<?php
/**
 * SendGrid Email Configuration
 * Location: /clients/sendgrid-config.php
 * 
 * SETUP STEPS:
 * ============
 * 1. Create a SendGrid account at https://sendgrid.com (free tier = 100 emails/day)
 * 2. Go to Settings → API Keys → Create API Key (Full Access or Mail Send only)
 * 3. Copy the API key (starts with SG.) and paste below
 * 4. Verify your sender:
 *    - Option A (Quick): Settings → Sender Authentication → Single Sender Verification
 *      → Add your email (e.g. surveys@relevantreflex.com) and verify via inbox
 *    - Option B (Production): Settings → Sender Authentication → Domain Authentication
 *      → Add 3 CNAME DNS records for relevantreflex.com
 *      → Then ANY email @relevantreflex.com can be used as sender
 * 5. Set SENDER_EMAIL below to your verified email
 *
 * YES - you can use any email from your domain (surveys@, noreply@, team@, etc.)
 * as long as it's verified in SendGrid via Single Sender or Domain Authentication.
 */

define('SENDGRID_API_KEY', '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');
define('SENDER_EMAIL',     'invitation@relevantreflex.com');
define('SENDER_NAME',      'Relevant Reflex Surveys');

/**
 * Send one email via SendGrid HTTP API
 */
function sendEmailViaSendGrid($to_email, $subject, $html_content) {
    $data = [
        'personalizations' => [[
            'to' => [['email' => $to_email]],
            'subject' => $subject
        ]],
        'from' => [
            'email' => SENDER_EMAIL,
            'name'  => SENDER_NAME
        ],
        'content' => [[
            'type'  => 'text/html',
            'value' => $html_content
        ]]
    ];

    $ch = curl_init('https://api.sendgrid.com/v3/mail/send');
    curl_setopt_array($ch, [
        CURLOPT_POST           => true,
        CURLOPT_POSTFIELDS     => json_encode($data),
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_HTTPHEADER     => [
            'Authorization: Bearer ' . SENDGRID_API_KEY,
            'Content-Type: application/json'
        ],
        CURLOPT_TIMEOUT        => 10,
        CURLOPT_SSL_VERIFYPEER => true
    ]);

    $response    = curl_exec($ch);
    $status_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    $curl_error  = curl_error($ch);
    curl_close($ch);

    if ($curl_error) {
        return ['success' => false, 'message' => 'cURL error: ' . $curl_error, 'status_code' => 0];
    }
    // SendGrid returns 202 Accepted
    if ($status_code === 202) {
        return ['success' => true, 'message' => 'Email sent', 'status_code' => 202];
    }
    $err = json_decode($response, true);
    $msg = $err['errors'][0]['message'] ?? ('HTTP ' . $status_code);
    return ['success' => false, 'message' => $msg, 'status_code' => $status_code];
}

/**
 * Calculate default incentive (in RUPEES)
 * Reads pricing_base_incentive and pricing_loi_increment_incentive from company_settings
 * (same source as estimator.php and view-project.php). Falls back to safe defaults if
 * settings cannot be loaded.
 */
function calculateDefaultIncentive($eloi) {
    static $base = null, $incr = null;
    if ($base === null) {
        $base = 10; $incr = 1; // safe defaults
        try {
            $pdo = getClientDBConnection();
            $stmt = $pdo->query("SELECT setting_key, setting_value FROM company_settings WHERE setting_key IN ('pricing_base_incentive', 'pricing_loi_increment_incentive')");
            while ($r = $stmt->fetch(PDO::FETCH_ASSOC)) {
                if ($r['setting_key'] === 'pricing_base_incentive') $base = (float)$r['setting_value'];
                elseif ($r['setting_key'] === 'pricing_loi_increment_incentive') $incr = (float)$r['setting_value'];
            }
        } catch (Exception $e) {
            error_log('calculateDefaultIncentive pricing load failed: ' . $e->getMessage());
        }
    }
    $extra = max(0, floor($eloi) - 5);
    return $base + ($extra * $incr);
}

/**
 * Build invitation email HTML (first send)
 */
function buildInvitationEmail($proxy_url, $eloi, $incentive) {
    $reward = '₹' . number_format($incentive, 0);
    return '<!DOCTYPE html>
<html>
<head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"></head>
<body style="margin:0;padding:0;font-family:Arial,Helvetica,sans-serif;background:#f4f4f7;">
<table role="presentation" width="100%" cellpadding="0" cellspacing="0" style="background:#f4f4f7;">
<tr><td align="center" style="padding:30px 10px;">
<table role="presentation" width="600" cellpadding="0" cellspacing="0" style="background:#fff;border-radius:12px;overflow:hidden;box-shadow:0 2px 8px rgba(0,0,0,0.08);">

<!-- Header -->
<tr><td style="background:linear-gradient(135deg,#0066cc 0%,#004499 100%);padding:32px 40px;text-align:center;">
<h1 style="color:#fff;font-size:26px;margin:0 0 6px;font-weight:700;">Relevant Reflex</h1>
<p style="color:#b3d4fc;font-size:13px;margin:0;letter-spacing:1px;text-transform:uppercase;">Survey Invitation</p>
</td></tr>

<!-- Body -->
<tr><td style="padding:40px;">
<p style="font-size:16px;color:#333;line-height:1.6;margin:0 0 20px;">Dear Participant,</p>
<p style="font-size:16px;color:#333;line-height:1.6;margin:0 0 20px;">
You have been selected to participate in an online survey. Your opinions are valuable and will help shape important decisions. We would greatly appreciate your time and input.
</p>

<!-- Survey Details -->
<table role="presentation" width="100%" cellpadding="0" cellspacing="0" style="background:#f0f7ff;border-radius:10px;margin:24px 0;">
<tr><td style="padding:24px;">
<table role="presentation" width="100%" cellpadding="0" cellspacing="0">
<tr>
<td width="50%" style="padding:8px 0;">
<p style="font-size:12px;color:#6b7280;text-transform:uppercase;font-weight:600;margin:0 0 4px;">Estimated Duration</p>
<p style="font-size:22px;color:#0066cc;font-weight:700;margin:0;">' . (int)$eloi . ' minutes</p>
</td>
<td width="50%" style="padding:8px 0;">
<p style="font-size:12px;color:#6b7280;text-transform:uppercase;font-weight:600;margin:0 0 4px;">Reward</p>
<p style="font-size:22px;color:#059669;font-weight:700;margin:0;">' . $reward . '</p>
</td>
</tr>
</table>
</td></tr>
</table>

<!-- CTA Button -->
<table role="presentation" width="100%" cellpadding="0" cellspacing="0" style="margin:30px 0;">
<tr><td align="center">
<a href="' . htmlspecialchars($proxy_url) . '" target="_blank" 
   style="display:inline-block;padding:16px 48px;background:linear-gradient(135deg,#059669 0%,#047857 100%);color:#fff;text-decoration:none;font-size:18px;font-weight:700;border-radius:8px;letter-spacing:0.5px;">
Take Survey Now &rarr;
</a>
</td></tr>
</table>

<!-- Fallback URL -->
<div style="background:#f9fafb;border:1px solid #e5e7eb;border-radius:8px;padding:16px;margin:20px 0;">
<p style="font-size:13px;color:#6b7280;margin:0 0 8px;">If the button above doesn\'t work, copy and paste this URL into your browser:</p>
<p style="font-size:13px;color:#0066cc;word-break:break-all;margin:0;">' . htmlspecialchars($proxy_url) . '</p>
</div>

<p style="font-size:14px;color:#6b7280;line-height:1.6;margin:24px 0 0;">
Please complete the survey at your earliest convenience. Your responses are completely confidential and will be used for research purposes only.
</p>
</td></tr>

<!-- Footer -->
<tr><td style="background:#1a1a1a;padding:24px 40px;text-align:center;">
<p style="font-size:13px;color:#9ca3af;margin:0 0 8px;">&copy; ' . date('Y') . ' Relevant Reflex India. All rights reserved.</p>
<p style="font-size:12px;color:#6b7280;margin:0;">You are receiving this email because you are a registered member of the Relevant Reflex panel.</p>
</td></tr>

</table>
</td></tr>
</table>
</body></html>';
}

/**
 * Build reminder email HTML (resend - 2nd/3rd dispatch)
 * Same survey info as the first time but with a REMINDER banner and friendly nudge copy.
 */
function buildReminderEmail($proxy_url, $eloi, $incentive) {
    $reward = '₹' . number_format($incentive, 0);
    return '<!DOCTYPE html>
<html>
<head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"></head>
<body style="margin:0;padding:0;font-family:Arial,Helvetica,sans-serif;background:#f4f4f7;">
<table role="presentation" width="100%" cellpadding="0" cellspacing="0" style="background:#f4f4f7;">
<tr><td align="center" style="padding:30px 10px;">
<table role="presentation" width="600" cellpadding="0" cellspacing="0" style="background:#fff;border-radius:12px;overflow:hidden;box-shadow:0 2px 8px rgba(0,0,0,0.08);">

<!-- Header with REMINDER banner -->
<tr><td style="background:linear-gradient(135deg,#0066cc 0%,#004499 100%);padding:32px 40px;text-align:center;">
<h1 style="color:#fff;font-size:26px;margin:0 0 6px;font-weight:700;">Relevant Reflex</h1>
<p style="color:#b3d4fc;font-size:13px;margin:0;letter-spacing:1px;text-transform:uppercase;">Survey Invitation</p>
</td></tr>

<!-- REMINDER Banner -->
<tr><td style="background:#fef3c7;padding:12px 40px;text-align:center;border-bottom:2px solid #fde68a;">
<p style="font-size:14px;color:#92400e;margin:0;font-weight:700;">&#128276; REMINDER: Your survey invitation is still waiting for you!</p>
</td></tr>

<!-- Body -->
<tr><td style="padding:40px;">
<p style="font-size:16px;color:#333;line-height:1.6;margin:0 0 20px;">Dear Participant,</p>
<p style="font-size:16px;color:#333;line-height:1.6;margin:0 0 20px;">
We noticed you haven\'t had a chance to take the survey we invited you to earlier. We would love to hear your opinion! The survey is still open and your participation would be greatly valued.
</p>

<!-- Survey Details (same as original) -->
<table role="presentation" width="100%" cellpadding="0" cellspacing="0" style="background:#f0f7ff;border-radius:10px;margin:24px 0;">
<tr><td style="padding:24px;">
<table role="presentation" width="100%" cellpadding="0" cellspacing="0">
<tr>
<td width="50%" style="padding:8px 0;">
<p style="font-size:12px;color:#6b7280;text-transform:uppercase;font-weight:600;margin:0 0 4px;">Estimated Duration</p>
<p style="font-size:22px;color:#0066cc;font-weight:700;margin:0;">' . (int)$eloi . ' minutes</p>
</td>
<td width="50%" style="padding:8px 0;">
<p style="font-size:12px;color:#6b7280;text-transform:uppercase;font-weight:600;margin:0 0 4px;">Reward</p>
<p style="font-size:22px;color:#059669;font-weight:700;margin:0;">' . $reward . '</p>
</td>
</tr>
</table>
</td></tr>
</table>

<!-- CTA Button -->
<table role="presentation" width="100%" cellpadding="0" cellspacing="0" style="margin:30px 0;">
<tr><td align="center">
<a href="' . htmlspecialchars($proxy_url) . '" target="_blank" 
   style="display:inline-block;padding:16px 48px;background:linear-gradient(135deg,#059669 0%,#047857 100%);color:#fff;text-decoration:none;font-size:18px;font-weight:700;border-radius:8px;letter-spacing:0.5px;">
Take Survey Now &rarr;
</a>
</td></tr>
</table>

<!-- Fallback URL -->
<div style="background:#f9fafb;border:1px solid #e5e7eb;border-radius:8px;padding:16px;margin:20px 0;">
<p style="font-size:13px;color:#6b7280;margin:0 0 8px;">If the button above doesn\'t work, copy and paste this URL into your browser:</p>
<p style="font-size:13px;color:#0066cc;word-break:break-all;margin:0;">' . htmlspecialchars($proxy_url) . '</p>
</div>

<p style="font-size:14px;color:#6b7280;line-height:1.6;margin:24px 0 0;">
Please complete the survey at your earliest convenience. Your responses are completely confidential and will be used for research purposes only.
</p>
</td></tr>

<!-- Footer -->
<tr><td style="background:#1a1a1a;padding:24px 40px;text-align:center;">
<p style="font-size:13px;color:#9ca3af;margin:0 0 8px;">&copy; ' . date('Y') . ' Relevant Reflex India. All rights reserved.</p>
<p style="font-size:12px;color:#6b7280;margin:0;">You are receiving this email because you are a registered member of the Relevant Reflex panel.</p>
</td></tr>

</table>
</td></tr>
</table>
</body></html>';
}