// Global variables
let scene, camera, renderer, controls;
let model, cuttingPlaneMesh;
let rotationSlider, autoRotateCheckbox, cuttingPlaneSlider;
let sliceCanvas, sliceCtx;
let isRecording = false;
let mediaRecorder;
let recordedChunks = [];
let animationId;
let sliceData = [];

// Initialize Three.js scene
function init3DScene() {
    const container = document.getElementById('canvas3d');
    
    // Scene setup
    scene = new THREE.Scene();
    scene.background = new THREE.Color(0x1a1a2e);
    
    // Camera setup
    camera = new THREE.PerspectiveCamera(
        75,
        container.clientWidth / container.clientHeight,
        0.1,
        1000
    );
    camera.position.set(0, 0, 100);
    
    // Renderer setup
    renderer = new THREE.WebGLRenderer({ antialias: true, preserveDrawingBuffer: true });
    renderer.setSize(container.clientWidth, container.clientHeight);
    renderer.localClippingEnabled = true;
    container.appendChild(renderer.domElement);
    
    // Controls
    controls = new THREE.OrbitControls(camera, renderer.domElement);
    controls.enableDamping = true;
    controls.dampingFactor = 0.05;
    
    // Lighting
    const ambientLight = new THREE.AmbientLight(0xffffff, 0.6);
    scene.add(ambientLight);
    
    const directionalLight = new THREE.DirectionalLight(0xffffff, 0.8);
    directionalLight.position.set(10, 10, 10);
    scene.add(directionalLight);
    
    // Create 3D model (composite sphere with inner structures)
    createCompositeModel();
    
    // Create cutting plane visualization
    createCuttingPlane();
    
    // Event listeners
    setupEventListeners();
    
    // Initialize slice canvas
    initSliceCanvas();
    
    // Start render loop
    animate();
}

// Create a composite 3D model
function createCompositeModel() {
    // Main outer shell
    const outerGeometry = new THREE.SphereGeometry(30, 32, 32);
    const outerMaterial = new THREE.MeshPhongMaterial({
        color: 0x4a90e2,
        transparent: true,
        opacity: 0.7,
        side: THREE.DoubleSide
    });
    
    model = new THREE.Mesh(outerGeometry, outerMaterial);
    model.name = 'compositeModel';
    scene.add(model);
    
    // Inner structures
    const innerGeometry1 = new THREE.SphereGeometry(15, 16, 16);
    const innerMaterial1 = new THREE.MeshPhongMaterial({
        color: 0x7ed321,
        transparent: true,
        opacity: 0.8
    });
    const innerSphere1 = new THREE.Mesh(innerGeometry1, innerMaterial1);
    innerSphere1.position.set(5, 5, -5);
    model.add(innerSphere1);
    
    const innerGeometry2 = new THREE.BoxGeometry(15, 15, 15);
    const innerMaterial2 = new THREE.MeshPhongMaterial({
        color: 0xf5a623,
        transparent: true,
        opacity: 0.8
    });
    const innerBox = new THREE.Mesh(innerGeometry2, innerMaterial2);
    innerBox.position.set(-8, -3, 8);
    innerBox.rotation.set(0.5, 0.3, 0.7);
    model.add(innerBox);
    
    // Additional small structures for complexity
    for (let i = 0; i < 5; i++) {
        const smallGeometry = new THREE.SphereGeometry(3 + Math.random() * 5, 8, 8);
        const smallMaterial = new THREE.MeshPhongMaterial({
            color: new THREE.Color().setHSL(0.5 + Math.random() * 0.3, 0.8, 0.6),
            transparent: true,
            opacity: 0.9
        });
        const smallSphere = new THREE.Mesh(smallGeometry, smallMaterial);
        smallSphere.position.set(
            (Math.random() - 0.5) * 40,
            (Math.random() - 0.5) * 40,
            (Math.random() - 0.5) * 40
        );
        model.add(smallSphere);
    }
    
    // Update slice data for all z positions
    updateSliceData();
}

// Generate slice data for 2D view
function updateSliceData() {
    sliceData = [];
    const resolution = parseInt(document.getElementById('sliceResolution').value);
    const totalSlices = 100;
    
    for (let z = 0; z < totalSlices; z++) {
        const zPos = (z - totalSlices / 2) / (totalSlices / 100);
        const sliceArray = [];
        
        for (let y = 0; y < resolution; y++) {
            const row = [];
            for (let x = 0; x < resolution; x++) {
                // Convert canvas coordinates to 3D space
                const xPos = (x - resolution / 2) / (resolution / 100);
                const yPos = (y - resolution / 2) / (resolution / 100);
                
                // Calculate density based on distance from center for outer sphere
                const distanceFromCenter = Math.sqrt(xPos * xPos + yPos * yPos + zPos * zPos);
                let density = 0;
                
                // Outer sphere (main shell)
                if (distanceFromCenter <= 30) {
                    density = 0.5 + (1 - distanceFromCenter / 30) * 0.5;
                    
                    // Inner sphere 1
                    const dist1 = Math.sqrt(
                        (xPos - 5) * (xPos - 5) + 
                        (yPos - 5) * (yPos - 5) + 
                        (zPos + 5) * (zPos + 5)
                    );
                    if (dist1 <= 15) {
                        density = Math.max(density, 0.8 + (1 - dist1 / 15) * 0.2);
                    }
                    
                    // Inner box (approximated)
                    const boxDistX = Math.abs(xPos + 8);
                    const boxDistY = Math.abs(yPos + 3);
                    const boxDistZ = Math.abs(zPos - 8);
                    if (boxDistX <= 12 && boxDistY <= 12 && boxDistZ <= 12) {
                        density = Math.max(density, 0.7 + (1 - boxDistX / 12) * 0.3 * 0.3);
                        density = Math.max(density, 0.7 + (1 - boxDistY / 12) * 0.3 * 0.3);
                        density = Math.max(density, 0.7 + (1 - boxDistZ / 12) * 0.3 * 0.3);
                    }
                    
                    // Small random structures
                    for (let i = 0; i < 5; i++) {
                        const posX = (Math.sin(i * 1.5) - 0.5) * 40;
                        const posY = (Math.cos(i * 1.3) - 0.5) * 40;
                        const posZ = (Math.sin(i) - 0.5) * 40;
                        
                        const smallDist = Math.sqrt(
                            (xPos - posX) * (xPos - posX) +
                            (yPos - posY) * (yPos - posY) +
                            (zPos - posZ) * (zPos - posZ)
                        );
                        const radius = 8 + i * 2;
                        
                        if (smallDist <= radius) {
                            density = Math.max(density, 0.6 + (1 - smallDist / radius) * 0.4);
                        }
                    }
                }
                
                row.push(density);
            }
            sliceArray.push(row);
        }
        
        sliceData.push(sliceArray);
    }
}

// Initialize slice canvas
function initSliceCanvas() {
    sliceCanvas = document.getElementById('sliceCanvas');
    sliceCtx = sliceCanvas.getContext('2d');
    
    const resolution = parseInt(document.getElementById('sliceResolution').value);
    sliceCanvas.width = resolution;
    sliceCanvas.height = resolution;
}

// Create cutting plane visualization
function createCuttingPlane() {
    const planeGeometry = new THREE.PlaneGeometry(100, 100);
    const planeMaterial = new THREE.MeshBasicMaterial({
        color: 0xff0000,
        transparent: true,
        opacity: 0.3,
        side: THREE.DoubleSide
    });
    
    cuttingPlaneMesh = new THREE.Mesh(planeGeometry, planeMaterial);
    cuttingPlaneMesh.rotation.x = -Math.PI / 2;
    cuttingPlaneMesh.visible = true;
    scene.add(cuttingPlaneMesh);
}

// Update 2D slice view
function updateSliceView(zPosition) {
    if (!sliceCtx || sliceData.length === 0) return;
    
    const resolution = parseInt(document.getElementById('sliceResolution').value);
    const sliceIndex = Math.floor((zPosition + 50) / 100 * (sliceData.length - 1));
    
    if (sliceIndex < 0 || sliceIndex >= sliceData.length) return;
    
    const slice = sliceData[sliceIndex];
    const imageData = sliceCtx.createImageData(resolution, resolution);
    const data = imageData.data;
    
    for (let y = 0; y < resolution; y++) {
        for (let x = 0; x < resolution; x++) {
            const density = slice[y][x];
            const index = (y * resolution + x) * 4;
            
            if (density > 0) {
                // Color based on density
                const hue = 0.6 - density * 0.3; // Blue to green to yellow
                const rgb = hslToRgb(hue, 0.8, 0.5 + density * 0.3);
                
                data[index] = rgb[0];     // R
                data[index + 1] = rgb[1]; // G
                data[index + 2] = rgb[2]; // B
                data[index + 3] = Math.floor(density * 255); // A
            } else {
                data[index] = 0;
                data[index + 1] = 0;
                data[index + 2] = 0;
                data[index + 3] = 0;
            }
        }
    }
    
    sliceCtx.putImageData(imageData, 0, 0);
    
    // Update slice info
    document.getElementById('sliceInfo').textContent = `Z = ${zPosition.toFixed(1)}`;
}

// Convert HSL to RGB
function hslToRgb(h, s, l) {
    const c = (1 - Math.abs(2 * l - 1)) * s;
    const x = c * (1 - Math.abs((h * 6) % 2 - 1));
    const m = l - c / 2;
    
    let r, g, b;
    if (h < 1/6) {
        r = c; g = x; b = 0;
    } else if (h < 2/6) {
        r = x; g = c; b = 0;
    } else if (h < 3/6) {
        r = 0; g = c; b = x;
    } else if (h < 4/6) {
        r = 0; g = x; b = c;
    } else if (h < 5/6) {
        r = x; g = 0; b = c;
    } else {
        r = c; g = 0; b = x;
    }
    
    return [
        Math.floor((r + m) * 255),
        Math.floor((g + m) * 255),
        Math.floor((b + m) * 255)
    ];
}

// Setup event listeners
function setupEventListeners() {
    rotationSlider = document.getElementById('rotationSlider');
    autoRotateCheckbox = document.getElementById('autoRotate');
    cuttingPlaneSlider = document.getElementById('cuttingPlane');
    
    // Rotation slider
    rotationSlider.addEventListener('input', (e) => {
        const value = e.target.value;
        document.getElementById('rotationValue').textContent = value + '°';
        if (model) {
            model.rotation.y = (value * Math.PI) / 180;
        }
    });
    
    // Auto rotate checkbox
    autoRotateCheckbox.addEventListener('change', (e) => {
        controls.autoRotate = e.target.checked;
    });
    
    // Cutting plane slider
    cuttingPlaneSlider.addEventListener('input', (e) => {
        const value = parseFloat(e.target.value);
        document.getElementById('planeValue').textContent = value.toFixed(1);
        updateCuttingPlane(value);
        updateSliceView(value);
    });
    
    // Speed slider
    const speedSlider = document.getElementById('scanSpeed');
    speedSlider.addEventListener('input', (e) => {
        document.getElementById('speedValue').textContent = e.target.value + 'x';
    });
    
    // Resolution selector
    document.getElementById('sliceResolution').addEventListener('change', () => {
        updateSliceData();
        initSliceCanvas();
        updateSliceView(parseFloat(cuttingPlaneSlider.value));
    });
    
    // Export button
    document.getElementById('exportBtn').addEventListener('click', exportScan);
}

// Update cutting plane position
function updateCuttingPlane(zPosition) {
    if (cuttingPlaneMesh) {
        cuttingPlaneMesh.position.z = zPosition;
    }
}

// Animation loop
function animate() {
    animationId = requestAnimationFrame(animate);
    
    controls.update();
    renderer.render(scene, camera);
}

// Export scan as video
async function exportScan() {
    if (isRecording) return;
    
    const exportBtn = document.getElementById('exportBtn');
    const progressBar = document.getElementById('exportProgress');
    const progressFill = progressBar.querySelector('.progress-fill');
    const progressText = progressBar.querySelector('.progress-text');
    
    exportBtn.disabled = true;
    progressBar.classList.remove('hidden');
    isRecording = true;
    
    // Setup MediaRecorder
    const stream = sliceCanvas.captureStream(30);
    const options = {
        mimeType: 'video/webm;codecs=vp8,opus',
        videoBitsPerSecond: 2500000
    };
    
    try {
        mediaRecorder = new MediaRecorder(stream, options);
        recordedChunks = [];
        
        mediaRecorder.ondataavailable = (event) => {
            if (event.data.size > 0) {
                recordedChunks.push(event.data);
            }
        };
        
        mediaRecorder.onstop = () => {
            const blob = new Blob(recordedChunks, { type: 'video/webm' });
            const url = URL.createObjectURL(blob);
            const a = document.createElement('a');
            a.href = url;
            a.download = `3d-scan-${Date.now()}.webm`;
            a.click();
            URL.revokeObjectURL(url);
            
            // Reset UI
            exportBtn.disabled = false;
            progressBar.classList.add('hidden');
            isRecording = false;
            
            // Reset cutting plane
            cuttingPlaneSlider.value = 0;
            updateCuttingPlane(0);
            updateSliceView(0);
        };
        
        // Start recording
        mediaRecorder.start();
        
        // Animate scan from top to bottom
        const scanSpeed = parseFloat(document.getElementById('scanSpeed').value);
        const totalSteps = 100;
        const stepDelay = 1000 / scanSpeed / totalSteps;
        
        for (let i = 0; i <= totalSteps; i++) {
            const zPosition = 50 - (i * 100 / totalSteps);
            cuttingPlaneSlider.value = zPosition;
            updateCuttingPlane(zPosition);
            updateSliceView(zPosition);
            
            // Update progress
            const progress = (i / totalSteps) * 100;
            progressFill.style.width = progress + '%';
            progressText.textContent = Math.floor(progress) + '%';
            
            await new Promise(resolve => setTimeout(resolve, stepDelay));
        }
        
        // Stop recording
        mediaRecorder.stop();
        
    } catch (err) {
        console.error('Recording failed:', err);
        alert('Video recording failed. Please check browser permissions.');
        exportBtn.disabled = false;
        progressBar.classList.add('hidden');
        isRecording = false;
    }
}

// Initialize on load
window.addEventListener('load', init3DScene);

// Handle window resize
window.addEventListener('resize', () => {
    const container = document.getElementById('canvas3d');
    if (camera && renderer) {
        camera.aspect = container.clientWidth / container.clientHeight;
        camera.updateProjectionMatrix();
        renderer.setSize(container.clientWidth, container.clientHeight);
    }
});