#!/usr/bin/env python
#
# Copyright (C) 2016 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 .controller_error import ControllerError, ControllerNotFoundError
from .link import Link
from .node_types import BUILTIN_NODE_TYPES
from gns3server.utils.packet_filter_validation import validate_bpf_syntax, FilterValidationError


class UDPLink(Link):
    def __init__(self, project, link_id=None):
        super().__init__(project, link_id=link_id)
        self._created = False
        self._link_data = []
        # Runtime-only Node references for marker commands (not serialized).
        self._marker_capture_nodes = {}

    @property
    def debug_link_data(self):
        """
        Use for the debug exports
        """
        return self._link_data
    
    def _get_node_filters(self, node1, node2):
        """
        Determine which node gets the active filters applied.
        
        :returns: Tuple of (node1_filters, node2_filters)
        """
        filter_node = self._get_filter_node()
        return (
            self.get_active_filters() if filter_node == node1 else {},
            self.get_active_filters() if filter_node == node2 else {},
        )

    async def create(self):
        """
        Create the link on the nodes
        """

        node1 = self._nodes[0]["node"]
        adapter_number1 = self._nodes[0]["adapter_number"]
        port_number1 = self._nodes[0]["port_number"]
        node2 = self._nodes[1]["node"]
        adapter_number2 = self._nodes[1]["adapter_number"]
        port_number2 = self._nodes[1]["port_number"]

        # Get an IP allowing communication between both host
        try:
            (node1_host, node2_host) = await node1.compute.get_ip_on_same_subnet(node2.compute)
        except ValueError as e:
            raise ControllerError(f"Cannot get an IP address on same subnet: {e}")

        # Reserve a UDP port on both side
        # Try pre-allocated ports first (used during batch project loading)
        port = self._project.pop_preallocated_udp_port(node1.compute.id)
        if port is not None:
            self._node1_port = port
        else:
            response = await node1.compute.post(f"/projects/{self._project.id}/ports/udp")
            self._node1_port = response.json["udp_port"]
        port = self._project.pop_preallocated_udp_port(node2.compute.id)
        if port is not None:
            self._node2_port = port
        else:
            response = await node2.compute.post(f"/projects/{self._project.id}/ports/udp")
            self._node2_port = response.json["udp_port"]

        node1_filters, node2_filters = self._get_node_filters(node1, node2)

        # Create the tunnel on both side
        self._link_data.append(
            {
                "lport": self._node1_port,
                "rhost": node2_host,
                "rport": self._node2_port,
                "type": "nio_udp",
                "filters": node1_filters,
                "suspend": self._suspended,
            }
        )
        await node1.post(f"/adapters/{adapter_number1}/ports/{port_number1}/nio", data=self._link_data[0], timeout=120)

        self._link_data.append(
            {
                "lport": self._node2_port,
                "rhost": node1_host,
                "rport": self._node1_port,
                "type": "nio_udp",
                "filters": node2_filters,
                "suspend": self._suspended,
            }
        )
        try:
            await node2.post(
                f"/adapters/{adapter_number2}/ports/{port_number2}/nio", data=self._link_data[1], timeout=120
            )
        except Exception as e:
            # We clean the first NIO
            await node1.delete(f"/adapters/{adapter_number1}/ports/{port_number1}/nio", timeout=120)
            raise e
        self._created = True

    async def update(self):
        """
        Update the link on the nodes
        """

        if len(self._link_data) == 0:
            return
        node1 = self._nodes[0]["node"]
        node2 = self._nodes[1]["node"]

        node1_filters, node2_filters = self._get_node_filters(node1, node2)

        adapter_number1 = self._nodes[0]["adapter_number"]
        port_number1 = self._nodes[0]["port_number"]
        self._link_data[0]["filters"] = node1_filters
        self._link_data[0]["suspend"] = self._suspended
        if node1.node_type not in ("ethernet_switch", "ethernet_hub"):
            await node1.put(
                f"/adapters/{adapter_number1}/ports/{port_number1}/nio", data=self._link_data[0], timeout=120
            )

        adapter_number2 = self._nodes[1]["adapter_number"]
        port_number2 = self._nodes[1]["port_number"]
        self._link_data[1]["filters"] = node2_filters
        self._link_data[1]["suspend"] = self._suspended
        if node2.node_type not in ("ethernet_switch", "ethernet_hub"):
            await node2.put(
                f"/adapters/{adapter_number2}/ports/{port_number2}/nio", data=self._link_data[1], timeout=221
            )

    async def delete(self):
        """
        Delete the link and free the resources
        """
        if not self._created:
            return
        try:
            node1 = self._nodes[0]["node"]
            adapter_number1 = self._nodes[0]["adapter_number"]
            port_number1 = self._nodes[0]["port_number"]
        except IndexError:
            return
        try:
            await node1.delete(f"/adapters/{adapter_number1}/ports/{port_number1}/nio", timeout=120)
        # If the node is already deleted (user selected multiple element and delete all in the same time)
        except ControllerNotFoundError:
            pass

        try:
            node2 = self._nodes[1]["node"]
            adapter_number2 = self._nodes[1]["adapter_number"]
            port_number2 = self._nodes[1]["port_number"]
        except IndexError:
            return
        try:
            await node2.delete(f"/adapters/{adapter_number2}/ports/{port_number2}/nio", timeout=120)
        # If the node is already deleted (user selected multiple element and delete all in the same time)
        except ControllerNotFoundError:
            pass
        await super().delete()

    async def reset(self):
        """
        Reset the link.
        """

        # recreate the link on the compute
        await self.delete()
        await self.create()

    async def start_capture(self, data_link_type="DLT_EN10MB", capture_file_name=None, wireshark=False, jwt_token=None):
        """
        Start capture on a link
        """
        if not capture_file_name:
            capture_file_name = self.default_capture_file_name()
        self._capture_node = self._choose_capture_side()
        data = {"capture_file_name": capture_file_name, "data_link_type": data_link_type}
        await self._capture_node["node"].post(
            "/adapters/{adapter_number}/ports/{port_number}/capture/start".format(
                adapter_number=self._capture_node["adapter_number"], port_number=self._capture_node["port_number"]
            ),
            data=data,
        )
        await super().start_capture(data_link_type=data_link_type, capture_file_name=capture_file_name, wireshark=wireshark, jwt_token=jwt_token)

    async def stop_capture(self):
        """
        Stop capture on a link
        """
        if self._capture_node:
            await self._capture_node["node"].post(
                "/adapters/{adapter_number}/ports/{port_number}/capture/stop".format(
                    adapter_number=self._capture_node["adapter_number"], port_number=self._capture_node["port_number"]
                )
            )
            self._capture_node = None
        await super().stop_capture()

    def _choose_capture_side(self):
        """
        Run capture on the best candidate.

        The ideal candidate is a node who on controller server and always
        running (capture will not be cut off)

        :returns: Node where the capture should run
        """

        for node in self._nodes:
            if (
                node["node"].compute.id == "local"
                and node["node"].node_type in BUILTIN_NODE_TYPES
                and node["node"].status == "started"
            ):
                return node

        for node in self._nodes:
            if node["node"].node_type in BUILTIN_NODE_TYPES and node["node"].status == "started":
                return node

        for node in self._nodes:
            if node["node"].compute.id == "local" and node["node"].status == "started":
                return node

        for node in self._nodes:
            if node["node"].node_type and node["node"].status == "started":
                return node

        raise ControllerError("Cannot capture because there is no running device on this link")

    async def node_updated(self, node):
        """
        Called when a node member of the link is updated
        """
        if self._capture_node and node == self._capture_node["node"] and node.status != "started":
            await self.stop_capture()
        # Tear down any marker whose capture-side node just stopped.
        for name, marker_info in list(self._markers.items()):
            if marker_info.get("capture_node_id") == node.id and node.status != "started":
                await self.stop_marker(name)

    def _capture_node_for_marker(self, name):
        """Return the stored (node, adapter_number, port_number) for a marker's capture side."""
        return self._marker_capture_nodes.get(name)

    def _store_capture_node_for_marker(self, name, capture_side):
        """Persist the capture-side identity (serializable refs) + runtime Node."""
        self._markers[name] = {
            **self._markers.get(name, {}),
            "capture_node_id": capture_side["node"].id,
            "capture_adapter": capture_side["adapter_number"],
            "capture_port": capture_side["port_number"],
        }
        self._marker_capture_nodes[name] = capture_side

    async def start_marker(self, name, bpf, tag=None):
        """
        Attach a traffic-insight marker to this link.

        :param name: stable filter name — echoed in MARK signals + pcap identity
        :param bpf: libpcap BPF expression
        :param tag: optional correlation id
        """

        if name in self._markers:
            raise ControllerError(f"Marker '{name}' already exists on link {self._id}")

        # Pre-validate BPF on the controller side before reaching ubridge.
        result = validate_bpf_syntax(bpf)
        if not result.get("valid"):
            raise ControllerError(f"Invalid BPF expression: {result.get('error', 'unknown error')}")

        capture_side = self._choose_capture_side()
        data = {"name": name, "bpf": bpf, "tag": tag, "link_id": self._id}
        await capture_side["node"].post(
            "/adapters/{adapter_number}/ports/{port_number}/markers/start".format(
                adapter_number=capture_side["adapter_number"], port_number=capture_side["port_number"]
            ),
            data=data,
        )
        self._store_capture_node_for_marker(name, capture_side)
        self._markers[name].update({"bpf": bpf, "tag": tag, "enabled": True})
        self._project.emit_notification("link.updated", self.asdict())
        self._project.dump()

    async def stop_marker(self, name):
        """
        Remove a traffic-insight marker from this link.

        :param name: filter name to remove
        """

        if name not in self._markers:
            raise ControllerNotFoundError(f"Marker '{name}' not found on link {self._id}")

        capture_side = self._marker_capture_nodes.get(name)
        if capture_side:
            await capture_side["node"].post(
                "/adapters/{adapter_number}/ports/{port_number}/markers/stop".format(
                    adapter_number=capture_side["adapter_number"],
                    port_number=capture_side["port_number"],
                ),
                data={"name": name},
            )
        self._markers.pop(name, None)
        self._marker_capture_nodes.pop(name, None)
        self._project.emit_notification("link.updated", self.asdict())
        self._project.dump()

    async def update_marker(self, name, bpf=None, tag=None, enabled=None):
        """
        Update an existing marker. A BPF change requires delete+re-add so the
        ubridge side flushes the pcap and the new filter takes effect.

        :param name: filter name to update
        :param bpf: new BPF expression (None = keep existing)
        :param tag: new tag id (None = keep existing)
        :param enabled: toggle (None = keep existing)
        """

        marker_info = self._markers.get(name)
        if not marker_info:
            raise ControllerNotFoundError(f"Marker '{name}' not found on link {self._id}")

        new_bpf = bpf if bpf is not None else marker_info["bpf"]
        new_tag = tag if tag is not None else marker_info.get("tag")
        new_enabled = enabled if enabled is not None else marker_info.get("enabled", True)

        if not new_enabled and marker_info.get("enabled", True):
            # Toggle off: remove from ubridge but keep state.
            await self.stop_marker(name)
            self._markers[name] = {**marker_info, "bpf": new_bpf, "tag": new_tag, "enabled": False}
            self._project.emit_notification("link.updated", self.asdict())
            self._project.dump()
            return

        capture_side = self._marker_capture_nodes.get(name)
        if new_bpf != marker_info.get("bpf") or new_tag != marker_info.get("tag"):
            # BPF or tag changed — re-validate, delete, re-add.
            if new_bpf != marker_info.get("bpf"):
                result = validate_bpf_syntax(new_bpf)
                if not result.get("valid"):
                    raise ControllerError(f"Invalid BPF expression: {result.get('error', 'unknown error')}")
            if capture_side:
                # Delete old filter from ubridge.
                await capture_side["node"].post(
                    "/adapters/{adapter_number}/ports/{port_number}/markers/stop".format(
                        adapter_number=capture_side["adapter_number"],
                        port_number=capture_side["port_number"],
                    ),
                    data={"name": name},
                )
                # Re-add with new params.
                data = {"name": name, "bpf": new_bpf, "tag": new_tag, "link_id": self._id}
                await capture_side["node"].post(
                    "/adapters/{adapter_number}/ports/{port_number}/markers/start".format(
                        adapter_number=capture_side["adapter_number"],
                        port_number=capture_side["port_number"],
                    ),
                    data=data,
                )
            self._markers[name] = {**marker_info, "bpf": new_bpf, "tag": new_tag, "enabled": True}

        self._project.emit_notification("link.updated", self.asdict())
        self._project.dump()