kuilu/src/terrain2d/texel_behaviour2d.rs

use crate::util::Vector2I;

use super::TexelID;
use bevy::prelude::*;
use lazy_static::lazy_static;
use std::{borrow::Cow, collections::HashMap};

lazy_static! {
    static ref ID_MAP: HashMap<TexelID, TexelBehaviour2D> = {
        let mut result = HashMap::new();

        result.insert(
            1,
            TexelBehaviour2D {
                name: Cow::Borrowed("loose sand"),
                color: Color::rgb(0.61, 0.49, 0.38),
                gravity: Some(TexelGravity::Down(200)),
                has_collision: true,
                ..default()
            },
        );

        result.insert(
            2,
            TexelBehaviour2D {
                name: Cow::Borrowed("loose stone"),
                color: Color::rgb(0.21, 0.19, 0.17),
                gravity: Some(TexelGravity::Down(200)),
                has_collision: true,
                ..default()
            },
        );

        result.insert(
            3,
            TexelBehaviour2D {
                name: Cow::Borrowed("loose sturdy stone"),
                color: Color::rgb(0.11, 0.11, 0.11),
                gravity: Some(TexelGravity::Down(200)),
                has_collision: true,
                ..default()
            },
        );

        result.insert(
            4,
            TexelBehaviour2D {
                name: Cow::Borrowed("water"),
                color: Color::rgba(0.0, 0.0, 1.0, 0.5),
                form: TexelForm::Liquid,
                gravity: Some(TexelGravity::Down(50)),
                ..default()
            },
        );

        result.insert(
            5,
            TexelBehaviour2D {
                name: Cow::Borrowed("oil"),
                color: Color::rgba(0.5, 0.5, 0.25, 0.5),
                form: TexelForm::Liquid,
                gravity: Some(TexelGravity::Down(20)),
                ..default()
            },
        );

        result.insert(
            6,
            TexelBehaviour2D {
                name: Cow::Borrowed("light gas"),
                color: Color::rgba(0.0, 1.0, 0.0, 0.5),
                form: TexelForm::Gas,
                gravity: Some(TexelGravity::Up(160)),
                ..default()
            },
        );

        result.insert(
            7,
            TexelBehaviour2D {
                name: Cow::Borrowed("heavy gas"),
                color: Color::rgba(1.0, 0.5, 0.5, 0.5),
                form: TexelForm::Gas,
                gravity: Some(TexelGravity::Down(60)),
                ..default()
            },
        );

        result.insert(
            8,
            TexelBehaviour2D {
                name: Cow::Borrowed("oxygen"),
                color: Color::rgba(0.5, 0.5, 0.5, 0.5),
                form: TexelForm::Gas,
                ..default()
            },
        );

        result.insert(
            11,
            TexelBehaviour2D {
                name: Cow::Borrowed("sand"),
                color: Color::rgb(0.61, 0.49, 0.38),
                has_collision: true,
                ..default()
            },
        );

        result.insert(
            12,
            TexelBehaviour2D {
                name: Cow::Borrowed("stone"),
                color: Color::rgb(0.21, 0.19, 0.17),
                has_collision: true,
                ..default()
            },
        );

        result.insert(
            13,
            TexelBehaviour2D {
                name: Cow::Borrowed("sturdy stone"),
                color: Color::rgb(0.11, 0.11, 0.11),
                has_collision: true,
                ..default()
            },
        );

        result
    };
    static ref FORM_DISPLACEMENT_PRIORITY: HashMap<TexelForm, u8> = {
        let mut result = HashMap::new();
        result.insert(TexelForm::Gas, 0);
        result.insert(TexelForm::Liquid, 1);
        result.insert(TexelForm::Solid, 2);
        result
    };
}

#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Hash)]
pub enum TexelForm {
    #[default]
    // Solid materials, when affected by gravity, create pyramid-like piles
    Solid,
    // Liquid materials, when affected by gravity, act like solids but also try to stabilise the surface level by traveling flat surfaces
    Liquid,
    // Gas materials act like liquids, but also have density/pressure that causes them to disperse
    Gas,
}

impl TexelForm {
    fn priority(&self) -> u8 {
        FORM_DISPLACEMENT_PRIORITY
            .get(self)
            .cloned()
            .unwrap_or_default()
    }
}

#[derive(Clone, Copy, Debug, PartialEq)]
pub enum TexelGravity {
    Down(u8),
    Up(u8),
}

impl From<TexelGravity> for Vector2I {
    fn from(gravity: TexelGravity) -> Self {
        match gravity {
            TexelGravity::Down(_) => Vector2I::DOWN,
            TexelGravity::Up(_) => Vector2I::UP,
        }
    }
}

impl TexelGravity {
    pub fn abs(&self) -> u8 {
        match self {
            TexelGravity::Down(grav) => *grav,
            TexelGravity::Up(grav) => *grav,
        }
    }
}

#[derive(Clone, Debug)]
pub struct TexelBehaviour2D {
    pub name: Cow<'static, str>,
    pub color: Color,
    pub form: TexelForm,
    pub has_collision: bool,
    pub gravity: Option<TexelGravity>,
    pub toughness: Option<f32>,
}

impl Default for TexelBehaviour2D {
    fn default() -> Self {
        TexelBehaviour2D {
            name: Cow::Borrowed("Unnamed material"),
            color: Color::PINK,
            form: TexelForm::Solid,
            has_collision: false,
            gravity: None,
            toughness: None,
        }
    }
}

impl TexelBehaviour2D {
    pub const OUT_OF_BOUNDS: Self = TexelBehaviour2D {
        name: Cow::Borrowed(":)"),
        color: Color::BLACK,
        has_collision: true,
        form: TexelForm::Solid,
        gravity: None,
        toughness: None,
    };

    pub fn from_id(id: &TexelID) -> Option<Self> {
        ID_MAP.get(id).cloned()
    }

    pub fn is_empty(id: &TexelID) -> bool {
        ID_MAP.get(id).is_none()
    }

    pub fn has_collision(id: &TexelID) -> bool {
        ID_MAP.get(id).map_or(false, |b| b.has_collision)
    }

    /// Can this type of material displace another?
    pub fn can_displace(from: &TexelBehaviour2D, to: &Option<TexelBehaviour2D>) -> bool {
        let to = if let Some(to) = to { to } else { return true };

        match (from.form, to.form) {
            (from_form, to_form) => {
                if from_form.priority() != to_form.priority() {
                    return from_form.priority() > to_form.priority();
                }
                if let (Some(from_grav), Some(to_grav)) = (from.gravity, to.gravity) {
                    match (from_grav, to_grav) {
                        (TexelGravity::Down(from_grav), TexelGravity::Down(to_grav)) => {
                            from_grav > to_grav
                        }
                        (TexelGravity::Up(from_grav), TexelGravity::Up(to_grav)) => {
                            from_grav > to_grav
                        }
                        (_, _) => true,
                    }
                } else {
                    // Solids can also be displaced, but only if the other material has gravity
                    to_form != TexelForm::Solid
                }
            }
        }
    }
}