// Web Bluetooth browser compatibility utilities

/**
 * Web Bluetooth support status
 */
export interface WebBluetoothSupport {
  supported: boolean;
  browserName: string;
  browserVersion: string;
  reason?: 'unsupported_browser' | 'insecure_context' | 'api_unavailable';
  helpUrl?: string;
}

/**
 * Supported browsers for Web Bluetooth
 * Chrome/Edge/Opera on desktop and Android support Web Bluetooth
 * Safari and Firefox do NOT support Web Bluetooth
 */
export const SUPPORTED_BROWSERS = ['Chrome', 'Edge', 'Opera', 'Samsung Internet'];

/**
 * URLs for browser help pages
 */
export const BROWSER_HELP_URLS: Record<string, string> = {
  Chrome: 'https://www.google.com/chrome/',
  Edge: 'https://www.microsoft.com/edge',
  Opera: 'https://www.opera.com/',
  'Samsung Internet': 'https://www.samsung.com/us/support/owners/app/samsung-internet',
};

/**
 * Detect the current browser name and version
 */
export function detectBrowser(): { name: string; version: string } {
  if (typeof navigator === 'undefined') {
    return { name: 'Unknown', version: '0' };
  }

  const userAgent = navigator.userAgent;
  let browserName = 'Unknown';
  let browserVersion = '0';

  // Edge (must be checked before Chrome as Edge contains "Chrome" in UA)
  if (userAgent.includes('Edg/')) {
    browserName = 'Edge';
    const match = userAgent.match(/Edg\/(\d+)/);
    browserVersion = match?.[1] || '0';
  }
  // Opera (must be checked before Chrome as Opera contains "Chrome" in UA)
  else if (userAgent.includes('OPR/') || userAgent.includes('Opera')) {
    browserName = 'Opera';
    const match = userAgent.match(/(?:OPR|Opera)\/(\d+)/);
    browserVersion = match?.[1] || '0';
  }
  // Samsung Internet (must be checked before Chrome)
  else if (userAgent.includes('SamsungBrowser')) {
    browserName = 'Samsung Internet';
    const match = userAgent.match(/SamsungBrowser\/(\d+)/);
    browserVersion = match?.[1] || '0';
  }
  // Chrome
  else if (userAgent.includes('Chrome/')) {
    browserName = 'Chrome';
    const match = userAgent.match(/Chrome\/(\d+)/);
    browserVersion = match?.[1] || '0';
  }
  // Safari (must be checked after Chrome-based browsers)
  else if (userAgent.includes('Safari') && !userAgent.includes('Chrome')) {
    browserName = 'Safari';
    const match = userAgent.match(/Version\/(\d+)/);
    browserVersion = match?.[1] || '0';
  }
  // Firefox
  else if (userAgent.includes('Firefox/')) {
    browserName = 'Firefox';
    const match = userAgent.match(/Firefox\/(\d+)/);
    browserVersion = match?.[1] || '0';
  }

  return { name: browserName, version: browserVersion };
}

/**
 * Check if the current browser supports Web Bluetooth API
 */
export function checkWebBluetoothSupport(): WebBluetoothSupport {
  const browser = detectBrowser();

  // Check if we're in a secure context (HTTPS or localhost)
  if (typeof window !== 'undefined' && !window.isSecureContext) {
    return {
      supported: false,
      browserName: browser.name,
      browserVersion: browser.version,
      reason: 'insecure_context',
    };
  }

  // Check if the Web Bluetooth API is available
  if (typeof navigator === 'undefined' || !('bluetooth' in navigator)) {
    // Determine reason based on browser
    const isKnownUnsupportedBrowser =
      browser.name === 'Safari' ||
      browser.name === 'Firefox';

    return {
      supported: false,
      browserName: browser.name,
      browserVersion: browser.version,
      reason: isKnownUnsupportedBrowser ? 'unsupported_browser' : 'api_unavailable',
      helpUrl: BROWSER_HELP_URLS.Chrome, // Suggest Chrome as alternative
    };
  }

  return {
    supported: true,
    browserName: browser.name,
    browserVersion: browser.version,
  };
}

/**
 * Get a user-friendly error message for unsupported browsers
 */
export function getUnsupportedBrowserMessage(support: WebBluetoothSupport): {
  title: string;
  message: string;
  suggestion: string;
} {
  switch (support.reason) {
    case 'unsupported_browser':
      return {
        title: 'Browser Not Supported',
        message: `${support.browserName} does not support Web Bluetooth, which is required to connect to WellNuo sensors.`,
        suggestion: 'Please use Chrome, Edge, or Opera browser to set up your sensors.',
      };

    case 'insecure_context':
      return {
        title: 'Secure Connection Required',
        message: 'Web Bluetooth requires a secure connection (HTTPS).',
        suggestion: 'Please access this page using HTTPS or localhost.',
      };

    case 'api_unavailable':
      return {
        title: 'Bluetooth Not Available',
        message: 'Web Bluetooth API is not available in this browser.',
        suggestion: 'Please use Chrome, Edge, or Opera browser to set up your sensors.',
      };

    default:
      return {
        title: 'Bluetooth Not Available',
        message: 'Could not access Bluetooth functionality.',
        suggestion: 'Please use Chrome, Edge, or Opera browser.',
      };
  }
}

/**
 * Type guard to check if we're running in a web browser
 */
export function isWebPlatform(): boolean {
  return typeof window !== 'undefined' && typeof document !== 'undefined';
}

/**
 * Type guard to check if Web Bluetooth is available
 */
export function hasWebBluetooth(): boolean {
  return typeof navigator !== 'undefined' && 'bluetooth' in navigator;
}