"""Modifications to the flow table from the controller."""

# System imports
from enum import Enum

# Local source tree imports
from pyof.v0x01.common.flow_match import Match
from pyof.v0x01.common.header import Header, Type
from pyof.v0x01.common.phy_port import Port
from pyof.v0x01.controller2switch.common import ListOfActions
from pyof.v0x01.foundation.base import GenericBitMask, GenericMessage
from pyof.v0x01.foundation.basic_types import UBInt16, UBInt32, UBInt64

# Third-party imports

__all__ = ('FlowMod', 'FlowModCommand', 'FlowModFlags')

# Enums


class FlowModCommand(Enum):
    """List the possible commands for a flow."""

    #: New flow
    OFPFC_ADD = 0
    #: Modify all flows
    OFPFC_MODIFY = 1
    #: Modify entry strictly matching wildcards
    OFPFC_MODIFY_STRICT = 2
    #: Delete all matching flows
    OFPFC_DELETE = 3
    #: Strictly match wildcards and priority
    OFPFC_DELETE_STRICT = 4


class FlowModFlags(GenericBitMask):
    """Types to be used in Flags field."""

    #: Send flow removed message when flow expires or is deleted
    OFPFF_SEND_FLOW_REM = 1 << 0
    #: Check for overlapping entries first
    OFPFF_CHECK_OVERLAP = 1 << 1
    #: Remark this is for emergency
    OFPFF_EMERG = 1 << 2


# Classes


class FlowMod(GenericMessage):
    """Modifies the flow table from the controller."""

    header = Header(message_type=Type.OFPT_FLOW_MOD)
    match = Match()
    cookie = UBInt64()
    command = UBInt16(enum_ref=FlowModCommand)
    idle_timeout = UBInt16()
    hard_timeout = UBInt16()
    priority = UBInt16()
    buffer_id = UBInt32()
    out_port = UBInt16(enum_ref=Port)
    flags = UBInt16(enum_ref=FlowModFlags)
    actions = ListOfActions()

    def __init__(self, xid=None, match=None, cookie=None, command=None,
                 idle_timeout=None, hard_timeout=None, priority=None,
                 buffer_id=None, out_port=None, flags=None, actions=None):
        """The constructor just assings parameters to object attributes.

        Args:
            xid (int): xid to be used on the message header.
            match (Match): Fields to match.
            cookie (int): Opaque controller-issued identifier.
            command (FlowModCommand): One of OFPFC_*.
            idle_timeout (int): Idle time before discarding (seconds).
            hard_timeout (int): Max time before discarding (seconds).
            priority (int): Priority level of flow entry.
            buffer_idle (int): Buffered packet to apply to (or -1).
                Not meaningful for OFPFC_DELETE*.
            out_port (Port): For OFPFC_DELETE* commands, require matching
                entries to include this as an output port.
                A value of OFPP_NONE indicates no restriction.
            flags (FlowModFlags): One of OFPFF_*.
            actions (ListOfActions): The action length is inferred from the
                length field in the header.
        """
        super().__init__(xid)
        self.match = match
        self.cookie = cookie
        self.command = command
        self.idle_timeout = idle_timeout
        self.hard_timeout = hard_timeout
        self.priority = priority
        self.buffer_id = buffer_id
        self.out_port = out_port
        self.flags = flags
        self.actions = [] if actions is None else actions