package apiproto

import (
	"fmt"
	"net/http"

	"google.golang.org/grpc/codes"
)

func (x *Error) Error() string {
	return fmt.Sprintf("%d: %s", x.Code, x.Message)
}

// Here we define errors that can be exposed in server API replies.
var (
	// ErrorInternal means server error, if returned this is a signal
	// that something went wrong with Centrifugo itself.
	ErrorInternal = &Error{
		Code:    100,
		Message: "internal server error",
	}
	// ErrorUnknownChannel means that namespace in channel name does not exist.
	ErrorUnknownChannel = &Error{
		Code:    102,
		Message: "unknown channel",
	}
	// ErrorNotFound means that method sent in command does not exist.
	ErrorNotFound = &Error{
		Code:    104,
		Message: "not found",
	}
	// ErrorBadRequest says that Centrifugo can not parse received data
	// because it is malformed.
	ErrorBadRequest = &Error{
		Code:    107,
		Message: "bad request",
	}
	// ErrorNotAvailable means that resource is not enabled.
	ErrorNotAvailable = &Error{
		Code:    108,
		Message: "not available",
	}
	// ErrorUnrecoverablePosition means that stream does not contain required
	// range of publications to fulfill a history query. This can be happen to
	// expiration, size limitation or due to wrong epoch.
	ErrorUnrecoverablePosition = &Error{
		Code:    112,
		Message: "unrecoverable position",
	}
	// ErrorConflict ...
	ErrorConflict = &Error{
		Code:    113,
		Message: "conflict",
	}
)

func MapErrorToHTTPCode(err *Error) int {
	switch err.Code {
	case ErrorInternal.Code:
		return http.StatusInternalServerError
	case ErrorUnknownChannel.Code, ErrorNotFound.Code:
		return http.StatusNotFound
	case ErrorBadRequest.Code, ErrorNotAvailable.Code:
		return http.StatusBadRequest
	case ErrorUnrecoverablePosition.Code:
		return http.StatusRequestedRangeNotSatisfiable
	case ErrorConflict.Code:
		return http.StatusConflict
	default:
		// Default to Internal Server Error for unmapped errors.
		// In general should be avoided - all new API errors must be explicitly described here.
		return http.StatusInternalServerError
	}
}

func MapErrorToGRPCCode(err *Error) codes.Code {
	switch err.Code {
	case ErrorInternal.Code:
		return codes.Internal
	case ErrorUnknownChannel.Code, ErrorNotFound.Code:
		return codes.NotFound
	case ErrorBadRequest.Code, ErrorNotAvailable.Code:
		return codes.InvalidArgument
	case ErrorUnrecoverablePosition.Code:
		return codes.OutOfRange
	case ErrorConflict.Code:
		return codes.AlreadyExists
	default:
		// Default to Internal Error for unmapped errors.
		// In general should be avoided - all new API errors must be explicitly described here.
		return codes.Internal
	}
}