import { Injectable, Logger } from '@nestjs/common';
import Decimal from 'decimal.js';
import { CDCEvent, TransactionClient } from '../../infrastructure/kafka/cdc-consumer.service';
import { ContributionCalculationService } from '../services/contribution-calculation.service';
import { ContributionRateService } from '../services/contribution-rate.service';

/**
 * 认种同步结果，用于事务提交后的算力计算
 */
export interface AdoptionSyncResult {
  originalAdoptionId: bigint;
  needsCalculation: boolean;
}

/**
 * 认种订单 CDC 事件处理器
 * 处理从1.0 planting-service同步过来的planting_orders数据
 *
 * 设计说明：
 * ===========================================
 * - handle() 方法100%同步数据，不跳过任何更新
 * - 算力计算只在 status 变为 MINING_ENABLED 时触发
 * - 算力计算在事务提交后执行（避免 Serializable 隔离级别的可见性问题）
 */
@Injectable()
export class AdoptionSyncedHandler {
  private readonly logger = new Logger(AdoptionSyncedHandler.name);

  constructor(
    private readonly contributionCalculationService: ContributionCalculationService,
    private readonly contributionRateService: ContributionRateService,
  ) {}

  /**
   * 处理认种 CDC 事件（在事务内执行）
   * 只负责数据同步，不调用算力计算
   * @returns AdoptionSyncResult 包含需要计算算力的认种ID
   */
  async handle(event: CDCEvent, tx: TransactionClient): Promise<AdoptionSyncResult | null> {
    const { op, before, after } = event.payload;

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

    // 获取认种日期，用于查询当日贡献值
    const data = after || before;
    const adoptionDate = data?.created_at || data?.createdAt || data?.paid_at || data?.paidAt;

    // 在事务外获取当日每棵树的贡献值
    let contributionPerTree = new Decimal('22617'); // 默认值
    if (adoptionDate) {
      try {
        contributionPerTree = await this.contributionRateService.getContributionPerTree(new Date(adoptionDate));
        this.logger.log(`[CDC] Got contributionPerTree for ${adoptionDate}: ${contributionPerTree.toString()}`);
      } catch (error) {
        this.logger.warn(`[CDC] Failed to get contributionPerTree, using default 22617`, error);
      }
    }

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

  /**
   * 在事务提交后计算算力（由 CDC dispatcher 在事务外调用）
   */
  async calculateContributionAfterCommit(result: AdoptionSyncResult): Promise<void> {
    if (!result || !result.needsCalculation) {
      return;
    }

    this.logger.log(`[CDC] Triggering contribution calculation for adoption: ${result.originalAdoptionId}`);
    try {
      await this.contributionCalculationService.calculateForAdoption(result.originalAdoptionId);
      this.logger.log(`[CDC] Contribution calculation completed for adoption: ${result.originalAdoptionId}`);
    } catch (error) {
      // 算力计算失败不影响数据同步，后续可通过批量任务重试
      this.logger.error(`[CDC] Failed to calculate contribution for adoption ${result.originalAdoptionId}`, error);
    }
  }

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

    const orderId = data.order_id || data.id;
    const accountSequence = data.account_sequence || data.accountSequence;
    const treeCount = data.tree_count || data.treeCount;
    const createdAt = data.created_at || data.createdAt || data.paid_at || data.paidAt;
    const selectedProvince = data.selected_province || data.selectedProvince || null;
    const selectedCity = data.selected_city || data.selectedCity || null;
    const status = data.status ?? null;

    this.logger.log(`[CDC] Adoption create: orderId=${orderId}, account=${accountSequence}, trees=${treeCount}, status=${status}, contributionPerTree=${contributionPerTree.toString()}`);

    if (!orderId || !accountSequence) {
      this.logger.warn(`[CDC] Invalid adoption data: missing order_id or account_sequence`, { data });
      return null;
    }

    const originalAdoptionId = BigInt(orderId);

    // 100%同步数据，使用真实的每棵树贡献值
    await tx.syncedAdoption.upsert({
      where: { originalAdoptionId },
      create: {
        originalAdoptionId,
        accountSequence,
        treeCount,
        adoptionDate: new Date(createdAt),
        status,
        selectedProvince,
        selectedCity,
        contributionPerTree,
        sourceSequenceNum: sequenceNum,
        syncedAt: new Date(),
      },
      update: {
        accountSequence,
        treeCount,
        adoptionDate: new Date(createdAt),
        status,
        selectedProvince,
        selectedCity,
        contributionPerTree,
        sourceSequenceNum: sequenceNum,
        syncedAt: new Date(),
      },
    });

    this.logger.log(`[CDC] Adoption synced: orderId=${orderId}, status=${status}`);

    // 只有 MINING_ENABLED 状态才触发算力计算
    const needsCalculation = status === 'MINING_ENABLED';
    return {
      originalAdoptionId,
      needsCalculation,
    };
  }

  private async handleUpdate(after: any, before: any, sequenceNum: bigint, tx: TransactionClient, contributionPerTree: Decimal): Promise<AdoptionSyncResult | null> {
    if (!after) {
      this.logger.warn(`[CDC] Adoption update: empty after data received`);
      return null;
    }

    const orderId = after.order_id || after.id;
    const originalAdoptionId = BigInt(orderId);
    const accountSequence = after.account_sequence || after.accountSequence;
    const treeCount = after.tree_count || after.treeCount;
    const createdAt = after.created_at || after.createdAt || after.paid_at || after.paidAt;
    const selectedProvince = after.selected_province || after.selectedProvince || null;
    const selectedCity = after.selected_city || after.selectedCity || null;
    const newStatus = after.status ?? null;
    const oldStatus = before?.status ?? null;

    this.logger.log(`[CDC] Adoption update: orderId=${orderId}, status=${oldStatus} -> ${newStatus}, contributionPerTree=${contributionPerTree.toString()}`);

    // 查询现有记录
    const existingAdoption = await tx.syncedAdoption.findUnique({
      where: { originalAdoptionId },
    });

    // 100%同步数据，使用真实的每棵树贡献值
    await tx.syncedAdoption.upsert({
      where: { originalAdoptionId },
      create: {
        originalAdoptionId,
        accountSequence,
        treeCount,
        adoptionDate: new Date(createdAt),
        status: newStatus,
        selectedProvince,
        selectedCity,
        contributionPerTree,
        sourceSequenceNum: sequenceNum,
        syncedAt: new Date(),
      },
      update: {
        accountSequence,
        treeCount,
        adoptionDate: new Date(createdAt),
        status: newStatus,
        selectedProvince,
        selectedCity,
        contributionPerTree,
        sourceSequenceNum: sequenceNum,
        syncedAt: new Date(),
      },
    });

    this.logger.log(`[CDC] Adoption synced: orderId=${orderId}, status=${newStatus}`);

    // 只有当 status 变为 MINING_ENABLED 且尚未计算过算力时，才触发算力计算
    const statusChangedToMiningEnabled = newStatus === 'MINING_ENABLED' && oldStatus !== 'MINING_ENABLED';
    const needsCalculation = statusChangedToMiningEnabled && !existingAdoption?.contributionDistributed;

    return {
      originalAdoptionId,
      needsCalculation,
    };
  }

  private async handleDelete(data: any): Promise<void> {
    if (!data) {
      this.logger.warn(`[CDC] Adoption delete: empty data received`);
      return;
    }
    const orderId = data.order_id || data.id;
    // 认种删除需要特殊处理（回滚算力）
    // 但通常不会发生删除操作
    this.logger.warn(`[CDC] Adoption delete event received: ${orderId}. This may require contribution rollback.`);
  }
}