const DEFAULT_PUBLIC_APP_URL = 'https://sc.jiansun.vip'

const LEGACY_PUBLIC_APP_ORIGINS = ['https://3d.yydd.ai']

function isPrivateOrLocalHost(hostname: string): boolean {
  const lower = hostname.toLowerCase()
  if (lower === 'localhost' || lower === '127.0.0.1' || lower === '::1') {
    return true
  }

  return /^192\.168\.|^10\.|^172\.(1[6-9]|2[0-9]|3[01])\./.test(lower)
}

function normalizeOrigin(value?: string | null): string | null {
  if (!value) return null

  const trimmed = value.trim()
  if (!trimmed) return null

  try {
    const parsed = new URL(trimmed.match(/^https?:\/\//i) ? trimmed : `https://${trimmed}`)
    if (isPrivateOrLocalHost(parsed.hostname)) {
      return null
    }
    return parsed.origin
  } catch {
    return null
  }
}

export function getPublicAppOrigin(): string {
  const candidates = [
    process.env.NEXT_PUBLIC_APP_PUBLIC_URL,
    process.env.APP_PUBLIC_URL,
    process.env.NEXTAUTH_URL,
    DEFAULT_PUBLIC_APP_URL,
  ]

  for (const candidate of candidates) {
    const normalized = normalizeOrigin(candidate)
    if (normalized) {
      return normalized
    }
  }

  return DEFAULT_PUBLIC_APP_URL
}

export function buildPublicMaterialShareUrl(materialId: string): string {
  return `${getPublicAppOrigin()}/share/${encodeURIComponent(materialId)}`
}

export function getAllowedPublicAppOrigins(): string[] {
  return Array.from(new Set([getPublicAppOrigin(), ...LEGACY_PUBLIC_APP_ORIGINS]))
}