package grpc

import (
	"context"
	"io"
	"net/http"
	"os"

	"go.unistack.org/micro/v3/errors"
	"google.golang.org/grpc/codes"
)

var errMapping = map[int32]codes.Code{
	http.StatusOK:                  codes.OK,
	http.StatusBadRequest:          codes.InvalidArgument,
	http.StatusRequestTimeout:      codes.DeadlineExceeded,
	http.StatusNotFound:            codes.NotFound,
	http.StatusConflict:            codes.AlreadyExists,
	http.StatusForbidden:           codes.PermissionDenied,
	http.StatusUnauthorized:        codes.Unauthenticated,
	http.StatusPreconditionFailed:  codes.FailedPrecondition,
	http.StatusNotImplemented:      codes.Unimplemented,
	http.StatusInternalServerError: codes.Internal,
	http.StatusServiceUnavailable:  codes.Unavailable,
}

// convertCode converts a standard Go error into its canonical code. Note that
// this is only used to translate the error returned by the server applications.
func convertCode(err error) codes.Code {
	switch err {
	case nil:
		return codes.OK
	case io.EOF:
		return codes.OutOfRange
	case io.ErrClosedPipe, io.ErrNoProgress, io.ErrShortBuffer, io.ErrShortWrite, io.ErrUnexpectedEOF:
		return codes.FailedPrecondition
	case os.ErrInvalid:
		return codes.InvalidArgument
	case context.Canceled:
		return codes.Canceled
	case context.DeadlineExceeded:
		return codes.DeadlineExceeded
	}
	switch {
	case os.IsExist(err):
		return codes.AlreadyExists
	case os.IsNotExist(err):
		return codes.NotFound
	case os.IsPermission(err):
		return codes.PermissionDenied
	}
	return codes.Unknown
}

func microError(err error) codes.Code {
	if err == nil {
		return codes.OK
	}

	var ec int32
	if verr, ok := err.(*errors.Error); ok {
		ec = verr.Code
	}

	if code, ok := errMapping[ec]; ok {
		return code
	}

	return codes.Unknown
}