// Copyright 2018 Bull S.A.S. Atos Technologies - Bull, Rue Jean Jaures, B.P.68, 78340, Les Clayes-sous-Bois, France.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package plugin

import (
	"fmt"

	"github.com/pkg/errors"
)

// RPCError is a wrapper dedicated to allow passing errors via RPC encoding
// It must be used for RPC server side in the response call method (ie plugin side actually)
type RPCError struct {
	Message string
	Stack   string
}

type stackTracer interface {
	StackTrace() errors.StackTrace
}

// This allows RPCError to implement error and display message plus stack
func (pErr *RPCError) Error() string {
	return fmt.Sprintf("%s%s", pErr.Message, pErr.Stack)
}

// RPCError needs to be explicitly typed "nil" before casting to error
// https://golang.org/doc/faq#nil_error
func toError(pErr *RPCError) error {
	if pErr != nil {
		return pErr
	}

	return nil
}

// NewRPCError allows to instantiate a RPCError from an error builtin type
func NewRPCError(err error) *RPCError {
	return &RPCError{Message: err.Error(), Stack: getStackTrace(err)}
}

// NewRPCErrorFromMessage allows to instantiate a RPCError from a message and variadic arguments
func NewRPCErrorFromMessage(m string, args ...interface{}) *RPCError {
	return &RPCError{Message: fmt.Sprintf(m, args...)}
}

// Internal : getStackTrace allows to get the error extended format.
// Each Frame of the error's StackTrace will be printed in detail.
func getStackTrace(err error) string {
	var stack string
	if err, ok := err.(stackTracer); ok {
		stack = fmt.Sprintf("%+v", err.StackTrace())
	}
	return stack
}