pub mod scatter;
pub mod tree;

pub use self::{scatter::apply_scatter_to, tree::apply_trees_to};

use crate::{
    column::ColumnSample,
    util::{RandomField, Sampler},
    Canvas, IndexRef,
};
use common::{
    assets::Asset,
    comp,
    generation::{ChunkSupplement, EntityInfo},
    lottery::Lottery,
    terrain::{Block, BlockKind, SpriteKind},
    vol::{BaseVol, ReadVol, RectSizedVol, WriteVol},
};
use noise::NoiseFn;
use rand::prelude::*;
use serde::Deserialize;
use std::{
    f32,
    ops::{Mul, Sub},
};
use vek::*;

#[derive(Deserialize)]
pub struct Colors {
    pub bridge: (u8, u8, u8),
    pub stalagtite: (u8, u8, u8),
}

const EMPTY_AIR: Block = Block::air(SpriteKind::Empty);

pub fn apply_paths_to(canvas: &mut Canvas) {
    let info = canvas.info();
    canvas.foreach_col(|canvas, wpos2d, col| {
        let surface_z = col.riverless_alt.floor() as i32;

        let noisy_color = |color: Rgb<u8>, factor: u32| {
            let nz = RandomField::new(0).get(Vec3::new(wpos2d.x, wpos2d.y, surface_z));
            color.map(|e| {
                (e as u32 + nz % (factor * 2))
                    .saturating_sub(factor)
                    .min(255) as u8
            })
        };

        if let Some((path_dist, path_nearest, path, _)) =
            col.path.filter(|(dist, _, path, _)| *dist < path.width)
        {
            let inset = 0;

            // Try to use the column at the centre of the path for sampling to make them
            // flatter
            let col_pos = -info.wpos().map(|e| e as f32) + path_nearest;
            let col00 = info.col(info.wpos() + col_pos.map(|e| e.floor() as i32) + Vec2::new(0, 0));
            let col10 = info.col(info.wpos() + col_pos.map(|e| e.floor() as i32) + Vec2::new(1, 0));
            let col01 = info.col(info.wpos() + col_pos.map(|e| e.floor() as i32) + Vec2::new(0, 1));
            let col11 = info.col(info.wpos() + col_pos.map(|e| e.floor() as i32) + Vec2::new(1, 1));
            let col_attr = |col: &ColumnSample| {
                Vec3::new(col.riverless_alt, col.alt, col.water_dist.unwrap_or(1000.0))
            };
            let [riverless_alt, alt, water_dist] = match (col00, col10, col01, col11) {
                (Some(col00), Some(col10), Some(col01), Some(col11)) => Lerp::lerp(
                    Lerp::lerp(col_attr(col00), col_attr(col10), path_nearest.x.fract()),
                    Lerp::lerp(col_attr(col01), col_attr(col11), path_nearest.x.fract()),
                    path_nearest.y.fract(),
                ),
                _ => col_attr(col),
            }
            .into_array();
            let (bridge_offset, depth) = (
                ((water_dist.max(0.0) * 0.2).min(f32::consts::PI).cos() + 1.0) * 5.0,
                ((1.0 - ((water_dist + 2.0) * 0.3).min(0.0).cos().abs())
                    * (riverless_alt + 5.0 - alt).max(0.0)
                    * 1.75
                    + 3.0) as i32,
            );
            let surface_z = (riverless_alt + bridge_offset).floor() as i32;

            for z in inset - depth..inset {
                let _ = canvas.set(
                    Vec3::new(wpos2d.x, wpos2d.y, surface_z + z),
                    if bridge_offset >= 2.0 && path_dist >= 3.0 || z < inset - 1 {
                        Block::new(
                            BlockKind::Rock,
                            noisy_color(info.index().colors.layer.bridge.into(), 8),
                        )
                    } else {
                        let path_color =
                            path.surface_color(col.sub_surface_color.map(|e| (e * 255.0) as u8));
                        Block::new(BlockKind::Earth, noisy_color(path_color, 8))
                    },
                );
            }
            let head_space = path.head_space(path_dist);
            for z in inset..inset + head_space {
                let pos = Vec3::new(wpos2d.x, wpos2d.y, surface_z + z);
                if canvas.get(pos).unwrap().kind() != BlockKind::Water {
                    let _ = canvas.set(pos, EMPTY_AIR);
                }
            }
        }
    });
}

pub fn apply_caves_to(canvas: &mut Canvas) {
    let info = canvas.info();
    canvas.foreach_col(|canvas, wpos2d, col| {
        let surface_z = col.riverless_alt.floor() as i32;

        if let Some((cave_dist, _, cave, _)) =
            col.cave.filter(|(dist, _, cave, _)| *dist < cave.width)
        {
            let cave_x = (cave_dist / cave.width).min(1.0);

            // Relative units
            let cave_floor = 0.0 - 0.5 * (1.0 - cave_x.powf(2.0)).max(0.0).sqrt() * cave.width;
            let cave_height = (1.0 - cave_x.powf(2.0)).max(0.0).sqrt() * cave.width;

            // Abs units
            let cave_base = (cave.alt + cave_floor) as i32;
            let cave_roof = (cave.alt + cave_height) as i32;

            for z in cave_base..cave_roof {
                if cave_x < 0.95
                    || info.index().noise.cave_nz.get(
                        Vec3::new(wpos2d.x, wpos2d.y, z)
                            .map(|e| e as f64 * 0.15)
                            .into_array(),
                    ) < 0.0
                {
                    // If the block a little above is liquid, we should stop carving out the cave in
                    // order to leave a ceiling, and not floating water
                    if canvas
                        .get(Vec3::new(wpos2d.x, wpos2d.y, z + 2))
                        .map(|b| b.is_liquid())
                        .unwrap_or(false)
                    {
                        break;
                    }

                    canvas.map(Vec3::new(wpos2d.x, wpos2d.y, z), |b| {
                        if b.is_liquid() { b } else { EMPTY_AIR }
                    });
                }
            }

            // Stalagtites
            let stalagtites = info
                .index()
                .noise
                .cave_nz
                .get(wpos2d.map(|e| e as f64 * 0.125).into_array())
                .sub(0.5)
                .max(0.0)
                .mul(
                    (col.alt - cave_roof as f32 - 5.0)
                        .mul(0.15)
                        .clamped(0.0, 1.0) as f64,
                )
                .mul(45.0) as i32;

            for z in cave_roof - stalagtites..cave_roof {
                canvas.set(
                    Vec3::new(wpos2d.x, wpos2d.y, z),
                    Block::new(
                        BlockKind::WeakRock,
                        info.index().colors.layer.stalagtite.into(),
                    ),
                );
            }

            let cave_depth = (col.alt - cave.alt).max(0.0);
            let difficulty = cave_depth / 100.0;

            // Scatter things in caves
            if RandomField::new(info.index().seed)
                .chance(wpos2d.into(), 0.001 * difficulty.powf(1.5))
                && cave_base < surface_z as i32 - 25
            {
                let kind = *Lottery::<SpriteKind>::load_expect("common.cave_scatter")
                    .choose_seeded(RandomField::new(info.index().seed + 1).get(wpos2d.into()));
                canvas.map(Vec3::new(wpos2d.x, wpos2d.y, cave_base), |block| {
                    block.with_sprite(kind)
                });
            }
        }
    });
}
#[allow(clippy::eval_order_dependence)]
pub fn apply_caves_supplement<'a>(
    // NOTE: Used only for dynamic elements like chests and entities!
    dynamic_rng: &mut impl Rng,
    wpos2d: Vec2<i32>,
    mut get_column: impl FnMut(Vec2<i32>) -> Option<&'a ColumnSample<'a>>,
    vol: &(impl BaseVol<Vox = Block> + RectSizedVol + ReadVol + WriteVol),
    index: IndexRef,
    supplement: &mut ChunkSupplement,
) {
    for y in 0..vol.size_xy().y as i32 {
        for x in 0..vol.size_xy().x as i32 {
            let offs = Vec2::new(x, y);

            let wpos2d = wpos2d + offs;

            // Sample terrain
            let col_sample = if let Some(col_sample) = get_column(offs) {
                col_sample
            } else {
                continue;
            };
            let surface_z = col_sample.riverless_alt.floor() as i32;

            if let Some((cave_dist, _, cave, _)) = col_sample
                .cave
                .filter(|(dist, _, cave, _)| *dist < cave.width)
            {
                let cave_x = (cave_dist / cave.width).min(1.0);

                // Relative units
                let cave_floor = 0.0 - 0.5 * (1.0 - cave_x.powf(2.0)).max(0.0).sqrt() * cave.width;

                // Abs units
                let cave_base = (cave.alt + cave_floor) as i32;

                let cave_depth = (col_sample.alt - cave.alt).max(0.0);
                let difficulty = cave_depth / 200.0;

                // Scatter things in caves
                if RandomField::new(index.seed).chance(wpos2d.into(), 0.001 * difficulty)
                    && cave_base < surface_z as i32 - 40
                {
                    let is_hostile: bool;
                    let entity = EntityInfo::at(Vec3::new(
                        wpos2d.x as f32,
                        wpos2d.y as f32,
                        cave_base as f32,
                    ))
                    .with_body(match dynamic_rng.gen_range(0, 6) {
                        0 => {
                            is_hostile = false;
                            let species = match dynamic_rng.gen_range(0, 4) {
                                0 => comp::quadruped_small::Species::Truffler,
                                1 => comp::quadruped_small::Species::Dodarock,
                                2 => comp::quadruped_small::Species::Holladon,
                                _ => comp::quadruped_small::Species::Batfox,
                            };
                            comp::quadruped_small::Body::random_with(dynamic_rng, &species).into()
                        },
                        1 => {
                            is_hostile = true;
                            let species = match dynamic_rng.gen_range(0, 5) {
                                0 => comp::quadruped_medium::Species::Tarasque,
                                _ => comp::quadruped_medium::Species::Bonerattler,
                            };
                            comp::quadruped_medium::Body::random_with(dynamic_rng, &species).into()
                        },
                        2 => {
                            is_hostile = true;
                            let species = match dynamic_rng.gen_range(0, 4) {
                                1 => comp::quadruped_low::Species::Rocksnapper,
                                _ => comp::quadruped_low::Species::Salamander,
                            };
                            comp::quadruped_low::Body::random_with(dynamic_rng, &species).into()
                        },
                        _ => {
                            is_hostile = true;
                            let species = match dynamic_rng.gen_range(0, 8) {
                                0 => comp::biped_large::Species::Ogre,
                                1 => comp::biped_large::Species::Cyclops,
                                2 => comp::biped_large::Species::Wendigo,
                                _ => comp::biped_large::Species::Troll,
                            };
                            comp::biped_large::Body::random_with(dynamic_rng, &species).into()
                        },
                    })
                    .with_alignment(if is_hostile {
                        comp::Alignment::Enemy
                    } else {
                        comp::Alignment::Wild
                    })
                    .with_automatic_name();

                    supplement.add_entity(entity);
                }
            }
        }
    }
}