type GenerateIDTokenRequest struct {
	Audience     string `json:"audience"`
	IncludeEmail bool   `json:"includeEmail"`
	// Delegates are the ordered, fully-qualified resource name for service
	// accounts in a delegation chain. Each service account must be granted
	// roles/iam.serviceAccountTokenCreator on the next service account in the
	// chain. The delegates must have the following format:
	// projects/-/serviceAccounts/{ACCOUNT_EMAIL_OR_UNIQUEID}. The - wildcard
	// character is required; replacing it with a project ID is invalid.
	// Optional.
	Delegates []string `json:"delegates,omitempty"`
}

type GenerateIDTokenResponse struct {
	Token string `json:"token"`
}

type IDTokenIAMOptions struct {
	// Client is required.
	Client *http.Client
	// Logger is required.
	Logger              *slog.Logger
	UniverseDomain      auth.CredentialsPropertyProvider
	ServiceAccountEmail string
	GenerateIDTokenRequest
}

type Options struct {
	// Tp is the source credential used to generate a token on the
	// impersonated service account. Required.
	Tp auth.TokenProvider

	// URL is the endpoint to call to generate a token
	// on behalf of the service account. Required.
	URL string
	// Scopes that the impersonated credential should have. Required.
	Scopes []string
	// Delegates are the service account email addresses in a delegation chain.
	// Each service account must be granted roles/iam.serviceAccountTokenCreator
	// on the next service account in the chain. Optional.
	Delegates []string
	// TokenLifetimeSeconds is the number of seconds the impersonation token will
	// be valid for. Defaults to 1 hour if unset. Optional.
	TokenLifetimeSeconds int
	// Client configures the underlying client used to make network requests
	// when fetching tokens. Required.
	Client *http.Client
	// Logger is used for debug logging. If provided, logging will be enabled
	// at the loggers configured level. By default logging is disabled unless
	// enabled by setting GOOGLE_SDK_GO_LOGGING_LEVEL in which case a default
	// logger will be used. Optional.
	Logger *slog.Logger
	// UniverseDomain is the default service domain for a given Cloud universe.
	UniverseDomain string
}