/** Shared or per-chain credentials. */
export type ChainCredential = string | Record<number, string>

/** Parses shared or per-chain credentials from an environment value. */
export function parseCredential(value: ChainCredential | undefined): parseCredential.ReturnType {
  if (!value) return undefined
  if (typeof value !== 'string') return value
  const credentials = (() => {
    try {
      return JSON.parse(value) as unknown
    } catch {
      return value
    }
  })()
  if (typeof credentials === 'string') return credentials
  if (
    !credentials ||
    typeof credentials !== 'object' ||
    Array.isArray(credentials) ||
    Object.values(credentials).some((credential) => typeof credential !== 'string')
  )
    throw new Error('Expected a credential or a chain-id-to-credential JSON object.')
  return credentials as Record<number, string>
}

export declare namespace parseCredential {
  /** Parsed shared or per-chain credentials. */
  type ReturnType = ChainCredential | undefined
}

/** Resolves a chain credential and infers its HTTP authorization scheme. */
export function resolveCredential(
  options: resolveCredential.Options,
): resolveCredential.ReturnType {
  const credentials = parseCredential(options.value)
  const credential = typeof credentials === 'string' ? credentials : credentials?.[options.chainId]
  if (!credential) return { basicAuth: undefined }
  if (credential.includes(':')) return { basicAuth: credential }
  return { basicAuth: undefined, bearerAuth: credential }
}

export declare namespace resolveCredential {
  /** Options for resolving a chain credential. */
  type Options = {
    /** Chain id selecting a per-chain credential. */
    chainId: number
    /** Shared or per-chain credentials. */
    value?: ChainCredential | undefined
  }

  /** Resolved HTTP authorization credentials. */
  type ReturnType = {
    /** Basic credentials inferred from a value containing a colon. */
    basicAuth: string | undefined
    /** Bearer credential inferred from a value without a colon. */
    bearerAuth?: string | undefined
  }
}