const webpush = require('web-push');

// VAPID Keys (sollten in Umgebungsvariablen gespeichert werden)
const vapidKeys = {
    publicKey: 'BJmNVx0C3XeVxeKGTP9c-Z4HcuZNmdk6QdiLocZgCmb-miCS0ESFO3W2TvJlRhhNAShV63pWA5p36BTVSetyTds',
    privateKey: 'HBdRCtmZUAzsWpVjZ2LDaoWliIPHldAb5ExAt8bvDeg'
};

// Configure web-push
webpush.setVapidDetails(
    'mailto:admin@reptilfpv.de',
    vapidKeys.publicKey,
    vapidKeys.privateKey
);

class PushService {
    constructor() {
        this.subscriptions = new Map(); // Map<playerId, Set<subscription>>
    }

    // Subscribe user to push notifications
    subscribe(userId, subscription) {
        if (!this.subscriptions.has(userId)) {
            this.subscriptions.set(userId, new Set());
        }
        this.subscriptions.get(userId).add(subscription);
        console.log(`User ${userId} subscribed to push notifications (${this.subscriptions.get(userId).size} total subscriptions)`);
    }

    // Unsubscribe user from push notifications
    unsubscribe(userId) {
        this.subscriptions.delete(userId);
        console.log(`User ${userId} unsubscribed from push notifications`);
    }

    // Unsubscribe specific device from push notifications
    unsubscribeDevice(userId, endpoint) {
        const subscriptions = this.subscriptions.get(userId);
        if (!subscriptions) {
            console.log(`No subscriptions found for user ${userId}`);
            return false;
        }

        // Find and remove the specific subscription by endpoint
        let removed = false;
        for (const subscription of subscriptions) {
            if (subscription.endpoint === endpoint) {
                subscriptions.delete(subscription);
                removed = true;
                break;
            }
        }

        // If no subscriptions left, remove the user entirely
        if (subscriptions.size === 0) {
            this.subscriptions.delete(userId);
            console.log(`User ${userId} unsubscribed from push notifications (all devices)`);
        } else {
            console.log(`Device ${endpoint} unsubscribed from push notifications for user ${userId} (${subscriptions.size} devices remaining)`);
        }

        return removed;
    }

    // Send push notification to specific user
    async sendToUser(userId, payload) {
        const subscriptions = this.subscriptions.get(userId);
        if (!subscriptions || subscriptions.size === 0) {
            console.log(`No subscriptions found for user ${userId}`);
            return false;
        }

        let successCount = 0;
        let totalCount = subscriptions.size;

        for (const subscription of subscriptions) {
            try {
                await webpush.sendNotification(subscription, JSON.stringify(payload));
                successCount++;
            } catch (error) {
                console.error(`Error sending push notification to user ${userId}:`, error);
                
                // If subscription is invalid, remove it
                if (error.statusCode === 410) {
                    subscriptions.delete(subscription);
                }
            }
        }

        console.log(`Push notification sent to ${successCount}/${totalCount} subscriptions for user ${userId}`);
        return successCount > 0;
    }

    // Send push notification to all subscribed users
    async sendToAll(payload) {
        const results = [];
        for (const [userId, subscription] of this.subscriptions) {
            const result = await this.sendToUser(userId, payload);
            results.push({ userId, success: result });
        }
        return results;
    }

    // Send achievement notification
    async sendAchievementNotification(userId, achievementName) {
        const payload = {
            title: '🏆 Neues Achievement!',
            body: `Du hast "${achievementName}" erreicht!`,
            icon: '/pictures/icon-192.png',
            badge: '/pictures/icon-192.png',
            data: {
                type: 'achievement',
                achievement: achievementName,
                timestamp: Date.now()
            },
            actions: [
                {
                    action: 'view',
                    title: 'Dashboard öffnen'
                }
            ]
        };

        return await this.sendToUser(userId, payload);
    }

    // Send best time notification
    async sendBestTimeNotification(userId, timeType, locationName) {
        const payload = {
            title: `🏁 ${timeType} Bestzeit!`,
            body: `Du hast die beste Zeit in ${locationName} erreicht!`,
            icon: '/pictures/icon-192.png',
            badge: '/pictures/icon-192.png',
            data: {
                type: 'best_time',
                timeType: timeType,
                location: locationName,
                timestamp: Date.now()
            },
            actions: [
                {
                    action: 'view',
                    title: 'Dashboard öffnen'
                }
            ]
        };

        return await this.sendToUser(userId, payload);
    }

    // Get subscription count
    getSubscriptionCount() {
        return this.subscriptions.size;
    }

    // Get all user IDs with subscriptions
    getSubscribedUsers() {
        return Array.from(this.subscriptions.keys());
    }
}

module.exports = new PushService();