import { Hex, Provider as core_Provider } from 'ox'
import { custom } from 'viem'
import { z } from 'zod/mini'

import * as Adapter from '../../Adapter.js'
import type * as Keystore from '../../Keystore.js'
import * as Rpc from '../../zod/rpc.js'
import * as u from '../../zod/utils.js'

/**
 * Builds an adapter that forwards wallet RPC to a remote wallet through a
 * single request function.
 *
 * Shared core for adapters whose wallet lives behind a request/response
 * session (e.g. Wata mobile web auth or postMessage). Access keys are
 * generated locally; every other wallet action round-trips through
 * `request`.
 */
export function fromRequest(options: fromRequest.Options): Adapter.Adapter {
  const {
    actions,
    bind,
    cleanup,
    close,
    icon,
    keystores,
    name,
    rdns,
    request: requestRemote,
  } = options

  return Adapter.define(
    { ...(icon ? { icon } : {}), name, rdns, schema: z.object({ address: u.address() }) },
    ({ getAccount, getClient, store }) => {
      // Late-bind the store so the request channel can reconcile local
      // connection state (e.g. a wallet `accountsChanged` notification).
      bind?.({ store })

      const provider = core_Provider.from({
        async request(request) {
          const { accounts, activeAccount, chainId } = store.getState()
          if (request.method === 'eth_chainId') return Hex.fromNumber(chainId)
          // Forward the active account + chain as request context so the wallet
          // acts against the session the app believes it is using rather than
          // whatever the wallet last selected for itself.
          const account = accounts[activeAccount]?.address
          return await requestRemote({
            method: request.method,
            params: request.params as readonly unknown[] | undefined,
            context: { chainId, ...(account ? { account } : {}) },
          })
        },
      })

      // Connect capabilities are read from the first account only: the remote
      // wallet connects a single account per exchange.
      function toConnectReturn(result: Rpc.wallet_connect.Encoded['returns']) {
        const capabilities = result.accounts[0]?.capabilities
        return {
          accounts: result.accounts.map((account) => ({ address: account.address })),
          ...(capabilities?.auth ? { auth: capabilities.auth } : {}),
          ...(capabilities?.identity ? { identity: capabilities.identity } : {}),
          ...(capabilities?.keyAuthorization
            ? { keyAuthorization: capabilities.keyAuthorization }
            : {}),
          ...(capabilities?.personalSign ? { personalSign: capabilities.personalSign } : {}),
          ...(capabilities?.signature ? { signature: capabilities.signature } : {}),
          ...(capabilities?.username !== undefined ? { username: capabilities.username } : {}),
        }
      }

      return {
        forwardsAuth: true,
        ...(keystores ? { accessKey: { keystores } } : {}),
        actions: {
          async createAccount(_parameters, request) {
            return toConnectReturn(
              (await provider.request(request)) as Rpc.wallet_connect.Encoded['returns'],
            )
          },
          async loadAccounts(_parameters, request) {
            return toConnectReturn(
              (await provider.request(request)) as Rpc.wallet_connect.Encoded['returns'],
            )
          },
          async deposit(_parameters, request) {
            return (await provider.request(request)) as Rpc.wallet_deposit.Encoded['returns']
          },
          async depositZone(parameters, request) {
            return (await provider.request({
              ...request,
              params: [z.encode(Rpc.wallet_depositZone.parameters, parameters)] as const,
            })) as Rpc.wallet_depositZone.Encoded['returns']
          },
          // `disconnect` (when `close` is set) only tears down the local
          // wallet session — it is never forwarded. No `switchChain` action:
          // chain selection is local state the provider handles itself, and
          // forwarding it would open a wallet session for nothing.
          ...(close ? { disconnect: close } : {}),
          async swap(_parameters, request) {
            return (await provider.request(request)) as Rpc.wallet_swap.Encoded['returns']
          },
          async transfer(parameters, request) {
            return (await provider.request({
              ...request,
              params: [z.encode(Rpc.wallet_transfer.parameters, parameters)] as const,
            })) as Rpc.wallet_transfer.Encoded['returns']
          },
          async withdrawZone(parameters, request) {
            return (await provider.request({
              ...request,
              params: [z.encode(Rpc.wallet_withdrawZone.parameters, parameters)] as const,
            })) as Rpc.wallet_withdrawZone.Encoded['returns']
          },
          ...actions?.({ getClient, request: requestRemote, store }),
        },
        ...(cleanup ? { cleanup } : close ? { cleanup: () => void close() } : {}),
        getAccount(parameters = {}) {
          return {
            account: {
              address: parameters.address ?? getAccount({ signable: false }).address,
              type: 'json-rpc' as const,
            },
            transport: custom(provider),
          }
        },
      }
    },
  )
}

export declare namespace fromRequest {
  /** Options for {@link fromRequest}. */
  export type Options = {
    /**
     * Adapter-specific action overrides layered over the request-forwarding
     * defaults. Receives the request channel plus the adapter's client and
     * store for actions that need local bookkeeping around an exchange.
     */
    actions?:
      | ((context: {
          getClient: Adapter.SetupFn.Parameters['getClient']
          request: Options['request']
          store: Adapter.SetupFn.Parameters['store']
        }) => Partial<Adapter.Instance['actions']>)
      | undefined
    /**
     * Called once during setup with the adapter's store, for late wiring
     * that needs to mutate local state (e.g. reconciling connection state
     * from a wallet `accountsChanged` notification on the request channel).
     */
    bind?: ((context: { store: Adapter.SetupFn.Parameters['store'] }) => void) | undefined
    /**
     * Tears down adapter-owned resources (sessions, mounted UI) when the
     * provider discards the adapter instance. @default `close`, when set.
     */
    cleanup?: (() => void) | undefined
    /** Data URI of the provider icon, announced via EIP-6963. */
    icon?: Adapter.Meta['icon'] | undefined
    /**
     * Default keystores backing locally generated access keys. Omit to use
     * the SDK default (non-extractable `webCryptoP256`). Pass an explicit
     * keystore where the transport's environment needs one — e.g. pure-JS
     * P-256 for React Native, which may lack WebCrypto and persists access
     * keys through string-based storage.
     */
    keystores?: Keystore.Keystores | undefined
    /**
     * Tears down the adapter's wallet session. Wired to the `disconnect`
     * action and instance cleanup; never forwarded to the remote wallet.
     * Omit for single-exchange transports with no session to clean up.
     */
    close?: (() => Promise<void>) | undefined
    /** Provider display name. */
    name: string
    /** Reverse-DNS provider identifier. */
    rdns: string
    /** Forwards a single wallet JSON-RPC request to the remote wallet. */
    request: (request: {
      /** JSON-RPC method name. */
      method: string
      /** JSON-RPC params. */
      params?: readonly unknown[] | undefined
      /** Session selectors (active account + chain) for the wallet to act on. */
      context?: { account?: string | undefined; chainId?: number | undefined } | undefined
    }) => Promise<unknown>
  }
}