import { useContext, useCallback, useState, useEffect } from 'react'
import { ConnectionContext } from '../providers/ConnectionProvider'
import type {
  NetworkId,
  UseSwitchNetworkReturn,
  WalletError
} from '@meshconnect/uwc-types'

/**
 * Hook for switching networks on the connected wallet
 * @returns Network switching function and loading states
 * @throws Error if used outside of ConnectionProvider
 * @example
 * ```tsx
 * const { switchNetwork, isLoading, isWaitingForUserApproval } = useSwitchNetwork()
 *
 * const handleSwitch = async () => {
 *   try {
 *     await switchNetwork('eip155:8453') // Switch to Base
 *   } catch (error) {
 *     console.error('Network switch failed:', error)
 *   }
 * }
 *
 * // Show loading UI
 * if (isWaitingForUserApproval) {
 *   return <div>Please approve in your wallet...</div>
 * }
 * if (isLoading) {
 *   return <div>Switching network...</div>
 * }
 * ```
 */
export function useSwitchNetwork(): UseSwitchNetworkReturn {
  const context = useContext(ConnectionContext)

  if (!context) {
    throw new Error('useSwitchNetwork must be used within a ConnectionProvider')
  }

  const { connector } = context
  const [isLoading, setIsLoading] = useState(false)
  const [isWaitingForUserApproval, setIsWaitingForUserApproval] =
    useState(false)
  const [error, setError] = useState<WalletError | undefined>()

  // Subscribe to loading state changes from the core
  useEffect(() => {
    const updateLoadingState = () => {
      const state = connector.getNetworkSwitchLoadingState()
      setIsLoading(state.isLoading)
      setIsWaitingForUserApproval(state.isWaitingForUserApproval)
    }

    // Check initial state
    updateLoadingState()

    // Subscribe to changes
    const unsubscribe = connector.subscribe(updateLoadingState)

    return unsubscribe
  }, [connector])

  const switchNetwork = useCallback(
    async (networkId: NetworkId) => {
      setError(undefined)
      try {
        await connector.switchNetwork(networkId)
      } catch (err) {
        const walletError = err as WalletError
        setError(walletError)
        throw err
      }
    },
    [connector]
  )

  return {
    switchNetwork,
    isLoading,
    isWaitingForUserApproval,
    error
  }
}