# Copyright (c) 2023-2026 Arista Networks, Inc.
# Use of this source code is governed by the Apache License 2.0
# that can be found in the LICENSE file.
"""Module containing input models for routing IS-IS tests."""

from __future__ import annotations

from ipaddress import IPv4Address, IPv4Network
from typing import Any, Literal
from warnings import warn

from pydantic import BaseModel, ConfigDict

from anta.custom_types import Interface


class ISISInstance(BaseModel):
    """Model for an IS-IS instance."""

    model_config = ConfigDict(extra="forbid")
    name: str
    """The name of the IS-IS instance."""
    vrf: str = "default"
    """VRF context of the IS-IS instance."""
    dataplane: Literal["MPLS", "mpls", "unset"] = "MPLS"
    """Configured SR data-plane for the IS-IS instance."""
    segments: list[Segment] | None = None
    """List of IS-IS SR segments associated with the instance. Required field in the `VerifyISISSegmentRoutingAdjacencySegments` test."""
    graceful_restart: bool = False
    """Graceful restart status."""
    graceful_restart_helper: bool = True
    """Graceful restart helper status."""

    def __str__(self) -> str:
        """Return a human-readable string representation of the ISISInstance for reporting."""
        return f"Instance: {self.name} VRF: {self.vrf}"


class Segment(BaseModel):
    """Model for an IS-IS segment."""

    model_config = ConfigDict(extra="forbid")
    interface: Interface
    """Local interface name."""
    level: Literal[1, 2] = 2
    """IS-IS level of the segment."""
    sid_origin: Literal["dynamic", "configured"] = "dynamic"
    """Origin of the segment ID."""
    address: IPv4Address
    """Adjacency IPv4 address of the segment."""

    def __str__(self) -> str:
        """Return a human-readable string representation of the Segment for reporting."""
        return f"Local Intf: {self.interface} Adj IP Address: {self.address}"


class ISISInterface(BaseModel):
    """Model for an IS-IS enabled interface."""

    model_config = ConfigDict(extra="forbid")
    name: Interface
    """Interface name."""
    vrf: str = "default"
    """VRF context of the interface."""
    level: Literal[1, 2] = 2
    """IS-IS level of the interface."""
    count: int | None = None
    """Expected number of IS-IS neighbors on this interface. Required field in the `VerifyISISNeighborCount` test."""
    mode: Literal["point-to-point", "broadcast", "passive"] | None = None
    """IS-IS network type of the interface. Required field in the `VerifyISISInterfaceMode` test."""

    def __str__(self) -> str:
        """Return a human-readable string representation of the ISISInterface for reporting."""
        return f"Interface: {self.name} VRF: {self.vrf} Level: {self.level}"


class InterfaceCount(ISISInterface):  # pragma: no cover
    """Alias for the ISISInterface model to maintain backward compatibility.

    When initialized, it will emit a deprecation warning and call the ISISInterface model.

    TODO: Remove this class in ANTA v2.0.0.
    """

    def __init__(self, **data: Any) -> None:  # noqa: ANN401
        """Initialize the InterfaceCount class, emitting a deprecation warning."""
        warn(
            message="InterfaceCount model is deprecated and will be removed in ANTA v2.0.0. Use the ISISInterface model instead.",
            category=DeprecationWarning,
            stacklevel=2,
        )
        super().__init__(**data)


class InterfaceState(ISISInterface):  # pragma: no cover
    """Alias for the ISISInterface model to maintain backward compatibility.

    When initialized, it will emit a deprecation warning and call the ISISInterface model.

    TODO: Remove this class in ANTA v2.0.0.
    """

    def __init__(self, **data: Any) -> None:  # noqa: ANN401
        """Initialize the InterfaceState class, emitting a deprecation warning."""
        warn(
            message="InterfaceState model is deprecated and will be removed in ANTA v2.0.0. Use the ISISInterface model instead.",
            category=DeprecationWarning,
            stacklevel=2,
        )
        super().__init__(**data)


class IsisInstance(ISISInstance):  # pragma: no cover
    """Alias for the ISISInstance model to maintain backward compatibility.

    When initialized, it will emit a deprecation warning and call the ISISInstance model.

    TODO: Remove this class in ANTA v2.0.0.
    """

    def __init__(self, **data: Any) -> None:  # noqa: ANN401
        """Initialize the IsisInstance class, emitting a deprecation warning."""
        warn(
            message="IsisInstance model is deprecated and will be removed in ANTA v2.0.0. Use the ISISInstance model instead.",
            category=DeprecationWarning,
            stacklevel=2,
        )
        super().__init__(**data)


class Tunnel(BaseModel):
    """Model for a IS-IS SR tunnel."""

    model_config = ConfigDict(extra="forbid")
    endpoint: IPv4Network
    """Endpoint of the tunnel."""
    vias: list[TunnelPath] | None = None
    """Optional list of paths to reach the endpoint."""

    def __str__(self) -> str:
        """Return a human-readable string representation of the Tunnel for reporting."""
        return f"Endpoint: {self.endpoint}"


class TunnelPath(BaseModel):
    """Model for a IS-IS tunnel path."""

    model_config = ConfigDict(extra="forbid")
    nexthop: IPv4Address | None = None
    """Nexthop of the tunnel."""
    type: Literal["ip", "tunnel"] | None = None
    """Type of the tunnel."""
    interface: Interface | None = None
    """Interface of the tunnel."""
    tunnel_id: Literal["TI-LFA", "ti-lfa", "unset"] | None = None
    """Computation method of the tunnel."""

    def __str__(self) -> str:
        """Return a human-readable string representation of the TunnelPath for reporting."""
        base_string = ""
        if self.nexthop:
            base_string += f" Next-hop: {self.nexthop}"
        if self.type:
            base_string += f" Type: {self.type}"
        if self.interface:
            base_string += f" Interface: {self.interface}"
        if self.tunnel_id:
            base_string += f" Tunnel ID: {self.tunnel_id}"

        return base_string.lstrip()


class Entry(Tunnel):  # pragma: no cover
    """Alias for the Tunnel model to maintain backward compatibility.

    When initialized, it will emit a deprecation warning and call the Tunnel model.

    TODO: Remove this class in ANTA v2.0.0.
    """

    def __init__(self, **data: Any) -> None:  # noqa: ANN401
        """Initialize the Entry class, emitting a deprecation warning."""
        warn(
            message="Entry model is deprecated and will be removed in ANTA v2.0.0. Use the Tunnel model instead.",
            category=DeprecationWarning,
            stacklevel=2,
        )
        super().__init__(**data)


class Vias(TunnelPath):  # pragma: no cover
    """Alias for the TunnelPath model to maintain backward compatibility.

    When initialized, it will emit a deprecation warning and call the TunnelPath model.

    TODO: Remove this class in ANTA v2.0.0.
    """

    def __init__(self, **data: Any) -> None:  # noqa: ANN401
        """Initialize the Vias class, emitting a deprecation warning."""
        warn(
            message="Vias model is deprecated and will be removed in ANTA v2.0.0. Use the TunnelPath model instead.",
            category=DeprecationWarning,
            stacklevel=2,
        )
        super().__init__(**data)
