use effectcraft_keyframe::Value;
use effectcraft_project::{Comp, ItemId, ItemKind, LayerSource, LightKind, PrimitiveKind, Project, Renderer as R3, build};
use effectcraft_time::{FrameRate, Tick};

use super::scene::{Material, Scene, TexInfo, Vertex, irradiance_map};
use super::shade::{self, PI};
use super::*;
use crate::{NoFootage, RenderOpts, Renderer};

// ---------------------------------------------------------------- shading

#[test]
fn brdf_matches_cook_torrance_formula() {
    // Reference: f = kd·c/π + D·G·F/(4·NV·NL), returned × NL × π.
    let n = [0.0, 0.0, 1.0];
    let v = shade::norm([0.3, 0.1, 1.0]);
    let l = shade::norm([-0.4, 0.2, 1.0]);
    let (base, metal, rough) = ([0.8, 0.4, 0.2], 0.3f32, 0.45f32);
    let got = shade::brdf(base, metal, rough, 1.0, 1.0, n, v, l);
    let h = shade::norm([v[0] + l[0], v[1] + l[1], v[2] + l[2]]);
    let (nv, nl, nh, vh) = (shade::dot(n, v), shade::dot(n, l), shade::dot(n, h), shade::dot(v, h));
    let a2 = (rough * rough).powi(2);
    let d = a2 / (PI * ((nh * nh) * (a2 - 1.0) + 1.0).powi(2));
    let k = (rough + 1.0).powi(2) / 8.0;
    let g = nv / (nv * (1.0 - k) + k) * nl / (nl * (1.0 - k) + k);
    for c in 0..3 {
        let f0 = 0.04 + (base[c] - 0.04) * metal;
        let f = f0 + (1.0 - f0) * (1.0 - vh).powi(5);
        let expect = ((1.0 - f) * (1.0 - metal) * base[c] / PI + d * g * f / (4.0 * nv * nl)) * nl * PI;
        assert!((got[c] - expect).abs() < 1e-5, "channel {c}: {} vs {expect}", got[c]);
    }
    // No light from behind the surface.
    assert_eq!(shade::brdf(base, metal, rough, 1.0, 1.0, n, v, [0.0, 0.0, -1.0]), [0.0; 3]);
    // A white rough dielectric lit head-on reflects about its base colour (π folded in).
    let w = shade::brdf([1.0; 3], 0.0, 1.0, 1.0, 1.0, n, n, n);
    assert!(w[0] > 0.95 && w[0] < 1.05, "{w:?}");
}

#[test]
fn ggx_distribution_is_normalised() {
    // ∫ D(h)·(n·h) dω = 1 over the hemisphere.
    for &rough in &[0.2f32, 0.5, 0.9] {
        let a = rough * rough;
        let n = 4000;
        let mut sum = 0.0f64;
        for i in 0..n {
            let th = (i as f64 + 0.5) / n as f64 * std::f64::consts::FRAC_PI_2;
            let c = th.cos() as f32;
            sum += shade::d_ggx(c, a) as f64 * c as f64 * th.sin() * std::f64::consts::FRAC_PI_2 / n as f64 * 2.0 * std::f64::consts::PI;
        }
        assert!((sum - 1.0).abs() < 0.02, "roughness {rough}: {sum}");
    }
}

#[test]
fn constant_environment_has_constant_irradiance() {
    let src = vec![[0.25, 0.5, 0.75, 1.0]; 64 * 32];
    let irr = irradiance_map(64, 32, &src, 32, 16);
    for p in &irr {
        for c in 0..3 {
            assert!((p[c] - src[0][c]).abs() < 1e-4, "{p:?}");
        }
    }
    // And a sky brighter than the ground lights upward-facing normals more.
    let sky: Vec<[f32; 4]> = (0..32).flat_map(|y| (0..64).map(move |_| if y < 16 { [1.0, 1.0, 1.0, 1.0] } else { [0.0, 0.0, 0.0, 1.0] })).collect();
    let irr = irradiance_map(64, 32, &sky, 32, 16);
    assert!(irr[16][0] > 0.9 && irr[15 * 32 + 16][0] < 0.1, "{:?} {:?}", irr[16], irr[15 * 32 + 16]);
}

#[test]
fn equirect_round_trip_and_env_brdf() {
    for (u, v) in [(0.1f32, 0.2f32), (0.5, 0.5), (0.9, 0.7)] {
        let d = shade::equirect_dir(u, v, 0.3);
        let (u2, v2) = shade::equirect_uv(d, 0.3);
        assert!((u - u2).abs() < 1e-4 && (v - v2).abs() < 1e-4);
    }
    // Up (−Y in AE space) is the top row.
    assert!(shade::equirect_uv([0.0, -1.0, 0.0], 0.0).1 < 1e-3);
    let (a, b) = shade::env_brdf(1.0, 0.0);
    assert!(a + b > 0.9 && a + b <= 1.05);
    let (a, b) = shade::env_brdf(0.1, 1.0);
    assert!(a >= 0.0 && b > -0.01 && a + b < 1.0);
}

// ---------------------------------------------------------------- rasteriser

/// A scene of axis-aligned quads (z = camera depth) seen by an orthographic identity camera
/// mapping world x/y straight to raster pixels.
fn quad_scene(w: u32, h: u32, quads: &[([f32; 4], f32, [f32; 4])]) -> Scene {
    let mut s = Scene { width: w, height: h, ssaa: 1, linear_io: true, ..Scene::default() };
    // clip: x → 2x/w − 1, y → 1 − 2y/h, z: depth 0..1000 → 1..0 (nearer = larger).
    s.clip = [[2.0 / w as f32, 0.0, 0.0, -1.0], [0.0, -2.0 / h as f32, 0.0, 1.0], [0.0, 0.0, -0.001, 1.0], [0.0, 0.0, 0.0, 1.0]];
    s.view = [[1.0, 0.0, 0.0, 0.0], [0.0, 1.0, 0.0, 0.0], [0.0, 0.0, 1.0, 0.0], [0.0, 0.0, 0.0, 1.0]];
    s.ortho = true;
    s.cam_fwd = [0.0, 0.0, 1.0];
    for (rect, z, color) in quads {
        let m = s.materials.len() as u32;
        s.materials.push(Material { base: *color, unlit: true, double_sided: true, alpha_mode: if color[3] < 1.0 { 2 } else { 0 }, ..Material::default() });
        let b = s.vertices.len() as u32;
        for (x, y) in [(rect[0], rect[1]), (rect[2], rect[1]), (rect[2], rect[3]), (rect[0], rect[3])] {
            s.vertices.push(Vertex { pos: [x, y, *z], normal: [0.0, 0.0, -1.0], uv: [0.0; 2], tangent: [1.0, 0.0, 0.0, 1.0], material: m });
        }
        s.indices.extend([b, b + 2, b + 1, b, b + 3, b + 2]);
    }
    // Opaque first, transparent (in given order) after.
    let tris: Vec<[u32; 3]> = s.indices.chunks(3).map(|t| [t[0], t[1], t[2]]).collect();
    let (o, t): (Vec<_>, Vec<_>) = tris.into_iter().partition(|t| !s.materials[s.vertices[t[0] as usize].material as usize].transparent());
    s.opaque_count = 3 * o.len() as u32;
    s.indices = o.into_iter().chain(t).flatten().collect();
    s
}

#[test]
fn depth_buffer_keeps_the_nearest_surface() {
    let red = [1.0, 0.0, 0.0, 1.0];
    let blue = [0.0, 0.0, 1.0, 1.0];
    // Blue is listed first but is farther away.
    let s = quad_scene(40, 30, &[([0.0, 0.0, 30.0, 20.0], 500.0, blue), ([10.0, 10.0, 40.0, 30.0], 100.0, red)]);
    let t = raster::render(&s);
    let px = |x: usize, y: usize| t.color[y * 40 + x];
    assert_eq!(px(5, 5), blue);
    assert_eq!(px(15, 15), red, "overlap: the nearer quad wins");
    assert_eq!(px(35, 25), red);
    assert_eq!(px(35, 5), [0.0; 4]);
    assert_eq!(t.depth[15 * 40 + 15], 100.0);
    assert!(t.depth[5 * 40 + 35].is_infinite());
}

#[test]
fn coverage_is_exact_for_pixel_aligned_quads() {
    // Shared diagonal edges are filled once (top-left rule): exact pixel counts.
    let s = quad_scene(32, 32, &[([4.0, 4.0, 20.0, 12.0], 10.0, [1.0, 1.0, 1.0, 0.5])]);
    let t = raster::render(&s);
    let covered = t.color.iter().filter(|c| c[3] > 0.0).count();
    assert_eq!(covered, 16 * 8);
    // Blended once (no double coverage along the diagonal).
    assert!(t.color.iter().all(|c| c[3] == 0.0 || (c[3] - 0.5).abs() < 1e-6));
    // Two transparent layers composite in order.
    let s = quad_scene(8, 8, &[([0.0, 0.0, 8.0, 8.0], 100.0, [1.0, 0.0, 0.0, 0.5]), ([0.0, 0.0, 8.0, 8.0], 50.0, [0.0, 0.0, 1.0, 0.5])]);
    let c = raster::render(&s).color[0];
    assert!((c[0] - 0.25).abs() < 1e-6 && (c[2] - 0.5).abs() < 1e-6 && (c[3] - 0.75).abs() < 1e-6, "{c:?}");
}

#[test]
fn textures_sample_bilinear_with_wrap_modes() {
    let t = TexInfo { offset: 0, width: 2, height: 1, wrap_u: 0, wrap_v: 1 };
    let texels = vec![[0.0, 0.0, 0.0, 1.0], [1.0, 1.0, 1.0, 1.0]];
    assert_eq!(shade::sample(&t, &texels, 0.25, 0.5)[0], 0.0);
    assert_eq!(shade::sample(&t, &texels, 0.5, 0.5)[0], 0.5);
    // Repeat wraps the right edge back to texel 0.
    assert!((shade::sample(&t, &texels, 1.0, 0.5)[0] - 0.5).abs() < 1e-6);
    let c = TexInfo { wrap_u: 1, ..t };
    assert_eq!(shade::sample(&c, &texels, 1.0, 0.5)[0], 1.0);
}

// ---------------------------------------------------------------- full renderer

fn project(w: u32, h: u32) -> (Project, ItemId) {
    let mut p = Project::default();
    let mut c = Comp::new(w, h, FrameRate::FPS_30, Tick::from_seconds_f64(1.0));
    c.renderer = R3::Advanced3D;
    let id = p.add_item("C", Default::default(), None, ItemKind::Comp(c.into()));
    (p, id)
}

fn add(p: &mut Project, cid: ItemId, src: LayerSource, edit: impl FnOnce(&mut effectcraft_project::Layer)) {
    let comp = p.comp(cid).unwrap().clone();
    let mut l = build::layer(p, &comp, "L", src, (comp.width, comp.height), None);
    edit(&mut l);
    p.comp_mut(cid).unwrap().layers.insert(0, l);
}

fn set(l: &mut effectcraft_project::Layer, path: &str, v: Value) {
    l.props.prop_mut(path).unwrap_or_else(|| panic!("{path}")).value = v;
}

fn render(p: &Project, cid: ItemId) -> crate::Image {
    Renderer::new(p, &NoFootage, RenderOpts::default()).comp_frame(cid, Tick::ZERO)
}

#[test]
fn lit_cube_renders_with_depth_and_shading() {
    let (mut p, cid) = project(160, 120);
    add(&mut p, cid, LayerSource::Primitive { kind: PrimitiveKind::Cube }, |l| {
        set(l, "geometryOptions/width", Value::Scalar(60.0));
        set(l, "geometryOptions/height", Value::Scalar(60.0));
        set(l, "geometryOptions/depth", Value::Scalar(60.0));
        set(l, "transform/rotationY", Value::Scalar(35.0));
        set(l, "transform/rotationX", Value::Scalar(-25.0));
        set(l, "materialOptions/baseColor", Value::Color([1.0, 1.0, 1.0, 1.0]));
    });
    let img = render(&p, cid);
    let centre = img.data[60 * 160 + 80];
    assert!(centre[3] > 0.99, "cube covers the centre: {centre:?}");
    assert_eq!(img.data[2 * 160 + 2][3], 0.0, "corner is empty");
    // No lights: unlit (base colour) — add a light and faces get different shades.
    add(&mut p, cid, LayerSource::Light { kind: LightKind::Parallel }, |_| {});
    let lit = render(&p, cid);
    let mut shades: Vec<i32> = lit.data.iter().filter(|q| q[3] > 0.99).map(|q| (q[0] * 20.0) as i32).collect();
    shades.sort();
    shades.dedup();
    assert!(shades.len() >= 3, "faces are shaded differently: {shades:?}");
    // Classic 3D draws no meshes.
    p.comp_mut(cid).unwrap().renderer = R3::Classic3D;
    assert!(render(&p, cid).data.iter().all(|q| q[3] == 0.0));
}

#[test]
fn shadows_darken_the_receiver() {
    let (mut p, cid) = project(200, 150);
    // A floor plane facing the camera, a sphere in front of it, a spot light behind the camera.
    add(&mut p, cid, LayerSource::Primitive { kind: PrimitiveKind::Plane }, |l| {
        set(l, "geometryOptions/width", Value::Scalar(400.0));
        set(l, "geometryOptions/height", Value::Scalar(400.0));
        set(l, "transform/position", Value::Vec3([100.0, 75.0, 200.0]));
        set(l, "materialOptions/baseColor", Value::Color([1.0, 1.0, 1.0, 1.0]));
    });
    add(&mut p, cid, LayerSource::Primitive { kind: PrimitiveKind::Sphere }, |l| {
        set(l, "geometryOptions/radius", Value::Scalar(30.0));
        set(l, "transform/position", Value::Vec3([100.0, 75.0, 50.0]));
        set(l, "materialOptions/castsShadows", Value::Enum(2));
    });
    add(&mut p, cid, LayerSource::Light { kind: LightKind::Point }, |l| {
        set(l, "transform/position", Value::Vec3([100.0, 75.0, -300.0]));
        set(l, "lightOptions/castsShadows", Value::Bool(true));
    });
    let img = render(&p, cid);
    // The sphere casts only (invisible); its shadow lands on the plane behind it.
    let mid = img.data[75 * 200 + 100];
    let side = img.data[75 * 200 + 20];
    assert!(mid[3] > 0.99 && side[3] > 0.99);
    assert!(mid[0] < side[0] * 0.5, "shadowed centre {mid:?} vs lit side {side:?}");
    // Without shadow casting the centre is lit.
    let l = &mut p.comp_mut(cid).unwrap().layers[0];
    set(l, "lightOptions/castsShadows", Value::Bool(false));
    let img = render(&p, cid);
    assert!(img.data[75 * 200 + 100][0] > side[0] * 0.8);
}

#[test]
fn accepts_shadows_only_draws_just_the_shadow() {
    // #1691: a shadow catcher (card or plane primitive, "Accepts Shadows: Only") in front of a
    // red backdrop card, an invisible sphere casting onto it, a point light behind the camera.
    let (mut p, cid) = project(200, 150);
    let red = p.add_item(
        "R",
        Default::default(),
        None,
        ItemKind::Solid(effectcraft_project::Solid { color: [1.0, 0.0, 0.0], width: 400, height: 400, pixel_aspect: 1.0 }),
    );
    add(&mut p, cid, LayerSource::Solid { item: red }, |l| {
        l.switches.three_d = true;
        set(l, "transform/position", Value::Vec3([100.0, 75.0, 300.0]));
        set(l, "materialOptions/acceptsShadows", Value::Enum(0));
    });
    let white = p.add_item(
        "W",
        Default::default(),
        None,
        ItemKind::Solid(effectcraft_project::Solid { color: [1.0, 1.0, 1.0], width: 400, height: 400, pixel_aspect: 1.0 }),
    );
    add(&mut p, cid, LayerSource::Solid { item: white }, |l| {
        l.switches.three_d = true;
        set(l, "transform/position", Value::Vec3([100.0, 75.0, 200.0]));
        set(l, "materialOptions/acceptsShadows", Value::Enum(2));
    });
    add(&mut p, cid, LayerSource::Primitive { kind: PrimitiveKind::Sphere }, |l| {
        set(l, "geometryOptions/radius", Value::Scalar(30.0));
        set(l, "transform/position", Value::Vec3([100.0, 75.0, 50.0]));
        set(l, "materialOptions/castsShadows", Value::Enum(2));
    });
    add(&mut p, cid, LayerSource::Light { kind: LightKind::Point }, |l| {
        set(l, "transform/position", Value::Vec3([100.0, 75.0, -300.0]));
        set(l, "lightOptions/castsShadows", Value::Bool(true));
    });
    let check = |img: &crate::Image, what: &str| {
        let (mid, side) = (img.data[75 * 200 + 100], img.data[75 * 200 + 60]);
        // Unshadowed: the catcher is see-through, the lit red card behind it shows.
        assert!(side[0] > 0.5 && side[1] < side[0] * 0.25 && side[3] > 0.99, "{what}: side {side:?}");
        // Shadowed: black over the red card.
        assert!(mid[0] < 0.02 && mid[3] > 0.99, "{what}: shadow {mid:?} vs side {side:?}");
    };
    check(&render(&p, cid), "card");
    // Nothing behind the catcher: only the shadow is opaque.
    let solo = |p: &Project| {
        let mut q = p.clone();
        q.comp_mut(cid).unwrap().layers.pop();
        let img = render(&q, cid);
        let (mid, side) = (img.data[75 * 200 + 100], img.data[75 * 200 + 60]);
        assert!(side[3] < 1e-3, "unshadowed catcher is transparent: {side:?}");
        assert!(mid[3] > 0.5 && mid[0] < 1e-3, "shadow is black: {mid:?}");
    };
    solo(&p);
    // The same with a plane primitive as the catcher.
    let layers = &mut p.comp_mut(cid).unwrap().layers;
    layers.remove(2);
    add(&mut p, cid, LayerSource::Primitive { kind: PrimitiveKind::Plane }, |l| {
        set(l, "geometryOptions/width", Value::Scalar(400.0));
        set(l, "geometryOptions/height", Value::Scalar(400.0));
        set(l, "transform/position", Value::Vec3([100.0, 75.0, 200.0]));
        set(l, "materialOptions/acceptsShadows", Value::Enum(2));
    });
    check(&render(&p, cid), "plane");
    solo(&p);
}

#[test]
fn cards_and_environment_light() {
    let (mut p, cid) = project(120, 90);
    let sid = p.add_item(
        "S",
        Default::default(),
        None,
        ItemKind::Solid(effectcraft_project::Solid { color: [0.5, 0.5, 0.5], width: 60, height: 40, pixel_aspect: 1.0 }),
    );
    add(&mut p, cid, LayerSource::Solid { item: sid }, |l| l.switches.three_d = true);
    let unlit = render(&p, cid);
    let c = unlit.data[20 * 120 + 30];
    assert!((c[0] - 0.5).abs() < 0.01 && c[3] > 0.99, "unlit card keeps its colour: {c:?}");
    assert_eq!(unlit.data[80 * 120 + 110][3], 0.0);
    // An Environment light sourcing a white environment layer brightens the card.
    let env = p.add_item(
        "E",
        Default::default(),
        None,
        ItemKind::Solid(effectcraft_project::Solid { color: [1.0, 1.0, 1.0], width: 64, height: 32, pixel_aspect: 1.0 }),
    );
    add(&mut p, cid, LayerSource::Solid { item: env }, |l| {
        l.environment = true;
        l.switches.three_d = true;
    });
    add(&mut p, cid, LayerSource::Light { kind: LightKind::Environment }, |_| {});
    let lit = render(&p, cid);
    let c2 = lit.data[20 * 120 + 30];
    assert!(c2[0] > 0.3, "{c2:?}");
    // The environment layer itself is not drawn.
    assert_eq!(lit.data[80 * 120 + 110][3], 0.0);
}

#[test]
fn depth_of_field_blurs_out_of_focus_surfaces() {
    let mut img = Image::new(64, 64);
    for y in 0..64 {
        for x in 0..64 {
            let v = if (x / 4 + y / 4) % 2 == 0 { 1.0 } else { 0.0 };
            img.data[y * 64 + x] = [v, v, v, 1.0];
        }
    }
    let var = |im: &Image| {
        let m: f32 = im.data.iter().map(|p| p[0]).sum::<f32>() / im.data.len() as f32;
        im.data.iter().map(|p| (p[0] - m).powi(2)).sum::<f32>() / im.data.len() as f32
    };
    let dof = crate::three_d::camera::Dof { focus: 1000.0, aperture: 40.0, blur_level: 1.0, iris: Default::default(), highlight: Default::default() };
    let sharp = depth_of_field(&img, &vec![1000.0; 64 * 64], &dof, 1.0);
    assert!((var(&sharp) - var(&img)).abs() < 1e-6, "in focus: unchanged");
    let blurred = depth_of_field(&img, &vec![3000.0; 64 * 64], &dof, 1.0);
    assert!(var(&blurred) < var(&img) * 0.3, "out of focus: blurred");
}

#[test]
fn extruded_text_renders_as_a_mesh() {
    let (mut p, cid) = project(200, 100);
    add(&mut p, cid, LayerSource::Text, |l| {
        l.switches.three_d = true;
        let doc = effectcraft_keyframe::TextDoc { text: "IO".into(), size: 60.0, fill: [1.0, 1.0, 1.0, 1.0], apply_fill: true, ..Default::default() };
        set(l, "text/sourceText", Value::Text(Box::new(doc)));
        let mut next = 10_000u64;
        l.props.children.push(build::extrusion_geometry_options(&mut build::Ids(&mut next)).into());
        set(l, "geometryOptions/extrusionDepth", Value::Scalar(30.0));
        set(l, "geometryOptions/bevelStyle", Value::Enum(1));
        set(l, "transform/rotationY", Value::Scalar(40.0));
    });
    let ctx = crate::EvalCtx { project: &p, comp_id: cid, comp: p.comp(cid).unwrap(), time: Tick::ZERO, expr: None, footage: None };
    let l = &ctx.comp.layers[0];
    let params = scene::extrusion_params(&ctx, l).unwrap();
    let meshes = scene::extruded_meshes(&ctx, l, &params);
    assert!(!meshes.is_empty());
    assert!(meshes.iter().all(|(m, _, _)| m.positions.iter().any(|q| (q[2] - 30.0).abs() < 1e-3)));
    let img = render(&p, cid);
    assert!(img.data.iter().filter(|q| q[3] > 0.5).count() > 200);
}

#[test]
fn shape_surface_items_colour_the_extruded_surfaces() {
    let (mut p, cid) = project(200, 200);
    add(&mut p, cid, LayerSource::Shape, |l| {
        l.switches.three_d = true;
        let mut next = 10_000u64;
        let ids = &mut build::Ids(&mut next);
        let surface = |ids: &mut build::Ids, m: &str, c: [f64; 4]| {
            let mut g = build::shape_surface(ids, m).unwrap();
            g.children.push(build::shape_surface_prop(ids, "color").unwrap().into());
            if let Some(effectcraft_project::Node::Prop(pr)) = g.children.last_mut() {
                pr.value = Value::Color(c);
            }
            g
        };
        // A white square whose group colours its sides green; the layer's Contents colour every
        // front blue and every side red, but the group's own Side wins.
        let rect = build::shape_rect(ids, [80.0, 80.0], [0.0, 0.0], 0.0);
        let fill = build::shape_fill(ids, [1.0, 1.0, 1.0, 1.0]);
        let side = surface(ids, "side", [0.0, 1.0, 0.0, 1.0]);
        let group = build::shape_group(ids, "Group 1", vec![rect, fill, side]);
        let front = surface(ids, "front", [0.0, 0.0, 1.0, 1.0]);
        let outer_side = surface(ids, "side", [1.0, 0.0, 0.0, 1.0]);
        let contents = l.props.sub_mut("contents").unwrap();
        contents.children.extend([group.into(), front.into(), outer_side.into()]);
        l.props.children.push(build::extrusion_geometry_options(ids).into());
        set(l, "geometryOptions/extrusionDepth", Value::Scalar(40.0));
        set(l, "transform/position", Value::Vec3([100.0, 100.0, 0.0]));
    });
    let ctx = crate::EvalCtx { project: &p, comp_id: cid, comp: p.comp(cid).unwrap(), time: Tick::ZERO, expr: None, footage: None };
    let l = &ctx.comp.layers[0];
    let params = scene::extrusion_params(&ctx, l).unwrap();
    let meshes = scene::extruded_meshes(&ctx, l, &params);
    // No bevel: Front, Side and Back (the Back keeps the fill's white).
    let colours: Vec<[f32; 4]> = meshes.iter().map(|m| m.1).collect();
    assert_eq!(colours, [[0.0, 0.0, 1.0, 1.0], [0.0, 1.0, 0.0, 1.0], [1.0, 1.0, 1.0, 1.0]]);
    assert!(meshes[0].0.normals.iter().all(|n| n[2] < -0.99), "front cap");
    assert!(meshes[1].0.normals.iter().all(|n| n[2].abs() < 1e-6), "walls");
    // Rendered (unlit: base colours) at an angle: the blue face and the green side both show.
    p.comp_mut(cid).unwrap().layers[0].props.prop_mut("transform/rotationY").unwrap().value = Value::Scalar(50.0);
    let img = render(&p, cid);
    let blue = img.data.iter().filter(|q| q[3] > 0.99 && q[2] > 0.9 && q[0] < 0.1 && q[1] < 0.1).count();
    let green = img.data.iter().filter(|q| q[3] > 0.99 && q[1] > 0.9 && q[0] < 0.1 && q[2] < 0.1).count();
    assert!(blue > 200 && green > 50, "blue {blue}, green {green}");
}

#[test]
fn text_animators_colour_the_extruded_surfaces() {
    let (mut p, cid) = project(200, 100);
    add(&mut p, cid, LayerSource::Text, |l| {
        l.switches.three_d = true;
        let doc = effectcraft_keyframe::TextDoc { text: "IO".into(), size: 60.0, fill: [1.0, 1.0, 1.0, 1.0], apply_fill: true, ..Default::default() };
        set(l, "text/sourceText", Value::Text(Box::new(doc)));
        let mut next = 10_000u64;
        let ids = &mut build::Ids(&mut next);
        let props = ["sideColor", "bevelColor"].iter().flat_map(|k| build::text_anim_props(ids, k, false)).collect();
        let anim = build::text_animator(ids, "Animator 1", props);
        l.props.group_mut("text/animators").unwrap().children.push(anim.into());
        set(l, "text/animators/#1/properties/sideColor", Value::Color([0.0, 1.0, 0.0, 1.0]));
        // Half the selection: the bevel colour blends half way over the fill.
        set(l, "text/animators/#1/selectors/#1/advanced/amount", Value::Scalar(50.0));
        l.props.children.push(build::extrusion_geometry_options(ids).into());
        set(l, "geometryOptions/extrusionDepth", Value::Scalar(30.0));
        set(l, "geometryOptions/bevelStyle", Value::Enum(1));
    });
    let ctx = crate::EvalCtx { project: &p, comp_id: cid, comp: p.comp(cid).unwrap(), time: Tick::ZERO, expr: None, footage: None };
    let l = &ctx.comp.layers[0];
    let params = scene::extrusion_params(&ctx, l).unwrap();
    let meshes = scene::extruded_meshes(&ctx, l, &params);
    // Two characters × (Front, Bevel, Side, Back).
    assert_eq!(meshes.len(), 8);
    for m in meshes.chunks(4) {
        assert_eq!(m[0].1, [1.0, 1.0, 1.0, 1.0], "front keeps the fill");
        assert_eq!(m[1].1, [1.0, 0.5, 0.5, 1.0], "bevel: red half way over white");
        assert_eq!(m[2].1, [0.5, 1.0, 0.5, 1.0], "side: green half way over white");
        assert_eq!(m[3].1, [1.0, 1.0, 1.0, 1.0], "back keeps the fill");
    }
}

// ---------------------------------------------------------------- motion blur, blend modes, mattes

fn solid(p: &mut Project, color: [f32; 3], w: u32, h: u32) -> ItemId {
    p.add_item("S", Default::default(), None, ItemKind::Solid(effectcraft_project::Solid { color, width: w, height: h, pixel_aspect: 1.0 }))
}

/// Pixels of row `y` whose alpha is partial (motion-blur smear or anti-aliasing).
fn partial(img: &crate::Image, y: u32) -> usize {
    (0..img.width).filter(|x| (0.05..0.95).contains(&img.data[(y * img.width + x) as usize][3])).count()
}

#[test]
fn motion_blur_smears_moving_meshes() {
    let (mut p, cid) = project(160, 120);
    add(&mut p, cid, LayerSource::Primitive { kind: PrimitiveKind::Cube }, |l| {
        set(l, "geometryOptions/width", Value::Scalar(30.0));
        set(l, "geometryOptions/height", Value::Scalar(30.0));
        set(l, "geometryOptions/depth", Value::Scalar(30.0));
        // 60 px per frame to the right.
        let pr = l.props.prop_mut("transform/position").unwrap();
        pr.keys = vec![
            effectcraft_keyframe::Keyframe::new(Tick::ZERO, Value::Vec3([50.0, 60.0, 0.0])),
            effectcraft_keyframe::Keyframe::new(Tick::from_seconds_f64(1.0), Value::Vec3([50.0 + 30.0 * 60.0, 60.0, 0.0])),
        ];
    });
    let sharp = render(&p, cid);
    let hard = partial(&sharp, 60);
    assert!(hard <= 4, "no blur without the switch: {hard}");
    p.comp_mut(cid).unwrap().layers[0].switches.motion_blur = true;
    let blurred = render(&p, cid);
    let smear = partial(&blurred, 60);
    // A 180° shutter smears over half a frame of motion (≈ 30 px).
    assert!(smear > 20, "smeared: {smear}");
    // Coverage is conserved: the summed alpha along the row stays about the cube's width.
    let sum = |im: &crate::Image| (0..160).map(|x| im.data[60 * 160 + x][3]).sum::<f32>();
    assert!((sum(&blurred) - sum(&sharp)).abs() < 4.0, "{} vs {}", sum(&blurred), sum(&sharp));
    // The comp's motion blur switch and the render option turn it off.
    p.comp_mut(cid).unwrap().enable_motion_blur = false;
    assert!(partial(&render(&p, cid), 60) <= 4);
    p.comp_mut(cid).unwrap().enable_motion_blur = true;
    let r = Renderer::new(&p, &NoFootage, RenderOpts { motion_blur: false, ..Default::default() });
    assert!(partial(&r.comp_frame(cid, Tick::ZERO), 60) <= 4);
    // Shutter angle 0 has no exposure time: no smear.
    p.comp_mut(cid).unwrap().shutter_angle = 0.0;
    assert!(partial(&render(&p, cid), 60) <= 4);
}

#[test]
fn blend_modes_and_occlusion_in_advanced_3d() {
    let (mut p, cid) = project(120, 90);
    let red = solid(&mut p, [1.0, 0.0, 0.0], 120, 90);
    let gray = solid(&mut p, [0.5, 0.5, 0.5], 60, 40);
    let blue = solid(&mut p, [0.0, 0.0, 1.0], 20, 20);
    // Back: a red card; middle: a gray Multiply card; front: a small blue card on the left.
    add(&mut p, cid, LayerSource::Solid { item: red }, |l| {
        l.switches.three_d = true;
    });
    add(&mut p, cid, LayerSource::Solid { item: gray }, |l| {
        l.switches.three_d = true;
        l.blend_mode = effectcraft_color::BlendMode::Multiply;
        set(l, "transform/position", Value::Vec3([60.0, 45.0, -20.0]));
        set(l, "transform/anchor", Value::Vec3([30.0, 20.0, 0.0]));
    });
    add(&mut p, cid, LayerSource::Solid { item: blue }, |l| {
        l.switches.three_d = true;
        set(l, "transform/position", Value::Vec3([45.0, 45.0, -40.0]));
        set(l, "transform/anchor", Value::Vec3([10.0, 10.0, 0.0]));
    });
    let img = render(&p, cid);
    let at = |x: usize, y: usize| img.data[y * 120 + x];
    // Multiply over red: half red, no gray.
    let c = at(70, 45);
    assert!((c[0] - 0.5).abs() < 0.02 && c[1] < 0.02 && c[2] < 0.02 && c[3] > 0.99, "multiplied {c:?}");
    // Outside the gray card: plain red.
    let r = at(115, 5);
    assert!(r[0] > 0.98 && r[1] < 0.02, "{r:?}");
    // The nearer blue card hides the Multiply card behind it.
    let b = at(40, 45);
    assert!(b[2] > 0.98 && b[0] < 0.02, "occluded {b:?}");
    // Normal mode for comparison: gray covers the red.
    p.comp_mut(cid).unwrap().layers[1].blend_mode = effectcraft_color::BlendMode::Normal;
    let n = render(&p, cid).data[45 * 120 + 70];
    assert!((n[0] - 0.5).abs() < 0.02 && (n[1] - 0.5).abs() < 0.02, "{n:?}");
}

#[test]
fn track_mattes_in_advanced_3d() {
    let (mut p, cid) = project(120, 90);
    let white = solid(&mut p, [1.0, 1.0, 1.0], 120, 90);
    let small = solid(&mut p, [1.0, 1.0, 1.0], 40, 30);
    // Layer order (top first): the matte, then the matted layer.
    add(&mut p, cid, LayerSource::Solid { item: white }, |l| l.switches.three_d = true);
    add(&mut p, cid, LayerSource::Solid { item: small }, |l| {
        l.switches.three_d = true;
        l.switches.video = false;
        // A 3D matte is seen through the camera.
        set(l, "transform/position", Value::Vec3([30.0, 30.0, 0.0]));
        set(l, "transform/anchor", Value::Vec3([20.0, 15.0, 0.0]));
    });
    let matte = p.comp(cid).unwrap().layers[0].id;
    p.comp_mut(cid).unwrap().layers[1].track_matte = Some(effectcraft_project::TrackMatte { layer: matte, kind: effectcraft_project::MatteKind::Alpha });
    let img = render(&p, cid);
    let inside = img.data[30 * 120 + 30];
    let outside = img.data[70 * 120 + 100];
    assert!(inside[3] > 0.99 && inside[0] > 0.99, "{inside:?}");
    assert!(outside[3] < 0.01, "{outside:?}");
    // An inverted alpha matte keeps the outside instead.
    p.comp_mut(cid).unwrap().layers[1].track_matte =
        Some(effectcraft_project::TrackMatte { layer: matte, kind: effectcraft_project::MatteKind::AlphaInverted });
    let img = render(&p, cid);
    assert!(img.data[30 * 120 + 30][3] < 0.01 && img.data[70 * 120 + 100][3] > 0.99);
}

#[test]
fn collapsed_precomps_join_the_advanced_3d_scene() {
    // A cube in a nested (Classic 3D) comp, collapsed into an Advanced 3D comp: the cube is
    // real geometry lit by the parent's light, not a flat card of the nested comp (which, being
    // Classic 3D, draws no meshes at all).
    let (mut p, cid) = project(160, 120);
    let mut nc = Comp::new(160, 120, FrameRate::FPS_30, Tick::from_seconds_f64(1.0));
    nc.renderer = R3::Classic3D;
    let nid = p.add_item("N", Default::default(), None, ItemKind::Comp(nc.into()));
    add(&mut p, nid, LayerSource::Primitive { kind: PrimitiveKind::Cube }, |l| {
        set(l, "geometryOptions/width", Value::Scalar(60.0));
        set(l, "geometryOptions/height", Value::Scalar(60.0));
        set(l, "geometryOptions/depth", Value::Scalar(60.0));
        set(l, "transform/rotationY", Value::Scalar(35.0));
        set(l, "transform/rotationX", Value::Scalar(-25.0));
        set(l, "materialOptions/baseColor", Value::Color([1.0, 1.0, 1.0, 1.0]));
    });
    add(&mut p, cid, LayerSource::Light { kind: LightKind::Parallel }, |_| {});
    add(&mut p, cid, LayerSource::Comp { item: nid }, |l| {
        l.switches.three_d = true;
        l.switches.collapse = true;
    });
    let shades = |img: &crate::Image| {
        let mut s: Vec<i32> = img.data.iter().filter(|q| q[3] > 0.99).map(|q| (q[0] * 20.0) as i32).collect();
        s.sort();
        s.dedup();
        s
    };
    let img = render(&p, cid);
    assert!(img.data[60 * 160 + 80][3] > 0.99, "the nested cube covers the centre");
    assert!(shades(&img).len() >= 3, "faces lit by the parent's light: {:?}", shades(&img));
    // The scene holds the cube's triangles (a card would be two).
    let r = Renderer::new(&p, &NoFootage, RenderOpts::default());
    let comp = p.comp(cid).unwrap();
    let ctx = crate::EvalCtx::new(&p, cid, comp, Tick::ZERO);
    let run: Vec<&effectcraft_project::Layer> = comp.layers.iter().filter(|l| l.is_3d() && !l.is_light()).collect();
    let s = scene_of(&r, &ctx, &run, (160, 120));
    assert!(s.indices.len() / 3 >= 12, "{} triangles", s.indices.len() / 3);
    // A 2D collapsed precomp draws its 3D layers through the parent's Advanced 3D renderer too.
    p.comp_mut(cid).unwrap().layers[0].switches.three_d = false;
    let flat = render(&p, cid);
    assert!(flat.data[60 * 160 + 80][3] > 0.99);
    assert!(shades(&flat).len() >= 3, "{:?}", shades(&flat));
    // Collapse off: the nested comp renders on its own (Classic 3D: no meshes).
    p.comp_mut(cid).unwrap().layers[0].switches.collapse = false;
    p.comp_mut(cid).unwrap().layers[0].switches.three_d = true;
    assert!(render(&p, cid).data.iter().all(|q| q[3] == 0.0));
}

#[test]
fn extruded_strokes_render_as_bevelled_meshes() {
    let (mut p, cid) = project(200, 120);
    add(&mut p, cid, LayerSource::Text, |l| {
        l.switches.three_d = true;
        let doc = effectcraft_keyframe::TextDoc {
            text: "I".into(),
            size: 80.0,
            fill: [1.0, 1.0, 1.0, 1.0],
            apply_fill: true,
            stroke: [1.0, 0.0, 0.0, 1.0],
            apply_stroke: true,
            stroke_width: 8.0,
            stroke_over_fill: false,
            ..Default::default()
        };
        set(l, "text/sourceText", Value::Text(Box::new(doc)));
        let mut next = 10_000u64;
        l.props.children.push(build::extrusion_geometry_options(&mut build::Ids(&mut next)).into());
        set(l, "geometryOptions/extrusionDepth", Value::Scalar(20.0));
        set(l, "geometryOptions/bevelStyle", Value::Enum(1));
    });
    let ctx = crate::EvalCtx { project: &p, comp_id: cid, comp: p.comp(cid).unwrap(), time: Tick::ZERO, expr: None, footage: None };
    let l = &ctx.comp.layers[0];
    let params = scene::extrusion_params(&ctx, l).unwrap();
    let meshes = scene::extruded_meshes(&ctx, l, &params);
    assert_eq!(meshes.len(), 2, "fill and stroke");
    let width = |m: &effectcraft_model::Primitive| {
        let (a, b) = m.positions.iter().fold((f32::INFINITY, f32::NEG_INFINITY), |(a, b), q| (a.min(q[0]), b.max(q[0])));
        b - a
    };
    let (fill, stroke) = (&meshes[0], &meshes[1]);
    assert_eq!(fill.1, [1.0, 1.0, 1.0, 1.0]);
    assert_eq!(stroke.1, [1.0, 0.0, 0.0, 1.0]);
    // The stroke reaches half its width beyond the fill on each side, and is extruded too.
    assert!((width(&stroke.0) - width(&fill.0) - 8.0).abs() < 1.0, "{} vs {}", width(&stroke.0), width(&fill.0));
    assert!(stroke.0.positions.iter().any(|q| q[2] > 19.0));
    // Fill Over Stroke: the fill's front cap sits in front of the stroke's.
    let front = |m: &effectcraft_model::Primitive| m.positions.iter().fold(f32::INFINITY, |a, q| a.min(q[2]));
    assert!(front(&fill.0) < front(&stroke.0));
    // Rendered (unlit: base colours): a red rim around the white face.
    let img = render(&p, cid);
    let red = img.data.iter().filter(|q| q[3] > 0.99 && q[0] > 0.9 && q[1] < 0.1).count();
    let white = img.data.iter().filter(|q| q[3] > 0.99 && q[1] > 0.9).count();
    assert!(red > 50 && white > 50, "red {red}, white {white}");
}

#[test]
fn stroke_regions_are_rings() {
    // A closed path's stroke covers a ring (the inside stays open), so an extruded stroke is a
    // hollow frame around its fill.
    let sq = effectcraft_path::rect([100.0, 100.0], [0.0, 0.0], 0.0);
    let st = effectcraft_path::StrokeStyle { width: 10.0, ..Default::default() };
    let r = crate::shapes::stroke_region(std::slice::from_ref(&sq), &st).unwrap();
    let a = effectcraft_path::boolean::filled_area(&r, effectcraft_path::FillRule::NonZero);
    assert!((a - (110.0 * 110.0 - 90.0 * 90.0)).abs() < 20.0, "{a}");
    let outlines = effectcraft_model::extrude::group_contours(scene::contours(&r, 0.25));
    assert_eq!(outlines.len(), 1);
    assert_eq!(outlines[0].holes.len(), 1);
}