import Redis, { RedisOptions } from "ioredis";
import logger from "@server/logger";
import config from "@server/lib/config";

class RedisManager {
    private static instance: RedisManager;
    private client: Redis | null = null;
    private subscriber: Redis | null = null;
    private publisher: Redis | null = null;
    private isEnabled: boolean = false;
    private subscribers: Map<
        string,
        Set<(channel: string, message: string) => void>
    > = new Map();

    private constructor() {
        this.isEnabled = config.getRawConfig().flags?.enable_redis || false;
        if (this.isEnabled) {
            this.initializeClients();
        }
    }

    public static getInstance(): RedisManager {
        if (!RedisManager.instance) {
            RedisManager.instance = new RedisManager();
        }
        return RedisManager.instance;
    }

    private getRedisConfig(): RedisOptions {
        const redisConfig = config.getRawConfig().redis!;
        const opts: RedisOptions =  {
            host: redisConfig.host!,
            port: redisConfig.port!,
            password: redisConfig.password,
            db: redisConfig.db,
            tls: {
                rejectUnauthorized: false
            },
        };
        return opts;
    }

    private initializeClients(): void {
        const config = this.getRedisConfig();

        try {
            // Main client for general operations
            this.client = new Redis(config);

            // Dedicated publisher client
            this.publisher = new Redis(config);

            // Dedicated subscriber client
            this.subscriber = new Redis(config);

            // Set up error handlers
            this.client.on("error", (err) => {
                logger.error("Redis client error:", err);
            });

            this.publisher.on("error", (err) => {
                logger.error("Redis publisher error:", err);
            });

            this.subscriber.on("error", (err) => {
                logger.error("Redis subscriber error:", err);
            });

            // Set up connection handlers
            this.client.on("connect", () => {
                logger.info("Redis client connected");
            });

            this.publisher.on("connect", () => {
                logger.info("Redis publisher connected");
            });

            this.subscriber.on("connect", () => {
                logger.info("Redis subscriber connected");
            });

            // Set up message handler for subscriber
            this.subscriber.on(
                "message",
                (channel: string, message: string) => {
                    const channelSubscribers = this.subscribers.get(channel);
                    if (channelSubscribers) {
                        channelSubscribers.forEach((callback) => {
                            try {
                                callback(channel, message);
                            } catch (error) {
                                logger.error(
                                    `Error in subscriber callback for channel ${channel}:`,
                                    error
                                );
                            }
                        });
                    }
                }
            );

            logger.info("Redis clients initialized successfully");
        } catch (error) {
            logger.error("Failed to initialize Redis clients:", error);
            this.isEnabled = false;
        }
    }

    public isRedisEnabled(): boolean {
        return this.isEnabled && this.client !== null;
    }

    public getClient(): Redis | null {
        return this.client;
    }

    public async set(
        key: string,
        value: string,
        ttl?: number
    ): Promise<boolean> {
        if (!this.isRedisEnabled() || !this.client) return false;

        try {
            if (ttl) {
                await this.client.setex(key, ttl, value);
            } else {
                await this.client.set(key, value);
            }
            return true;
        } catch (error) {
            logger.error("Redis SET error:", error);
            return false;
        }
    }

    public async get(key: string): Promise<string | null> {
        if (!this.isRedisEnabled() || !this.client) return null;

        try {
            return await this.client.get(key);
        } catch (error) {
            logger.error("Redis GET error:", error);
            return null;
        }
    }

    public async del(key: string): Promise<boolean> {
        if (!this.isRedisEnabled() || !this.client) return false;

        try {
            await this.client.del(key);
            return true;
        } catch (error) {
            logger.error("Redis DEL error:", error);
            return false;
        }
    }

    public async sadd(key: string, member: string): Promise<boolean> {
        if (!this.isRedisEnabled() || !this.client) return false;

        try {
            await this.client.sadd(key, member);
            return true;
        } catch (error) {
            logger.error("Redis SADD error:", error);
            return false;
        }
    }

    public async srem(key: string, member: string): Promise<boolean> {
        if (!this.isRedisEnabled() || !this.client) return false;

        try {
            await this.client.srem(key, member);
            return true;
        } catch (error) {
            logger.error("Redis SREM error:", error);
            return false;
        }
    }

    public async smembers(key: string): Promise<string[]> {
        if (!this.isRedisEnabled() || !this.client) return [];

        try {
            return await this.client.smembers(key);
        } catch (error) {
            logger.error("Redis SMEMBERS error:", error);
            return [];
        }
    }

    public async hset(
        key: string,
        field: string,
        value: string
    ): Promise<boolean> {
        if (!this.isRedisEnabled() || !this.client) return false;

        try {
            await this.client.hset(key, field, value);
            return true;
        } catch (error) {
            logger.error("Redis HSET error:", error);
            return false;
        }
    }

    public async hget(key: string, field: string): Promise<string | null> {
        if (!this.isRedisEnabled() || !this.client) return null;

        try {
            return await this.client.hget(key, field);
        } catch (error) {
            logger.error("Redis HGET error:", error);
            return null;
        }
    }

    public async hdel(key: string, field: string): Promise<boolean> {
        if (!this.isRedisEnabled() || !this.client) return false;

        try {
            await this.client.hdel(key, field);
            return true;
        } catch (error) {
            logger.error("Redis HDEL error:", error);
            return false;
        }
    }

    public async hgetall(key: string): Promise<Record<string, string>> {
        if (!this.isRedisEnabled() || !this.client) return {};

        try {
            return await this.client.hgetall(key);
        } catch (error) {
            logger.error("Redis HGETALL error:", error);
            return {};
        }
    }

    public async publish(channel: string, message: string): Promise<boolean> {
        if (!this.isRedisEnabled() || !this.publisher) return false;

        try {
            await this.publisher.publish(channel, message);
            return true;
        } catch (error) {
            logger.error("Redis PUBLISH error:", error);
            return false;
        }
    }

    public async subscribe(
        channel: string,
        callback: (channel: string, message: string) => void
    ): Promise<boolean> {
        if (!this.isRedisEnabled() || !this.subscriber) return false;

        try {
            // Add callback to subscribers map
            if (!this.subscribers.has(channel)) {
                this.subscribers.set(channel, new Set());
                // Only subscribe to the channel if it's the first subscriber
                await this.subscriber.subscribe(channel);
            }

            this.subscribers.get(channel)!.add(callback);
            return true;
        } catch (error) {
            logger.error("Redis SUBSCRIBE error:", error);
            return false;
        }
    }

    public async unsubscribe(
        channel: string,
        callback?: (channel: string, message: string) => void
    ): Promise<boolean> {
        if (!this.isRedisEnabled() || !this.subscriber) return false;

        try {
            const channelSubscribers = this.subscribers.get(channel);
            if (!channelSubscribers) return true;

            if (callback) {
                // Remove specific callback
                channelSubscribers.delete(callback);
                if (channelSubscribers.size === 0) {
                    this.subscribers.delete(channel);
                    await this.subscriber.unsubscribe(channel);
                }
            } else {
                // Remove all callbacks for this channel
                this.subscribers.delete(channel);
                await this.subscriber.unsubscribe(channel);
            }

            return true;
        } catch (error) {
            logger.error("Redis UNSUBSCRIBE error:", error);
            return false;
        }
    }

    public async disconnect(): Promise<void> {
        try {
            if (this.client) {
                await this.client.quit();
                this.client = null;
            }
            if (this.publisher) {
                await this.publisher.quit();
                this.publisher = null;
            }
            if (this.subscriber) {
                await this.subscriber.quit();
                this.subscriber = null;
            }
            this.subscribers.clear();
            logger.info("Redis clients disconnected");
        } catch (error) {
            logger.error("Error disconnecting Redis clients:", error);
        }
    }
}

export const redisManager = RedisManager.getInstance();
export default redisManager;