/**
 * Progress Page JavaScript
 * Handles Server-Sent Events (SSE) for real-time QC progress updates
 */

// Get DOM elements
const progressBar = document.getElementById('progressBar');
const progressText = document.getElementById('progressText');

// Get total checks count from template
const totalChecks = window.totalChecks || 0;
let completedChecks = 0;

// Create EventSource for Server-Sent Events
const eventSource = new EventSource('/progress/stream');

// Handle incoming progress events
eventSource.onmessage = function(event) {
    const data = JSON.parse(event.data);

    if (data.check_id === 'system') {
        handleSystemEvent(data);
    } else {
        handleCheckEvent(data);
    }
};

// Handle SSE errors
eventSource.onerror = function(error) {
    console.error('SSE Error:', error);

    // Close the connection
    eventSource.close();

    // Show error message
    alert('Lost connection to server. Please refresh the page.');
};

/**
 * Handle check-specific progress events
 * @param {Object} data - Event data {check_id, status, message}
 */
function handleCheckEvent(data) {
    const checkElement = document.getElementById(`check_${data.check_id}`);
    if (!checkElement) {
        console.warn(`Check element not found: check_${data.check_id}`);
        return;
    }

    const statusElement = checkElement.querySelector('.check-status');
    const messageElement = checkElement.querySelector('.check-message');

    // Update status class
    statusElement.className = 'check-status';
    statusElement.classList.add(`status-${data.status}`);

    // Update message
    messageElement.textContent = data.message;

    // Update progress if completed
    if (['passed', 'error', 'failed', 'skipped'].includes(data.status)) {
        completedChecks++;
        updateProgressBar();
    }
}

/**
 * Handle system-level events
 * @param {Object} data - Event data {check_id: 'system', status, message}
 */
function handleSystemEvent(data) {
    if (data.status === 'started') {
        console.log('QC checks started:', data.message);
    } else if (data.status === 'generating_report') {
        progressText.textContent = 'Generating report...';
    } else if (data.status === 'completed') {
        // Store report path in session storage
        sessionStorage.setItem('report_path', data.message);

        // Close SSE connection
        eventSource.close();

        // Redirect to results page
        window.location.href = '/results';
    } else if (data.status === 'error') {
        // Close SSE connection
        eventSource.close();

        // Show error message
        alert(`Error running QC checks:\n\n${data.message}`);

        // Redirect back to upload page
        setTimeout(() => {
            window.location.href = '/';
        }, 2000);
    }
}

/**
 * Update progress bar and text
 */
function updateProgressBar() {
    const percentage = (completedChecks / totalChecks) * 100;

    progressBar.style.width = `${percentage}%`;
    progressBar.textContent = `${Math.round(percentage)}%`;

    progressText.textContent = `${completedChecks} of ${totalChecks} checks completed`;
}