import { BadRequestException, Injectable, NotFoundException } from '@nestjs/common';
import { Prisma } from '@prisma/client';
import { PrismaService } from '../prisma/prisma.service';
import { shanghaiDateRange } from '../common/shanghai-date-range';

export interface SubmitCertificationDto {
  tenantId: string;
  companyName: string;
  licenseNo?: string;
  contactName?: string;
  contactPhone?: string;
  materials?: Record<string, unknown>;
}

export interface ReviewCertificationDto {
  reviewerId?: string;
  reason?: string;
}

@Injectable()
export class CertificationService {
  constructor(private readonly prisma: PrismaService) {}

  async list(tenantId?: string, status?: string, keyword?: string, submittedAtFrom?: string, submittedAtTo?: string) {
    const records = await this.prisma.enterpriseCertification.findMany({
      where: {
        tenantId,
        status: status && status !== 'all' ? status : undefined,
        submittedAt: shanghaiDateRange(submittedAtFrom, submittedAtTo),
        OR: keyword ? [
          { companyName: { contains: keyword } },
          { licenseNo: { contains: keyword } },
          { contactName: { contains: keyword } },
          { contactPhone: { contains: keyword } },
          { tenant: { name: { contains: keyword } } },
        ] : undefined,
      },
      include: { tenant: true },
      orderBy: { createdAt: 'desc' },
    });
    return this.attachReviewers(records);
  }

  async get(id: string) {
    const certification = await this.prisma.enterpriseCertification.findUnique({
      where: { id },
      include: { tenant: true },
    });
    if (!certification) {
      throw new NotFoundException('Enterprise certification not found');
    }
    return (await this.attachReviewers([certification]))[0];
  }

  async submit(data: SubmitCertificationDto) {
    const tenant = await this.prisma.tenant.findUnique({ where: { id: data.tenantId } });
    if (!tenant) {
      throw new NotFoundException('Tenant not found');
    }
    const certification = await this.prisma.enterpriseCertification.create({
      data: {
        tenantId: data.tenantId,
        companyName: data.companyName,
        licenseNo: data.licenseNo,
        contactName: data.contactName,
        contactPhone: data.contactPhone,
        materials: data.materials as Prisma.InputJsonValue | undefined,
        status: 'pending',
      },
    });
    await this.prisma.tenant.update({
      where: { id: data.tenantId },
      data: { certificationStatus: 'pending' },
    });
    await this.prisma.operationLog.create({
      data: {
        tenantId: data.tenantId,
        action: 'enterprise_certification.submit',
        resource: 'enterprise_certification',
        resourceId: certification.id,
        detail: { companyName: data.companyName } as Prisma.InputJsonValue,
      },
    });
    return certification;
  }

  approve(id: string, data: ReviewCertificationDto) {
    return this.review(id, 'approved', data);
  }

  reject(id: string, data: ReviewCertificationDto) {
    if (!data.reason) {
      throw new BadRequestException('Reject reason is required');
    }
    return this.review(id, 'rejected', data);
  }

  private async review(id: string, status: 'approved' | 'rejected', data: ReviewCertificationDto) {
    const certification = await this.prisma.enterpriseCertification.findUnique({ where: { id } });
    if (!certification) {
      throw new NotFoundException('Enterprise certification not found');
    }
    let reviewer: { id: string; username: string; displayName: string } | null = null;
    if (data.reviewerId) {
      reviewer = await this.prisma.user.findUnique({
        where: { id: data.reviewerId },
        select: { id: true, username: true, displayName: true },
      });
      if (!reviewer) {
        throw new BadRequestException('reviewerId does not reference an existing user');
      }
    }
    const updated = await this.prisma.enterpriseCertification.update({
      where: { id },
      data: {
        status,
        rejectReason: status === 'rejected' ? data.reason : null,
        reviewerId: data.reviewerId,
        reviewedAt: new Date(),
      },
    });
    await this.prisma.tenant.update({
      where: { id: certification.tenantId },
      data: { certificationStatus: status },
    });
    await this.prisma.operationLog.create({
      data: {
        tenantId: certification.tenantId,
        userId: data.reviewerId,
        action: `enterprise_certification.${status}`,
        resource: 'enterprise_certification',
        resourceId: id,
        detail: { reason: data.reason } as Prisma.InputJsonValue,
      },
    });
    return { ...updated, reviewer };
  }

  private async attachReviewers<T extends { reviewerId: string | null }>(records: T[]) {
    const reviewerIds = [...new Set(records.map((record) => record.reviewerId).filter((id): id is string => Boolean(id)))];
    const reviewers = reviewerIds.length ? await this.prisma.user.findMany({
      where: { id: { in: reviewerIds } },
      select: { id: true, username: true, displayName: true },
    }) : [];
    const reviewerById = new Map(reviewers.map((reviewer) => [reviewer.id, reviewer]));
    return records.map((record) => ({
      ...record,
      reviewer: record.reviewerId ? reviewerById.get(record.reviewerId) ?? null : null,
    }));
  }
}