// +build go1.6,!go1.7

/*
 * Copyright 2016, Google Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

package grpc

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

	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
	"google.golang.org/grpc/transport"

	"golang.org/x/net/context"
)

// dialContext connects to the address on the named network.
func dialContext(ctx context.Context, network, address string) (net.Conn, error) {
	return (&net.Dialer{Cancel: ctx.Done()}).Dial(network, address)
}

func sendHTTPRequest(ctx context.Context, req *http.Request, conn net.Conn) error {
	req.Cancel = ctx.Done()
	if err := req.Write(conn); err != nil {
		return fmt.Errorf("failed to write the HTTP request: %v", err)
	}
	return nil
}

// toRPCErr converts an error into an error from the status package.
func toRPCErr(err error) error {
	if _, ok := status.FromError(err); ok {
		return err
	}
	switch e := err.(type) {
	case transport.StreamError:
		return status.Error(e.Code, e.Desc)
	case transport.ConnectionError:
		return status.Error(codes.Internal, e.Desc)
	default:
		switch err {
		case context.DeadlineExceeded:
			return status.Error(codes.DeadlineExceeded, err.Error())
		case context.Canceled:
			return status.Error(codes.Canceled, err.Error())
		case ErrClientConnClosing:
			return status.Error(codes.FailedPrecondition, err.Error())
		}
	}
	return status.Error(codes.Unknown, err.Error())
}

// 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
}