use super::{LeavesMode, MapRenderSettings, MeshgenInfo, Vertex, CUBE};
use cgmath::Point3;
use mt_net::MapBlock;

#[derive(Clone)]
pub(super) struct MeshData {
    pub vertices: Vec<Vertex>,
    pub vertices_blend: Vec<Vertex>,
}

impl MeshData {
    pub fn new(cap: usize) -> Self {
        Self {
            vertices: Vec::with_capacity(cap),
            vertices_blend: Vec::with_capacity(cap),
        }
    }

    pub fn cap(&self) -> usize {
        std::cmp::max(self.vertices.capacity(), self.vertices_blend.capacity())
    }
}

pub(super) fn create_mesh(
    mkinfo: &MeshgenInfo,
    settings: &MapRenderSettings,
    pos: Point3<i16>,
    block: Box<MapBlock>,
    buffer: &mut MeshData,
) {
    for (index, content) in block.param_0.iter().enumerate() {
        let def = match &mkinfo.nodes[*content as usize] {
            Some(x) => x,
            None => continue,
        };

        use mt_net::{DrawType, Param1Type};
        use std::array::from_fn as array;

        let mut tiles = &def.tiles;
        let mut draw_type = def.draw_type;

        match draw_type {
            DrawType::AllFacesOpt => {
                draw_type = match settings.leaves {
                    LeavesMode::Opaque => DrawType::Cube,
                    LeavesMode::Simple => {
                        tiles = &def.special_tiles;

                        DrawType::GlassLike
                    }
                    LeavesMode::Fancy => DrawType::AllFaces,
                };
            }
            DrawType::None => continue,
            _ => {}
        }

        let light = match def.param1_type {
            Param1Type::Light => block.param_1[index] as f32 / 15.0, // FIXME
            _ => 1.0,
        };

        let pos: [i16; 3] = array(|i| ((index >> (4 * i)) & 0xf) as i16);

        for (f, face) in CUBE.iter().enumerate() {
            let dir = FACE_DIR[f];
            let npos: [i16; 3] = array(|i| dir[i] + pos[i]);
            if npos.iter().all(|x| (0..16).contains(x)) {
                let nindex = npos[0] | (npos[1] << 4) | (npos[2] << 8);

                if let Some(ndef) = &mkinfo.nodes[block.param_0[nindex as usize] as usize] {
                    if ndef.draw_type == DrawType::Cube {
                        continue;
                    }
                }
            }

            let tile = &tiles[f];
            let texture = mkinfo.textures[tile.texture.custom].cube_tex_coords[f];

            let mut add_vertex = |vertex: (usize, &([f32; 3], [f32; 2]))| {
                buffer.vertices.push(Vertex {
                    pos: array(|i| pos[i] as f32 + vertex.1 .0[i]),
                    tex_coords: texture[vertex.0],
                    light,
                });
            };

            face.iter().enumerate().for_each(&mut add_vertex);
            /*if !backface_cull {
                face.iter().enumerate().rev().for_each(&mut add_vertex);
            }*/
        }
    }
}

#[rustfmt::skip]
const FACE_DIR: [[i16; 3]; 6] = [
	[ 0,  1,  0],
	[ 0, -1,  0],
	[ 1,  0,  0],
	[-1,  0,  0],
	[ 0,  0,  1],
	[ 0,  0, -1],
];