import { Controller, Get, Logger, Post, Query, Req, Res } from '@nestjs/common';
import type { Request, Response } from 'express';
import { Public } from '../../common/auth';
import { decryptWechatMessage, sameHex, wechatSignature, xmlField } from '../../common/wechat-msg';
import { InjectConfig, type AppConfig } from '../../config/config';
import { PaymentsService } from './payments.service';

/** 取原始请求体。虚拟支付回调是 XML，必须拿到未经解析的字节。 */
function rawBodyOf(req: Request): string {
  const withRaw = req as Request & { rawBody?: Buffer };
  if (withRaw.rawBody) return withRaw.rawBody.toString('utf8');
  return typeof req.body === 'string' ? req.body : String(req.body ?? '');
}

/**
 * 虚拟支付回调。由微信服务器调用，不带小程序身份，靠签名与业务校验保证安全。
 * 请求体是 XML，应答也必须是 XML。
 */
@Controller('v1/payments')
export class PaymentsController {
  private readonly logger = new Logger(PaymentsController.name);

  constructor(
    private readonly payments: PaymentsService,
    @InjectConfig() private readonly cfg: AppConfig,
  ) {}

  /**
   * 微信配置「消息推送 URL」时的验签请求。
   * 后台点保存会发 GET ?signature&timestamp&nonce&echostr（安全模式换成 msg_signature + 加密 echostr），
   * 验签通过必须原样返回 echostr，否则一直提示「服务器地址验证失败」。
   */
  @Public()
  @Get('notify')
  verify(@Query() query: Record<string, string>, @Res() res: Response): void {
    const token = this.cfg.WX_MSG_TOKEN;
    const aesKey = this.cfg.WX_MSG_AES_KEY;
    const timestamp = query.timestamp ?? '';
    const nonce = query.nonce ?? '';
    const echostr = query.echostr ?? '';

    if (token && query.msg_signature && aesKey) {
      if (sameHex(wechatSignature(token, timestamp, nonce, echostr), query.msg_signature)) {
        res.type('text/plain').send(decryptWechatMessage(aesKey, echostr));
        return;
      }
    } else if (token && sameHex(wechatSignature(token, timestamp, nonce), query.signature ?? '')) {
      res.type('text/plain').send(echostr);
      return;
    }

    this.logger.warn('消息推送地址校验失败：签名不匹配，或 .env 未配置 WX_MSG_TOKEN');
    res.status(401).send('');
  }

  @Public()
  @Post('notify')
  async notify(@Req() req: Request, @Res() res: Response): Promise<void> {
    const body = this.decode(req);
    if (body.includes('xpay_goods_deliver_notify')) {
      res.type('application/xml').send(await this.payments.handleDeliverNotify(body));
      return;
    }
    // 退款推送走的是同一个消息推送地址，漏了这段退款就永远不会被记上
    if (body.includes('xpay_refund_notify')) {
      res.type('application/xml').send(await this.payments.handleRefundNotify(body));
      return;
    }
    // 地址会收到全部事件（投诉、风控、代币等），其余统一回 success 表示已收到
    res.type('text/plain').send('success');
  }

  @Public()
  @Post('refund-notify')
  async refundNotify(@Req() req: Request, @Res() res: Response): Promise<void> {
    res.type('application/xml').send(await this.payments.handleRefundNotify(this.decode(req)));
  }

  /** 取原始报文；安全模式下包体是 <Encrypt> 密文，先解出来。 */
  private decode(req: Request): string {
    const raw = rawBodyOf(req);
    const aesKey = this.cfg.WX_MSG_AES_KEY;
    if (!aesKey || !raw.includes('<Encrypt>')) return raw;
    try {
      return decryptWechatMessage(aesKey, xmlField(raw, 'Encrypt'));
    } catch (err) {
      this.logger.error(`消息推送解密失败，请核对 WX_MSG_AES_KEY：${err instanceof Error ? err.message : err}`);
      return raw;
    }
  }
}