import { BadRequestException } from '@nestjs/common';
import { plainToInstance } from 'class-transformer';
import { validateSync } from 'class-validator';

import { IncomingHttpHeaders } from 'node:http';
import { UAParser } from 'ua-parser-js';

export const fromChecksum = (checksum: string): Buffer => {
  return Buffer.from(checksum, checksum.length === 28 ? 'base64' : 'hex');
};

export const fromMaybeArray = <T>(param: T | T[]) => (Array.isArray(param) ? param[0] : param);

const getAppVersionFromUA = (ua: string) =>
  ua.match(/^Immich_(?:Android|iOS)_(?<appVersion>.+)$/)?.groups?.appVersion ?? null;

export const getUserAgentDetails = (headers: IncomingHttpHeaders) => {
  const userAgent = UAParser(headers['user-agent']);
  const appVersion = getAppVersionFromUA(headers['user-agent'] ?? '');

  return {
    deviceType: userAgent.browser.name || userAgent.device.type || (headers['devicemodel'] as string) || '',
    deviceOS: userAgent.os.name || (headers['devicetype'] as string) || '',
    appVersion,
  };
};

export function validateSyncOrReject<T extends object>(cls: new () => T, obj: any): T {
  const dto = plainToInstance(cls, obj, { excludeExtraneousValues: true });
  const errors = validateSync(dto);
  if (errors.length === 0) {
    return dto;
  }

  const constraints = [];
  for (const error of errors) {
    if (error.constraints) {
      constraints.push(...Object.values(error.constraints));
    }

    if (!error.children) {
      continue;
    }

    for (const child of error.children) {
      if (child.constraints) {
        constraints.push(...Object.values(child.constraints));
      }
    }
  }
  throw new BadRequestException(constraints);
}