/**
 * 浏览器注入钱包(EIP-1193)接入:EIP-6963 多钱包发现 + personal_sign 封装。
 * 不引钱包 SDK;WalletConnect 等远程签名方案不在支持范围。
 */

/** EIP-1193 provider 最小接口 */
export interface Eip1193Provider {
  request(args: { method: string; params?: unknown[] }): Promise<unknown>
}

/** EIP-6963 announce 事件携带的钱包信息 */
export interface WalletDetail {
  info: { uuid: string; name: string; icon: string; rdns: string }
  provider: Eip1193Provider
}

interface Eip6963AnnounceEvent extends Event {
  detail: WalletDetail
}

/** 兼容旧式单一注入的 window.ethereum */
declare global {
  interface Window {
    ethereum?: Eip1193Provider
  }
}

/**
 * 发现已安装的注入钱包:广播 EIP-6963 请求并收集 announce;
 * 无响应时回退 window.ethereum(旧式单钱包注入)。
 */
export function discoverWallets(collectMs = 300): Promise<WalletDetail[]> {
  return new Promise((resolve) => {
    const found: WalletDetail[] = []
    const onAnnounce = (e: Event) => {
      const detail = (e as Eip6963AnnounceEvent).detail
      if (detail?.provider && !found.some((w) => w.info.uuid === detail.info.uuid)) found.push(detail)
    }
    window.addEventListener('eip6963:announceProvider', onAnnounce)
    window.dispatchEvent(new Event('eip6963:requestProvider'))
    setTimeout(() => {
      window.removeEventListener('eip6963:announceProvider', onAnnounce)
      if (!found.length && window.ethereum) {
        found.push({
          info: { uuid: 'legacy', name: '浏览器钱包', icon: '', rdns: 'legacy.injected' },
          provider: window.ethereum,
        })
      }
      resolve(found)
    }, collectMs)
  })
}

/** 连接钱包并返回首个授权账户地址;用户拒绝时抛出钱包侧错误 */
export async function requestAccount(provider: Eip1193Provider): Promise<string> {
  const accounts = (await provider.request({ method: 'eth_requestAccounts' })) as string[]
  const addr = accounts?.[0]
  if (!addr) throw new Error('钱包未返回账户地址')
  return addr
}

/** 对消息做 personal_sign(EIP-191);返回 0x 前缀的 65 字节签名 hex */
export async function personalSign(
  provider: Eip1193Provider,
  message: string,
  address: string,
): Promise<string> {
  const sig = (await provider.request({
    method: 'personal_sign',
    params: [message, address],
  })) as string
  if (!sig || typeof sig !== 'string') throw new Error('钱包未返回签名')
  return sig
}

/** 钱包侧用户拒绝(EIP-1193 code 4001);拒绝不作为错误提示 */
export function isUserRejected(e: unknown): boolean {
  return typeof e === 'object' && e !== null && (e as { code?: number }).code === 4001
}