// Copyright (C) 2014 Nippon Telegraph and Telephone Corporation.
//
// 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 bgp

import (
	"fmt"
	"strings"
)

const AS_TRANS = 23456

const BGP_PORT = 179

type FSMState int

const (
	_ FSMState = iota
	BGP_FSM_IDLE
	BGP_FSM_CONNECT
	BGP_FSM_ACTIVE
	BGP_FSM_OPENSENT
	BGP_FSM_OPENCONFIRM
	BGP_FSM_ESTABLISHED
)

// partially taken from http://www.iana.org/assignments/protocol-numbers/protocol-numbers.xhtml
type Protocol int

const (
	Unknown Protocol = iota
	ICMP             = 0x01
	IGMP             = 0x02
	TCP              = 0x06
	EGP              = 0x08
	IGP              = 0x09
	UDP              = 0x11
	RSVP             = 0x2e
	GRE              = 0x2f
	OSPF             = 0x59
	IPIP             = 0x5e
	PIM              = 0x67
	SCTP             = 0x84
)

var ProtocolNameMap = map[Protocol]string{
	Unknown: "unknown",
	ICMP:    "icmp",
	IGMP:    "igmp",
	TCP:     "tcp",
	EGP:     "egp",
	IGP:     "igp",
	UDP:     "udp",
	RSVP:    "rsvp",
	GRE:     "gre",
	OSPF:    "ospf",
	IPIP:    "ipip",
	PIM:     "pim",
	SCTP:    "sctp",
}

var ProtocolValueMap = map[string]Protocol{
	ProtocolNameMap[ICMP]: ICMP,
	ProtocolNameMap[IGMP]: IGMP,
	ProtocolNameMap[TCP]:  TCP,
	ProtocolNameMap[EGP]:  EGP,
	ProtocolNameMap[IGP]:  IGP,
	ProtocolNameMap[UDP]:  UDP,
	ProtocolNameMap[RSVP]: RSVP,
	ProtocolNameMap[GRE]:  GRE,
	ProtocolNameMap[OSPF]: OSPF,
	ProtocolNameMap[IPIP]: IPIP,
	ProtocolNameMap[PIM]:  PIM,
	ProtocolNameMap[SCTP]: SCTP,
}

func (p Protocol) String() string {
	name, ok := ProtocolNameMap[p]
	if !ok {
		return fmt.Sprintf("%d", p)
	}
	return name
}

type TCPFlag int

const (
	TCP_FLAG_FIN    = 0x01
	TCP_FLAG_SYN    = 0x02
	TCP_FLAG_RST    = 0x04
	TCP_FLAG_PUSH   = 0x08
	TCP_FLAG_ACK    = 0x10
	TCP_FLAG_URGENT = 0x20
)

var TCPFlagNameMap = map[TCPFlag]string{
	TCP_FLAG_FIN:    "fin",
	TCP_FLAG_SYN:    "syn",
	TCP_FLAG_RST:    "rst",
	TCP_FLAG_PUSH:   "push",
	TCP_FLAG_ACK:    "ack",
	TCP_FLAG_URGENT: "urgent",
}

var TCPFlagValueMap = map[string]TCPFlag{
	TCPFlagNameMap[TCP_FLAG_FIN]:    TCP_FLAG_FIN,
	TCPFlagNameMap[TCP_FLAG_SYN]:    TCP_FLAG_SYN,
	TCPFlagNameMap[TCP_FLAG_RST]:    TCP_FLAG_RST,
	TCPFlagNameMap[TCP_FLAG_PUSH]:   TCP_FLAG_PUSH,
	TCPFlagNameMap[TCP_FLAG_ACK]:    TCP_FLAG_ACK,
	TCPFlagNameMap[TCP_FLAG_URGENT]: TCP_FLAG_URGENT,
}

func (f TCPFlag) String() string {
	ss := make([]string, 0, 6)
	for _, v := range []TCPFlag{TCP_FLAG_FIN, TCP_FLAG_SYN, TCP_FLAG_RST, TCP_FLAG_PUSH, TCP_FLAG_ACK, TCP_FLAG_URGENT} {
		if f&v > 0 {
			ss = append(ss, TCPFlagNameMap[v])
		}
	}
	return strings.Join(ss, "|")
}