import { Injectable, Logger } from '@nestjs/common';
import { CDCEvent, TransactionClient } from '../../infrastructure/kafka/cdc-consumer.service';
import { ContributionAccountAggregate } from '../../domain/aggregates/contribution-account.aggregate';

/**
 * 用户 CDC 事件处理器
 * 处理从身份服务同步过来的用户数据
 *
 * 设计说明：100%同步数据，不跳过任何字段更新
 */
@Injectable()
export class UserSyncedHandler {
  private readonly logger = new Logger(UserSyncedHandler.name);

  constructor() {}

  async handle(event: CDCEvent, tx: TransactionClient): Promise<void> {
    const { op, before, after } = event.payload;

    this.logger.log(`[CDC] User event received: op=${op}, seq=${event.sequenceNum}`);
    this.logger.debug(`[CDC] User event payload: ${JSON.stringify(after || before)}`);

    try {
      switch (op) {
        case 'c': // create
        case 'r': // read (snapshot)
          await this.handleCreate(after, event.sequenceNum, tx);
          break;
        case 'u': // update
          await this.handleUpdate(after, event.sequenceNum, tx);
          break;
        case 'd': // delete
          await this.handleDelete(before);
          break;
        default:
          this.logger.warn(`[CDC] Unknown CDC operation: ${op}`);
      }
    } catch (error) {
      this.logger.error(`[CDC] Failed to handle user CDC event, op=${op}, seq=${event.sequenceNum}`, error);
      throw error;
    }
  }

  private async handleCreate(data: any, sequenceNum: bigint, tx: TransactionClient): Promise<void> {
    if (!data) {
      this.logger.warn(`[CDC] User create: empty data received`);
      return;
    }

    const userId = data.user_id ?? data.id;
    const accountSequence = data.account_sequence ?? data.accountSequence;
    const phone = data.phone_number ?? data.phone ?? null;
    const status = data.status ?? null;

    this.logger.log(`[CDC] User create: userId=${userId}, accountSequence=${accountSequence}, status=${status}`);

    if (!userId || !accountSequence) {
      this.logger.warn(`[CDC] Invalid user data: missing user_id or account_sequence`, { data });
      return;
    }

    // 100%同步数据
    await tx.syncedUser.upsert({
      where: { accountSequence },
      create: {
        originalUserId: BigInt(userId),
        accountSequence,
        phone,
        status,
        sourceSequenceNum: sequenceNum,
        syncedAt: new Date(),
      },
      update: {
        originalUserId: BigInt(userId),
        phone,
        status,
        sourceSequenceNum: sequenceNum,
        syncedAt: new Date(),
      },
    });

    // 为用户创建算力账户（如果不存在）
    const existingAccount = await tx.contributionAccount.findUnique({
      where: { accountSequence },
    });

    if (!existingAccount) {
      const newAccount = ContributionAccountAggregate.create(accountSequence);
      const persistData = newAccount.toPersistence();
      await tx.contributionAccount.create({
        data: persistData,
      });
      this.logger.log(`[CDC] Created contribution account for user: ${accountSequence}`);
    }

    this.logger.log(`[CDC] User synced: ${accountSequence}`);
  }

  private async handleUpdate(data: any, sequenceNum: bigint, tx: TransactionClient): Promise<void> {
    if (!data) {
      this.logger.warn(`[CDC] User update: empty data received`);
      return;
    }

    const userId = data.user_id ?? data.id;
    const accountSequence = data.account_sequence ?? data.accountSequence;
    const phone = data.phone_number ?? data.phone ?? null;
    const status = data.status ?? null;

    this.logger.log(`[CDC] User update: userId=${userId}, accountSequence=${accountSequence}, status=${status}`);

    if (!userId || !accountSequence) {
      this.logger.warn(`[CDC] Invalid user update data: missing user_id or account_sequence`, { data });
      return;
    }

    // 100%同步数据
    await tx.syncedUser.upsert({
      where: { accountSequence },
      create: {
        originalUserId: BigInt(userId),
        accountSequence,
        phone,
        status,
        sourceSequenceNum: sequenceNum,
        syncedAt: new Date(),
      },
      update: {
        originalUserId: BigInt(userId),
        phone,
        status,
        sourceSequenceNum: sequenceNum,
        syncedAt: new Date(),
      },
    });

    this.logger.log(`[CDC] User synced: ${accountSequence}`);
  }

  private async handleDelete(data: any): Promise<void> {
    if (!data) {
      this.logger.warn(`[CDC] User delete: empty data received`);
      return;
    }
    const accountSequence = data.account_sequence ?? data.accountSequence;
    // 用户删除一般不处理，保留历史数据
    this.logger.log(`[CDC] User delete event received: ${accountSequence} (not processed, keeping history)`);
  }
}