// This is the core JavaScript for the Spectrogram Editor.
// It handles file loading (.spec), visualization, tool interaction, and saving.

// --- Global Variables ---
let currentSpecData = null; // Stores the currently displayed/edited spectrogram data
let originalSpecData = null; // Stores the pristine, initially loaded spectrogram data
let dctSize = 512; // Default DCT size, read from header

let undoStack = [];
let redoStack = [];
const MAX_HISTORY_SIZE = 50;

let activeTool = null; // 'line', 'ellipse', 'noise', etc.
let isDrawing = false;
let startX, startY; // For tracking mouse down position

let shapes = []; // Array to store all drawn shapes (lines, ellipses, etc.)

// Web Audio Context
const audioContext = new (window.AudioContext || window.webkitAudioContext)();

// Audio Constants (should match C++ side)
const SAMPLE_RATE = 32000; 
const MAX_FREQ = SAMPLE_RATE / 2; // Nyquist frequency
const MIN_FREQ = 20; // Lower bound for log scale visualization

// --- Utility Functions for Audio Processing ---
// JavaScript equivalent of C++ idct_512
function javascript_idct_512(input) {
    const output = new Float32Array(dctSize);
    const PI = Math.PI;
    const N = dctSize;

    for (let n = 0; n < N; ++n) {
        let sum = input[0] / 2.0;
        for (let k = 1; k < N; ++k) {
            sum += input[k] * Math.cos((PI / N) * k * (n + 0.5));
        }
        output[n] = sum * (2.0 / N);
    }
    return output;
}

// Hanning window for smooth audio transitions (JavaScript equivalent)
function hanningWindow(size) {
    const window = new Float32Array(size);
    const PI = Math.PI;
    for (let i = 0; i < size; i++) {
        window[i] = 0.5 * (1 - Math.cos((2 * PI * i) / (size - 1)));
    }
    return window;
}

const hanningWindowArray = hanningWindow(dctSize); // Pre-calculate window

// --- File Handling ---
const specFileInput = document.getElementById('specFileInput');
specFileInput.addEventListener('change', handleFileSelect);

async function handleFileSelect(event) {
    const file = event.target.files[0];
    if (!file) {
        return;
    }

    try {
        const buffer = await file.arrayBuffer();
        const dataView = new DataView(buffer);

        // Parse SPEC header
        const header = {
            magic: String.fromCharCode(...new Uint8Array(buffer.slice(0, 4))),
            version: dataView.getInt32(4, true),
            dct_size: dataView.getInt32(8, true),
            num_frames: dataView.getInt32(12, true)
        };

        if (header.magic !== "SPEC" || header.version !== 1) {
            console.error("Invalid SPEC file format.");
            alert("Invalid SPEC file format. Please load a valid .spec file.");
            return;
        }

        dctSize = header.dct_size;
        const dataStart = 16;
        const numBytes = header.num_frames * header.dct_size * Float32Array.BYTES_PER_ELEMENT;
        const spectralDataFloat = new Float32Array(buffer, dataStart, header.num_frames * header.dct_size);

        originalSpecData = { header: header, data: new Float32Array(spectralDataFloat) }; // Store pristine copy
        currentSpecData = { header: header, data: new Float32Array(spectralDataFloat) }; // Editable copy

        shapes = []; // Clear shapes on new file load
        undoStack = []; // Clear undo history
        redoStack = []; // Clear redo history

        console.log("Loaded SPEC file:", header);
        redrawCanvas(); // Redraw with new data

    } catch (error) {
        console.error("Error loading SPEC file:", error);
        alert("Failed to load SPEC file. Check console for details.");
    }
}

// --- Spectrogram Visualization ---
const canvas = document.getElementById('spectrogramCanvas');
const ctx = canvas.getContext('2d');

// Add canvas event listeners
canvas.addEventListener('mousedown', handleMouseDown);
canvas.addEventListener('mousemove', handleMouseMove);
canvas.addEventListener('mouseup', handleMouseUp);
canvas.addEventListener('mouseout', handleMouseUp); // Treat mouse out as mouse up

// Function to get a color based on intensity (0 to 1)
function getColorForIntensity(intensity) {
    // Example: Blue to white/yellow gradient
    const h = (1 - intensity) * 240; // Hue from blue (240) to red (0), inverse for intensity
    const s = 100; // Saturation
    const l = intensity * 50 + 50; // Lightness from 50 to 100
    return `hsl(${h}, ${s}%, ${l}%)`;
}

function drawSpectrogram(specData) {
    const width = canvas.width; 
    const height = canvas.height;

    ctx.clearRect(0, 0, width, height);
    ctx.fillStyle = '#ffffff';
    ctx.fillRect(0, 0, width, height);

    if (!specData || !specData.data || specData.header.num_frames === 0 || specData.data.length === 0) {
        console.warn("No spectrogram data or invalid header/data to draw.");
        return;
    }

    const numFrames = specData.header.num_frames;
    const frameWidth = width / numFrames; // Width of each time frame

    // Draw each frame's spectral data with log frequency scale
    for (let frameIndex = 0; frameIndex < numFrames; frameIndex++) {
        const frameDataStart = frameIndex * dctSize;
        const xPos = frameIndex * frameWidth;

        // To draw with log scale, we iterate over canvas y-coordinates
        // and map them back to frequency bins
        for (let y = 0; y < height; y++) {
            const binIndex = canvasYToBinIndexLog(y, specData);
            if (binIndex < 0 || binIndex >= dctSize) continue; // Out of bounds

            const value = specData.data[frameDataStart + binIndex];
            const intensity = Math.min(1, Math.abs(value) / 1.0); // Assuming values are normalized to [-1, 1]
            
            ctx.fillStyle = getColorForIntensity(intensity);
            ctx.fillRect(xPos, height - y - 1, frameWidth, 1); // Draw a 1-pixel height line for each y
        }
    }

    // Draw active shapes on top (previews for current drawing tool)
    shapes.forEach(shape => {
        drawShape(shape);
    });
}

function drawShape(shape) {
    // This draws the final, persistent shape. Preview is drawn in handleMouseMove.
    ctx.strokeStyle = shape.color || 'red';
    ctx.lineWidth = shape.width || 2;
    
    switch (shape.type) {
        case 'line':
            ctx.beginPath();
            ctx.moveTo(shape.x1, shape.y1);
            ctx.lineTo(shape.x2, shape.y2);
            ctx.stroke();
            break;
        case 'ellipse':
            ctx.beginPath();
            ctx.ellipse(shape.cx, shape.cy, shape.rx, shape.ry, 0, 0, 2 * Math.PI);
            ctx.stroke();
            break;
        case 'noise_rect': // Noise is visualized as a rectangle
            ctx.fillStyle = 'rgba(0, 0, 255, 0.2)';
            ctx.fillRect(shape.x, shape.y, shape.width, shape.height);
            ctx.strokeStyle = 'blue';
            ctx.strokeRect(shape.x, shape.y, shape.width, shape.height);
            break;
    }
}

// --- Mouse Event Handlers ---
function getMousePos(event) {
    const rect = canvas.getBoundingClientRect();
    return {
        x: event.clientX - rect.left,
        y: event.clientY - rect.top
    };
}

function handleMouseDown(event) {
    if (!activeTool || !currentSpecData) return;
    isDrawing = true;
    const pos = getMousePos(event);
    startX = pos.x;
    startY = pos.y;
}

function handleMouseMove(event) {
    if (!isDrawing || !activeTool) return;
    const pos = getMousePos(event);
    
    redrawCanvas(); // Clear and redraw persistent state

    ctx.strokeStyle = 'rgba(0, 0, 0, 0.5)'; // Preview color
    ctx.lineWidth = 1;
    ctx.setLineDash([5, 5]); // Dashed line for preview

    switch (activeTool) {
        case 'line':
            ctx.beginPath();
            ctx.moveTo(startX, startY);
            ctx.lineTo(pos.x, pos.y);
            ctx.stroke();
            break;
        case 'ellipse':
            // Draw preview ellipse based on start and current pos (bounding box)
            const rx = Math.abs(pos.x - startX) / 2;
            const ry = Math.abs(pos.y - startY) / 2;
            const cx = startX + (pos.x - startX) / 2;
            const cy = startY + (pos.y - startY) / 2;
            if (rx > 0 && ry > 0) {
                ctx.beginPath();
                ctx.ellipse(cx, cy, rx, ry, 0, 0, 2 * Math.PI);
                ctx.stroke();
            }
            break;
        case 'noise':
            // Draw preview rectangle for noise area
            const rectX = Math.min(startX, pos.x);
            const rectY = Math.min(startY, pos.y);
            const rectW = Math.abs(pos.x - startX);
            const rectH = Math.abs(pos.y - startY);
            ctx.strokeRect(rectX, rectY, rectW, rectH);
            break;
    }
    ctx.setLineDash([]); // Reset line dash
}

function handleMouseUp(event) {
    if (!isDrawing || !activeTool || !currentSpecData) return;
    isDrawing = false;
    const endPos = getMousePos(event);

    let newShape = null;

    switch (activeTool) {
        case 'line': {
            const startCoords = canvasToSpectrogramCoords(startX, startY, currentSpecData);
            const endCoords = canvasToSpectrogramCoords(endPos.x, endPos.y, currentSpecData);
            newShape = {
                type: 'line',
                x1: startX, y1: startY,
                x2: endPos.x, y2: endPos.y,
                frame1: startCoords.frame, bin1: startCoords.bin,
                frame2: endCoords.frame, bin2: endCoords.bin,
                amplitude: 0.5, // Default amplitude
                width: 2,       // Default width (in canvas pixels for drawing, bins for spec)
                color: 'red',
            };
            break;
        }
        case 'ellipse': {
            const rx = Math.abs(endPos.x - startX) / 2;
            const ry = Math.abs(endPos.y - startY) / 2;
            const cx = startX + (endPos.x - startX) / 2;
            const cy = startY + (endPos.y - startY) / 2;

            const centerCoords = canvasToSpectrogramCoords(cx, cy, currentSpecData);
            // Map canvas radii to frequency/time spans. Log scale aware.
            const radiusXFrames = Math.floor((rx / canvas.width) * currentSpecData.header.num_frames);
            const radiusYFreq = canvasDeltaYToFreqDeltaLog(ry, canvas.height); // Delta in Hz
            const centerFreq = canvasYToFreqLog(cy, canvas.height); // Center in Hz
            const binCRadius = freqToBinIndexLog(centerFreq * Math.pow(2, (radiusY / canvas.height) * Math.log2(MAX_FREQ / MIN_FREQ)));
            const binCMin = freqToBinIndexLog(centerFreq / Math.pow(2, (radiusY / canvas.height) * Math.log2(MAX_FREQ / MIN_FREQ)));

            newShape = {
                type: 'ellipse',
                cx: cx, cy: cy,
                rx: rx, ry: ry,
                frameC: centerCoords.frame, binC: centerCoords.bin,
                radiusFrames: radiusXFrames,
                minBin: binCMin, maxBin: binCRadius,
                amplitude: 0.5,
                color: 'green',
            };
            break;
        }
        case 'noise': {
            const rectX = Math.min(startX, endPos.x);
            const rectY = Math.min(startY, endPos.y);
            const rectW = Math.abs(endPos.x - startX);
            const rectH = Math.abs(endPos.y - startY);

            const startCoords = canvasToSpectrogramCoords(rectX, rectY, currentSpecData);
            const endCoords = canvasToSpectrogramCoords(rectX + rectW, rectY + rectH, currentSpecData);

            newShape = {
                type: 'noise_rect',
                x: rectX, y: rectY,
                width: rectW, height: rectH,
                frame1: startCoords.frame, bin1: startCoords.bin,
                frame2: endCoords.frame, bin2: endCoords.bin,
                amplitude: 0.3, // Default noise amplitude
                density: 0.5,   // Default noise density
                color: 'blue',
            };
            break;
        }
    }

    if (newShape) {
        // Capture the state *before* applying the new shape for undo
        const previousDataSnapshot = new Float32Array(currentSpecData.data); // Copy of actual data
        const previousShapesSnapshot = shapes.map(s => ({ ...s })); // Deep copy shapes array

        applyShapeToSpectrogram(newShape, currentSpecData); // Modify currentSpecData directly
        shapes.push(newShape);
        addAction({ 
            type: 'add_shape', 
            shape: newShape, 
            undo: () => {
                // To undo, restore previous shapes and previous data
                shapes = previousShapesSnapshot;
                currentSpecData.data = previousDataSnapshot;
            },
            redo: () => {
                // To redo, add the shape back and apply it to current data
                shapes.push(newShape);
                applyShapeToSpectrogram(newShape, currentSpecData);
            }
        });
    }
    redrawCanvas(); // Final redraw after action
    updateUndoRedoButtons();
}

// --- Spectrogram Data Manipulation ---
function applyShapeToSpectrogram(shape, targetSpecData) {
    if (!targetSpecData || !targetSpecData.data || targetSpecData.header.num_frames === 0) return;

    const numFrames = targetSpecData.header.num_frames;

    switch (shape.type) {
        case 'line':
            // Bresenham's-like line drawing to apply to spectrogram data
            let x0 = shape.frame1, y0 = shape.bin1;
            let x1 = shape.frame2, y1 = shape.bin2;

            const dx = Math.abs(x1 - x0);
            const dy = Math.abs(y1 - y0);
            const sx = (x0 < x1) ? 1 : -1;
            const sy = (y0 < y1) ? 1 : -1;
            let err = dx - dy;

            let currentX = x0;
            let currentY = y0;

            while (true) {
                if (currentX >= 0 && currentX < numFrames && currentY >= 0 && currentY < dctSize) {
                    // Apply amplitude and width
                    for (let b = -shape.width; b <= shape.width; b++) {
                        const binToAffect = currentY + b;
                        if (binToAffect >= 0 && binToAffect < dctSize) {
                            targetSpecData.data[currentX * dctSize + binToAffect] += shape.amplitude;
                            // Clamp value
                            targetSpecData.data[currentX * dctSize + binToAffect] = Math.max(-1, Math.min(1, targetSpecData.data[currentX * dctSize + binToAffect]));
                        }
                    }
                }

                if (currentX === x1 && currentY === y1) break;
                const e2 = 2 * err;
                if (e2 > -dy) { err -= dy; currentX += sx; }
                if (e2 < dx) { err += dx; currentY += sy; }
            }
            break;
        case 'ellipse':
            // Apply ellipse to spectrogram data (log frequency aware)
            const centerFrame = shape.frameC;
            const centerBin = shape.binC;
            const radiusFrames = shape.radiusFrames;
            const minBin = shape.minBin;
            const maxBin = shape.maxBin;

            for (let f = centerFrame - radiusFrames; f <= centerFrame + radiusFrames; f++) {
                if (f < 0 || f >= numFrames) continue;
                for (let b = minBin; b <= maxBin; b++) {
                    if (b < 0 || b >= dctSize) continue;

                    // Check if (f, b) is within the ellipse
                    const normX = (f - centerFrame) / radiusFrames;
                    // Calculate relative frequency based on log scale
                    const currentFreq = binIndexToFreqLog(b);
                    const centerFreq = binIndexToFreqLog(centerBin);
                    const minFreq = binIndexToFreqLog(minBin);
                    const maxFreq = binIndexToFreqLog(maxBin);

                    const logNormY = (Math.log(currentFreq) - Math.log(centerFreq)) / (Math.log(maxFreq) - Math.log(minFreq));

                    if (normX * normX + logNormY * logNormY <= 1) {
                        targetSpecData.data[f * dctSize + b] += shape.amplitude;
                        targetSpecData.data[f * dctSize + b] = Math.max(-1, Math.min(1, targetSpecData.data[f * dctSize + b]));
                    }
                }
            }
            break;
        case 'noise_rect':
            // Apply noise to a rectangular region
            const frameStart = Math.max(0, Math.min(numFrames - 1, shape.frame1));
            const frameEnd = Math.max(0, Math.min(numFrames - 1, shape.frame2));
            const binStart = Math.max(0, Math.min(dctSize - 1, shape.bin1));
            const binEnd = Math.max(0, Math.min(dctSize - 1, shape.bin2));

            for (let f = frameStart; f <= frameEnd; f++) {
                for (let b = binStart; b <= binEnd; b++) {
                    if (Math.random() < shape.density) {
                        targetSpecData.data[f * dctSize + b] += (Math.random() * 2 - 1) * shape.amplitude; // Random value between -amp and +amp
                        // Clamp value
                        targetSpecData.data[f * dctSize + b] = Math.max(-1, Math.min(1, targetSpecData.data[f * dctSize + b]));
                    }
                }
            }
            break;
    }
}

// --- Tool Interactions (Button Clicks) ---
const lineToolButton = document.getElementById('lineTool');
const ellipseToolButton = document.getElementById('ellipseTool');
const noiseToolButton = document.getElementById('noiseTool');
const undoButton = document.getElementById('undoButton');
const redoButton = document.getElementById('redoButton'); 
const listenOriginalButton = document.getElementById('listenOriginalButton');
const listenGeneratedButton = document.getElementById('listenGeneratedButton');

lineToolButton.addEventListener('click', () => { activeTool = 'line'; console.log('Line tool selected'); });
ellipseToolButton.addEventListener('click', () => { activeTool = 'ellipse'; console.log('Ellipse tool selected'); });
noiseToolButton.addEventListener('click', () => { activeTool = 'noise'; console.log('Noise tool selected'); });

// --- Undo/Redo Logic ---
function addAction(action) {
    undoStack.push(action);
    if (undoStack.length > MAX_HISTORY_SIZE) {
        undoStack.shift(); 
    }
    redoStack = []; 
    updateUndoRedoButtons();
}

function handleUndo() {
    if (undoStack.length === 0) {
        console.log('Undo stack is empty.');
        return;
    }
    const actionToUndo = undoStack.pop();
    actionToUndo.undo(); 
    redoStack.push(actionToUndo);
    redrawCanvas(); 
    updateUndoRedoButtons();
}

function handleRedo() {
    if (redoStack.length === 0) {
        console.log('Redo stack is empty.');
        return;
    }

    const actionToRedo = redoStack.pop();
    actionToRedo.redo(); 
    undoStack.push(actionToRedo);
    redrawCanvas(); 
    updateUndoRedoButtons();
}

function redrawCanvas() {
    console.log('Redrawing canvas...');
    if (!originalSpecData) {
        ctx.clearRect(0, 0, canvas.width, canvas.height);
        ctx.fillStyle = '#ffffff';
        ctx.fillRect(0, 0, canvas.width, canvas.height);
        return;
    }

    // Start with a fresh copy of the original data
    currentSpecData.data = new Float32Array(originalSpecData.data); 

    // Replay all shapes from the `shapes` array to `currentSpecData`
    shapes.forEach(shape => {
        applyShapeToSpectrogram(shape, currentSpecData); 
    });

    drawSpectrogram(currentSpecData); 
}

function updateUndoRedoButtons() {
    undoButton.disabled = undoStack.length === 0;
    redoButton.disabled = redoStack.length === 0; 
}

// --- Utility to map canvas coords to spectrogram bins/frames (LOG SCALE) ---
// Maps a linear frequency bin index to its corresponding frequency in Hz
function binIndexToFreq(binIndex) {
    return (binIndex / dctSize) * MAX_FREQ;
}

// Maps a frequency in Hz to its corresponding linear bin index
function freqToBinIndex(freq) {
    return Math.floor((freq / MAX_FREQ) * dctSize);
}

// Maps a frequency (Hz) to its corresponding log-scaled bin index
function freqToBinIndexLog(freq) {
    if (freq < MIN_FREQ) freq = MIN_FREQ; // Clamp minimum frequency
    const logMin = Math.log(MIN_FREQ);
    const logMax = Math.log(MAX_FREQ);
    const logFreq = Math.log(freq);
    const normalizedLog = (logFreq - logMin) / (logMax - logMin);
    return Math.floor(normalizedLog * dctSize);
}

// Maps a log-scaled bin index to its corresponding frequency in Hz
function binIndexToFreqLog(binIndex) {
    const normalizedLog = binIndex / dctSize;
    const logMin = Math.log(MIN_FREQ);
    const logMax = Math.log(MAX_FREQ);
    const logFreq = normalizedLog * (logMax - logMin) + logMin;
    return Math.exp(logFreq);
}

// Converts a frequency (Hz) to a Y-coordinate on the canvas (log scale)
function freqToCanvasYLog(freq, canvasHeight) {
    if (freq < MIN_FREQ) freq = MIN_FREQ; // Clamp minimum frequency
    const logMin = Math.log(MIN_FREQ);
    const logMax = Math.log(MAX_FREQ);
    const logFreq = Math.log(freq);
    const normalizedLog = (logFreq - logMin) / (logMax - logMin);
    return canvasHeight * (1 - normalizedLog); // Y-axis is inverted
}

// Converts a Y-coordinate on the canvas to a frequency (Hz) (log scale)
function canvasYToFreqLog(canvasY, canvasHeight) {
    const normalizedLog = 1 - (canvasY / canvasHeight);
    const logMin = Math.log(MIN_FREQ);
    const logMax = Math.log(MAX_FREQ);
    const logFreq = normalizedLog * (logMax - logMin) + logMin;
    return Math.exp(logFreq);
}

// Converts canvas Y-coordinate to log-scaled bin index
function canvasYToBinIndexLog(canvasY, specData) {
    const freq = canvasYToFreqLog(canvasY, canvas.height);
    return freqToBinIndex(freq); // Use linear bin index from calculated log freq
}

// Converts log-scaled bin index to canvas Y-coordinate
function binIndexToCanvasYLog(binIndex, specData) {
    const freq = binIndexToFreq(binIndex);
    return freqToCanvasYLog(freq, canvas.height);
}

// Helper to get frequency delta from canvas delta (for ellipse radius in freq)
function canvasDeltaYToFreqDeltaLog(canvasDeltaY, canvasHeight) {
    // This is an approximation as delta in log scale is not linear
    // For small deltas around a center, it can be approximated
    const centerCanvasY = canvasHeight / 2;
    const freqAtCenter = canvasYToFreqLog(centerCanvasY, canvasHeight);
    const freqAtCenterPlusDelta = canvasYToFreqLog(centerCanvasY - canvasDeltaY, canvasHeight);
    return Math.abs(freqAtCenterPlusDelta - freqAtCenter);
}

// Initial setup for canvas size (can be updated on window resize)
window.addEventListener('resize', () => {
    if (originalSpecData) {
        canvas.width = window.innerWidth * 0.7;
        canvas.height = 400; // Fixed height
        redrawCanvas();
    }
});

// Initial call to set button states
updateUndoRedoButtons();

// --- Audio Playback ---
let currentAudioSource = null; // To stop currently playing audio

async function playSpectrogramData(specData) {
    if (!specData || !specData.data || specData.header.num_frames === 0) {
        alert("No spectrogram data to play.");
        return;
    }

    if (currentAudioSource) {
        currentAudioSource.stop();
        currentAudioSource.disconnect();
        currentAudioSource = null;
    }

    const sampleRate = SAMPLE_RATE; // Fixed sample rate
    const numFrames = specData.header.num_frames;
    const totalAudioSamples = numFrames * dctSize; // Total samples in time domain

    const audioBuffer = audioContext.createBuffer(1, totalAudioSamples, sampleRate);
    const audioData = audioBuffer.getChannelData(0); // Mono channel

    const windowArray = hanningWindow(dctSize); // Generate Hanning window for each frame

    // Convert spectrogram frames (frequency domain) to audio samples (time domain)
    for (let frameIndex = 0; frameIndex < numFrames; frameIndex++) {
        const spectralFrame = specData.data.slice(frameIndex * dctSize, (frameIndex + 1) * dctSize);
        const timeDomainFrame = javascript_idct_512(spectralFrame);

        // Apply Hanning window for smooth transitions
        for (let i = 0; i < dctSize; i++) {
            const globalIndex = frameIndex * dctSize + i;
            if (globalIndex < totalAudioSamples) {
                audioData[globalIndex] += timeDomainFrame[i] * windowArray[i];
            }
        }
    }

    currentAudioSource = audioContext.createBufferSource();
    currentAudioSource.buffer = audioBuffer;
    currentAudioSource.connect(audioContext.destination);
    currentAudioSource.start();

    console.log(`Playing audio (Sample Rate: ${sampleRate}, Duration: ${audioBuffer.duration.toFixed(2)}s)`);
}

// --- Playback Button Event Listeners ---
listenOriginalButton.addEventListener('click', () => {
    if (originalSpecData) {
        playSpectrogramData(originalSpecData);
    } else {
        alert("No original SPEC data loaded.");
    }
});

listenGeneratedButton.addEventListener('click', () => {
    if (currentSpecData) {
        // Ensure currentSpecData reflects all shapes before playing
        redrawCanvas(); // This updates currentSpecData based on shapes
        playSpectrogramData(currentSpecData);
    } else {
        alert("No generated SPEC data to play.");
    }
});

// --- Utility for sizeof(float) in JS context ---
// This is a workaround since typeof(float) is not directly available.
// Float32Array.BYTES_PER_ELEMENT is used in handleFileSelect.
function sizeof(type) {
    if (type === 'float') {
        return Float32Array.BYTES_PER_ELEMENT;
    }
    return 0; 
}