//===----------------------------------------------------------------------===//

//

// This source file is part of the SwiftNIO open source project

//

// Copyright (c) 2022 Apple Inc. and the SwiftNIO project authors

// Licensed under Apache License v2.0

//

// See LICENSE.txt for license information

// See CONTRIBUTORS.txt for the list of SwiftNIO project authors

//

// SPDX-License-Identifier: Apache-2.0

//

//===----------------------------------------------------------------------===//

/// In the Internet Protocol version 4 (IPv4) [RFC791] there is a field

/// called "Protocol" to identify the next level protocol.  This is an 8

/// bit field.  In Internet Protocol version 6 (IPv6) [RFC8200], this field

/// is called the "Next Header" field.

public struct NIOIPProtocol: RawRepresentable, Hashable, Sendable {

    public typealias RawValue = UInt8

    public var rawValue: RawValue

    @inlinable

    public init(rawValue: RawValue) {

        self.rawValue = rawValue

    }

}

extension NIOIPProtocol {

    /// - precondition: `rawValue` must fit into an `UInt8`

    public init(_ rawValue: Int) {

        self.init(rawValue: UInt8(rawValue))

    }

}

// Subset of https://www.iana.org/assignments/protocol-numbers/protocol-numbers.xhtml with an RFC

extension NIOIPProtocol {

    /// IPv6 Hop-by-Hop Option - [RFC8200]

    @inlinable

    public static var hopopt: NIOIPProtocol {

        Self(rawValue: 0)

    }

    /// Internet Control Message - [RFC792]

    @inlinable

    public static var icmp: NIOIPProtocol {

        Self(rawValue: 1)

    }

    /// Internet Group Management - [RFC1112]

    @inlinable

    public static var igmp: NIOIPProtocol {

        Self(rawValue: 2)

    }

    /// Gateway-to-Gateway - [RFC823]

    @inlinable

    public static var ggp: NIOIPProtocol {

        Self(rawValue: 3)

    }

    /// IPv4 encapsulation - [RFC2003]

    @inlinable

    public static var ipv4: NIOIPProtocol {

        Self(rawValue: 4)

    }

    /// Stream - [RFC1190][RFC1819]

    @inlinable

    public static var st: NIOIPProtocol {

        Self(rawValue: 5)

    }

    /// Transmission Control - [RFC9293]

    @inlinable

    public static var tcp: NIOIPProtocol {

        Self(rawValue: 6)

    }

    /// Exterior Gateway Protocol - [RFC888][David_Mills]

    @inlinable

    public static var egp: NIOIPProtocol {

        Self(rawValue: 8)

    }

    /// Network Voice Protocol - [RFC741][Steve_Casner]

    @inlinable

    public static var nvpIi: NIOIPProtocol {

        Self(rawValue: 11)

    }

    /// User Datagram - [RFC768][Jon_Postel]

    @inlinable

    public static var udp: NIOIPProtocol {

        Self(rawValue: 17)

    }

    /// Host Monitoring - [RFC869][Bob_Hinden]

    @inlinable

    public static var hmp: NIOIPProtocol {

        Self(rawValue: 20)

    }

    /// Reliable Data Protocol - [RFC908][Bob_Hinden]

    @inlinable

    public static var rdp: NIOIPProtocol {

        Self(rawValue: 27)

    }

    /// Internet Reliable Transaction - [RFC938][Trudy_Miller]

    @inlinable

    public static var irtp: NIOIPProtocol {

        Self(rawValue: 28)

    }

    /// ISO Transport Protocol Class 4 - [RFC905][<mystery contact>]

    @inlinable

    public static var isoTp4: NIOIPProtocol {

        Self(rawValue: 29)

    }

    /// Bulk Data Transfer Protocol - [RFC969][David_Clark]

    @inlinable

    public static var netblt: NIOIPProtocol {

        Self(rawValue: 30)

    }

    /// Datagram Congestion Control Protocol - [RFC4340]

    @inlinable

    public static var dccp: NIOIPProtocol {

        Self(rawValue: 33)

    }

    /// IPv6 encapsulation - [RFC2473]

    @inlinable

    public static var ipv6: NIOIPProtocol {

        Self(rawValue: 41)

    }

    /// Reservation Protocol - [RFC2205][RFC3209][Bob_Braden]

    @inlinable

    public static var rsvp: NIOIPProtocol {

        Self(rawValue: 46)

    }

    /// Generic Routing Encapsulation - [RFC2784][Tony_Li]

    @inlinable

    public static var gre: NIOIPProtocol {

        Self(rawValue: 47)

    }

    /// Dynamic Source Routing Protocol - [RFC4728]

    @inlinable

    public static var dsr: NIOIPProtocol {

        Self(rawValue: 48)

    }

    /// Encap Security Payload - [RFC4303]

    @inlinable

    public static var esp: NIOIPProtocol {

        Self(rawValue: 50)

    }

    /// Authentication Header - [RFC4302]

    @inlinable

    public static var ah: NIOIPProtocol {

        Self(rawValue: 51)

    }

    /// NBMA Address Resolution Protocol - [RFC1735]

    @inlinable

    public static var narp: NIOIPProtocol {

        Self(rawValue: 54)

    }

    /// ICMP for IPv6 - [RFC8200]

    @inlinable

    public static var ipv6Icmp: NIOIPProtocol {

        Self(rawValue: 58)

    }

    /// No Next Header for IPv6 - [RFC8200]

    @inlinable

    public static var ipv6Nonxt: NIOIPProtocol {

        Self(rawValue: 59)

    }

    /// Destination Options for IPv6 - [RFC8200]

    @inlinable

    public static var ipv6Opts: NIOIPProtocol {

        Self(rawValue: 60)

    }

    /// EIGRP - [RFC7868]

    @inlinable

    public static var eigrp: NIOIPProtocol {

        Self(rawValue: 88)

    }

    /// OSPFIGP - [RFC1583][RFC2328][RFC5340][John_Moy]

    @inlinable

    public static var ospfigp: NIOIPProtocol {

        Self(rawValue: 89)

    }

    /// Ethernet-within-IP Encapsulation - [RFC3378]

    @inlinable

    public static var etherip: NIOIPProtocol {

        Self(rawValue: 97)

    }

    /// Encapsulation Header - [RFC1241][Robert_Woodburn]

    @inlinable

    public static var encap: NIOIPProtocol {

        Self(rawValue: 98)

    }

    /// Protocol Independent Multicast - [RFC7761][Dino_Farinacci]

    @inlinable

    public static var pim: NIOIPProtocol {

        Self(rawValue: 103)

    }

    /// IP Payload Compression Protocol - [RFC2393]

    @inlinable

    public static var ipcomp: NIOIPProtocol {

        Self(rawValue: 108)

    }

    /// Virtual Router Redundancy Protocol - [RFC5798]

    @inlinable

    public static var vrrp: NIOIPProtocol {

        Self(rawValue: 112)

    }

    /// Layer Two Tunneling Protocol - [RFC3931][Bernard_Aboba]

    @inlinable

    public static var l2tp: NIOIPProtocol {

        Self(rawValue: 115)

    }

    /// Fibre Channel - [Murali_Rajagopal][RFC6172]

    @inlinable

    public static var fc: NIOIPProtocol {

        Self(rawValue: 133)

    }

    /// MANET Protocols - [RFC5498]

    @inlinable

    public static var manet: NIOIPProtocol {

        Self(rawValue: 138)

    }

    /// Host Identity Protocol - [RFC7401]

    @inlinable

    public static var hip: NIOIPProtocol {

        Self(rawValue: 139)

    }

    /// Shim6 Protocol - [RFC5533]

    @inlinable

    public static var shim6: NIOIPProtocol {

        Self(rawValue: 140)

    }

    /// Wrapped Encapsulating Security Payload - [RFC5840]

    @inlinable

    public static var wesp: NIOIPProtocol {

        Self(rawValue: 141)

    }

    /// Robust Header Compression - [RFC5858]

    @inlinable

    public static var rohc: NIOIPProtocol {

        Self(rawValue: 142)

    }

    /// Ethernet - [RFC8986]

    @inlinable

    public static var ethernet: NIOIPProtocol {

        Self(rawValue: 143)

    }

    /// AGGFRAG encapsulation payload for ESP - [RFC-ietf-ipsecme-iptfs-19]

    @inlinable

    public static var aggfrag: NIOIPProtocol {

        Self(rawValue: 144)

    }

}

extension NIOIPProtocol: CustomStringConvertible {

    private var name: String? {

        switch self {

        case .hopopt: return "IPv6 Hop-by-Hop Option"

        case .icmp: return "Internet Control Message"

        case .igmp: return "Internet Group Management"

        case .ggp: return "Gateway-to-Gateway"

        case .ipv4: return "IPv4 encapsulation"

        case .st: return "Stream"

        case .tcp: return "Transmission Control"

        case .egp: return "Exterior Gateway Protocol"

        case .nvpIi: return "Network Voice Protocol"

        case .udp: return "User Datagram"

        case .hmp: return "Host Monitoring"

        case .rdp: return "Reliable Data Protocol"

        case .irtp: return "Internet Reliable Transaction"

        case .isoTp4: return "ISO Transport Protocol Class 4"

        case .netblt: return "Bulk Data Transfer Protocol"

        case .dccp: return "Datagram Congestion Control Protocol"

        case .ipv6: return "IPv6 encapsulation"

        case .rsvp: return "Reservation Protocol"

        case .gre: return "Generic Routing Encapsulation"

        case .dsr: return "Dynamic Source Routing Protocol"

        case .esp: return "Encap Security Payload"

        case .ah: return "Authentication Header"

        case .narp: return "NBMA Address Resolution Protocol"

        case .ipv6Icmp: return "ICMP for IPv6"

        case .ipv6Nonxt: return "No Next Header for IPv6"

        case .ipv6Opts: return "Destination Options for IPv6"

        case .eigrp: return "EIGRP"

        case .ospfigp: return "OSPFIGP"

        case .etherip: return "Ethernet-within-IP Encapsulation"

        case .encap: return "Encapsulation Header"

        case .pim: return "Protocol Independent Multicast"

        case .ipcomp: return "IP Payload Compression Protocol"

        case .vrrp: return "Virtual Router Redundancy Protocol"

        case .l2tp: return "Layer Two Tunneling Protocol"

        case .fc: return "Fibre Channel"

        case .manet: return "MANET Protocols"

        case .hip: return "Host Identity Protocol"

        case .shim6: return "Shim6 Protocol"

        case .wesp: return "Wrapped Encapsulating Security Payload"

        case .rohc: return "Robust Header Compression"

        case .ethernet: return "Ethernet"

        case .aggfrag: return "AGGFRAG encapsulation payload for ESP"

        default: return nil

        }

    }

    public var description: String {

        let name = self.name ?? "Unknown Protocol"

        return "\(name) - \(rawValue)"

    }

}