// 网络管理：智能检测并切换内外网
const INTERNAL_HOST = '192.168.58.20:4320'

function getExternalHost(): string {
  if (typeof window === 'undefined') return ''
  return window.location.host
}

export interface NetworkStatus {
  isInternal: boolean
  host: string
}

let currentNetwork: NetworkStatus | null = null

let isChecking = false

// 检测内网是否可达
async function checkInternalNetwork(): Promise<boolean> {
  try {
    const controller = new AbortController()
    const timeoutId = setTimeout(() => controller.abort(), 2000) // 2秒超时

    const response = await fetch(`http://${INTERNAL_HOST}/api/health`, {
      method: 'HEAD',
      signal: controller.signal,
      mode: 'no-cors' // 避免CORS问题
    })

    clearTimeout(timeoutId)
    return true // 如果请求没有抛出错误，说明内网可达
  } catch (error) {
    // 网络不可达或超时
    return false
  }
}

// 初始化网络检测
export async function initializeNetwork(): Promise<NetworkStatus> {
  if (typeof window === 'undefined') {
    return { isInternal: false, host: '' }
  }

  if (isChecking && currentNetwork) {
    return currentNetwork
  }

  isChecking = true
  const externalHost = getExternalHost()

  try {
    // 当前如果是访问内网地址，直接使用内网
    if (window.location.hostname === '192.168.58.20') {
      currentNetwork = {
        isInternal: true,
        host: INTERNAL_HOST
      }
      return currentNetwork
    }

    // 当前访问的是公网或localhost，尝试检测内网
    const isInternalAvailable = await checkInternalNetwork()

    if (isInternalAvailable) {
      // 内网可达，切换到内网
      currentNetwork = {
        isInternal: true,
        host: INTERNAL_HOST
      }
      console.log('✅ 内网可达，已切换到内网模式')
    } else {
      // 内网不可达，使用当前网络（公网）
      currentNetwork = {
        isInternal: false,
        host: externalHost
      }
      console.log('⚠️ 内网不可达，使用公网模式')
    }
  } catch (error) {
    console.error('网络检测失败:', error)
    // 检测失败，使用当前网络
    currentNetwork = {
      isInternal: false,
      host: externalHost
    }
  } finally {
    isChecking = false
  }

  return currentNetwork
}

// 获取当前网络状态
export function getNetworkStatus(): NetworkStatus {
  if (!currentNetwork) {
    const externalHost = getExternalHost()
    return { isInternal: false, host: externalHost }
  }
  return currentNetwork
}

// 获取API基础URL
export function getApiBaseUrl(): string {
  if (!currentNetwork) {
    return '' // 使用相对路径
  }
  return currentNetwork.isInternal ? `http://${currentNetwork.host}` : ''
}

// 定期检测网络（可选，用于自动重连）
export function startNetworkMonitoring(intervalMs: number = 30000) {
  setInterval(async () => {
    // 如果当前使用公网，定期尝试切换回内网
    if (currentNetwork && !currentNetwork.isInternal) {
      const isInternalAvailable = await checkInternalNetwork()
      if (isInternalAvailable) {
        currentNetwork = {
          isInternal: true,
          host: INTERNAL_HOST
        }
        console.log('🔄 已自动切换回内网模式')
        // 触发页面刷新或状态更新
        if (typeof window !== 'undefined') {
          window.dispatchEvent(new CustomEvent('network-changed', { 
            detail: currentNetwork 
          }))
        }
      }
    }
  }, intervalMs)
}