/*
 *
 * 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 stats

import (
	"net"

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

// ConnTagInfo defines the relevant information needed by connection context tagger.
type ConnTagInfo struct {
	// RemoteAddr is the remote address of the corresponding connection.
	RemoteAddr net.Addr
	// LocalAddr is the local address of the corresponding connection.
	LocalAddr net.Addr
	// TODO add QOS related fields.
}

// RPCTagInfo defines the relevant information needed by RPC context tagger.
type RPCTagInfo struct {
	// FullMethodName is the RPC method in the format of /package.service/method.
	FullMethodName string
}

// Handler defines the interface for the related stats handling (e.g., RPCs, connections).
type Handler interface {
	// TagRPC can attach some information to the given context.
	// The returned context is used in the rest lifetime of the RPC.
	TagRPC(context.Context, *RPCTagInfo) context.Context
	// HandleRPC processes the RPC stats.
	HandleRPC(context.Context, RPCStats)

	// TagConn can attach some information to the given context.
	// The returned context will be used for stats handling.
	// For conn stats handling, the context used in HandleConn for this
	// connection will be derived from the context returned.
	// For RPC stats handling,
	//  - On server side, the context used in HandleRPC for all RPCs on this
	// connection will be derived from the context returned.
	//  - On client side, the context is not derived from the context returned.
	TagConn(context.Context, *ConnTagInfo) context.Context
	// HandleConn processes the Conn stats.
	HandleConn(context.Context, ConnStats)
}