//   ▄████████▄      +        ███ +  ▄█████████ ███     +
//  ███▀    ▀███ +         +  ███    ███▀  +    ███ +       +
//  ███  +   ███ ███   ███ █████████ ███        ███  ███   ███
//  ███     +███ ███   ███    ███    ███▐██████ ███  ███   ███
//  ███ +    ███ ███+  ███   +███    ███     +  ███  ███ + ███
//  ███▄    ▄███ ███▄  ███    ███ +  ███  +     ███  ███▄  ███
//   ▀████████▀ + ▀███████    ███▄   ███▄       ▀████ ▀███████
//       +                  +                +             ███
//  +   ▀████████████████████████████████████████████████████▀
//
// Various common functions and constants

use bevy::prelude::*;
use crate::prelude::*;

pub use bevy::math::{DVec3, DQuat};
pub use std::f32::consts::PI as PI32;
pub use std::f64::consts::PI;

pub const GAME_NAME: &str = "OutFly";
pub const CONF_FILE: &str = "outfly.toml";
pub const FONT: &str = "fonts/Yupiter-Regular.ttf";

pub const EPSILON32: f32 = 1e-9;
pub const EPSILON: f64 = 1e-9;

#[inline]
pub fn bool2vis(boolean: bool) -> Visibility {
    if boolean {
        Visibility::Inherited
    } else {
        Visibility::Hidden
    }
}

#[inline]
pub fn style_fullscreen() -> Style {
    Style {
        width: Val::Vw(100.0),
        height: Val::Vh(100.0),
        position_type: PositionType::Absolute,
        top: Val::Px(0.0),
        left: Val::Px(0.0),
        ..default()
    }
}

#[inline]
pub fn style_centered() -> Style {
    Style {
        width: Val::Percent(100.0),
        height: Val::Percent(100.0),
        align_items: AlignItems::Center,
        justify_content: JustifyContent::SpaceAround,
        ..default()
    }
}

pub fn alive(settings: Res<Settings>) -> bool {
    return settings.alive;
}

pub fn in_control(settings: Res<Settings>) -> bool {
    return settings.in_control();
}

pub fn in_shadow(
    light_source_pos: DVec3,
    light_source_r: f64,
    shadow_caster_pos: DVec3,
    shadow_caster_r: f64,
    camera_pos: DVec3
) -> bool {
    if light_source_r < shadow_caster_r {
        error!("common::in_shadow only works if light_source_r > shadow_caster_r");
        return false;
    }

    let direction = (shadow_caster_pos - light_source_pos).normalize();
    let shadow_caster_to_player = camera_pos - shadow_caster_pos;

    // Calculate the distance to the shadow caster if the player was projected
    // onto the line of the shadow, with positive numbers = in the shadow,
    // negative numbers = in between light source and shadow caster.
    let projection_length = shadow_caster_to_player.dot(direction);
    if projection_length < 0.0 {
        return false;
    }

    let projection = projection_length * direction;

    // Calculate the vector to the closest point along the shadow line
    let closest_vector = shadow_caster_to_player - projection;

    let distance_between_light_and_caster = (shadow_caster_pos - light_source_pos).length();
    let max_distance = shadow_caster_r + ((shadow_caster_r - light_source_r) / distance_between_light_and_caster) * projection_length;

    return closest_vector.length() < max_distance;
}