import schedule from "node-cron";
import pool from "../db/pool.js";
import { getIO, getSocketId } from "../socket.js";

// Run every hour
export const startExpirationJob = () => {
    schedule.schedule("0 * * * *", async () => {
        console.log("Running listing expiration check...");
        const client = await pool.connect();
        try {
            await client.query("BEGIN");

            // 1. Identify expired listings (active & not updated in last 48h)
            // Using INTERVAL '48 hours'
            const findExpiredQuery = `
                SELECT id, title, seller_id 
                FROM listings 
                WHERE status = 'active' 
                AND updated_at < NOW() - INTERVAL '48 hours'
                AND deleted = FALSE
                FOR UPDATE SKIP LOCKED
            `;
            const { rows: expiredListings } = await client.query(findExpiredQuery);

            if (expiredListings.length === 0) {
                await client.query("COMMIT");
                return;
            }

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

            // 2. Update status to 'expired'
            const expiredIds = expiredListings.map(l => l.id);
            await client.query(`
                UPDATE listings 
                SET status = 'expired' 
                WHERE id = ANY($1::uuid[])
            `, [expiredIds]);

            // 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 client.query(`
                    INSERT INTO notifications (user_id, type, message, data)
                    VALUES ($1, 'listing_expired', $2, $3)
                `, [listing.seller_id, message, { 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 }
                    });
                }
            }

            await client.query("COMMIT");
            console.log("Expiration check completed successfully.");

        } catch (err) {
            await client.query("ROLLBACK");
            console.error("Error in expiration job:", err);
        } finally {
            client.release();
        }
    });
};