// Shared JavaScript across all pages
let csvData = [];
let headers = [];

// DOM Elements
const dropZone = document.getElementById('dropZone');
const csvFileInput = document.getElementById('csvFile');
const previewSection = document.getElementById('previewSection');
const tableHeaders = document.getElementById('tableHeaders');
const tableBody = document.getElementById('tableBody');
const generateVizBtn = document.getElementById('generateViz');
const vizGallery = document.getElementById('vizGallery');
const chartContainer = document.getElementById('chartContainer');

// Initialize app
document.addEventListener('DOMContentLoaded', function() {
    initializeEventListeners();
});

function initializeEventListeners() {
    // File input change
    csvFileInput.addEventListener('change', handleFileSelect);
    
    // Drag and drop events
    dropZone.addEventListener('dragover', handleDragOver);
    dropZone.addEventListener('dragleave', handleDragLeave);
    dropZone.addEventListener('drop', handleDrop);
    
    // Generate visualizations
    generateVizBtn.addEventListener('click', generateVisualizations);
}

function handleDragOver(e) {
    e.preventDefault();
    dropZone.classList.add('drop-zone-active');
}

function handleDragLeave(e) {
    e.preventDefault();
    dropZone.classList.remove('drop-zone-active');
}

function handleDrop(e) {
    e.preventDefault();
    dropZone.classList.remove('drop-zone-active');
    
    const files = e.dataTransfer.files;
    if (files.length > 0) {
        processCSVFile(files[0]);
    }
}

function handleFileSelect(e) {
    const file = e.target.files[0];
    if (file) {
        processCSVFile(file);
    }
}

function processCSVFile(file) {
    if (file.type !== 'text/csv' && !file.name.endsWith('.csv')) {
        alert('Please upload a valid CSV file.');
        return;
    }
    
    const reader = new FileReader();
    reader.onload = function(e) {
        const csvText = e.target.result;
        parseCSV(csvText);
    };
    reader.readAsText(file);
}

function parseCSV(csvText) {
    const lines = csvText.split('\n').filter(line => line.trim() !== '');
    if (lines.length === 0) return;
    
    // Extract headers
    headers = lines[0].split(',').map(header => header.trim());
    
    // Extract data rows
    csvData = lines.slice(1).map(line => {
        const values = line.split(',').map(value => value.trim());
        return values;
    });
    
    displayPreview();
}

function displayPreview() {
    // Show preview section
    previewSection.classList.remove('hidden');
    
    // Populate headers
    tableHeaders.innerHTML = headers.map(header => 
        `<th class="px-6 py-4 text-left font-semibold">${header}</th>`
    ).join('');
    
    // Populate data (show first 10 rows for preview)
    const previewData = csvData.slice(0, 10);
    tableBody.innerHTML = previewData.map(row => 
        `<tr class="hover:bg-cyan-500/10">${row.map(cell => 
            `<td class="px-6 py-4 border-b border-gray-700">${cell}</td>`
        ).join('')}</tr>`
    ).join('');
    
    // Scroll to preview
    previewSection.scrollIntoView({ behavior: 'smooth' });
}

function generateVisualizations() {
    if (csvData.length === 0) return;
    
    // Show visualization gallery
    vizGallery.classList.remove('hidden');
    chartContainer.innerHTML = '';
    
    // Generate different chart types
    generateBarChart();
    generateLineChart();
    generatePieChart();
    generateScatterPlot();
    
    // Scroll to gallery
    vizGallery.scrollIntoView({ behavior: 'smooth' });
}

function generateBarChart() {
    const canvas = document.createElement('canvas');
    canvas.className = 'glass-card p-4';
    chartContainer.appendChild(canvas);
    
    // Sample data for demonstration
    const ctx = canvas.getContext('2d');
    new Chart(ctx, {
        type: 'bar',
        data: {
            labels: headers.slice(0, 5),
            datasets: [{
                label: 'Sample Data',
                data: [65, 59, 80, 81, 56],
                backgroundColor: [
                    'rgba(0, 255, 255, 0.7)',
                    'rgba(168, 85, 247, 0.7)',
                    'rgba(34, 211, 238, 0.7)',
                    'rgba(139, 92, 246, 0.7)',
                    'rgba(45, 212, 191, 0.7)'
                ],
                borderColor: [
                    'rgba(0, 255, 255, 1)',
                    'rgba(168, 85, 247, 1)',
                    'rgba(34, 211, 238, 1)',
                    'rgba(139, 92, 246, 1)',
                    'rgba(45, 212, 191, 1)'
                ],
                borderWidth: 2
            }]
        },
        options: {
            responsive: true,
            plugins: {
                title: {
                    display: true,
                    text: 'Bar Chart Visualization',
                    color: 'white',
                    font: { size: 16 }
            },
            legend: {
                labels: { color: 'white' }
            }
        },
        scales: {
            y: {
                beginAtZero: true,
                ticks: { color: 'white' }
            },
            x: {
                ticks: { color: 'white' }
            }
        }
    });
}

function generateLineChart() {
    const canvas = document.createElement('canvas');
    canvas.className = 'glass-card p-4';
    chartContainer.appendChild(canvas);
    
    const ctx = canvas.getContext('2d');
    new Chart(ctx, {
        type: 'line',
        data: {
            labels: ['Jan', 'Feb', 'Mar', 'Apr', 'May'],
            datasets: [{
                label: 'Trend Line',
                data: [12, 19, 3, 5, 2],
                borderColor: 'rgba(0, 255, 255, 1)',
                backgroundColor: 'rgba(0, 255, 255, 0.1)',
                borderWidth: 3,
                tension: 0.4,
                fill: true
            }]
        },
        options: {
            responsive: true,
            plugins: {
                title: {
                    display: true,
                    text: 'Line Chart Trend',
                    color: 'white',
                    font: { size: 16 }
            },
            legend: {
                labels: { color: 'white' }
            }
        },
        scales: {
            y: {
                beginAtZero: true,
                ticks: { color: 'white' }
            },
            x: {
                ticks: { color: 'white' }
            }
        }
    });
}

function generatePieChart() {
    const canvas = document.createElement('canvas');
    canvas.className = 'glass-card p-4';
    chartContainer.appendChild(canvas);
    
    const ctx = canvas.getContext('2d');
    new Chart(ctx, {
        type: 'pie',
        data: {
            labels: ['Category A', 'Category B', 'Category C', 'Category D'],
            datasets: [{
                data: [30, 25, 20, 25],
                backgroundColor: [
                    'rgba(0, 255, 255, 0.8)',
                    'rgba(168, 85, 247, 0.8)',
                    'rgba(34, 211, 238, 0.8)',
                    'rgba(139, 92, 246, 0.8)'
                ],
                borderColor: 'rgba(255, 255, 255, 0.3)',
                borderWidth: 2
            }]
        },
        options: {
            responsive: true,
            plugins: {
                title: {
                    display: true,
                    text: 'Pie Chart Distribution',
                    color: 'white',
                    font: { size: 16 }
            },
            legend: {
                labels: { color: 'white' }
            }
        }
    });
}

function generateScatterPlot() {
    const canvas = document.createElement('canvas');
    canvas.className = 'glass-card p-4';
    chartContainer.appendChild(canvas);
    
    const ctx = canvas.getContext('2d');
    new Chart(ctx, {
        type: 'scatter',
        data: {
            datasets: [{
                label: 'Data Points',
                data: [
                    { x: 10, y: 20 }, { x: 15, y: 25 }, { x: 20, y: 30 },
                    { x: 25, y: 35 }, { x: 30, y: 40 }, { x: 35, y: 45 }
                ],
                backgroundColor: 'rgba(168, 85, 247, 0.7)',
                borderColor: 'rgba(168, 85, 247, 1)',
                borderWidth: 2,
                pointRadius: 6
            }]
        },
        options: {
            responsive: true,
            plugins: {
                title: {
                    display: true,
                    text: 'Scatter Plot Correlation',
                    color: 'white',
                    font: { size: 16 }
            },
            legend: {
                labels: { color: 'white' }
            }
        },
        scales: {
            y: {
                beginAtZero: true,
                ticks: { color: 'white' }
            },
            x: {
                ticks: { color: 'white' }
            }
        }
    });
}

// Utility function to download visualization
function downloadChart(chartId, filename) {
    const canvas = document.getElementById(chartId);
    const link = document.createElement('a');
    link.download = filename;
    link.href = canvas.toDataURL();
    link.click();
}

console.log('DataViz Liquid Glass Studio loaded successfully!');