import { Injectable, NotFoundException, ConflictException } from '@nestjs/common';
import { PrismaService } from '../prisma/prisma.service';
import { CreateEmployeeDto } from './dto/create-employee.dto';
import { UpdateEmployeeDto } from './dto/update-employee.dto';

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

  async findAll(tenantId: string) {
    return this.prisma.employee.findMany({
      where: { tenantId },
      include: { _count: { select: { assets: true } } },
      orderBy: { createdAt: 'desc' },
    });
  }

  async findById(tenantId: string, id: string) {
    const employee = await this.prisma.employee.findFirst({
      where: { id, tenantId },
      include: { assets: true },
    });
    if (!employee) throw new NotFoundException('Employee not found');
    return employee;
  }

  async create(tenantId: string, dto: CreateEmployeeDto) {
    const count = await this.prisma.employee.count({ where: { tenantId } });
    const employeeNo = `E-${String(count + 1).padStart(4, '0')}`;

    return this.prisma.employee.create({
      data: { tenantId, employeeNo, ...dto, salary: dto.salary || null },
    });
  }

  async update(tenantId: string, id: string, dto: UpdateEmployeeDto) {
    const existing = await this.prisma.employee.findFirst({ where: { id, tenantId } });
    if (!existing) throw new NotFoundException('Employee not found');

    return this.prisma.employee.update({
      where: { id },
      data: {
        ...(dto.firstName && { firstName: dto.firstName }),
        ...(dto.lastName && { lastName: dto.lastName }),
        ...(dto.email !== undefined && { email: dto.email }),
        ...(dto.phone !== undefined && { phone: dto.phone }),
        ...(dto.position && { position: dto.position }),
        ...(dto.department !== undefined && { department: dto.department }),
        ...(dto.status && { status: dto.status }),
        ...(dto.salary !== undefined && { salary: dto.salary }),
        ...(dto.notes !== undefined && { notes: dto.notes }),
        ...(dto.userId !== undefined && { userId: dto.userId || null }),
        ...(dto.status === 'terminated' && { terminatedAt: new Date() }),
      },
    });
  }
}