//! Catálogo headless de la **vegetación** del creador de mundos: estampa las 8
//! [`Forma`](llimphi_voxel::Forma)s (cactus, grama, arbusto, árbol, conífera,
//! palmera, helecho, flor) en fila sobre un llano de pasto y las rinde de una toma.
//!
//! `cargo run -p llimphi-voxel --example flora_demo --release` → `/tmp/flora.png`

use std::fs::File;
use std::io::BufWriter;

use llimphi_3d::glam::Vec3;
use llimphi_3d::{Atmosphere, Camera3d, Scene3d, VoxelGrid, VoxelRenderer};
use llimphi_hal::{wgpu, Hal};
use llimphi_raster::peniko::Color;
use llimphi_raster::{vello, Renderer};
use llimphi_voxel::{Forma, Material, Project};

const W: u32 = 1280;
const H: u32 = 540;
const FMT: wgpu::TextureFormat = wgpu::TextureFormat::Rgba8Unorm;

fn main() {
    let dim: [u32; 3] = [150, 52, 66];
    let ground_h: u32 = 5;

    // Llano de pasto.
    let mut grid = VoxelGrid::new(dim);
    let grass = Material::Grass.color();
    for x in 0..dim[0] {
        for z in 0..dim[2] {
            for y in 0..ground_h {
                // leve moteado del suelo para que no sea una loza plana
                let t = ((x * 7 + z * 13 + y) % 11) as i32 - 5;
                let c = |v: u8| (v as i32 + t).clamp(0, 255) as u8;
                grid.set(x, y, z, [c(grass[0]), c(grass[1]), c(grass[2])]);
            }
        }
    }

    // Un bioma cualquiera para acceder a `stamp_flora` (no usa sus campos).
    let project = Project::starter();
    let bioma = project.biomas.iter().find(|b| b.name == "bosque").expect("bosque");

    let leaf = Material::Leaf.color();
    let cactus = Material::Cactus.color();
    let wheat = Material::Wheat.color();
    let bloom = Material::Bloom.color();
    // Fila delantera = 1ª tanda, fila trasera = 2ª tanda (selva/bosque/pradera).
    let catalogo: [(Forma, [u8; 3]); 16] = [
        (Forma::Pasto, grass),
        (Forma::Flor, bloom),
        (Forma::Helecho, cactus),
        (Forma::Arbusto, leaf),
        (Forma::Arbol, leaf),
        (Forma::Conifera, [40, 96, 58]),
        (Forma::Palmera, [72, 142, 72]),
        (Forma::Columnar, cactus),
        (Forma::Bambu, cactus),
        (Forma::Platanera, [78, 148, 78]),
        (Forma::Roble, leaf),
        (Forma::Hongo, [176, 58, 48]),
        (Forma::Tocon, leaf),
        (Forma::Trigo, wheat),
        (Forma::Junco, [70, 120, 66]),
        (Forma::Lavanda, bloom),
    ];

    let per_row = 8u32;
    let step = dim[0] / (per_row + 1);
    let z_front = dim[2] * 62 / 100;
    let z_back = dim[2] * 30 / 100;
    for (i, (forma, col)) in catalogo.iter().enumerate() {
        let col_idx = (i as u32) % per_row;
        let row = (i as u32) / per_row;
        let x = step * (col_idx + 1);
        let z = if row == 0 { z_front } else { z_back };
        bioma.stamp_flora(&mut grid, *forma, *col, x, ground_h, z, dim);
    }

    let hal = pollster::block_on(Hal::new(None)).expect("hal");
    let mut renderer = Renderer::new(&hal).expect("renderer");
    let mut vr = VoxelRenderer::new(&hal.device, &hal.queue, FMT, &grid);
    vr.sun_dir = [0.5, 0.55, 0.35];
    vr.atmosphere = Atmosphere {
        sky_zenith: [96, 150, 210],
        sky_horizon: [200, 218, 226],
        fog_density: 0.12 / dim[0] as f32,
        god_rays: 0.0,
    };

    // Cámara en 3/4 y algo elevada: separa las dos filas y lee cada silueta.
    let camera = Camera3d::orbit(
        Vec3::new(0.0, dim[1] as f32 * 0.08, 0.0),
        14_f32.to_radians(),
        18_f32.to_radians(),
        dim[0] as f32 * 0.66,
    );

    let mut scene = Scene3d::new();
    let pixels = render(&hal, &mut renderer, &mut scene, &mut vr, &camera);
    write_png(&pixels, "/tmp/flora.png");
    eprintln!("escrito /tmp/flora.png — catálogo de 8 formas de vegetación");
}

fn render(
    hal: &Hal,
    renderer: &mut Renderer,
    scene: &mut Scene3d,
    vr: &mut VoxelRenderer,
    camera: &Camera3d,
) -> Vec<u8> {
    let inter = hal.device.create_texture(&wgpu::TextureDescriptor {
        label: Some("inter"),
        size: wgpu::Extent3d { width: W, height: H, depth_or_array_layers: 1 },
        mip_level_count: 1,
        sample_count: 1,
        dimension: wgpu::TextureDimension::D2,
        format: FMT,
        usage: wgpu::TextureUsages::STORAGE_BINDING
            | wgpu::TextureUsages::TEXTURE_BINDING
            | wgpu::TextureUsages::RENDER_ATTACHMENT
            | wgpu::TextureUsages::COPY_SRC,
        view_formats: &[],
    });
    let view = inter.create_view(&wgpu::TextureViewDescriptor::default());
    renderer
        .render_to_view(hal, &vello::Scene::new(), &view, W, H, Color::from_rgba8(0, 0, 0, 255))
        .expect("base");
    let mut enc = hal
        .device
        .create_command_encoder(&wgpu::CommandEncoderDescriptor { label: Some("flora") });
    scene.render(&hal.device, &hal.queue, &mut enc, &view, (W, H), camera, Some(vr), &[]);
    hal.queue.submit(std::iter::once(enc.finish()));
    let _ = hal.device.poll(wgpu::PollType::wait_indefinitely());
    readback(hal, &inter)
}

fn readback(hal: &Hal, target: &wgpu::Texture) -> Vec<u8> {
    let unpadded = (W * 4) as usize;
    let align = wgpu::COPY_BYTES_PER_ROW_ALIGNMENT as usize;
    let padded = unpadded.div_ceil(align) * align;
    let buf = hal.device.create_buffer(&wgpu::BufferDescriptor {
        label: Some("readback"),
        size: (padded * H as usize) as u64,
        usage: wgpu::BufferUsages::MAP_READ | wgpu::BufferUsages::COPY_DST,
        mapped_at_creation: false,
    });
    let mut enc = hal
        .device
        .create_command_encoder(&wgpu::CommandEncoderDescriptor { label: None });
    enc.copy_texture_to_buffer(
        wgpu::TexelCopyTextureInfo {
            texture: target,
            mip_level: 0,
            origin: wgpu::Origin3d::ZERO,
            aspect: wgpu::TextureAspect::All,
        },
        wgpu::TexelCopyBufferInfo {
            buffer: &buf,
            layout: wgpu::TexelCopyBufferLayout {
                offset: 0,
                bytes_per_row: Some(padded as u32),
                rows_per_image: Some(H),
            },
        },
        wgpu::Extent3d { width: W, height: H, depth_or_array_layers: 1 },
    );
    hal.queue.submit(std::iter::once(enc.finish()));
    let slice = buf.slice(..);
    let (tx, rx) = std::sync::mpsc::channel();
    slice.map_async(wgpu::MapMode::Read, move |r| {
        let _ = tx.send(r);
    });
    let _ = hal.device.poll(wgpu::PollType::wait_indefinitely());
    rx.recv().unwrap().unwrap();
    let data = slice.get_mapped_range();
    let mut pixels = Vec::with_capacity((W * H * 4) as usize);
    for row in 0..H as usize {
        let s = row * padded;
        pixels.extend_from_slice(&data[s..s + unpadded]);
    }
    drop(data);
    buf.unmap();
    pixels
}

fn write_png(pixels: &[u8], path: &str) {
    let file = File::create(path).expect("png");
    let mut enc = png::Encoder::new(BufWriter::new(file), W, H);
    enc.set_color(png::ColorType::Rgba);
    enc.set_depth(png::BitDepth::Eight);
    let mut wtr = enc.write_header().unwrap();
    wtr.write_image_data(pixels).unwrap();
}