#!/usr/bin/env python2
#
# Copyright 2017-present Open Networking Foundation
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# 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 License for the specific language governing permissions and
# limitations under the License.
#
import argparse
import json
import os
import sys

import bmv2
import helper


def error(msg):
    print >> sys.stderr, ' - ERROR! ' + msg

def info(msg):
    print >> sys.stdout, ' - ' + msg


class ConfException(Exception):
    pass


def main():
    parser = argparse.ArgumentParser(description='P4Runtime Simple Controller')

    parser.add_argument('-a', '--p4runtime-server-addr',
                        help='address and port of the switch\'s P4Runtime server (e.g. 192.168.0.1:50051)',
                        type=str, action="store", required=True)
    parser.add_argument('-d', '--device-id',
                        help='Internal device ID to use in P4Runtime messages',
                        type=int, action="store", required=True)
    parser.add_argument('-p', '--proto-dump-file',
                        help='path to file where to dump protobuf messages sent to the switch',
                        type=str, action="store", required=True)
    parser.add_argument("-c", '--runtime-conf-file',
                        help="path to input runtime configuration file (JSON)",
                        type=str, action="store", required=True)

    args = parser.parse_args()

    if not os.path.exists(args.runtime_conf_file):
        parser.error("File %s does not exist!" % args.runtime_conf_file)
    workdir = os.path.dirname(os.path.abspath(args.runtime_conf_file))
    with open(args.runtime_conf_file, 'r') as sw_conf_file:
        program_switch(addr=args.p4runtime_server_addr,
                       device_id=args.device_id,
                       sw_conf_file=sw_conf_file,
                       workdir=workdir,
                       proto_dump_fpath=args.proto_dump_file)


def check_switch_conf(sw_conf, workdir):
    required_keys = ["p4info"]
    files_to_check = ["p4info"]
    target_choices = ["bmv2"]

    if "target" not in sw_conf:
        raise ConfException("missing key 'target'")
    target = sw_conf['target']
    if target not in target_choices:
        raise ConfException("unknown target '%s'" % target)

    if target == 'bmv2':
        required_keys.append("bmv2_json")
        files_to_check.append("bmv2_json")

    for conf_key in required_keys:
        if conf_key not in sw_conf or len(sw_conf[conf_key]) == 0:
            raise ConfException("missing key '%s' or empty value" % conf_key)

    for conf_key in files_to_check:
        real_path = os.path.join(workdir, sw_conf[conf_key])
        if not os.path.exists(real_path):
            raise ConfException("file does not exist %s" % real_path)


def program_switch(addr, device_id, sw_conf_file, workdir, proto_dump_fpath):
    sw_conf = json_load_byteified(sw_conf_file)
    try:
        check_switch_conf(sw_conf=sw_conf, workdir=workdir)
    except ConfException as e:
        error("While parsing input runtime configuration: %s" % str(e))
        return

    info('Using P4Info file %s...' % sw_conf['p4info'])
    p4info_fpath = os.path.join(workdir, sw_conf['p4info'])
    p4info_helper = helper.P4InfoHelper(p4info_fpath)

    target = sw_conf['target']

    info("Connecting to P4Runtime server on %s (%s)..." % (addr, target))

    if target == "bmv2":
        sw = bmv2.Bmv2SwitchConnection(address=addr, device_id=device_id,
                                       proto_dump_file=proto_dump_fpath)
    else:
        raise Exception("Don't know how to connect to target %s" % target)

    try:
        sw.MasterArbitrationUpdate()

        if target == "bmv2":
            info("Setting pipeline config (%s)..." % sw_conf['bmv2_json'])
            bmv2_json_fpath = os.path.join(workdir, sw_conf['bmv2_json'])
            sw.SetForwardingPipelineConfig(p4info=p4info_helper.p4info,
                                           bmv2_json_file_path=bmv2_json_fpath)
        else:
            raise Exception("Should not be here")

        if 'table_entries' in sw_conf:
            table_entries = sw_conf['table_entries']
            info("Inserting %d table entries..." % len(table_entries))
            for entry in table_entries:
                info(tableEntryToString(entry))
                insertTableEntry(sw, entry, p4info_helper)

        if 'multicast_group_entries' in sw_conf:
            group_entries = sw_conf['multicast_group_entries']
            info("Inserting %d group entries..." % len(group_entries))
            for entry in group_entries:
                info(groupEntryToString(entry))
                insertMulticastGroupEntry(sw, entry, p4info_helper)

    finally:
        sw.shutdown()


def insertTableEntry(sw, flow, p4info_helper):
    table_name = flow['table']
    match_fields = flow.get('match') # None if not found
    action_name = flow['action_name']
    default_action = flow.get('default_action') # None if not found
    action_params = flow['action_params']
    priority = flow.get('priority')  # None if not found

    table_entry = p4info_helper.buildTableEntry(
        table_name=table_name,
        match_fields=match_fields,
        default_action=default_action,
        action_name=action_name,
        action_params=action_params,
        priority=priority)

    sw.WriteTableEntry(table_entry)


# object hook for josn library, use str instead of unicode object
# https://stackoverflow.com/questions/956867/how-to-get-string-objects-instead-of-unicode-from-json
def json_load_byteified(file_handle):
    return _byteify(json.load(file_handle, object_hook=_byteify),
                    ignore_dicts=True)


def _byteify(data, ignore_dicts=False):
    # if this is a unicode string, return its string representation
    if isinstance(data, unicode):
        return data.encode('utf-8')
    # if this is a list of values, return list of byteified values
    if isinstance(data, list):
        return [_byteify(item, ignore_dicts=True) for item in data]
    # if this is a dictionary, return dictionary of byteified keys and values
    # but only if we haven't already byteified it
    if isinstance(data, dict) and not ignore_dicts:
        return {
            _byteify(key, ignore_dicts=True): _byteify(value, ignore_dicts=True)
            for key, value in data.iteritems()
        }
    # if it's anything else, return it in its original form
    return data


def tableEntryToString(flow):
    if 'match' in flow:
        match_str = ['%s=%s' % (match_name, str(flow['match'][match_name])) for match_name in
                     flow['match']]
        match_str = ', '.join(match_str)
    elif 'default_action' in flow and flow['default_action']:
        match_str = '(default action)'
    else:
        match_str = '(any)'
    params = ['%s=%s' % (param_name, str(flow['action_params'][param_name])) for param_name in
              flow['action_params']]
    params = ', '.join(params)
    return "%s: %s => %s(%s)" % (
        flow['table'], match_str, flow['action_name'], params)


def groupEntryToString(rule):
    group_id = rule["multicast_group_id"]
    replicas = ['%d' % replica["egress_port"] for replica in rule['replicas']]
    ports_str = ', '.join(replicas)
    return 'Group {0} => ({1})'.format(group_id, ports_str)

def insertMulticastGroupEntry(sw, rule, p4info_helper):
    mc_entry = p4info_helper.buildMulticastGroupEntry(rule["multicast_group_id"], rule['replicas'])
    sw.WriteMulticastGroupEntry(mc_entry)


if __name__ == '__main__':
    main()
