/**
 * Withdrawal Event Consumer Service for Blockchain Service
 *
 * Consumes withdrawal request events from wallet-service via Kafka.
 * Creates transaction requests for MPC signing and blockchain broadcasting.
 */

import { Injectable, Logger, OnModuleInit, OnModuleDestroy } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';
import { Kafka, Consumer, logLevel, EachMessagePayload } from 'kafkajs';

export const WITHDRAWAL_TOPICS = {
  WITHDRAWAL_REQUESTED: 'wallet.withdrawals',
  SYSTEM_WITHDRAWAL_REQUESTED: 'wallet.system-withdrawals',
} as const;

export interface WithdrawalRequestedPayload {
  orderNo: string;
  accountSequence: string;
  userId: string;
  walletId: string;
  amount: string;
  fee: string;
  netAmount: string;
  assetType: string;
  chainType: string;
  toAddress: string;
}

export interface SystemWithdrawalRequestedPayload {
  orderNo: string;
  fromAccountSequence: string;
  fromAccountName: string;
  toAccountSequence: string;
  toAddress: string;
  amount: string;
  chainType: string;
}

export type WithdrawalEventHandler = (payload: WithdrawalRequestedPayload) => Promise<void>;
export type SystemWithdrawalEventHandler = (payload: SystemWithdrawalRequestedPayload) => Promise<void>;

@Injectable()
export class WithdrawalEventConsumerService implements OnModuleInit, OnModuleDestroy {
  private readonly logger = new Logger(WithdrawalEventConsumerService.name);
  private kafka: Kafka;
  private consumer: Consumer;
  private isConnected = false;

  private withdrawalRequestedHandler?: WithdrawalEventHandler;
  private systemWithdrawalRequestedHandler?: SystemWithdrawalEventHandler;

  constructor(private readonly configService: ConfigService) {}

  async onModuleInit() {
    const brokers = this.configService.get<string>('KAFKA_BROKERS')?.split(',') || ['localhost:9092'];
    const clientId = this.configService.get<string>('KAFKA_CLIENT_ID') || 'blockchain-service';
    const groupId = 'blockchain-service-withdrawal-events';

    this.logger.log(`[INIT] Withdrawal Event Consumer initializing...`);
    this.logger.log(`[INIT] ClientId: ${clientId}`);
    this.logger.log(`[INIT] GroupId: ${groupId}`);
    this.logger.log(`[INIT] Brokers: ${brokers.join(', ')}`);
    this.logger.log(`[INIT] Topics: ${Object.values(WITHDRAWAL_TOPICS).join(', ')}`);

    // 企业级重试配置：指数退避，最多重试约 2.5 小时
    this.kafka = new Kafka({
      clientId,
      brokers,
      logLevel: logLevel.WARN,
      retry: {
        initialRetryTime: 1000,        // 1 秒
        maxRetryTime: 300000,          // 最大 5 分钟
        retries: 15,                   // 最多 15 次
        multiplier: 2,                 // 指数退避因子
        restartOnFailure: async () => true,
      },
    });

    this.consumer = this.kafka.consumer({
      groupId,
      sessionTimeout: 30000,
      heartbeatInterval: 3000,
    });

    try {
      this.logger.log(`[CONNECT] Connecting Withdrawal Event consumer...`);
      await this.consumer.connect();
      this.isConnected = true;
      this.logger.log(`[CONNECT] Withdrawal Event consumer connected successfully`);

      await this.consumer.subscribe({
        topics: Object.values(WITHDRAWAL_TOPICS),
        fromBeginning: false,
      });
      this.logger.log(`[SUBSCRIBE] Subscribed to withdrawal topics`);

      await this.startConsuming();
    } catch (error) {
      this.logger.error(`[ERROR] Failed to connect Withdrawal Event consumer`, error);
    }
  }

  async onModuleDestroy() {
    if (this.isConnected) {
      await this.consumer.disconnect();
      this.logger.log('Withdrawal Event consumer disconnected');
    }
  }

  /**
   * Register handler for withdrawal requested events
   */
  onWithdrawalRequested(handler: WithdrawalEventHandler): void {
    this.withdrawalRequestedHandler = handler;
    this.logger.log(`[REGISTER] WithdrawalRequested handler registered`);
  }

  /**
   * Register handler for system withdrawal requested events
   */
  onSystemWithdrawalRequested(handler: SystemWithdrawalEventHandler): void {
    this.systemWithdrawalRequestedHandler = handler;
    this.logger.log(`[REGISTER] SystemWithdrawalRequested handler registered`);
  }

  private async startConsuming(): Promise<void> {
    await this.consumer.run({
      eachMessage: async ({ topic, partition, message }: EachMessagePayload) => {
        const offset = message.offset;
        this.logger.log(`[RECEIVE] Message received: topic=${topic}, partition=${partition}, offset=${offset}`);

        try {
          const value = message.value?.toString();
          if (!value) {
            this.logger.warn(`[RECEIVE] Empty message received on ${topic}`);
            return;
          }

          this.logger.log(`[RECEIVE] Raw message: ${value.substring(0, 500)}...`);

          const parsed = JSON.parse(value);
          const eventType = parsed.eventType;
          const payload = parsed.payload || parsed;

          this.logger.log(`[RECEIVE] Event type: ${eventType}`);

          if (eventType === 'wallet.withdrawal.requested') {
            this.logger.log(`[HANDLE] Processing WithdrawalRequested event`);
            this.logger.log(`[HANDLE] orderNo: ${payload.orderNo}`);
            this.logger.log(`[HANDLE] chainType: ${payload.chainType}`);
            this.logger.log(`[HANDLE] toAddress: ${payload.toAddress}`);
            this.logger.log(`[HANDLE] amount: ${payload.amount}`);

            if (this.withdrawalRequestedHandler) {
              await this.withdrawalRequestedHandler(payload as WithdrawalRequestedPayload);
              this.logger.log(`[HANDLE] WithdrawalRequested handler completed`);
            } else {
              this.logger.warn(`[HANDLE] No handler registered for WithdrawalRequested`);
            }
          } else if (eventType === 'wallet.system-withdrawal.requested') {
            this.logger.log(`[HANDLE] Processing SystemWithdrawalRequested event`);
            this.logger.log(`[HANDLE] orderNo: ${payload.orderNo}`);
            this.logger.log(`[HANDLE] fromAccountSequence: ${payload.fromAccountSequence}`);
            this.logger.log(`[HANDLE] toAccountSequence: ${payload.toAccountSequence}`);
            this.logger.log(`[HANDLE] toAddress: ${payload.toAddress}`);
            this.logger.log(`[HANDLE] amount: ${payload.amount}`);

            if (this.systemWithdrawalRequestedHandler) {
              await this.systemWithdrawalRequestedHandler(payload as SystemWithdrawalRequestedPayload);
              this.logger.log(`[HANDLE] SystemWithdrawalRequested handler completed`);
            } else {
              this.logger.warn(`[HANDLE] No handler registered for SystemWithdrawalRequested`);
            }
          } else {
            this.logger.warn(`[RECEIVE] Unknown event type: ${eventType}`);
          }
        } catch (error) {
          this.logger.error(`[ERROR] Error processing withdrawal event from ${topic}`, error);
        }
      },
    });

    this.logger.log(`[START] Started consuming withdrawal events`);
  }
}