<?php
session_start();
require_once 'db/config.php';
require_once 'mail/MailService.php';

header('Content-Type: application/json');

// --- Helper function to fetch webinar details ---
function get_webinar_details($id) {
    if (empty($id)) return null;
    try {
        $stmt = db()->prepare("SELECT id, title, description, scheduled_at, presenter FROM webinars WHERE id = ?");
        $stmt->execute([$id]);
        return $stmt->fetch(PDO::FETCH_ASSOC);
    } catch (PDOException $e) {
        error_log("Database error fetching webinar ID $id: " . $e->getMessage());
        return null;
    }
}

// --- Only allow POST requests ---
if ($_SERVER["REQUEST_METHOD"] !== "POST") {
    echo json_encode(['success' => false, 'error' => 'Invalid request method.']);
    exit;
}

$webinar_id = filter_input(INPUT_POST, 'webinar_id', FILTER_VALIDATE_INT) ?: 1;
$webinar = get_webinar_details($webinar_id);

if (!$webinar) {
    http_response_code(404);
    echo json_encode(['success' => false, 'error' => 'Webinar not found.']);
    exit;
}

// --- DATA CAPTURE ---
$email = filter_input(INPUT_POST, 'email', FILTER_VALIDATE_EMAIL);
$first_name = filter_input(INPUT_POST, 'first_name', FILTER_SANITIZE_STRING);
$last_name = filter_input(INPUT_POST, 'last_name', FILTER_SANITIZE_STRING);
$company = filter_input(INPUT_POST, 'company', FILTER_SANITIZE_STRING);
$how_did_you_hear = filter_input(INPUT_POST, 'how_did_you_hear', FILTER_SANITIZE_STRING);
$timezone = filter_input(INPUT_POST, 'timezone', FILTER_SANITIZE_STRING);

// --- VALIDATION ---
if (!$first_name || !$last_name || !$email) {
    echo json_encode(['success' => false, 'error' => 'Please fill out all required fields.']);
    exit;
}

try {
    // --- CHECK IF ALREADY REGISTERED OR SOFT-DELETED -- -
    $stmt = db()->prepare("SELECT id, deleted_at FROM attendees WHERE webinar_id = ? AND email = ?");
    $stmt->execute([$webinar_id, $email]);
    $existing_user = $stmt->fetch(PDO::FETCH_ASSOC);

    if ($existing_user) {
        if ($existing_user['deleted_at'] !== null) {
            // --- USER IS SOFT-DELETED, SO REACTIVATE AND UPDATE ---
            $sql = "UPDATE attendees SET first_name = ?, last_name = ?, company = ?, how_did_you_hear = ?, timezone = ?, deleted_at = NULL, consented = 1 WHERE id = ?";
            $stmt = db()->prepare($sql);
            $stmt->execute([$first_name, $last_name, $company, $how_did_you_hear, $timezone, $existing_user['id']]);
        } else {
            // --- USER IS ACTIVE, SO REJECT ---
            echo json_encode(['success' => false, 'error' => 'You are already registered for this webinar.']);
            exit;
        }
    } else {
        // --- REGISTER NEW USER ---
        $password_hash = password_hash($email . time(), PASSWORD_DEFAULT);
        $sql = "INSERT INTO attendees (webinar_id, first_name, last_name, email, company, how_did_you_hear, password, timezone) 
                VALUES (?, ?, ?, ?, ?, ?, ?, ?)";
        $stmt = db()->prepare($sql);
        $stmt->execute([$webinar_id, $first_name, $last_name, $email, $company, $how_did_you_hear, $password_hash, $timezone]);
    }
    
    // --- SEND CONFIRMATION EMAIL ---
    $webinar_date_obj = new DateTime('2025-11-19 10:00:00', new DateTimeZone('America/New_York'));
    $subject = "Confirmation: You're Registered for Building Scalable Apps with AppWizzy";
    $body_html = "<h1>You're in!</h1><p>Thanks for registering for our webinar: <strong>Building Scalable Apps with AppWizzy</strong>.</p><p style='font-size: 0.8em;'><strong>Professional Vibe-Coding Webinar</strong></p><p>It will take place on <strong>" . $webinar_date_obj->format('l, F j, Y \a\t g:i A T') . "</strong>.</p><p>You can now log in to your dashboard to see the details.</p>";
    MailService::sendMail($email, $subject, $body_html);

    // --- PREPARE SUCCESS RESPONSE ---
    $webinar_date = new DateTime('2025-11-19 10:00:00', new DateTimeZone('America/New_York'));
    $webinar_date->setTimezone(new DateTimeZone('UTC'));
    $start_time_utc = $webinar_date->format('Ymd\THis\Z');
    $webinar_date->add(new DateInterval('PT1H')); // Assume 1 hour duration
    $end_time_utc = $webinar_date->format('Ymd\THis\Z');

    $event_title = 'Building Scalable Apps with AppWizzy at 4PM CET';
    $event_description = 'Professional Vibe-Coding Webinar\n\nJoin us for this webinar at 4PM CET | 10AM EST | 7AM PST. The fastest way to go from an idea to a working app you own, running on your server, with your database, using real frameworks.';

    $google_link = 'https://www.google.com/calendar/render?action=TEMPLATE&text=' . urlencode($event_title) . '&dates=' . $start_time_utc . '/' . $end_time_utc . '&details=' . urlencode($event_description) . '&location=' . urlencode('Online') . '&ctz=UTC';
    
    $ics_content = implode("\r\n", [
        'BEGIN:VCALENDAR',
        'VERSION:2.0',
        'PRODID:-//Flatlogic//Building Scalable Apps with AppWizzy//EN',
        'BEGIN:VEVENT',
        'URL:' . 'http://' . $_SERVER['HTTP_HOST'],
        'DTSTART:' . $start_time_utc,
        'DTEND:' . $end_time_utc,
        'SUMMARY:' . $event_title,
        'DESCRIPTION:' . str_replace("\n", "\\n", $event_description),
        'LOCATION:Online',
        'END:VEVENT',
        'END:VCALENDAR'
    ]);
    $outlook_link = 'data:text/calendar;charset=utf-8,' . rawurlencode($ics_content);

    echo json_encode([
        'success' => true,
        'webinar_title' => 'Building Scalable Apps with AppWizzy<br><small><strong>Professional Vibe-Coding Webinar</strong></small>',
        'google_link' => $google_link,
        'outlook_link' => $outlook_link
    ]);

} catch (Exception $e) {
    error_log("Registration error: " . $e->getMessage());
    http_response_code(500);
    echo json_encode(['success' => false, 'error' => 'An unexpected server error occurred. Please try again.']);
}
