# Copyright 2013, Big Switch Networks, Inc.
#
# LoxiGen is licensed under the Eclipse Public License, version 1.0 (EPL), with
# the following special exception:
#
# LOXI Exception
#
# As a special exception to the terms of the EPL, you may distribute libraries
# generated by LoxiGen (LoxiGen Libraries) under the terms of your choice, provided
# that copyright and licensing notices generated by LoxiGen are not altered or removed
# from the LoxiGen Libraries and the notice provided below is (i) included in
# the LoxiGen Libraries, if distributed in source code form and (ii) included in any
# documentation for the LoxiGen Libraries, if distributed in binary form.
#
# Notice: "Copyright 2013, Big Switch Networks, Inc. This library was generated by the LoxiGen Compiler."
#
# You may not use this file except in compliance with the EPL or LOXI Exception. You may obtain
# a copy of the EPL at:
#
# http://www.eclipse.org/legal/epl-v10.html
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# EPL for the specific language governing permissions and limitations
# under the EPL.

from collections import namedtuple

OFTypeData = namedtuple("OFTypeData", ["init", "pack", "unpack"])

type_data = {

    ## Primitives

    'char': OFTypeData(
        init='0',
        pack='struct.pack("!B", %s)',
        unpack='%s.read("!B")[0]'),

    'uint8_t': OFTypeData(
        init='0',
        pack='struct.pack("!B", %s)',
        unpack='%s.read("!B")[0]'),

    'uint16_t': OFTypeData(
        init='0',
        pack='struct.pack("!H", %s)',
        unpack='%s.read("!H")[0]'),

    'uint32_t': OFTypeData(
        init='0',
        pack='struct.pack("!L", %s)',
        unpack='%s.read("!L")[0]'),

    'uint64_t': OFTypeData(
        init='0',
        pack='struct.pack("!Q", %s)',
        unpack='%s.read("!Q")[0]'),

    'of_port_no_t': OFTypeData(
        init='0',
        pack='util.pack_port_no(%s)',
        unpack='util.unpack_port_no(%s)'),

    'of_fm_cmd_t': OFTypeData(
        init='0',
        pack='util.pack_fm_cmd(%s)',
        unpack='util.unpack_fm_cmd(%s)'),

    'of_wc_bmap_t': OFTypeData(
        init='util.init_wc_bmap()',
        pack='util.pack_wc_bmap(%s)',
        unpack='util.unpack_wc_bmap(%s)'),

    'of_match_bmap_t': OFTypeData(
        init='util.init_match_bmap()',
        pack='util.pack_match_bmap(%s)',
        unpack='util.unpack_match_bmap(%s)'),

    'of_ipv6_t': OFTypeData(
        init="'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'",
        pack='struct.pack("!16s", %s)',
        unpack="%s.read('!16s')[0]"),

    'of_mac_addr_t': OFTypeData(
        init='[0,0,0,0,0,0]',
        pack='struct.pack("!6B", *%s)',
        unpack="list(%s.read('!6B'))"),

    'of_octets_t': OFTypeData(
        init="''",
        pack='%s',
        unpack='str(%s.read_all())'),

    ## Strings

    'of_port_name_t': OFTypeData(
        init="''",
        pack='struct.pack("!16s", %s)',
        unpack='%s.read("!16s")[0].rstrip("\\x00")'),

    'of_table_name_t': OFTypeData(
        init="''",
        pack='struct.pack("!32s", %s)',
        unpack='%s.read("!32s")[0].rstrip("\\x00")'),

    'of_serial_num_t': OFTypeData(
        init="''",
        pack='struct.pack("!32s", %s)',
        unpack='%s.read("!32s")[0].rstrip("\\x00")'),

    'of_desc_str_t': OFTypeData(
        init="''",
        pack='struct.pack("!256s", %s)',
        unpack='%s.read("!256s")[0].rstrip("\\x00")'),

    ## Embedded structs
    # TODO add helper to generate these

    'of_match_t': OFTypeData(
        init='common.match()',
        pack='%s.pack()',
        unpack='common.match.unpack(%s)'),

    'of_port_desc_t': OFTypeData(
        init='common.port_desc()',
        pack='%s.pack()',
        unpack='common.port_desc.unpack(%s)'),

    'of_meter_features_t': OFTypeData(
        init='common.meter_features()',
        pack='%s.pack()',
        unpack='common.meter_features.unpack(%s)'),

    'of_bsn_vport_q_in_q_t': OFTypeData(
        init='common.bsn_vport_q_in_q()',
        pack='%s.pack()',
        unpack='common.bsn_vport_q_in_q.unpack(%s)'),

    ## TLV Lists

    'list(of_action_t)': OFTypeData(
        init='[]',
        pack='util.pack_list(%s)',
        unpack='action.unpack_list(%s)'),

    'list(of_table_features_t)': OFTypeData(
        init='[]',
        pack='util.pack_list(%s)',
        unpack=None),

    'list(of_flow_stats_entry_t)': OFTypeData(
        init='[]',
        pack='util.pack_list(%s)',
        unpack='common.unpack_list_flow_stats_entry(%s)'),

    'list(of_bucket_t)': OFTypeData(
        init='[]',
        pack='util.pack_list(%s)',
        unpack='common.unpack_list_bucket(%s)'),

    'list(of_packet_queue_t)': OFTypeData(
        init='[]',
        pack='util.pack_list(%s)',
        unpack='common.unpack_list_packet_queue(%s)'),

    'list(of_meter_stats_t)': OFTypeData(
        init='[]',
        pack='util.pack_list(%s)',
        unpack='common.unpack_list_meter_stats(%s)'),

    # HACK need the match_v3 length field
    'list(of_oxm_t)': OFTypeData(
        init='[]',
        pack='util.pack_list(%s)',
        unpack='oxm.unpack_list(%s.slice(_length-4))'),

    'list(of_group_stats_entry_t)': OFTypeData(
        init='[]',
        pack='util.pack_list(%s)',
        unpack='common.unpack_list_group_stats_entry(%s)'),

    'list(of_hello_elem_t)': OFTypeData(
        init='[]',
        pack='util.pack_list(%s)',
        unpack='common.unpack_list_hello_elem(%s)'),

    'list(of_action_id_t)': OFTypeData(
        init='[]',
        pack='util.pack_list(%s)',
        unpack=None),

    'list(of_group_desc_stats_entry_t)': OFTypeData(
        init='[]',
        pack='util.pack_list(%s)',
        unpack='common.unpack_list_group_desc_stats_entry(%s)'),

    'list(of_queue_prop_t)': OFTypeData(
        init='[]',
        pack='util.pack_list(%s)',
        unpack='common.unpack_list_queue_prop(%s)'),

    'list(of_instruction_t)': OFTypeData(
        init='[]',
        pack='util.pack_list(%s)',
        unpack='instruction.unpack_list(%s)'),

    'list(of_table_feature_prop_t)': OFTypeData(
        init='[]',
        pack='util.pack_list(%s)',
        unpack=None),

    'list(of_meter_band_t)': OFTypeData(
        init='[]',
        pack='util.pack_list(%s)',
        unpack='meter_band.unpack_list(%s)'),

    ## Lists with fixed-length elements

    'list(of_bucket_counter_t)': OFTypeData(
        init='[]',
        pack='util.pack_list(%s)',
        unpack='loxi.generic_util.unpack_list(%s, common.bucket_counter.unpack)'),

    'list(of_uint32_t)': OFTypeData(
        init='[]',
        pack='util.pack_list(%s)',
        unpack='loxi.generic_util.unpack_list(%s, common.uint32.unpack)'),

    'list(of_queue_stats_entry_t)': OFTypeData(
        init='[]',
        pack='util.pack_list(%s)',
        unpack='loxi.generic_util.unpack_list(%s, common.queue_stats_entry.unpack)'),

    'list(of_table_stats_entry_t)': OFTypeData(
        init='[]',
        pack='util.pack_list(%s)',
        unpack='loxi.generic_util.unpack_list(%s, common.table_stats_entry.unpack)'),

    'list(of_uint8_t)': OFTypeData(
        init='[]',
        pack='util.pack_list(%s)',
        unpack='loxi.generic_util.unpack_list(%s, common.uint8.unpack)'),

    'list(of_port_stats_entry_t)': OFTypeData(
        init='[]',
        pack='util.pack_list(%s)',
        unpack='loxi.generic_util.unpack_list(%s, common.port_stats_entry.unpack)'),

    'list(of_bsn_interface_t)': OFTypeData(
        init='[]',
        pack='util.pack_list(%s)',
        unpack='loxi.generic_util.unpack_list(%s, common.bsn_interface.unpack)'),

    'list(of_meter_band_stats_t)': OFTypeData(
        init='[]',
        pack='util.pack_list(%s)',
        unpack='loxi.generic_util.unpack_list(%s, common.meter_band_stats.unpack)'),

    'list(of_port_desc_t)': OFTypeData(
        init='[]',
        pack='util.pack_list(%s)',
        unpack='loxi.generic_util.unpack_list(%s, common.port_desc.unpack)'),
}

class OFType(object):
    """
    Encapsulates knowledge about the OpenFlow type system.
    """

    version = None
    base = None

    def __init__(self, string, version):
        self.version = version
        self.base = string
        self.type_data = type_data.get(self.base)

    def gen_init_expr(self):
        if self.type_data and self.type_data.init:
            return self.type_data.init
        else:
            return "loxi.unimplemented('init %s')" % self.base

    def gen_pack_expr(self, value_expr):
        if self.type_data and self.type_data.pack:
            return self.type_data.pack % value_expr
        else:
            "loxi.unimplemented('pack %s')" % self.base

    def gen_unpack_expr(self, reader_expr):
        if self.type_data and self.type_data.unpack:
            return self.type_data.unpack % reader_expr
        else:
            "loxi.unimplemented('unpack %s')" % self.base