import schedule from "node-cron";
import { insert, execute } from "../db/queryHelper/index.js";
import { getIO, getSocketId } from "../socket.js";

// Run every hour
export const startExpirationJob = () => {
    schedule.schedule("0 * * * *", async () => {
        console.log("Running listing expiration check...");
        try {
            const result = await execute({
                type: 'transaction',
                handler: async (trx) => {
                    // 1. Identify expired listings (active & not updated in last 48h)
                    const expiredListings = await trx('listings')
                        .select('id', 'title', 'seller_id')
                        .where({ status: 'active', deleted: false })
                        .whereRaw("updated_at < NOW() - INTERVAL '48 hours'")
                        .forUpdate()
                        .skipLocked();

                    if (expiredListings.length === 0) {
                        return [];
                    }

                    console.log(`Found ${expiredListings.length} listings to expire.`);

                    // 2. Update status to 'expired'
                    const expiredIds = expiredListings.map(l => l.id);
                    await trx('listings')
                        .whereIn('id', expiredIds)
                        .update({ status: 'expired' });

                    // 3. Create Notifications & Real-time Alerts
                    for (const listing of expiredListings) {
                        const message = `Your listing "${listing.title}" has expired after 48 hours of inactivity. Click here to re-list it.`;
                        
                        // Insert Notification
                        await trx('notifications').insert({
                            user_id: listing.seller_id,
                            type: 'listing_expired',
                            message,
                            data: { listing_id: listing.id }
                        });

                        // Real-time Socket Emit
                        const socketId = getSocketId(listing.seller_id);
                        if (socketId) {
                            getIO().to(socketId).emit("notification", {
                                type: "listing_expired",
                                message,
                                data: { listing_id: listing.id }
                            });
                        }
                    }

                    return expiredListings;
                }
            });

            if (result && result.length > 0) {
                console.log("Expiration check completed successfully.");
            }
        } catch (err) {
            console.error("Error in expiration job:", err);
        }
    });
};