import { Injectable, Logger, OnModuleInit } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';
import Redis from 'ioredis';

const SESSION_TTL = 3600; // 1 hour

@Injectable()
export class SessionService implements OnModuleInit {
    private readonly logger = new Logger(SessionService.name);
    private redis: Redis;

    constructor(private config: ConfigService) {}

    onModuleInit() {
        const url = this.config.get<string>('redis.url', 'redis://localhost:6379');
        this.redis = new Redis(url);
        this.redis.on('connect', () => this.logger.log('Redis connected'));
        this.redis.on('error', (err) => this.logger.error(`Redis error: ${err.message}`));
    }

    private key(agentId: string): string {
        return `agent:session:${agentId}`;
    }

    async lockSession(agentId: string, memberId: string): Promise<void> {
        await this.redis.set(this.key(agentId), memberId, 'EX', SESSION_TTL);
    }

    async isSessionLocked(agentId: string): Promise<string | null> {
        return this.redis.get(this.key(agentId));
    }

    async refreshSession(agentId: string): Promise<void> {
        await this.redis.expire(this.key(agentId), SESSION_TTL);
    }

    async unlockSession(agentId: string): Promise<void> {
        await this.redis.del(this.key(agentId));
    }
}