import grpc

from backend.gobgp_api import gobgp_pb2_grpc, attribute_pb2
from backend.gobgp_api.gobgp_pb2 import TableType, Family, ListPeerRequest, ListPathRequest


def get_bgp_data(gobgp_host):
    _timeout = 10

    channel = grpc.insecure_channel('{}:50051'.format(gobgp_host))
    stub = gobgp_pb2_grpc.GobgpApiStub(channel)
    data = []

    peers = stub.ListPeer(ListPeerRequest(), _timeout)
    for peer in peers:
        entry = {
            "local_id": peer.peer.state.router_id,
            "local_as": peer.peer.conf.peer_as,
            "peers": [],  # we don't export any peers
            "routes": [],
        }
        neigh = peer.peer.conf.neighbor_address

        for af in [Family.Afi.AFI_IP, Family.Afi.AFI_IP6]:
            req = ListPathRequest(
                name=neigh,
                table_type=TableType.ADJ_IN,
                family=Family(afi=af, safi=Family.Safi.SAFI_UNICAST),
                sort_type=ListPathRequest.SortType.PREFIX)
            rib = stub.ListPath(req)
            for dest in rib:
                prefix = dest.destination.prefix
                for path in dest.destination.paths:
                    as_path = []
                    next_hop = "<unknown>"  # currently here to prevent error from NOT NULL constraint

                    # parse attrs
                    for pattr in path.pattrs:
                        if pattr.type_url == "type.googleapis.com/gobgpapi.NextHopAttribute":
                            nh = attribute_pb2.NextHopAttribute()
                            nh.ParseFromString(pattr.value)
                            next_hop = nh.next_hop
                        elif pattr.type_url == "type.googleapis.com/gobgpapi.AsPathAttribute":
                            asp = attribute_pb2.AsPathAttribute()
                            asp.ParseFromString(pattr.value)
                            for seg in asp.segments:
                                if seg.type == 2:
                                    as_path = seg.numbers
                        elif pattr.type_url == "type.googleapis.com/gobgpapi.MpReachNLRIAttribute":
                            mpreach = attribute_pb2.MpReachNLRIAttribute()
                            mpreach.ParseFromString(pattr.value)
                            next_hop = mpreach.next_hops[0]

                    if not as_path:
                        continue

                    route = {
                        "prefix": prefix,
                        "path": as_path,
                        "nexthop": next_hop,
                    }
                    entry["routes"].append(route)

        data.append(entry)
    return data