySlot) -> &mut Self::Output {
        &mut self[ability_slot as usize]
    }
}