export { bodyHash, buildSignMessage, type SignedEnvelope } from '@trumpsignal/contracts/signing'
import { buildSignMessage, type SignedEnvelope } from '@trumpsignal/contracts/signing'

/**
 * Produce {timestamp, signature} for a given action + optional body.
 * Caller supplies wagmi's `signMessageAsync`.
 */
/**
 * Get-or-create a cached "view" envelope for a wallet. Reused across page loads
 * within a short window below the server's 5-minute skew allowance.
 * Backend's replay-guard is disabled for the view action so the same sig can
 * be used multiple times while it remains fresh.
 */
const VIEW_TTL_MS = 4 * 60 * 1000 // 4 min — stays safely inside backend's 5 min skew window

/**
 * Read-only: returns a cached, not-yet-expired view envelope if one exists.
 * Never signs — never triggers a wallet popup. Returns null if no fresh cache.
 */
export function getCachedViewEnvelope(action: string, wallet: string): SignedEnvelope | null {
  if (typeof window === 'undefined') return null
  const cacheKey = `ts:view:${action}:${wallet.toLowerCase()}`
  const raw = sessionStorage.getItem(cacheKey)
  if (!raw) return null
  try {
    const env = JSON.parse(raw) as SignedEnvelope
    if (Date.now() - env.timestamp < VIEW_TTL_MS) return env
    sessionStorage.removeItem(cacheKey)
  } catch (err) {
    console.warn('[signedRequest] corrupt cached envelope, ignoring', err)
    sessionStorage.removeItem(cacheKey)
  }
  return null
}

export async function getOrCreateViewEnvelope(params: {
  action: string
  wallet: string
  signMessageAsync: (args: { message: string }) => Promise<string>
}): Promise<SignedEnvelope> {
  if (typeof window === 'undefined') throw new Error('view envelope requires browser')
  const wallet = params.wallet.toLowerCase()
  const cacheKey = `ts:view:${params.action}:${wallet}`
  const raw = sessionStorage.getItem(cacheKey)
  if (raw) {
    try {
      const env = JSON.parse(raw) as SignedEnvelope
      if (Date.now() - env.timestamp < VIEW_TTL_MS) return env
    } catch (err) {
      console.warn('[signedRequest] corrupt cached envelope, ignoring', err)
      sessionStorage.removeItem(cacheKey)
    }
  }
  const env = await signRequest({
    action: params.action,
    wallet,
    body: null,
    signMessageAsync: params.signMessageAsync,
  })
  sessionStorage.setItem(cacheKey, JSON.stringify(env))
  return env
}

export async function signRequest(params: {
  action: string
  wallet: string
  body: unknown | null
  signMessageAsync: (args: { message: string }) => Promise<string>
}): Promise<SignedEnvelope> {
  const timestamp = Date.now()
  const message = await buildSignMessage(params.action, params.wallet, timestamp, params.body)
  const signature = await params.signMessageAsync({ message })
  return { wallet: params.wallet.toLowerCase(), timestamp, signature }
}