// services/redis-service.mjs
import Redis from 'ioredis';
import dotenv from 'dotenv';
import { logger } from '../utils/logger.mjs';

dotenv.config();

const redisUrl = process.env.REDIS_URL;
let redisClient;

export const ACTIVITY_KEY_PREFIX = 'activity:'; // Exported for use in cache-manager
const STAFF_KEY = 'staffs:all';

try {
    if (redisUrl) {
        redisClient = new Redis(redisUrl);

        redisClient.on('connect', () => {
            logger.info('Connected to Redis successfully!');
        });

        redisClient.on('error', (err) => {
            logger.error('Redis connection error:', err);
        });
    } else {
        logger.error('REDIS_URL not defined. Redis client not initialized.');
    }
} catch (error) {
    logger.error('Failed to initialize Redis client:', error);
}


/**
 * Gets activity data from Redis.
 * @param {string} activityId
 * @returns {Promise<object|null>} Parsed JSON object or null if not found/error.
 */
export async function getActivityData(activityId) {
    if (!redisClient) {
        logger.warn('Redis client not available, skipping getActivityData');
        return null;
    }
    try {
        const data = await redisClient.get(`${ACTIVITY_KEY_PREFIX}${activityId}`);
        return data ? JSON.parse(data) : null;
    } catch (err) {
        logger.error(`Error getting activity ${activityId} from Redis:`, err);
        return null;
    }
}

/**
 * Sets activity data in Redis.
 * @param {string} activityId
 * @param {object} data The activity data object.
 * @returns {Promise<void>}
 */
export async function setActivityData(activityId, data) {
    if (!redisClient) {
        logger.warn('Redis client not available, skipping setActivityData');
        return;
    }
    try {
        await redisClient.set(`${ACTIVITY_KEY_PREFIX}${activityId}`, JSON.stringify(data));
    } catch (err) {
        logger.error(`Error setting activity ${activityId} in Redis:`, err);
    }
}

/**
 * Gets staff data from Redis.
 * @returns {Promise<object|null>} Parsed JSON object or null if not found/error.
 */
export async function getStaffData() {
    if (!redisClient) {
        logger.warn('Redis client not available, skipping getStaffData');
        return null;
    }
    try {
        const data = await redisClient.get(STAFF_KEY);
        return data ? JSON.parse(data) : null;
    } catch (err) {
        logger.error('Error getting staff data from Redis:', err);
        return null;
    }
}

/**
 * Sets staff data in Redis.
 * @param {object} data The staff data object.
 * @returns {Promise<void>}
 */
export async function setStaffData(data) {
    if (!redisClient) {
        logger.warn('Redis client not available, skipping setStaffData');
        return;
    }
    try {
        await redisClient.set(STAFF_KEY, JSON.stringify(data));
    } catch (err) {
        logger.error('Error setting staff data in Redis:', err);
    }
}

/**
 * Gets all activity keys from Redis.
 * This can be resource-intensive on large datasets. Use with caution.
 * @returns {Promise<string[]>} An array of keys.
 */
export async function getAllActivityKeys() {
    if (!redisClient) {
        logger.warn('Redis client not available, skipping getAllActivityKeys');
        return [];
    }
    try {
        // Using SCAN for better performance than KEYS on production Redis
        let cursor = '0';
        const keys = [];
        do {
            const [nextCursor, foundKeys] = await redisClient.scan(cursor, 'MATCH', `${ACTIVITY_KEY_PREFIX}*`, 'COUNT', '100');
            keys.push(...foundKeys);
            cursor = nextCursor;
        } while (cursor !== '0');
        logger.info(`Found ${keys.length} activity keys in Redis using SCAN.`);
        return keys;
    } catch (err) {
        logger.error('Error getting all activity keys from Redis using SCAN:', err);
        return []; // Fallback or indicate error
    }
}


export function getRedisClient() {
    return redisClient;
}