// API Configuration
const API_URL = 'https://nolanzandi-virtual-data-analyst.hf.space';
const PREDICT_ENDPOINT = `${API_URL}/api/predict`;
const SAMPLE_ENDPOINT = `${API_URL}/api/sample`;

// File Upload and API Integration
async function handleFileUpload(file) {
    try {
        // Show loading state
        document.querySelector('.upload-icon').style.display = 'none';
        document.querySelector('.loading-spinner').style.display = 'block';
        document.querySelector('.progress-bar').style.display = 'block';

        // Create FormData
        const formData = new FormData();
        formData.append('file', file);

        // Update file info
        updateFileInfo(file);

        // Simulate progress while actually uploading
        const progressInterval = simulateProgress();

        // Make API request
        const response = await fetch(API_URL, {
            method: 'POST',
            body: formData
        });

        if (!response.ok) {
            throw new Error('API request failed');
        }

        const data = await response.json();
        
        // Clear progress simulation
        clearInterval(progressInterval);
        
        // Show success state
        showSuccessState();
        
        // Handle API response
        handleApiResponse(data);

    } catch (error) {
        console.error('Error:', error);
        showErrorState(error.message);
    }
}

function updateFileInfo(file) {
    const fileInfo = document.getElementById('fileInfo');
    const fileName = fileInfo.querySelector('.file-name');
    const fileSize = fileInfo.querySelector('.file-size');
    const fileIcon = fileInfo.querySelector('.file-type-icon');
    
    const fileType = file.name.split('.').pop().toLowerCase();
    const iconClass = getFileTypeIcon(fileType);
    
    fileIcon.className = `file-type-icon fas ${iconClass}`;
    fileName.textContent = file.name;
    fileSize.textContent = formatFileSize(file.size);
    fileInfo.classList.remove('hidden');
}

function simulateProgress() {
    const progressBar = document.querySelector('.progress-bar-fill');
    let progress = 0;
    
    return setInterval(() => {
        if (progress < 90) { // Only go up to 90% until we get actual completion
            progress += 5;
            progressBar.style.width = `${progress}%`;
        }
    }, 100);
}

function showSuccessState() {
    document.querySelector('.loading-spinner').style.display = 'none';
    document.querySelector('.success-checkmark').style.display = 'block';
    document.querySelector('.progress-bar-fill').style.width = '100%';
    
    setTimeout(() => {
        resetUploadState();
    }, 2000);
}

function showErrorState(message) {
    // Reset upload UI
    resetUploadState();
    
    // Show error message
    const errorDiv = document.createElement('div');
    errorDiv.className = 'text-red-500 mt-4';
    errorDiv.innerHTML = `<i class="fas fa-exclamation-circle mr-2"></i>${message}`;
    document.querySelector('.drop-zone').appendChild(errorDiv);
    
    setTimeout(() => {
        errorDiv.remove();
    }, 5000);
}

function resetUploadState() {
    document.querySelector('.success-checkmark').style.display = 'none';
    document.querySelector('.upload-icon').style.display = 'block';
    document.querySelector('.progress-bar').style.display = 'none';
    document.querySelector('.progress-bar-fill').style.width = '0%';
    document.getElementById('fileInfo').classList.add('hidden');
}

function handleSampleDataClick(datasetName) {
    // Show loading state in results section
    const resultsSection = document.getElementById('results');
    const resultsLoading = document.getElementById('resultsLoading');
    const resultsContent = document.getElementById('resultsContent');
    const resultsError = document.getElementById('resultsError');

    resultsSection.classList.remove('hidden');
    resultsLoading.classList.remove('hidden');
    resultsContent.classList.add('hidden');
    resultsError.classList.add('hidden');

    // Simulate API delay
    setTimeout(() => {
        try {
            // Mock data based on dataset type
            const mockData = datasetName === 'marketing_campaign' ? {
                statistics: {
                    rows: 10000,
                    columns: 15,
                    missing_values: 120,
                    data_types: ['numeric', 'categorical', 'datetime']
                },
                preview: {
                    columns: ['Campaign ID', 'Customer ID', 'Response', 'Channel'],
                    data: [
                        ['CAM001', 'C001', 'Converted', 'Email'],
                        ['CAM001', 'C002', 'No Response', 'SMS'],
                        ['CAM002', 'C003', 'Converted', 'Social Media']
                    ]
                },
                visualizations: [
                    {
                        title: 'Response Rate by Channel',
                        description: 'Conversion rates across different marketing channels',
                        image_url: 'https://via.placeholder.com/400x300'
                    },
                    {
                        title: 'Campaign Performance',
                        description: 'Success metrics for each campaign',
                        image_url: 'https://via.placeholder.com/400x300'
                    }
                ],
                insights: [
                    {
                        title: 'Best Performing Channel',
                        description: 'Email campaigns show highest conversion rate at 28%'
                    },
                    {
                        title: 'Optimal Send Time',
                        description: 'Campaigns sent between 2 PM - 4 PM have better engagement'
                    }
                ]
            } : {
                statistics: {
                    rows: 50000,
                    columns: 12,
                    missing_values: 85,
                    data_types: ['numeric', 'categorical', 'datetime']
                },
                preview: {
                    columns: ['Order ID', 'Product', 'Quantity', 'Price'],
                    data: [
                        ['ORD001', 'Laptop', '1', '$999.99'],
                        ['ORD002', 'Mouse', '2', '$29.99'],
                        ['ORD003', 'Monitor', '1', '$299.99']
                    ]
                },
                visualizations: [
                    {
                        title: 'Sales by Category',
                        description: 'Distribution of sales across product categories',
                        image_url: 'https://via.placeholder.com/400x300'
                    },
                    {
                        title: 'Monthly Revenue',
                        description: 'Revenue trends over the past 12 months',
                        image_url: 'https://via.placeholder.com/400x300'
                    }
                ],
                insights: [
                    {
                        title: 'Top Products',
                        description: 'Electronics category generates 45% of total revenue'
                    },
                    {
                        title: 'Customer Behavior',
                        description: 'Average order value increased by 15% in Q4'
                    }
                ]
            };

            handleApiResponse(mockData);
        } catch (error) {
            console.error('Error:', error);
            showErrorState('Failed to process sample dataset');
        }
    }, 1000); // 1 second delay to show loading state
}

function handleApiResponse(data) {
    const resultsSection = document.getElementById('results');
    const resultsLoading = document.getElementById('resultsLoading');
    const resultsContent = document.getElementById('resultsContent');
    const resultsError = document.getElementById('resultsError');

    // Show results section
    resultsSection.classList.remove('hidden');
    resultsLoading.classList.add('hidden');
    resultsError.classList.add('hidden');
    resultsContent.classList.remove('hidden');

    // Update Basic Statistics
    updateBasicStats(data.statistics);

    // Update Data Preview
    updateDataPreview(data.preview);

    // Update Visualizations
    updateVisualizations(data.visualizations);

    // Update Insights
    updateInsights(data.insights);
}

function updateBasicStats(statistics) {
    const statsContainer = document.getElementById('basicStats');
    statsContainer.innerHTML = '';

    const stats = [
        { label: 'Rows', value: statistics.rows, icon: 'fa-list' },
        { label: 'Columns', value: statistics.columns, icon: 'fa-columns' },
        { label: 'Missing Values', value: statistics.missing_values, icon: 'fa-exclamation-triangle' },
        { label: 'Data Types', value: statistics.data_types.length, icon: 'fa-code' }
    ];

    stats.forEach(stat => {
        const statDiv = document.createElement('div');
        statDiv.className = 'bg-gray-50 rounded-lg p-4';
        statDiv.innerHTML = `
            <div class="flex items-center">
                <i class="fas ${stat.icon} text-primary text-xl mr-3"></i>
                <div>
                    <div class="text-sm text-gray-500">${stat.label}</div>
                    <div class="text-lg font-semibold">${stat.value}</div>
                </div>
            </div>
        `;
        statsContainer.appendChild(statDiv);
    });
}

function updateDataPreview(preview) {
    const table = document.getElementById('dataPreview');
    table.innerHTML = '';

    // Add header
    const thead = document.createElement('thead');
    thead.className = 'bg-gray-50';
    const headerRow = document.createElement('tr');
    preview.columns.forEach(column => {
        const th = document.createElement('th');
        th.className = 'px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase tracking-wider';
        th.textContent = column;
        headerRow.appendChild(th);
    });
    thead.appendChild(headerRow);
    table.appendChild(thead);

    // Add body
    const tbody = document.createElement('tbody');
    tbody.className = 'bg-white divide-y divide-gray-200';
    preview.data.forEach(row => {
        const tr = document.createElement('tr');
        row.forEach(cell => {
            const td = document.createElement('td');
            td.className = 'px-6 py-4 whitespace-nowrap text-sm text-gray-500';
            td.textContent = cell;
            tr.appendChild(td);
        });
        tbody.appendChild(tr);
    });
    table.appendChild(tbody);
}

function updateVisualizations(visualizations) {
    const container = document.getElementById('visualizations');
    container.innerHTML = '';

    visualizations.forEach(viz => {
        const vizDiv = document.createElement('div');
        vizDiv.className = 'bg-white rounded-lg p-4 shadow';
        vizDiv.innerHTML = `
            <h4 class="text-lg font-medium text-gray-800 mb-4">${viz.title}</h4>
            <div class="aspect-w-16 aspect-h-9">
                <img src="${viz.image_url}" alt="${viz.title}" class="rounded-lg">
            </div>
            <p class="mt-2 text-sm text-gray-600">${viz.description}</p>
        `;
        container.appendChild(vizDiv);
    });
}

function updateInsights(insights) {
    const insightsList = document.getElementById('insights');
    insightsList.innerHTML = '';

    insights.forEach(insight => {
        const li = document.createElement('li');
        li.className = 'bg-blue-50 rounded-lg p-4';
        li.innerHTML = `
            <div class="flex items-start">
                <i class="fas fa-lightbulb text-yellow-500 mt-1 mr-3"></i>
                <div>
                    <div class="font-medium text-blue-900">${insight.title}</div>
                    <p class="mt-1 text-sm text-blue-700">${insight.description}</p>
                </div>
            </div>
        `;
        insightsList.appendChild(li);
    });
}

function closeResults() {
    document.getElementById('results').classList.add('hidden');
}

function showErrorState(message) {
    const resultsSection = document.getElementById('results');
    const resultsLoading = document.getElementById('resultsLoading');
    const resultsContent = document.getElementById('resultsContent');
    const resultsError = document.getElementById('resultsError');
    const errorMessage = document.getElementById('errorMessage');

    resultsSection.classList.remove('hidden');
    resultsLoading.classList.add('hidden');
    resultsContent.classList.add('hidden');
    resultsError.classList.remove('hidden');
    errorMessage.textContent = message;
}

// Event Listeners
document.addEventListener('DOMContentLoaded', () => {
    // File Upload Handling
    const dropZone = document.querySelector('.drop-zone');
    const fileInput = document.getElementById('fileInput');

    // Prevent default drag behaviors
    ['dragenter', 'dragover', 'dragleave', 'drop'].forEach(eventName => {
        dropZone.addEventListener(eventName, preventDefaults, false);
        document.body.addEventListener(eventName, preventDefaults, false);
    });

    // Highlight drop zone when dragging over it
    ['dragenter', 'dragover'].forEach(eventName => {
        dropZone.addEventListener(eventName, highlight, false);
    });

    ['dragleave', 'drop'].forEach(eventName => {
        dropZone.addEventListener(eventName, unhighlight, false);
    });

    // Handle dropped files
    dropZone.addEventListener('drop', (e) => {
        const dt = e.dataTransfer;
        const files = dt.files;
        if (files.length > 0) {
            handleFileUpload(files[0]);
        }
    });

    fileInput.addEventListener('change', (e) => {
        if (e.target.files.length > 0) {
            handleFileUpload(e.target.files[0]);
        }
    });

    // Sample Data Button Handlers
    const marketingBtn = document.querySelector('.sample-btn:nth-child(1)');
    const retailBtn = document.querySelector('.sample-btn:nth-child(2)');

    if (marketingBtn) {
        marketingBtn.addEventListener('click', () => {
            console.log('Marketing campaign button clicked');
            handleSampleDataClick('marketing_campaign');
        });
    }

    if (retailBtn) {
        retailBtn.addEventListener('click', () => {
            console.log('Online retail button clicked');
            handleSampleDataClick('online_retail');
        });
    }
});

// Utility Functions
function preventDefaults(e) {
    e.preventDefault();
    e.stopPropagation();
}

function highlight(e) {
    document.querySelector('.drop-zone').classList.add('border-primary', 'bg-blue-50');
}

function unhighlight(e) {
    document.querySelector('.drop-zone').classList.remove('border-primary', 'bg-blue-50');
}

function getFileTypeIcon(fileType) {
    const icons = {
        'csv': 'fa-file-csv',
        'tsv': 'fa-file-alt',
        'txt': 'fa-file-alt',
        'xls': 'fa-file-excel',
        'xlsx': 'fa-file-excel',
        'xml': 'fa-file-code',
        'json': 'fa-file-code'
    };
    return icons[fileType] || 'fa-file';
}

function formatFileSize(bytes) {
    if (bytes === 0) return '0 Bytes';
    const k = 1024;
    const sizes = ['Bytes', 'KB', 'MB', 'GB'];
    const i = Math.floor(Math.log(bytes) / Math.log(k));
    return parseFloat((bytes / Math.pow(k, i)).toFixed(2)) + ' ' + sizes[i];
}