package merrors

import (
	"errors"
	"strings"
	"time"
)

// ThrottleDetails describes a temporary request limit without coupling callers
// to a transport-specific response format.
type ThrottleDetails struct {
	ScopeKind  string
	RetryAfter time.Duration
}

type throttleDetailsError struct {
	base    error
	msg     string
	details ThrottleDetails
}

func (e throttleDetailsError) Error() string {
	return Wrap(e.base, e.msg).Error()
}

func (e throttleDetailsError) Unwrap() error {
	return e.base
}

// WithThrottle annotates an error with retry information while preserving its
// classification for errors.Is and errors.As.
func WithThrottle(base error, scopeKind string, retryAfter time.Duration, msg string) error {
	return throttleDetailsError{
		base: base,
		msg:  msg,
		details: ThrottleDetails{
			ScopeKind:  strings.TrimSpace(scopeKind),
			RetryAfter: retryAfter,
		},
	}
}

// ThrottleDetailsFrom returns retry information attached by WithThrottle.
func ThrottleDetailsFrom(err error) (ThrottleDetails, bool) {
	var throttled throttleDetailsError
	if !errors.As(err, &throttled) {
		return ThrottleDetails{}, false
	}
	return throttled.details, true
}