<?php
/**
 * Smart Notification Triggers
 * 
 * Centralized service for sending intelligent, context-aware notifications.
 * Call these methods from relevant endpoints (e.g., after invoice upload, approval, etc.)
 */

declare(strict_types=1);

namespace App\Services;

use App\Core\Database;

class SmartNotifications
{
    /**
     * Notify admin when quota usage reaches 80%
     */
    public static function checkQuotaWarning(string $tenantId): void
    {
        try {
            $db = Database::getInstance();
            $stmt = $db->prepare("SELECT max_invoices_per_month, invoices_used_this_month FROM subscriptions WHERE tenant_id = ?");
            $stmt->execute([$tenantId]);
            $sub = $stmt->fetch();

            if (!$sub) return;

            $usage = ($sub['max_invoices_per_month'] > 0) 
                ? ($sub['invoices_used_this_month'] / $sub['max_invoices_per_month']) * 100 
                : 0;

            if ($usage >= 80 && $usage < 100) {
                // Find admin user
                $adminStmt = $db->prepare("SELECT id FROM users WHERE tenant_id = ? AND role = 'admin' LIMIT 1");
                $adminStmt->execute([$tenantId]);
                $adminId = $adminStmt->fetchColumn();

                if ($adminId) {
                    self::send($tenantId, $adminId, 'quota_warning',
                        '⚠️ اقتربت من حد الباقة',
                        'استخدمت ' . round($usage) . '% من حصة الفواتير الشهرية. فكّر بالترقية لتجنب التوقف.',
                        ['usage_percent' => round($usage)]
                    );
                }
            }
        } catch (\Throwable $e) {
            error_log("[SmartNotifications] Quota warning failed: " . $e->getMessage());
        }
    }

    /**
     * Notify user when invoice is approved
     */
    public static function invoiceApproved(string $tenantId, string $uploaderId, string $invoiceId, string $invoiceNumber): void
    {
        self::send($tenantId, $uploaderId, 'invoice_approved',
            '✅ تم اعتماد الفاتورة',
            "الفاتورة رقم {$invoiceNumber} تم اعتمادها وهي جاهزة للإرسال لجوفوترا.",
            ['invoice_id' => $invoiceId]
        );
    }

    /**
     * Notify when JoFotara submission succeeds
     */
    public static function jofotaraSuccess(string $tenantId, string $userId, string $invoiceId, string $uuid): void
    {
        self::send($tenantId, $userId, 'jofotara_success',
            '🎉 تم إرسال الفاتورة لجوفوترا',
            "الفاتورة أُرسلت بنجاح. UUID: {$uuid}",
            ['invoice_id' => $invoiceId, 'jofotara_uuid' => $uuid]
        );
    }

    /**
     * Notify when JoFotara submission fails
     */
    public static function jofotaraRejected(string $tenantId, string $userId, string $invoiceId, string $error): void
    {
        self::send($tenantId, $userId, 'jofotara_rejected',
            '❌ رُفضت الفاتورة من جوفوترا',
            "الفاتورة لم تُقبل: {$error}",
            ['invoice_id' => $invoiceId]
        );
    }

    /**
     * Notify admin about pending invoices (daily digest)
     */
    public static function pendingInvoicesDigest(string $tenantId): void
    {
        try {
            $db = Database::getInstance();
            $stmt = $db->prepare("SELECT COUNT(*) FROM invoices WHERE tenant_id = ? AND status = 'extracted'");
            $stmt->execute([$tenantId]);
            $count = (int)$stmt->fetchColumn();

            if ($count === 0) return;

            $adminStmt = $db->prepare("SELECT id FROM users WHERE tenant_id = ? AND role = 'admin' LIMIT 1");
            $adminStmt->execute([$tenantId]);
            $adminId = $adminStmt->fetchColumn();

            if ($adminId) {
                self::send($tenantId, $adminId, 'pending_digest',
                    "📋 لديك {$count} فاتورة بانتظار المراجعة",
                    "هناك {$count} فاتورة مستخرجة لم تُراجع بعد. راجعها واعتمدها لإرسالها لجوفوترا.",
                    ['pending_count' => $count]
                );
            }
        } catch (\Throwable $e) {
            error_log("[SmartNotifications] Pending digest failed: " . $e->getMessage());
        }
    }

    /**
     * Welcome notification for new users
     */
    public static function welcomeUser(string $tenantId, string $userId, string $name): void
    {
        self::send($tenantId, $userId, 'welcome',
            "مرحباً بك في مُصادَق، {$name}! 🎉",
            'ابدأ برفع أول فاتورة — صوّرها أو ارفع PDF والذكاء الاصطناعي يكمل الباقي.',
            []
        );
    }

    /**
     * Core send method — writes to DB (push handled by NotificationService)
     */
    private static function send(string $tenantId, string $userId, string $type, string $title, string $body, array $data): void
    {
        try {
            $db = Database::getInstance();

            // Deduplicate: don't send same type within 1 hour
            $dedup = $db->prepare("
                SELECT id FROM notifications 
                WHERE user_id = ? AND type = ? AND created_at > DATE_SUB(NOW(), INTERVAL 1 HOUR)
                LIMIT 1
            ");
            $dedup->execute([$userId, $type]);
            if ($dedup->fetch()) return;

            $db->prepare("
                INSERT INTO notifications (id, tenant_id, user_id, type, title, body, data, created_at)
                VALUES (UUID(), ?, ?, ?, ?, ?, ?, NOW())
            ")->execute([$tenantId, $userId, $type, $title, $body, json_encode($data, JSON_UNESCAPED_UNICODE)]);

            // Try push notification (non-blocking)
            try {
                $notifService = new NotificationService();
                $notifService->sendNotification($userId, $title, $body, $data);
            } catch (\Throwable $e) {
                // Push failure is non-critical
            }
        } catch (\Throwable $e) {
            error_log("[SmartNotifications] Send failed: " . $e->getMessage());
        }
    }
}