import { BadRequestException, Injectable } from '@nestjs/common';
import { PrismaService } from '../prisma/prisma.service';
import { ActiveUserPayload } from '../auth/decorator/current-user.decorator';
import { RekammedisService } from '../rekammedis/rekammedis.service';
import { CreateRekamMedisDto } from '../rekammedis/dto/create-rekammedis.dto';

@Injectable()
export class ValidationService {
  constructor(
    private prisma: PrismaService,
    private rekamMedisService: RekammedisService,
  ) {}

  private handlers: Record<
    string,
    {
      approveCreate?: (queue: any) => Promise<any>;
      approveUpdate?: (queue: any) => Promise<any>;
      approveDelete?: (queue: any) => Promise<any>;
    }
  > = {
    rekam_medis: {
      approveCreate: async (queue: any) => {
        const payload = queue.dataPayload as Partial<CreateRekamMedisDto>;
        const result =
          await this.rekamMedisService.createRekamMedisToDBAndBlockchain(
            payload as CreateRekamMedisDto,
            Number(queue.user_id_request),
          );

        return {
          ...result,
          id: result.id_visit,
        };
      },
      approveUpdate: async (queue: any) => {
        const payload = queue.dataPayload as Partial<CreateRekamMedisDto>;
        return this.rekamMedisService.updateRekamMedisToDBAndBlockchain(
          queue.record_id,
          payload as CreateRekamMedisDto,
          Number(queue.user_id_request),
        );
      },
      approveDelete: async (queue: any) => {
        return this.rekamMedisService.deleteRekamMedisFromDB(queue.record_id, {
          sub: queue.user_id_request.toString(),
        } as ActiveUserPayload);
      },
    },
    pemberian_tindakan: {
      approveCreate: async (queue: any) => {
        const payload = queue.dataPayload;
        console.log('Approving create for pemberian_tindakan:', payload);
        // return this.prisma.pemberian_tindakan.create({
        //   data: {
        //     ...payload,
        //   },
        // });
      },
    },
    pemberian_obat: {},
  };

  async getAllValidationsQueue() {
    const result = await this.prisma.validation_queue.findMany({
      where: { status: 'PENDING' },
    });
    const totalCount = await this.prisma.validation_queue.count({
      where: { status: 'PENDING' },
    });
    return { data: result, totalCount };
  }

  async getAllValidationQueueDashboard() {
    const result = await this.prisma.validation_queue.findMany({
      where: { status: 'PENDING' },
      take: 5,
      orderBy: { created_at: 'desc' },
    });
    const totalCount = await this.prisma.validation_queue.count({
      where: { status: 'PENDING' },
    });
    return { data: result, totalCount };
  }

  // For service internal use
  async getValidationQueueById(id: number) {
    return await this.prisma.validation_queue.findUnique({
      where: { id },
    });
  }

  // For front-end detail view
  async getValidationQueue(id: number) {
    const result = await this.getValidationQueueById(id);
    if (!result) return null;
    if (result.action !== 'UPDATE') return result;
    const previousLog = await this.fetchPreviousLog(
      result.table_name,
      result.record_id,
    );
    return { previousLog, ...result };
  }

  private async fetchPreviousLog(tableName: string, recordId: string) {
    if (!recordId) return null;
    switch (tableName) {
      case 'pemberian_tindakan':
        return this.prisma.pemberian_tindakan.findUnique({
          where: { id: Number(recordId) },
        });
      case 'rekam_medis':
        return this.prisma.rekam_medis.findUnique({
          where: { id_visit: recordId },
        });
      case 'pemberian_obat':
        return this.prisma.pemberian_obat.findUnique({
          where: { id: Number(recordId) },
        });
      default:
        return null;
    }
  }

  private async approveWithHandler(queue: any) {
    const handler = this.handlers[queue.table_name];
    if (!handler) throw new Error('Unsupported table');
    switch (queue.action) {
      case 'CREATE':
        if (!handler.approveCreate)
          throw new Error('Create not implemented for table');
        return handler.approveCreate(queue);
      case 'UPDATE':
        if (!handler.approveUpdate)
          throw new Error('Update not implemented for table');
        return handler.approveUpdate(queue);
      case 'DELETE':
        if (!handler.approveDelete)
          throw new Error('Delete not implemented for table');
        return handler.approveDelete(queue);
      default:
        throw new Error('Unknown action');
    }
  }

  async approveValidation(id: number, user: ActiveUserPayload) {
    const validationQueue = await this.getValidationQueueById(id);
    if (!validationQueue) {
      throw new BadRequestException('Validation queue not found');
    }
    if (!validationQueue.dataPayload) {
      throw new Error('Data payload is missing');
    }
    try {
      const approvalResult = await this.approveWithHandler(validationQueue);
      console.log('Approval result:', approvalResult);
      const updated = await this.prisma.validation_queue.update({
        where: { id: validationQueue.id },
        data: {
          record_id: approvalResult.id,
          status: 'APPROVED',
          user_id_process: Number(user.sub),
          processed_at: new Date(),
        },
      });
      return { ...updated, approvalResult };
    } catch (error) {
      console.error('Error approving validation:', (error as Error).message);
      throw error;
    }
  }

  async rejectValidation(id: number, user: ActiveUserPayload) {
    const validationQueue = await this.getValidationQueueById(id);
    if (!validationQueue) {
      throw new Error('Validation queue not found');
    }
    const updated = await this.prisma.validation_queue.update({
      where: { id: validationQueue.id },
      data: {
        status: 'REJECTED',
        user_id_process: Number(user.sub),
        processed_at: new Date(),
      },
    });
    return updated;
  }
}