/*
 * Copyright (c) 2017-2019 Cisco and/or its affiliates.
 * 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.
 */

#include <src/config.h>

#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>

#include <parc/assert/parc_Assert.h>

#include <parc/algol/parc_Memory.h>
#include <parc/algol/parc_Network.h>

#include <src/config/controlSetDebug.h>
#include <src/core/dispatcher.h>
#include <src/core/forwarder.h>

#include <src/utils/commands.h>
#include <src/utils/utils.h>

static CommandReturn _controlSetStrategy_Execute(CommandParser *parser,
                                                 CommandOps *ops,
                                                 PARCList *args);
static CommandReturn _controlSetStrategy_HelpExecute(CommandParser *parser,
                                                     CommandOps *ops,
                                                     PARCList *args);

static const char *_commandSetStrategy = "set strategy";
static const char *_commandSetStrategyHelp = "help set strategy";

static const char *_commandSetStrategyOptions[LAST_STRATEGY_VALUE] = {
    "loadbalancer",
    "random",
    "random_per_dash_segment",
    "loadbalancer_with_delay",
    "loadbalancer_by_rate",
    "loadbalancer_best_route"};

// ====================================================

CommandOps *controlSetStrategy_Create(ControlState *state) {
  return commandOps_Create(state, _commandSetStrategy, NULL,
                           _controlSetStrategy_Execute, commandOps_Destroy);
}

CommandOps *controlSetStrategy_HelpCreate(ControlState *state) {
  return commandOps_Create(state, _commandSetStrategyHelp, NULL,
                           _controlSetStrategy_HelpExecute, commandOps_Destroy);
}

// ====================================================

strategy_type _validStrategy(const char *strategy) {
  strategy_type validStrategy = LAST_STRATEGY_VALUE;

  for (int i = 0; i < LAST_STRATEGY_VALUE; i++) {
    if (strcmp(_commandSetStrategyOptions[i], strategy) == 0) {
      validStrategy = i;
      break;
    }
  }
  return validStrategy;
}

static CommandReturn _controlSetStrategy_HelpExecute(CommandParser *parser,
                                                     CommandOps *ops,
                                                     PARCList *args) {
  printf("set strategy <prefix> <strategy>\n");
  printf("prefix: ipv4/ipv6 address (ex: 1234::/64)\n");
  printf("strategy: strategy identifier\n");
  printf("available strategies:\n");
  printf("    random\n");
  printf("    loadbalancer\n");
  printf("    random_per_dash_segment\n");
  printf("    loadbalancer_with_delay\n");
  printf("\n");
  return CommandReturn_Success;
}

static CommandReturn _controlSetStrategy_Execute(CommandParser *parser,
                                                 CommandOps *ops,
                                                 PARCList *args) {
  ControlState *state = ops->closure;

  if (parcList_Size(args) != 4) {
    _controlSetStrategy_HelpExecute(parser, ops, args);
    return CommandReturn_Failure;
  }

  if (((strcmp(parcList_GetAtIndex(args, 0), "set") != 0) ||
       (strcmp(parcList_GetAtIndex(args, 1), "strategy") != 0))) {
    _controlSetStrategy_HelpExecute(parser, ops, args);
    return CommandReturn_Failure;
  }

  const char *prefixStr = parcList_GetAtIndex(args, 2);
  char addr[strlen(prefixStr) + 1];
  // separate address and len
  char *slash;
  uint32_t len = UINT32_MAX;
  strcpy(addr, prefixStr);
  slash = strrchr(addr, '/');
  if (slash != NULL) {
    len = atoi(slash + 1);
    *slash = '\0';
  }
  if (len == 0) {
    printf("ERROR: a prefix can not be of length 0\n");
    return CommandReturn_Failure;
  }

  // allocate command payload
  set_strategy_command *setStrategyCommand =
      parcMemory_AllocateAndClear(sizeof(set_strategy_command));

  // check and set IP address
  if (inet_pton(AF_INET, addr, &setStrategyCommand->address.ipv4) == 1) {
    if (len == UINT32_MAX) {
      printf("Netmask not specified: set to 32 by default\n");
      len = 32;
    } else if (len > 32) {
      printf("ERROR: exceeded INET mask length, max=32\n");
      parcMemory_Deallocate(&setStrategyCommand);
      return CommandReturn_Failure;
    }
    setStrategyCommand->addressType = ADDR_INET;
  } else if (inet_pton(AF_INET6, addr, &setStrategyCommand->address.ipv6) ==
             1) {
    if (len == UINT32_MAX) {
      printf("Netmask not specified: set to 128 by default\n");
      len = 128;
    } else if (len > 128) {
      printf("ERROR: exceeded INET6 mask length, max=128\n");
      parcMemory_Deallocate(&setStrategyCommand);
      return CommandReturn_Failure;
    }
    setStrategyCommand->addressType = ADDR_INET6;
  } else {
    printf("Error: %s is not a valid network address \n", addr);
    parcMemory_Deallocate(&setStrategyCommand);
    return CommandReturn_Failure;
  }

  const char *strategyStr = parcList_GetAtIndex(args, 3);
  // check valid strategy
  strategy_type strategy;
  if ((strategy = _validStrategy(strategyStr)) == LAST_STRATEGY_VALUE) {
    printf("Error: invalid strategy \n");
    parcMemory_Deallocate(&setStrategyCommand);
    _controlSetStrategy_HelpExecute(parser, ops, args);
    return CommandReturn_Failure;
  }

  // Fill remaining payload fields
  setStrategyCommand->len = len;
  setStrategyCommand->strategyType = strategy;

  // send message and receive response
  struct iovec *response = utils_SendRequest(
      state, SET_STRATEGY, setStrategyCommand, sizeof(set_strategy_command));

  if (!response) {  // get NULL pointer
    return CommandReturn_Failure;
  }

  parcMemory_Deallocate(&response);  // free iovec pointer
  return CommandReturn_Success;
}