const DEFAULT_CONTRAST_BACKEND_ORIGIN = 'https://contrast.dev'

export const LOOPBACK_PROBE_HOSTNAMES = ['127.0.0.1', '::1'] as const

export function normalizeHostname(hostname: string): string {
  return hostname.replace(/^\[|\]$/g, '').toLowerCase()
}

export function buildLoopbackProbeBaseUrl(
  protocol: 'http:' | 'ws:',
  hostname: string,
  port: number,
): string {
  const normalizedHostname = normalizeHostname(hostname)
  const urlHost = normalizedHostname.includes(':')
    ? `[${normalizedHostname}]`
    : normalizedHostname
  return `${protocol}//${urlHost}:${port}`
}

export function isLoopbackHost(hostname: string): boolean {
  const normalized = normalizeHostname(hostname)
  return (
    normalized === 'localhost' ||
    normalized.endsWith('.localhost') ||
    normalized === '0.0.0.0' ||
    normalized === '::1' ||
    /^127(?:\.\d{1,3}){3}$/.test(normalized)
  )
}

export function buildBrowserAssetProxyUrl(targetUrl: string): string {
  const proxyPath = isLoopbackHost(new URL(targetUrl).hostname)
    ? '/__bundle-proxy'
    : '/__fetch-proxy'
  return `${proxyPath}?url=${encodeURIComponent(targetUrl)}`
}

export function isContrastBackendHost(hostname: string): boolean {
  const normalized = normalizeHostname(hostname)
  return (
    isLoopbackHost(normalized) ||
    normalized === 'contrast.dev' ||
    normalized.endsWith('.contrast.dev')
  )
}

export function isContrastBackendOrigin(origin: string): boolean {
  try {
    return isContrastBackendHost(new URL(origin).hostname)
  } catch {
    return false
  }
}

export function resolveContrastBackendOrigin(currentOrigin?: string | null): string {
  const origin = currentOrigin?.trim()
  if (!origin) return DEFAULT_CONTRAST_BACKEND_ORIGIN

  try {
    const parsed = new URL(origin)
    if (isLoopbackHost(parsed.hostname) || isContrastBackendHost(parsed.hostname)) {
      return parsed.origin
    }
  } catch {}

  return DEFAULT_CONTRAST_BACKEND_ORIGIN
}

export { DEFAULT_CONTRAST_BACKEND_ORIGIN }