import axios from "axios";

export function capitalizeFirstLetter(str?: string | null): string {
  if (!str) return "";
  return str.charAt(0).toUpperCase() + str.slice(1);
}

export function formatBytes(bytes: number, decimals = 2): string {
  if (bytes === 0) return '0 Bytes';
  const k = 1024;
  const dm = decimals < 0 ? 0 : decimals;
  const sizes = ['Bytes', 'KB', 'MB', 'GB', 'TB'];
  const i = Math.floor(Math.log(bytes) / Math.log(k));
  return parseFloat((bytes / Math.pow(k, i)).toFixed(dm)) + ' ' + sizes[i];
}

export async function testInternetConnection(): Promise<boolean> {
  try {
    const response = await axios.get('https://1.1.1.1/cdn-cgi/trace', {
      timeout: 5000,
      headers: {
        'Cache-Control': 'no-cache',
      }
    });
    return response.status === 200;
  } catch (error) {
    console.error("Error testing internet connection:", error);
    return false;
  }
}

export function generateRandomString(length: number): string {
  const characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
  let result = '';
  for (let i = 0; i < length; i++) {
    result += characters.charAt(Math.floor(Math.random() * characters.length));
  }
  return result;
}

export function generateUUID(): string {
  const arr = new Uint8Array(16);
  if (window.crypto && window.crypto.getRandomValues) {
    window.crypto.getRandomValues(arr);
  } else {
    // Fallback for non-secure contexts where window.crypto is not available
    // This is not cryptographically secure, but can be used for non-critical purposes
    for (let i = 0; i < 16; i++) {
      arr[i] = Math.floor(Math.random() * 256);
    }
  }

  arr[6] = (arr[6] & 0x0f) | 0x40; // Version 4
  arr[8] = (arr[8] & 0x3f) | 0x80; // Variant bits

  const hex = Array.from(arr, byte => byte.toString(16).padStart(2, '0')).join('');
  return `${hex.slice(0, 8)}-${hex.slice(8, 12)}-${hex.slice(12, 16)}-${hex.slice(16, 20)}-${hex.slice(20)}`;
}