mod tree;

use crate::{
    column::{ColumnGen, ColumnSample},
    util::{HashCache, RandomField, Sampler, SamplerMut},
    World, CONFIG,
};
use common::{
    terrain::{structure::StructureBlock, Block},
    vol::{ReadVol, Vox},
};
use noise::NoiseFn;
use std::{
    cell::RefCell,
    ops::{Add, Div, Mul, Neg, Sub},
};
use vek::*;

pub struct BlockGen<'a> {
    world: &'a World,
    column_cache: RefCell<HashCache<Vec2<i32>, Option<ColumnSample<'a>>>>,
    column_gen: ColumnGen<'a>,
}

impl<'a> BlockGen<'a> {
    pub fn new(world: &'a World, column_gen: ColumnGen<'a>) -> Self {
        Self {
            world,
            column_cache: RefCell::new(HashCache::with_capacity(1024)),
            column_gen,
        }
    }

    fn sample_column(&self, wpos: Vec2<i32>) -> Option<ColumnSample> {
        let column_gen = &self.column_gen;
        self.column_cache
            .borrow_mut()
            .get(Vec2::from(wpos), |wpos| column_gen.get(wpos))
            .clone()
    }

    fn get_cliff_height(&self, wpos: Vec2<i32>, close_cliffs: &[(Vec2<i32>, u32); 9], cliff_hill: f32) -> f32 {
        close_cliffs
            .iter()
            .fold(0.0f32, |max_height, (cliff_pos, seed)| {
                let cliff_pos3d = Vec3::from(*cliff_pos);

                let height = RandomField::new(seed + 1).get(cliff_pos3d) % 48;
                let radius = RandomField::new(seed + 2).get(cliff_pos3d) % 48 + 8;

                match self.sample_column(Vec2::from(*cliff_pos)) {
                    Some(cliff_sample) => max_height.max(if cliff_sample.cliffs && cliff_pos.distance_squared(wpos) < (radius * radius) as i32 {
                        cliff_sample.alt + height as f32 * (1.0 - cliff_sample.chaos) + cliff_hill
                    } else {
                        0.0
                    }),
                    None => max_height,
                }
            })
    }
}

impl<'a> SamplerMut for BlockGen<'a> {
    type Index = Vec3<i32>;
    type Sample = Option<Block>;

    fn get(&mut self, wpos: Vec3<i32>) -> Option<Block> {
        let ColumnSample {
            alt,
            chaos,
            water_level,
            river,
            surface_color,
            tree_density,
            forest_kind,
            close_trees,
            cave_xy,
            cave_alt,
            rock,
            cliffs,
            cliff_hill,
            close_cliffs,
            temp,
            ..
        } = self.sample_column(Vec2::from(wpos))?;

        let wposf = wpos.map(|e| e as f64);

        // Apply warping

        let warp = (self
            .world
            .sim()
            .gen_ctx
            .warp_nz
            .get((wposf.div(Vec3::new(150.0, 150.0, 150.0))).into_array())
            as f32)
            .mul((chaos - 0.1).max(0.0))
            .mul(115.0);

        let turb = Vec2::new(
            self.world.sim().gen_ctx.turb_x_nz.get((wposf.div(48.0)).into_array()) as f32,
            self.world.sim().gen_ctx.turb_y_nz.get((wposf.div(48.0)).into_array()) as f32,
        ) * 12.0;

        let wpos_turb = Vec2::from(wpos) + turb.map(|e| e as i32);
        let cliff_height = self.get_cliff_height(wpos_turb, &close_cliffs, cliff_hill);

        let height = (alt + warp).max(cliff_height);
        let water_height = water_level + warp;

        // Sample blocks

        let stone_col = Rgb::new(200, 220, 255);
        let dirt_col = Rgb::new(79, 67, 60);

        let air = Block::empty();
        let stone = Block::new(2, stone_col);
        let surface_stone = Block::new(1, Rgb::new(200, 220, 255));
        let dirt = Block::new(1, dirt_col);
        let sand = Block::new(1, Rgb::new(180, 150, 50));
        let water = Block::new(1, Rgb::new(100, 150, 255));
        let warm_stone = Block::new(1, Rgb::new(165, 165, 130));

        let block = if (wposf.z as f32) < height - 3.0 {
            let col = Lerp::lerp(dirt_col, stone_col, (height - 4.0 - wposf.z as f32) * 0.15);

            // Underground
            if (wposf.z as f32) > alt - 32.0 * chaos {
                Some(Block::new(1, col))
            } else {
                Some(Block::new(2, col))
            }
        } else if (wposf.z as f32) < height {
            let col = Lerp::lerp(
                dirt_col.map(|e| e as f32 / 255.0),
                surface_color,
                (wposf.z as f32 - (height - 4.0)) * 0.25,
            );
            // Surface
            Some(Block::new(1, col.map(|e| (e * 255.0) as u8)))
        } else if (wposf.z as f32) < water_height {
            // Ocean
            Some(water)
        } else {
            None
        };

        // Caves
        let block = block.and_then(|block| {
            // Underground
            let cave = cave_xy.powf(2.0)
                * (wposf.z as f32 - cave_alt)
                    .div(40.0)
                    .powf(4.0)
                    .neg()
                    .add(1.0)
                > 0.9993;

            if cave {
                None
            } else {
                Some(block)
            }
        });

        // Rocks
        let block = block.or_else(|| {
            if (height + 2.5 - wposf.z as f32).div(7.5).abs().powf(2.0) < rock {
                let field0 = RandomField::new(self.world.sim().seed + 0);
                let field1 = RandomField::new(self.world.sim().seed + 1);
                let field2 = RandomField::new(self.world.sim().seed + 2);

                Some(Block::new(
                    2,
                    stone_col
                        - Rgb::new(
                            field0.get(wpos) as u8 % 32,
                            field1.get(wpos) as u8 % 32,
                            field2.get(wpos) as u8 % 32,
                        ),
                ))
            } else {
                None
            }
        });

        fn block_from_structure(
            sblock: StructureBlock,
            pos: Vec3<i32>,
            structure_pos: Vec2<i32>,
            structure_seed: u32,
            sample: &ColumnSample,
        ) -> Block {
            let field = RandomField::new(structure_seed + 0);

            let lerp = 0.5
                + ((field.get(Vec3::from(structure_pos)) % 256) as f32 / 256.0 - 0.5) * 0.75
                + ((field.get(Vec3::from(pos)) % 256) as f32 / 256.0 - 0.5) * 0.2;

            match sblock {
                StructureBlock::TemperateLeaves => Block::new(
                    1,
                    Lerp::lerp(
                        Rgb::new(0.0, 80.0, 40.0),
                        Rgb::new(120.0, 255.0, 10.0),
                        lerp,
                    )
                    .map(|e| e as u8),
                ),
                StructureBlock::PineLeaves => Block::new(
                    1,
                    Lerp::lerp(Rgb::new(0.0, 60.0, 50.0), Rgb::new(30.0, 100.0, 10.0), lerp)
                        .map(|e| e as u8),
                ),
                StructureBlock::PalmLeaves => Block::new(
                    1,
                    Lerp::lerp(
                        Rgb::new(30.0, 100.0, 30.0),
                        Rgb::new(120.0, 255.0, 0.0),
                        lerp,
                    )
                    .map(|e| e as u8),
                ),
                StructureBlock::Block(block) => block,
            }
        }

        let block = match block {
            Some(block) => block,
            None => (&close_trees)
                .iter()
                .fold(air, |block, (tree_pos, tree_seed)| {
                    match self.sample_column(Vec2::from(*tree_pos)) {
                        Some(tree_sample)
                            if tree_sample.tree_density
                                > 0.5 + (*tree_seed as f32 / 1000.0).fract() * 0.2
                                && tree_sample.alt > tree_sample.water_level =>
                        {
                            let cliff_height = self.get_cliff_height(*tree_pos, &tree_sample.close_cliffs, cliff_hill);
                            let height = tree_sample.alt.max(cliff_height);
                            let tree_pos3d = Vec3::new(tree_pos.x, tree_pos.y, height as i32);
                            let rpos = wpos - tree_pos3d;

                            let trees = tree::kinds(tree_sample.forest_kind); // Choose tree kind

                            block.or(trees[*tree_seed as usize % trees.len()]
                                .get((rpos * 128) / 128) // Scaling
                                .map(|b| {
                                    block_from_structure(
                                        *b,
                                        rpos,
                                        *tree_pos,
                                        *tree_seed,
                                        &tree_sample,
                                    )
                                })
                                .unwrap_or(Block::empty()))
                        }
                        _ => block,
                    }
                }),
        };

        Some(block)
    }
}