import { Injectable, Logger, OnModuleInit } from '@nestjs/common';
import IP2Region from 'ip2region';
import type { IpRegion } from './geo.types';

function cleanRegionName(value?: string | null): string | null {
  if (!value) return null;
  const trimmed = value.trim();
  if (!trimmed || trimmed === '0' || trimmed === '内网IP') return null;
  return trimmed;
}

@Injectable()
export class IpGeoService implements OnModuleInit {
  private readonly logger = new Logger(IpGeoService.name);
  private query: IP2Region | null = null;

  onModuleInit() {
    try {
      this.query = new IP2Region();
    } catch (error) {
      this.logger.warn(`ip2region 初始化失败: ${error instanceof Error ? error.message : error}`);
    }
  }

  resolve(ip: string | null): IpRegion {
    if (!ip || !this.query) {
      return { province: null, city: null, district: null };
    }
    if (ip === '127.0.0.1' || ip.startsWith('192.168.') || ip.startsWith('10.')) {
      return { province: null, city: null, district: null };
    }

    try {
      const result = this.query.search(ip) as {
        province?: string;
        city?: string;
        region?: string;
      };
      return {
        province: cleanRegionName(result?.province),
        city: cleanRegionName(result?.city),
        district: cleanRegionName(result?.region),
      };
    } catch (error) {
      this.logger.debug(`IP 解析失败 ${ip}: ${error instanceof Error ? error.message : error}`);
      return { province: null, city: null, district: null };
    }
  }
}