import { useContext, useCallback, useState } from 'react'
import { ConnectionContext } from '../providers/ConnectionProvider'
import type {
  EIP712TypedData,
  UseSignTypedDataReturn,
  WalletError
} from '@meshconnect/uwc-types'

/**
 * Hook for signing EIP-712 typed structured data (eth_signTypedData_v4).
 *
 * Used by ERC-3009 (Transfer With Authorization) and EIP-2612 (Permit) relay
 * flows — the user signs an off-chain authorization and Mesh's backend submits
 * the transaction and pays gas. EVM-only (eip155); throws for TON connections.
 *
 * @returns Object containing signTypedData function, loading state, last signature, and error
 * @throws Error if used outside of ConnectionProvider
 * @example
 * ```tsx
 * const { signTypedData, isLoading, signature } = useSignTypedData()
 *
 * const handleSign = async () => {
 *   try {
 *     const sig = await signTypedData(typedData)
 *     // send sig to the relay endpoint
 *   } catch (error) {
 *     console.error('Failed to sign:', error)
 *   }
 * }
 * ```
 */
export function useSignTypedData(): UseSignTypedDataReturn {
  const context = useContext(ConnectionContext)

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

  const { connector, session } = context
  const [isLoading, setIsLoading] = useState(false)
  const [signature, setSignature] = useState<string | undefined>()
  const [error, setError] = useState<WalletError | undefined>()

  const signTypedData = useCallback(
    async (typedData: EIP712TypedData): Promise<string> => {
      if (!session.activeAddress) {
        throw new Error('No wallet connected')
      }

      setIsLoading(true)
      setError(undefined)
      try {
        const sig = await connector.signTypedData(typedData)
        setSignature(sig)
        return sig
      } catch (err) {
        const walletError = err as WalletError
        setError(walletError)
        throw err
      } finally {
        setIsLoading(false)
      }
    },
    [connector, session.activeAddress]
  )

  return {
    signTypedData,
    isLoading,
    signature,
    error
  }
}