import { Injectable, Logger } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';

/** HTTP endpoint documented by 0098sms.com for sending via query string. */
const SMS_0098_SEND_URL =
  'http://www.0098sms.com/sendsmslink.aspx';

@Injectable()
export class SmsService {
  private readonly logger = new Logger(SmsService.name);

  constructor(private readonly config: ConfigService) {}

  /** True when username, password, and sender line are all set. */
  isConfigured(): boolean {
    const username = this.config.get<string>('SMS_USERNAME');
    const password = this.getPassword();
    const sender = this.config.get<string>('SMS_SENDER');
    return Boolean(username && password && sender);
  }

  /**
   * Formats mobile for 0098 `TO` (Iranian mobiles as 09xxxxxxxxx).
   */
  normalizePhoneForSms(mobile: string): string {
    const digits = String(mobile ?? '').replace(/\D/g, '');
    if (digits.startsWith('98') && digits.length === 12) {
      return `0${digits.slice(2)}`;
    }
    if (digits.startsWith('0') && digits.length === 11) {
      return digits;
    }
    if (digits.length === 10 && digits.startsWith('9')) {
      return `0${digits}`;
    }
    return digits;
  }

  async sendOtpSms(mobile: string, code: string): Promise<boolean> {
    const text = `کد ورود شما: ${code}`;
    return this.sendSms(mobile, text);
  }

  async sendSms(phone: string, text: string): Promise<boolean> {
    const username = this.config.get<string>('SMS_USERNAME');
    const password = this.getPassword();
    const sender = this.config.get<string>('SMS_SENDER');
    const domain = this.config.get<string>('SMS_DOMAIN') ?? '0098';

    if (!username || !password || !sender) {
      return false;
    }

    const params = new URLSearchParams({
      FROM: sender,
      TO: this.normalizePhoneForSms(phone),
      TEXT: text,
      USERNAME: username,
      PASSWORD: password,
      DOMAIN: domain,
    });

    const url = `${SMS_0098_SEND_URL}?${params.toString()}`;

    try {
      const res = await fetch(url);
      const body = await res.text();
      if (!res.ok) {
        this.logger.warn(
          `SMS HTTP ${res.status}: ${body.slice(0, 300)}`,
        );
        return false;
      }
      return true;
    } catch (e) {
      this.logger.error(
        '[SMS] request failed',
        e instanceof Error ? e.stack : e,
      );
      return false;
    }
  }

  private getPassword(): string | undefined {
    return (
      this.config.get<string>('SMS_PASSWORD') ??
      this.config.get<string>('SMS_API_KEY')
    );
  }
}