// GeoJSON model viewer for the Models/Textures tab. Uses the shared GeoBuilder
// geometry math (bone transforms + box/per-face UV) and renders world-space
// cubes with Three.js. Textures are served through the gated pack_asset and
// vanilla_asset endpoints, resolved per cube:
//   1. afw_bone_textures (pack member), composited over the vanilla entity
//      skin when one exists (NoN `*_features` overlays sit on the vanilla base)
//   2. the model's default pack skin (server-matched)
//   3. the bundled vanilla entity skin
//   4. gray
(function () {
    let renderer = null;
    let scene = null;
    let camera = null;
    let meshRoot = null;
    let rafId = null;
    const textureLoader = new THREE.TextureLoader();
    const materialCache = {};
    let vanillaIndex = null;
    let vanillaIndexPromise = null;

    function assetUrl(baseUrl, member) {
        return baseUrl.replace('ASSET', member);
    }

    function entityNameFromMember(member) {
        let base = member.slice(member.lastIndexOf('/') + 1);
        if (base.endsWith('.geo.json')) base = base.slice(0, -'.geo.json'.length);
        for (const suffix of ['.mf', '.fm', '.m', '.f', '.g']) {
            if (base.endsWith(suffix)) { base = base.slice(0, -suffix.length); break; }
        }
        return base;
    }

    function buildGeometry(size, uv, tw, th) {
        const g = GeoBuilder.cubeGeometry(size, uv, tw, th);
        const geometry = new THREE.BufferGeometry();
        geometry.setAttribute('position', new THREE.Float32BufferAttribute(g.positions, 3));
        geometry.setAttribute('uv', new THREE.Float32BufferAttribute(g.uvs, 2));
        geometry.setIndex(g.indices);
        geometry.computeVertexNormals();
        return geometry;
    }

    function fetchVanillaIndex(opts) {
        if (vanillaIndexPromise) return vanillaIndexPromise;
        if (!opts.vanillaBaseUrl) {
            vanillaIndexPromise = Promise.resolve({});
        } else {
            vanillaIndexPromise = fetch(assetUrl(opts.vanillaBaseUrl, 'entity_index.json'))
                .then(r => r.ok ? r.json() : {})
                .catch(() => ({}));
        }
        return vanillaIndexPromise;
    }

    function vanillaSkinUrl(opts, index, entity) {
        const rel = (index && index[entity]) || null;
        return rel ? assetUrl(opts.vanillaBaseUrl, 'entity/' + rel) : null;
    }

    // desc: { url, vanillaUrl } — url is the pack/overlay member, vanillaUrl the
    // base skin to composite it over (when available).
    function resolveTexture(cube, entity, opts, index) {
        if (cube.texture) {
            return {
                url: assetUrl(opts.baseUrl, cube.texture),
                vanillaUrl: vanillaSkinUrl(opts, index, entity),
            };
        }
        if (opts.defaultTexture) {
            return { url: assetUrl(opts.baseUrl, opts.defaultTexture), vanillaUrl: null };
        }
        const rel = (index && index[entity]) || null;
        if (rel) {
            return { url: null, vanillaUrl: vanillaSkinUrl(opts, index, entity) };
        }
        return null;
    }

    function loadImage(url) {
        return new Promise((resolve, reject) => {
            const img = new Image();
            img.crossOrigin = 'anonymous';
            img.onload = () => resolve(img);
            img.onerror = () => reject(new Error('img'));
            img.src = url;
        });
    }

    async function prepareMaterial(desc, tw, th) {
        const key = (desc.url || '') + '|' + (desc.vanillaUrl || '');
        if (materialCache[key]) return materialCache[key];

        let texture = null;
        if (desc.url && desc.vanillaUrl) {
            try {
                const [overlay, base] = await Promise.all([loadImage(desc.url), loadImage(desc.vanillaUrl)]);
                const canvas = document.createElement('canvas');
                canvas.width = tw;
                canvas.height = th;
                const ctx = canvas.getContext('2d');
                ctx.drawImage(base, 0, 0, tw, th);
                ctx.drawImage(overlay, 0, 0, tw, th);
                texture = new THREE.CanvasTexture(canvas);
            } catch (e) {
                texture = null;
            }
        }
        const singleUrl = texture ? null : (desc.url || desc.vanillaUrl);
        if (singleUrl) texture = textureLoader.load(singleUrl);

        let material;
        if (texture) {
            texture.wrapS = THREE.ClampToEdgeWrapping;
            texture.wrapT = THREE.ClampToEdgeWrapping;
            material = new THREE.MeshStandardMaterial({ map: texture, roughness: 0.9, metalness: 0.0 });
            if (singleUrl) {
                textureLoader.load(singleUrl, undefined, undefined, () => {
                    if (material.map) material.map.dispose();
                    material.map = null;
                    material.color.setHex(0x9a9a9a);
                    material.needsUpdate = true;
                });
            }
        } else {
            material = new THREE.MeshStandardMaterial({ color: 0x9a9a9a, roughness: 0.9 });
        }
        materialCache[key] = material;
        return material;
    }

    function disposeObject(obj) {
        obj.traverse((node) => {
            if (node.geometry) node.geometry.dispose();
        });
        for (const key in materialCache) {
            if (materialCache[key].map) materialCache[key].map.dispose();
            materialCache[key].dispose();
        }
        for (const key in materialCache) delete materialCache[key];
    }

    function render(member, container, opts) {
        if (renderer) dispose();
        const width = container.clientWidth || 480;
        const height = container.clientHeight || 480;

        scene = new THREE.Scene();
        scene.background = new THREE.Color(0x1e1e2e);
        camera = new THREE.PerspectiveCamera(50, width / height, 0.1, 2000);
        camera.position.set(0, 20, 60);
        camera.lookAt(0, 12, 0);

        renderer = new THREE.WebGLRenderer({ antialias: true, preserveDrawingBuffer: true });
        renderer.setSize(width, height);
        renderer.setPixelRatio(window.devicePixelRatio || 1);
        container.appendChild(renderer.domElement);

        scene.add(new THREE.AmbientLight(0xffffff, 0.6));
        const key = new THREE.DirectionalLight(0xffffff, 0.9);
        key.position.set(30, 60, 30);
        scene.add(key);
        const fill = new THREE.DirectionalLight(0xffffff, 0.3);
        fill.position.set(-30, 20, -30);
        scene.add(fill);

        meshRoot = new THREE.Group();
        scene.add(meshRoot);

        const entity = entityNameFromMember(member);
        fetch(assetUrl(opts.baseUrl, member), { headers: { 'Accept': 'application/json' } })
            .then(r => { if (!r.ok) throw new Error('http'); return r.json(); })
            .then(geo => Promise.all([geo, fetchVanillaIndex(opts)]))
            .then(([geo, index]) => {
                const built = GeoBuilder.build(geo);
                if (!built.cubes.length) throw new Error('no cubes');
                const tw = built.texture_width, th = built.texture_height;
                const jobs = built.cubes.map((cube) => {
                    const desc = resolveTexture(cube, entity, opts, index);
                    return desc ? prepareMaterial(desc, tw, th) : Promise.resolve(null);
                });
                return Promise.all(jobs).then((materials) => ({ built, materials }));
            })
            .then(({ built, materials }) => {
                for (let i = 0; i < built.cubes.length; i++) {
                    const cube = built.cubes[i];
                    const geometry = buildGeometry(cube.size, cube.uv, built.texture_width, built.texture_height);
                    let material = materials[i];
                    if (!material) {
                        material = new THREE.MeshStandardMaterial({ color: 0x9a9a9a, roughness: 0.9 });
                    }
                    const mesh = new THREE.Mesh(geometry, material);
                    mesh.matrix = new THREE.Matrix4().fromArray(cube.matrix);
                    mesh.matrixAutoUpdate = false;
                    meshRoot.add(mesh);
                }

                const box = new THREE.Box3().setFromObject(meshRoot);
                const center = box.getCenter(new THREE.Vector3());
                const size = box.getSize(new THREE.Vector3());
                const radius = Math.max(size.x, size.y, size.z) / 2 || 10;
                meshRoot.position.sub(center);
                camera.position.set(radius * 2.2, radius * 1.6, radius * 2.6);
                camera.near = radius / 10;
                camera.far = radius * 40;
                camera.updateProjectionMatrix();
                camera.lookAt(0, 0, 0);
            })
            .catch(() => {
                container.innerHTML = '<p class="empty-hint">Could not load this model.</p>';
            });

        let isDragging = false;
        let lastX = 0, lastY = 0;
        renderer.domElement.addEventListener('mousedown', (e) => {
            isDragging = true; lastX = e.clientX; lastY = e.clientY;
        });
        window.addEventListener('mouseup', () => { isDragging = false; });
        window.addEventListener('mousemove', (e) => {
            if (!isDragging || !meshRoot) return;
            const dx = e.clientX - lastX, dy = e.clientY - lastY;
            lastX = e.clientX; lastY = e.clientY;
            meshRoot.rotation.y += dx * 0.01;
            meshRoot.rotation.x += dy * 0.01;
        });
        renderer.domElement.addEventListener('wheel', (e) => {
            e.preventDefault();
            camera.position.multiplyScalar(e.deltaY > 0 ? 1.06 : 0.94);
        }, { passive: false });

        function animate() {
            rafId = requestAnimationFrame(animate);
            renderer.render(scene, camera);
        }
        animate();
    }

    function dispose() {
        if (rafId) { cancelAnimationFrame(rafId); rafId = null; }
        if (renderer) {
            if (meshRoot) disposeObject(meshRoot);
            renderer.dispose();
            if (renderer.domElement && renderer.domElement.parentNode) {
                renderer.domElement.parentNode.removeChild(renderer.domElement);
            }
        }
        renderer = null;
        scene = null;
        camera = null;
        meshRoot = null;
    }

    window.PacksModelViewer = { render: render, dispose: dispose };
})();