<?php
/**
 * Formazione — Email reminder cron script
 * Run daily: 0 7 * * * php /var/www/html/public/userarea/cron/send_training_reminders.php
 *
 * Sends "due_soon" emails when next_due_date is within the reminder window
 *   (override reminder_days > topic default > 30 days).
 * Sends "expired" emails when next_due_date is in the past.
 * Skips rows with next_due_date IS NULL (one-off trainings).
 * Skips already-sent notifications (same training + addressee + next_due_date).
 * Recipients: the employee (employees.email or auth_users.email) + every HR user
 *   with role Admin / Superuser / employee-hr / manager.
 *
 * Optional CLI flags:
 *   --dry-run             — log only, no SMTP, no DB write
 *   --only-email=foo@bar  — restrict to a single addressee (for testing)
 */

require_once __DIR__ . '/../class/db-functions.php';
require_once __DIR__ . '/../../../vendor/autoload.php';

use Dotenv\Dotenv;
use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\Exception;

$dotenv = Dotenv::createImmutable(__DIR__ . '/../../../');
$dotenv->load();

$db  = DBHandlerSelect::getInstance();
$pdo = $db->getConnection();

$today  = date('Y-m-d');
$appUrl = rtrim($_ENV['APP_URL'] ?? 'http://localhost:8001', '/');

/* CLI flags */
$dryRun    = false;
$onlyEmail = null;
foreach (array_slice($argv ?? [], 1) as $a) {
    if ($a === '--dry-run' || $a === '-n') {
        $dryRun = true;
    } elseif (strpos($a, '--only-email=') === 0) {
        $onlyEmail = substr($a, strlen('--only-email='));
    }
}

$sent = 0;
$skipped = 0;
$errors = 0;

/* Candidate trainings (with optional override reminder + topic default).
   Only the most recent record per (employee, topic) — older history rows skipped. */
$stmt = $pdo->query("
    SELECT et.id, et.employee_id, et.completed_date, et.next_due_date,
           et.reminder_days, et.delivered_by,
           tt.name AS topic_name, tt.default_reminder_days AS topic_default_rem,
           e.first_name, e.last_name, e.employee_code,
           e.email AS employee_email_direct,
           au.email AS employee_email_auth
    FROM employee_trainings et
    JOIN training_topics tt ON tt.id = et.training_topic_id
    JOIN employees e ON e.id = et.employee_id
    LEFT JOIN auth_users au ON au.id = e.auth_user_id
    WHERE et.next_due_date IS NOT NULL
      AND NOT EXISTS (
          SELECT 1 FROM employee_trainings et2
          WHERE et2.employee_id = et.employee_id
            AND et2.training_topic_id = et.training_topic_id
            AND (et2.completed_date > et.completed_date
                 OR (et2.completed_date = et.completed_date AND et2.id > et.id))
      )
");
$rows = $stmt->fetchAll(PDO::FETCH_ASSOC);

if (empty($rows)) {
    echo date('Y-m-d H:i:s') . " — Nessuna formazione da notificare.\n";
    exit(0);
}

/* HR addressees (one query, reused per training) */
$hrUsers = $pdo->query("
    SELECT u.id, u.email, TRIM(CONCAT(COALESCE(u.first_name,''),' ',COALESCE(u.last_name,''))) AS name
    FROM auth_users u
    JOIN auth_roles r ON r.id = u.role_id
    WHERE r.name IN ('Admin','Superuser','employee-hr','manager')
      AND u.email IS NOT NULL AND u.email <> ''
")->fetchAll(PDO::FETCH_ASSOC);

$checkSent = $pdo->prepare("
    SELECT COUNT(*) FROM training_reminder_log
    WHERE training_id = ? AND addressee_email = ? AND next_due_date = ?
");
$insertLog = $pdo->prepare("
    INSERT INTO training_reminder_log
        (training_id, addressee_email, next_due_date, status_at_send, sent_at)
    VALUES (?, ?, ?, ?, NOW())
");

foreach ($rows as $r) {
    $rem = $r['reminder_days'] !== null
        ? (int)$r['reminder_days']
        : ($r['topic_default_rem'] !== null ? (int)$r['topic_default_rem'] : 30);
    $isOverdue = $r['next_due_date'] < $today;
    $daysLeft  = (int)((strtotime($r['next_due_date']) - strtotime($today)) / 86400);

    if (!$isOverdue && $daysLeft > $rem) {
        continue; // not yet in the reminder window
    }
    $type = $isOverdue ? 'expired' : 'update_to_be_scheduled';

    $employeeFullName = trim($r['first_name'] . ' ' . $r['last_name']);
    $employeeEmail    = !empty($r['employee_email_direct'])
        ? $r['employee_email_direct']
        : (!empty($r['employee_email_auth']) ? $r['employee_email_auth'] : null);

    /* Collect addressees (employee + HR), deduplicated by lowercased email */
    $recipients = [];
    if ($employeeEmail) {
        $key = strtolower(trim($employeeEmail));
        $recipients[$key] = ['email' => $employeeEmail, 'name' => $employeeFullName, 'is_hr' => false];
    }
    foreach ($hrUsers as $hr) {
        $key = strtolower(trim((string)$hr['email']));
        if ($key === '' || isset($recipients[$key])) continue;
        $recipients[$key] = ['email' => $hr['email'], 'name' => trim((string)$hr['name']), 'is_hr' => true];
    }
    if (empty($recipients)) {
        continue;
    }

    foreach ($recipients as $email => $rec) {
        if ($onlyEmail !== null && strcasecmp($rec['email'], $onlyEmail) !== 0) continue;

        $checkSent->execute([$r['id'], $rec['email'], $r['next_due_date']]);
        if ($checkSent->fetchColumn() > 0) {
            $skipped++;
            continue;
        }

        try {
            $mail = new PHPMailer(true);

            // SMTP config from .env
            $mailer = $_ENV['MAIL_MAILER'] ?? 'mail';
            if ($mailer === 'smtp') {
                $mail->isSMTP();
                $mail->Host = $_ENV['MAIL_HOST'] ?? 'localhost';
                $mail->Port = (int)($_ENV['MAIL_PORT'] ?? 587);
                if (!empty($_ENV['MAIL_USERNAME']) && $_ENV['MAIL_USERNAME'] !== 'null') {
                    $mail->SMTPAuth = true;
                    $mail->Username = $_ENV['MAIL_USERNAME'];
                    $mail->Password = $_ENV['MAIL_PASSWORD'] ?? '';
                }
                $enc = $_ENV['MAIL_ENCRYPTION'] ?? '';
                if ($enc && $enc !== 'null') {
                    $mail->SMTPSecure = $enc;
                }
            }

            $mail->CharSet = 'UTF-8';
            $mail->setFrom(
                $_ENV['MAIL_FROM_ADDRESS'] ?? 'noreply@zibogomma.it',
                $_ENV['MAIL_FROM_NAME']    ?? 'Formazione ZIBOGOMMA'
            );
            $mail->addAddress($rec['email'], $rec['name'] ?: $rec['email']);

            $profileUrl = $appUrl . '/userarea/employee-profile.php?id=' . (int)$r['employee_id'] . '#tab-training';
            $topicText  = $r['topic_name'] . ' — ' . $employeeFullName
                        . (!empty($r['employee_code']) ? ' (' . $r['employee_code'] . ')' : '');

            if ($isOverdue) {
                $mail->Subject = '⚠️ Formazione scaduta: ' . $r['topic_name'];
                $mail->Body = buildHtml(
                    'Formazione scaduta',
                    $topicText,
                    'Completata il <strong>' . date('d/m/Y', strtotime($r['completed_date'])) . '</strong>. '
                    . 'Il prossimo aggiornamento era previsto per <strong>' . date('d/m/Y', strtotime($r['next_due_date'])) . '</strong>'
                    . ' (scaduta da <strong>' . abs($daysLeft) . ' giorni</strong>).',
                    '#dc3545',
                    $profileUrl,
                    $rec['is_hr']
                );
            } else {
                $mail->Subject = '📚 Formazione in scadenza: ' . $r['topic_name'];
                $daysText = $daysLeft === 0 ? 'oggi' : 'tra <strong>' . $daysLeft . ' giorni</strong>';
                $mail->Body = buildHtml(
                    'Formazione in scadenza',
                    $topicText,
                    'Completata il <strong>' . date('d/m/Y', strtotime($r['completed_date'])) . '</strong>. '
                    . 'Prossimo aggiornamento previsto per <strong>' . date('d/m/Y', strtotime($r['next_due_date'])) . '</strong>'
                    . ' (' . $daysText . ').',
                    '#e8930c',
                    $profileUrl,
                    $rec['is_hr']
                );
            }

            $mail->isHTML(true);
            $mail->AltBody = strip_tags(str_replace('<br>', "\n", $mail->Body));

            if ($dryRun) {
                echo date('H:i:s') . " ◌ DRY {$type} → {$rec['email']} — {$r['topic_name']}\n";
                $sent++;
                continue;
            }

            $mail->send();
            $insertLog->execute([$r['id'], $rec['email'], $r['next_due_date'], $type]);
            $sent++;
            echo date('H:i:s') . " ✓ {$type} → {$rec['email']} — {$r['topic_name']}\n";

        } catch (Exception $e) {
            $errors++;
            echo date('H:i:s') . " ✗ Errore {$rec['email']}: {$e->getMessage()}\n";
        }
    }
}

/* ============================================================================
   NOT-PRESENT reminders — mandatory topics with no record for an employee.
   Notify HR only.
   De-dup by (employee_id, training_topic_id, addressee_email).
   ============================================================================ */
$missingStmt = $pdo->query("
    SELECT e.id AS employee_id, e.first_name, e.last_name, e.employee_code,
           tt.id AS topic_id, tt.name AS topic_name
    FROM employees e
    CROSS JOIN training_topics tt
    WHERE tt.is_active = 1 AND tt.is_mandatory = 1
      AND (e.status IS NULL OR e.status = 'active')
      AND NOT EXISTS (
          SELECT 1 FROM employee_trainings et
          WHERE et.employee_id = e.id AND et.training_topic_id = tt.id
      )
    ORDER BY e.last_name, e.first_name, tt.name
");
$missingRows = $missingStmt->fetchAll(PDO::FETCH_ASSOC);

$checkMissingSent = $pdo->prepare("
    SELECT COUNT(*) FROM training_reminder_log
    WHERE employee_id = ? AND training_topic_id = ? AND addressee_email = ?
      AND status_at_send = 'not_present'
");
$insertMissingLog = $pdo->prepare("
    INSERT INTO training_reminder_log
        (training_id, employee_id, training_topic_id, addressee_email, next_due_date, status_at_send, sent_at)
    VALUES (NULL, ?, ?, ?, NULL, 'not_present', NOW())
");

foreach ($missingRows as $m) {
    $employeeFullName = trim($m['first_name'] . ' ' . $m['last_name']);

    foreach ($hrUsers as $hr) {
        $email = trim((string)$hr['email']);
        if ($email === '') continue;
        if ($onlyEmail !== null && strcasecmp($email, $onlyEmail) !== 0) continue;

        $checkMissingSent->execute([$m['employee_id'], $m['topic_id'], $email]);
        if ($checkMissingSent->fetchColumn() > 0) {
            $skipped++;
            continue;
        }

        try {
            $mail = new PHPMailer(true);
            $mailer = $_ENV['MAIL_MAILER'] ?? 'mail';
            if ($mailer === 'smtp') {
                $mail->isSMTP();
                $mail->Host = $_ENV['MAIL_HOST'] ?? 'localhost';
                $mail->Port = (int)($_ENV['MAIL_PORT'] ?? 587);
                if (!empty($_ENV['MAIL_USERNAME']) && $_ENV['MAIL_USERNAME'] !== 'null') {
                    $mail->SMTPAuth = true;
                    $mail->Username = $_ENV['MAIL_USERNAME'];
                    $mail->Password = $_ENV['MAIL_PASSWORD'] ?? '';
                }
                $enc = $_ENV['MAIL_ENCRYPTION'] ?? '';
                if ($enc && $enc !== 'null') {
                    $mail->SMTPSecure = $enc;
                }
            }

            $mail->CharSet = 'UTF-8';
            $mail->setFrom(
                $_ENV['MAIL_FROM_ADDRESS'] ?? 'noreply@zibogomma.it',
                $_ENV['MAIL_FROM_NAME']    ?? 'Formazione ZIBOGOMMA'
            );
            $mail->addAddress($email, trim((string)$hr['name']) ?: $email);

            $profileUrl = $appUrl . '/userarea/employee-profile.php?id=' . (int)$m['employee_id'] . '#tab-training';
            $topicText  = $m['topic_name'] . ' — ' . $employeeFullName
                        . (!empty($m['employee_code']) ? ' (' . $m['employee_code'] . ')' : '');

            $mail->Subject = '🔔 Formazione obbligatoria non presente: ' . $m['topic_name'];
            $mail->Body = buildHtml(
                'Formazione obbligatoria non presente',
                $topicText,
                'Il dipendente <strong>' . htmlspecialchars($employeeFullName) . '</strong> non ha nessuna registrazione per il corso obbligatorio <strong>' . htmlspecialchars($m['topic_name']) . '</strong>. Programma la prima erogazione.',
                '#6b7280',
                $profileUrl,
                true
            );
            $mail->isHTML(true);
            $mail->AltBody = strip_tags(str_replace('<br>', "\n", $mail->Body));

            if ($dryRun) {
                echo date('H:i:s') . " ◌ DRY not_present → {$email} — {$m['topic_name']} / {$employeeFullName}\n";
                $sent++;
                continue;
            }

            $mail->send();
            $insertMissingLog->execute([$m['employee_id'], $m['topic_id'], $email]);
            $sent++;
            echo date('H:i:s') . " ✓ not_present → {$email} — {$m['topic_name']} / {$employeeFullName}\n";

        } catch (Exception $e) {
            $errors++;
            echo date('H:i:s') . " ✗ Errore {$email}: {$e->getMessage()}\n";
        }
    }
}

echo "\n" . date('Y-m-d H:i:s') . " — Completato. Inviate: {$sent}, Saltate: {$skipped}, Errori: {$errors}\n";

// --- HTML email template ---
function buildHtml(string $title, string $topic, string $message, string $accentColor, string $url, bool $isForHr): string
{
    $greeting = $isForHr
        ? 'Una formazione richiede attenzione.'
        : 'Una delle tue formazioni richiede attenzione.';
    return '
<!DOCTYPE html>
<html>
<head><meta charset="UTF-8"></head>
<body style="margin:0;padding:0;background:#f4f6f9;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif">
<table width="100%" cellpadding="0" cellspacing="0" style="padding:30px 0">
<tr><td align="center">
<table width="560" cellpadding="0" cellspacing="0" style="background:#fff;border-radius:12px;overflow:hidden;box-shadow:0 2px 8px rgba(0,0,0,0.06)">
    <tr><td style="background:' . $accentColor . ';padding:20px 30px">
        <h1 style="margin:0;color:#fff;font-size:18px">' . htmlspecialchars($title) . '</h1>
    </td></tr>
    <tr><td style="padding:30px">
        <p style="margin:0 0 12px;color:#444;font-size:14px">' . htmlspecialchars($greeting) . '</p>
        <h2 style="margin:0 0 15px;color:#2c3e6b;font-size:16px">' . htmlspecialchars($topic) . '</h2>
        <p style="margin:0 0 20px;color:#444;font-size:14px;line-height:1.6">' . $message . '</p>
        <a href="' . htmlspecialchars($url) . '" style="display:inline-block;background:#5a8fd8;color:#fff;padding:10px 24px;border-radius:6px;text-decoration:none;font-weight:600;font-size:14px">Apri profilo</a>
    </td></tr>
    <tr><td style="padding:15px 30px;background:#f8f9fb;border-top:1px solid #eee">
        <p style="margin:0;color:#999;font-size:11px">ZIBOGOMMA — Formazione</p>
    </td></tr>
</table>
</td></tr>
</table>
</body>
</html>';
}