use nalgebra::{vector, Vector2};
use protobuf::SpecialFields;
use rapier2d_f64::prelude::{
    ColliderBuilder, ColliderSet, RigidBodyBuilder, RigidBodyHandle, RigidBodySet,
};
use starkingdoms_protocol::planet::PlanetType;
use std::collections::HashMap;

use crate::entity::{get_entity_id, Entities, Entity, EntityId};
use crate::orbit::constants::{EARTH_MASS, EARTH_RADIUS, MARS_APHELION, MARS_MASS, MARS_PERIHELION, MARS_RADIUS, MOON_APOAPSIS, MOON_MASS, MOON_PERIAPSIS, MOON_RADIUS};
use crate::orbit::orbit::{calculate_point_on_orbit, calculate_world_position_of_orbit};
use crate::{manager::ClientHandlerMessage, SCALE};

pub const GRAVITY: f64 = 0.02;

#[derive(Clone, Debug)]
pub struct Planet {
    pub planet_type: PlanetType,
    pub body_handle: RigidBodyHandle,
    pub position: (f64, f64),
    pub radius: f64,
    pub mass: f64,
}

impl Planet {
    pub fn gravity(&self, position: (f64, f64), mass: f64) -> (f64, f64) {
        let distance = (position.0 - self.position.0).hypot(position.1 - self.position.1);
        let force = GRAVITY * ((self.mass * mass) / (distance * distance));
        let mut direction =
            Vector2::new(self.position.0 - position.0, self.position.1 - position.1);
        direction.set_magnitude(force);
        (direction.x, direction.y)
    }
}

#[derive(Default, Clone)]
pub struct Planets {
    pub planets: HashMap<String, Planet>,
}

impl Planets {
    pub fn get_planet(&self, planet_id: &str) -> Option<&Planet> {
        self.planets.get(planet_id)
    }

    pub fn get_planet_mut(&mut self, planet_id: &str) -> Option<&mut Planet> {
        self.planets.get_mut(planet_id)
    }

    pub fn make_planet(
        _planet_id: &str,
        planet_type: PlanetType,
        mass: f64,
        radius: f64,
        position: (f64, f64),
        rigid_body_set: &mut RigidBodySet,
        collider_set: &mut ColliderSet,
    ) -> (EntityId, Entity) {
        let collider = ColliderBuilder::ball(radius / SCALE).build();
        let body = RigidBodyBuilder::kinematic_position_based()
            .translation(vector![position.0 / SCALE, position.1 / SCALE])
            .dominance_group(127)
            .additional_mass(0.0);
        let body_handle = rigid_body_set.insert(body);

        collider_set.insert_with_parent(collider, body_handle, rigid_body_set);

        let entity_id = get_entity_id();
        (
            entity_id,
            Entity::Planet(Planet {
                planet_type,
                body_handle,
                position: (position.0 / SCALE, position.1 / SCALE),
                radius: radius / SCALE,
                mass,
            }),
        )
    }

    pub fn create_planets(
        rigid_body_set: &mut RigidBodySet,
        collider_set: &mut ColliderSet,
        entities: &mut Entities,
    ) -> Vec<EntityId> {
        let mut planet_ids: Vec<EntityId> = Vec::new();
        let (earth_id, entity) = Self::make_planet(
            "earth",
            PlanetType::Earth,
            EARTH_MASS,
            EARTH_RADIUS,
            (100.0, 100.0),
            rigid_body_set,
            collider_set,
        );
        entities.insert(earth_id, entity);
        planet_ids.push(earth_id);

        let moon_start_point;
        #[allow(clippy::expect_used)]
        if let Entity::Planet(earth) = entities.get(&earth_id).expect("earth does not exist") {
            moon_start_point = calculate_world_position_of_orbit(
                calculate_point_on_orbit(MOON_PERIAPSIS, MOON_APOAPSIS, 0.0),
                vector![earth.position.0, earth.position.1],
            );
        } else {
            moon_start_point = vector![0., 0.];
        }

        let (moon_id, moon) = Self::make_planet(
            "moon",
            PlanetType::Moon,
            MOON_MASS,
            MOON_RADIUS,
            (moon_start_point[0], moon_start_point[1]),
            rigid_body_set,
            collider_set,
        );
        entities.insert(moon_id, moon);
        planet_ids.push(moon_id);

        let mars_start_point;
        #[allow(clippy::expect_used)]
        if let Entity::Planet(moon) = entities.get(&moon_id).expect("moon does not exist") {
            mars_start_point = calculate_world_position_of_orbit(
                calculate_point_on_orbit(MARS_PERIHELION, MARS_APHELION, 0.0),
                vector![moon.position.0, moon.position.1],
            );
        } else {
            mars_start_point = vector![0., 0.];
        }

        let (mars_id, mars) = Self::make_planet(
            "mars",
            PlanetType::Mars,
            MARS_MASS,
            MARS_RADIUS,
            (mars_start_point[0], mars_start_point[1]),
            rigid_body_set,
            collider_set,
        );
        entities.insert(mars_id, mars);
        planet_ids.push(mars_id);

        planet_ids
    }

    pub fn to_protocol(&self) -> ClientHandlerMessage {
        let mut planets = vec![];

        for (_, planet) in self.planets.clone() {
            // TODO: Adjust codegen to use f64
            planets.push(starkingdoms_protocol::planet::Planet {
                planet_type: planet.planet_type.into(),
                x: planet.position.0 * SCALE,
                y: planet.position.1 * SCALE,
                radius: planet.radius * SCALE, // DO NOT * SCALE - THIS VALUE IS NOT SCALED! YES IT IS
                special_fields: SpecialFields::default(),
            });
        }

        ClientHandlerMessage::PlanetData { planets }
    }

    pub fn gravity(&self, position: (f64, f64), mass: f64) -> (f64, f64) {
        let mut direction = Vector2::zeros();
        for (_, planet) in self.planets.clone() {
            let planet_grav = planet.gravity(position, mass);
            direction.x += planet_grav.0;
            direction.y += planet_grav.1;
        }
        (direction.x, direction.y)
    }
}