/*
* Redox - A modern, asynchronous, and wicked fast C++11 client for Redis
*
*    https://github.com/hmartiro/redox
*
* Copyright 2015 - Hayk Martirosyan <hayk.mart at gmail dot com>
*
* 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 <vector>
#include <set>
#include <unordered_set>

#include "command.hpp"
#include "client.hpp"

using namespace std;

namespace redox {

template<class ReplyT>
Command<ReplyT>::Command(
    Redox* rdx,
    long id,
    const std::vector<std::string>& cmd,
    const std::function<void(Command<ReplyT>&)>& callback,
    double repeat, double after, bool free_memory, log::Logger& logger
) : rdx_(rdx), id_(id), cmd_(cmd), repeat_(repeat), after_(after), free_memory_(free_memory),
    callback_(callback), last_error_(),  logger_(logger) {
  timer_guard_.lock();
}

template<class ReplyT>
void Command<ReplyT>::wait() {
  std::unique_lock<std::mutex> lk(waiter_lock_);
  waiter_.wait(lk, [this]() { return waiting_done_.load(); });
  waiting_done_ = {false};
}

template<class ReplyT>
void Command<ReplyT>::processReply(redisReply* r) {

  last_error_.clear();
  reply_obj_ = r;

  if(reply_obj_ == nullptr) {
    reply_status_ = ERROR_REPLY;
    last_error_ = "Received null redisReply* from hiredis.";
    logger_.error() << last_error_;
    Redox::disconnectedCallback(rdx_->ctx_, REDIS_ERR);

  } else {
    lock_guard<mutex> lg(reply_guard_);
    parseReplyObject();
  }

  invoke();

  pending_--;

  waiting_done_ = true;
  waiter_.notify_all();

  // Always free the reply object for repeating commands
  if(repeat_ > 0) {
    freeReply();

  } else {

    // User calls .free()
    if (!free_memory_) return;

    // Free non-repeating commands automatically
    // once we receive expected replies
    if(pending_ == 0) free();
  }
}

// This is the only method in Command that has
// access to private members of Redox
template<class ReplyT>
void Command<ReplyT>::free() {

  lock_guard<mutex> lg(rdx_->free_queue_guard_);
  rdx_->commands_to_free_.push(id_);
  ev_async_send(rdx_->evloop_, &rdx_->watcher_free_);
}

template<class ReplyT>
void Command<ReplyT>::freeReply() {

  if (reply_obj_ == nullptr) return;

  freeReplyObject(reply_obj_);
  reply_obj_ = nullptr;
}

/**
* Create a copy of the reply and return it. Use a guard
* to make sure we don't return a reply while it is being
* modified.
*/
template<class ReplyT>
ReplyT Command<ReplyT>::reply() {
  std::lock_guard<std::mutex> lg(reply_guard_);
  if (!ok()) {
    logger_.warning() << cmd() << ": Accessing reply value while status != OK.";
  }
  return reply_val_;
}

template<class ReplyT>
std::string Command<ReplyT>::cmd() const {
  return rdx_->vecToStr(cmd_);
}

template<class ReplyT>
bool Command<ReplyT>::isExpectedReply(int type) {

  if(reply_obj_->type == type) {
    reply_status_ = OK_REPLY;
    return true;
  }

  if(checkErrorReply() || checkNilReply()) return false;

  std::stringstream errorMessage;
  errorMessage << "Received reply of type " << reply_obj_->type
        << ", expected type " << type << ".";
  last_error_ = errorMessage.str();
  logger_.error() << cmd() << ": " << last_error_;
  reply_status_ = WRONG_TYPE;
  return false;
}

template<class ReplyT>
bool Command<ReplyT>::isExpectedReply(int typeA, int typeB) {

  if((reply_obj_->type == typeA) || (reply_obj_->type == typeB)) {
    reply_status_ = OK_REPLY;
    return true;
  }

  if(checkErrorReply() || checkNilReply()) return false;

  std::stringstream errorMessage;
  errorMessage << "Received reply of type " << reply_obj_->type
        << ", expected type " << typeA << " or " << typeB << ".";
  last_error_ = errorMessage.str();
  logger_.error() << cmd() << ": " << last_error_;
  reply_status_ = WRONG_TYPE;
  return false;
}

template<class ReplyT>
bool Command<ReplyT>::checkErrorReply() {

  if (reply_obj_->type == REDIS_REPLY_ERROR) {
    if (reply_obj_->str != 0) {
      last_error_ = reply_obj_->str;
    }

    logger_.error() << cmd() << ": " << last_error_;
    reply_status_ = ERROR_REPLY;
    return true;
  }
  return false;
}

template<class ReplyT>
bool Command<ReplyT>::checkNilReply() {

  if (reply_obj_->type == REDIS_REPLY_NIL) {
    logger_.warning() << cmd() << ": Nil reply.";
    reply_status_ = NIL_REPLY;
    return true;
  }
  return false;
}

// ----------------------------------------------------------------------------
// Specializations of parseReplyObject for all expected return types
// ----------------------------------------------------------------------------

template<>
void Command<redisReply*>::parseReplyObject() {
  if(!checkErrorReply()) reply_status_ = OK_REPLY;
  reply_val_ = reply_obj_;
}

template<>
void Command<string>::parseReplyObject() {
  if(!isExpectedReply(REDIS_REPLY_STRING, REDIS_REPLY_STATUS)) return;
  reply_val_ = {reply_obj_->str, static_cast<size_t>(reply_obj_->len)};
}

template<>
void Command<char*>::parseReplyObject() {
  if(!isExpectedReply(REDIS_REPLY_STRING, REDIS_REPLY_STATUS)) return;
  reply_val_ = reply_obj_->str;
}

template<>
void Command<int>::parseReplyObject() {

  if(!isExpectedReply(REDIS_REPLY_INTEGER)) return;
  reply_val_ = (int) reply_obj_->integer;
}

template<>
void Command<long long int>::parseReplyObject() {

  if(!isExpectedReply(REDIS_REPLY_INTEGER)) return;
  reply_val_ = reply_obj_->integer;
}

template<>
void Command<nullptr_t>::parseReplyObject() {

  if(!isExpectedReply(REDIS_REPLY_NIL)) return;
  reply_val_ = nullptr;
}

template<>
void Command<vector<string>>::parseReplyObject() {

  if(!isExpectedReply(REDIS_REPLY_ARRAY)) return;

  for(size_t i = 0; i < reply_obj_->elements; i++) {
    redisReply* r = *(reply_obj_->element + i);
    reply_val_.emplace_back(r->str, r->len);
  }
}

template<>
void Command<unordered_set<string>>::parseReplyObject() {

  if(!isExpectedReply(REDIS_REPLY_ARRAY)) return;

  for(size_t i = 0; i < reply_obj_->elements; i++) {
    redisReply* r = *(reply_obj_->element + i);
    reply_val_.emplace(r->str, r->len);
  }
}

template<>
void Command<set<string>>::parseReplyObject() {

  if(!isExpectedReply(REDIS_REPLY_ARRAY)) return;

  for(size_t i = 0; i < reply_obj_->elements; i++) {
    redisReply* r = *(reply_obj_->element + i);
    reply_val_.emplace(r->str, r->len);
  }
}

// Explicit template instantiation for available types, so that the generated
// library contains them and we can keep the method definitions out of the
// header file.
template class Command<redisReply*>;
template class Command<string>;
template class Command<char*>;
template class Command<int>;
template class Command<long long int>;
template class Command<nullptr_t>;
template class Command<vector<string>>;
template class Command<set<string>>;
template class Command<unordered_set<string>>;

} // End namespace redox