import { Injectable, NotFoundException, BadRequestException } from '@nestjs/common';
import { InjectRepository } from '@nestjs/typeorm';
import { Repository, Not } from 'typeorm';
import { Classroom } from '../entities/classroom.entity';
import { ClassroomRental } from '../entities/classroom-rental.entity';
import { CreateClassroomDto, UpdateClassroomDto } from './dto/classroom.dto';

@Injectable()
export class ClassroomsService {
  constructor(
    @InjectRepository(Classroom) private repo: Repository<Classroom>,
    @InjectRepository(ClassroomRental) private rentalRepo: Repository<ClassroomRental>,
  ) {}

  async findAll(query?: { building?: string; roomType?: string; includeArchived?: boolean }) {
    const where: any = {};
    if (query?.building) where.building = query.building;
    if (query?.roomType) where.roomType = query.roomType;
    if (!query?.includeArchived) where.status = Not('archived');
    return this.repo.find({ where, order: { building: 'ASC', name: 'ASC' } });
  }

  async findOne(id: number) {
    const cls = await this.repo.findOne({ where: { id } });
    if (!cls) throw new NotFoundException('教室不存在');
    return cls;
  }

  async create(dto: CreateClassroomDto) {
    const exists = await this.repo.findOne({ where: { name: dto.name } });
    if (exists) throw new BadRequestException(`教室 ${dto.name} 已存在`);
    return this.repo.save(this.repo.create(dto));
  }

  async update(id: number, dto: UpdateClassroomDto) {
    await this.findOne(id);
    await this.repo.update(id, dto);
    return this.repo.findOne({ where: { id } });
  }

  async remove(id: number) {
    await this.findOne(id);
    // 若存在未结束的租赁订单，不允许归档
    const active = await this.rentalRepo.count({ where: { classroomId: id, status: 'active' } });
    if (active > 0) throw new BadRequestException('该教室存在进行中的租赁订单，无法归档');
    await this.repo.update(id, { status: 'archived' });
    return { message: '已归档' };
  }

  async restore(id: number) {
    const cls = await this.findOne(id);
    if (cls.status !== 'archived') throw new BadRequestException('该教室未被归档');
    await this.repo.update(id, { status: 'available' });
    return { message: '已恢复' };
  }

  async batchImport(rows: { name: string; building?: string; floor?: number; capacity?: number; roomType?: string; courseType?: string; supervisor?: string }[]) {
    let imported = 0;
    let skipped = 0;
    for (const row of rows) {
      if (!row.name || !row.name.trim()) { skipped++; continue; }
      const name = row.name.trim();
      const exists = await this.repo.findOne({ where: { name } });
      if (exists) { skipped++; continue; }
      await this.repo.save(this.repo.create({
        name,
        building: row.building?.trim() || undefined,
        floor: row.floor || undefined,
        capacity: row.capacity || 30,
        roomType: row.roomType?.trim() || '大',
        courseType: row.courseType?.trim() || undefined,
        supervisor: row.supervisor?.trim() || undefined,
      }));
      imported++;
    }
    return { message: `成功导入 ${imported} 间教室，跳过 ${skipped} 条（重复或空行）`, imported, skipped };
  }
}