#
# Copyright (C) 2020 GNS3 Technologies Inc.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.


from enum import Enum
from typing import List, Optional, Union

from pydantic import BaseModel, Field


class UDPNIOType(str, Enum):
    udp = "nio_udp"


class UDPNIO(BaseModel):
    """
    UDP Network Input/Output properties.
    """

    type: UDPNIOType
    lport: int = Field(..., gt=0, le=65535, description="Local port")
    rhost: str = Field(..., description="Remote host")
    rport: int = Field(..., gt=0, le=65535, description="Remote port")
    suspend: Optional[bool] = Field(None, description="Suspend the NIO")
    filters: Optional[dict] = Field(
        None,
        description="Packet filters (relay-supported types only: delay/packet_loss/corrupt/frequency_drop/bpf — "
        "the netem extensions and the quota mode need a kernel-datapath NIO)",
    )
    markers: Optional[dict] = Field(None, description="Traffic-insight markers")


class EthernetNIOType(str, Enum):
    ethernet = "nio_ethernet"


class EthernetNIO(BaseModel):
    """
    Generic Ethernet Network Input/Output properties.
    """

    type: EthernetNIOType
    ethernet_device: str = Field(..., description="Ethernet device name e.g. eth0")


class TAPNIOType(str, Enum):
    tap = "nio_tap"


class TAPNIO(BaseModel):
    """
    TAP Network Input/Output properties.
    """

    type: TAPNIOType
    tap_device: str = Field(..., description="TAP device name e.g. tap0")


class BridgeNIOType(str, Enum):
    bridge = "nio_bridge"


class BridgeNIO(BaseModel):
    """
    Kernel-datapath bridge Network Input/Output properties. The NIO tells the
    node to enslave its veth host end into the named kernel bridge instead of
    wiring a uBridge UDP relay. Impairment filters run on the veth host end:
    delay/packet_loss/corrupt and the netem extensions (rate, reorder,
    gemodel, duplicate, seed, limit, jitter distributions, loss correlation)
    as one tc netem qdisc, bpf as cls_bpf match-drop classifiers (needs a
    uBridge reporting cbpf), frequency_drop and quota as the eBPF stateful
    classifier (needs ebpf). Markers and packet capture are served by
    uBridge's AF_PACKET modules on the veth host end.

    ``bridge`` may be None: the anchor is then bridged by an Ethernet switch
    (its own kernel bridge absorbed it) and the node applies only carrier,
    markers and impairments — never bridge membership.
    """

    type: BridgeNIOType
    # Required-but-nullable: the NIO factories read nio_settings["bridge"],
    # and the create/update routes drop unset fields — an omitted key would
    # pass validation and then surface as a KeyError (500) during binding.
    bridge: Optional[str] = Field(
        ...,
        description="Kernel bridge name e.g. gns3a1b2c3d4e5; None when an Ethernet switch "
        "owns the anchor's bridge membership (absorbed link)",
    )
    suspend: Optional[bool] = Field(None, description="Suspend the NIO")
    filters: Optional[dict] = Field(
        None,
        description="Packet filters served on the veth host end (netem surface + extensions via one tc netem qdisc, "
        "bpf via cls_bpf, frequency_drop/quota via the eBPF classifier)",
    )
    markers: Optional[dict] = Field(None, description="Traffic-insight markers (attached to the veth host end)")


class AnchorNIOType(str, Enum):
    anchor = "nio_anchor"


class AnchorNIO(BaseModel):
    """
    Anchor-absorbing Network Input/Output properties, for a node that owns a
    kernel bridge (the Ethernet switch): the named foreign interface — the
    peer's kernel-datapath anchor — is joined to the node's own bridge with
    the node's port settings applied to it. The mirror of BridgeNIO; filters,
    markers and capture ride the NIO and attach to the named anchor.
    """

    type: AnchorNIOType
    anchor: str = Field(..., description="Host interface to absorb e.g. gv00010203e0p0")
    peer: Optional[str] = Field(
        None,
        description="Switch-to-switch cascade: the other end of the veth pair this port is one end of. Present on "
        "exactly one side (the owner, which creates and destroys the pair); absent for an absorbed anchor",
    )
    suspend: Optional[bool] = Field(None, description="Suspend the NIO")
    filters: Optional[dict] = Field(
        None,
        description="Packet filters served on the absorbed anchor (netem surface + extensions via one tc netem "
        "qdisc, bpf via cls_bpf, frequency_drop/quota via the eBPF classifier)",
    )
    markers: Optional[dict] = Field(None, description="Traffic-insight markers (attached to the absorbed anchor)")


class MarkerToggle(BaseModel):
    """
    Body for the per-marker enable/disable toggle endpoint: flips a running
    uBridge marker filter with ``enable_packet_filter on|off`` (no NIO rebuild,
    so the pcap identity and emitted counter are preserved).
    """

    enabled: bool


class MarkerRebuild(BaseModel):
    """
    Body for the per-marker rebuild endpoint: re-install a single uBridge marker
    filter with new BPF/tag/direction via ``delete_packet_filter`` + add (NOT a
    bridge-wide reset), so sibling markers keep their pcaps open. The marker's
    own pcap is reopened by uBridge on re-add (new capture session for the new
    BPF), which is expected.
    """

    bpf: str
    tag: Optional[int] = None
    direction: Optional[str] = None
    enabled: bool = True
    link_id: str = ""


class BatchNIOEntry(BaseModel):
    """
    A single NIO binding to create as part of a project-wide batch.
    """

    node_id: str = Field(..., description="Node the NIO is attached to")
    adapter_number: int = Field(0, ge=0, description="Adapter number")
    port_number: int = Field(0, ge=0, description="Port number")
    nio: Union[UDPNIO, BridgeNIO, AnchorNIO] = Field(..., description="NIO settings")


class BatchNIOCreate(BaseModel):
    """
    Body for the project-wide batch NIO endpoint: create many NIO bindings in a
    single request (used during project open) to avoid one HTTP round-trip per
    NIO between controller and compute.
    """

    nios: List[BatchNIOEntry] = Field(..., description="NIO bindings to create")