import { useState, useEffect } from 'react'
import { ConfigService, PublicConfigResponse } from '@/lib/services'

/* 全局缓存 */
let cachedConfig: PublicConfigResponse | null = null
let cachePromise: Promise<PublicConfigResponse> | null = null
let cacheTime = 0
const CACHE_DURATION = 5 * 60 * 1000

/**
 * 获取公共配置（带缓存）
 * 
 * @example
 * ```tsx
 * const { config, loading, error } = usePublicConfig()
 * ```
 */
export function usePublicConfig() {
  const [config, setConfig] = useState<PublicConfigResponse | null>(cachedConfig)
  const [loading, setLoading] = useState(!cachedConfig)
  const [error, setError] = useState<Error | null>(null)

  useEffect(() => {
    let mounted = true

    const fetchConfig = async () => {
      const now = Date.now()

      if (cachedConfig && (now - cacheTime) < CACHE_DURATION) {
        if (mounted) {
          setConfig(cachedConfig)
          setLoading(false)
        }
        return
      }

      if (!cachePromise) {
        cachePromise = ConfigService.getPublicConfig()
      }

      try {
        const data = await cachePromise
        if (mounted) {
          cachedConfig = data
          cacheTime = now
          setConfig(data)
          setError(null)
        }
      } catch (err) {
        if (mounted) {
          setError(err instanceof Error ? err : new Error('获取配置失败'))
        }
      } finally {
        cachePromise = null
        if (mounted) {
          setLoading(false)
        }
      }
    }

    fetchConfig()

    return () => {
      mounted = false
    }
  }, [])

  return { config, loading, error }
}