const Redis = require('ioredis');

const redis = new Redis({
    host: process.env.REDIS_HOST,
    port: process.env.REDIS_PORT
});

// Client dedicato per subscribe (ioredis richiede client separato)
const redisSub = new Redis({
    host: process.env.REDIS_HOST,
    port: process.env.REDIS_PORT
});

redis.on('error', (error) => {
    console.error('Redis error:', error);
});

redis.on('connect', () => {
    console.log('Server connected to Redis DB');
});

redisSub.on('error', (error) => {
    console.error('Redis sub error:', error);
});

const sensors_hash_map = 'sensors:sessions';

async function setSession(sensorID, metadata) {
    await redis.hset(sensors_hash_map, sensorID, JSON.stringify(metadata));
}

async function getSession(sensorID) {
    return await redis.hget(sensors_hash_map, sensorID);
}

async function deleteSession(sensorID) {
    await redis.hdel(sensors_hash_map, sensorID);
}

async function getSessions() {
    return await redis.hgetall(sensors_hash_map);
}

// --- Pub/Sub per live watchers ---

async function publishSensorData(sensorId, data) {
    await redis.publish(`sensor:data:${sensorId}`, JSON.stringify(data));
}

async function addWatcher(sensorId) {
    return await redis.incr(`sensor:watchers:${sensorId}`);
}

async function removeWatcher(sensorId) {
    const count = await redis.decr(`sensor:watchers:${sensorId}`);
    if (count <= 0) {
        await redis.del(`sensor:watchers:${sensorId}`);
        return 0;
    }
    return count;
}

async function getWatcherCount(sensorId) {
    const count = await redis.get(`sensor:watchers:${sensorId}`);
    return parseInt(count) || 0;
}

async function checkRedis() {
    try {
        await redis.ping();
        return true;
    } catch (error) {
        return false;
    }
}

module.exports = {
    setSession,
    getSession,
    deleteSession,
    getSessions,
    publishSensorData,
    addWatcher,
    removeWatcher,
    getWatcherCount,
    checkRedis,
    redis,
    redisSub
};