#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>

#if defined(_WIN32)
#include <winsock2.h>
#include <ws2tcpip.h>
#else
#include <netdb.h>
#include <sys/socket.h>
#endif

#include <limits>
#include <memory>
#include "etcd/Client.hpp"
#include "etcd/KeepAlive.hpp"
#include "etcd/v3/action_constants.hpp"
#include "etcd/v3/Action.hpp"
#include "etcd/v3/AsyncTxnResponse.hpp"
#include "etcd/v3/AsyncRangeResponse.hpp"
#include "etcd/v3/AsyncWatchResponse.hpp"
#include "etcd/v3/AsyncDeleteRangeResponse.hpp"
#include "etcd/v3/AsyncLockResponse.hpp"
#include "etcd/v3/Transaction.hpp"
#include <iostream>

#include "etcd/v3/AsyncSetAction.hpp"
#include "etcd/v3/AsyncCompareAndSwapAction.hpp"
#include "etcd/v3/AsyncCompareAndDeleteAction.hpp"
#include "etcd/v3/AsyncUpdateAction.hpp"
#include "etcd/v3/AsyncGetAction.hpp"
#include "etcd/v3/AsyncDeleteAction.hpp"
#include "etcd/v3/AsyncWatchAction.hpp"
#include "etcd/v3/AsyncLeaseAction.hpp"
#include "etcd/v3/AsyncLockAction.hpp"
#include "etcd/v3/AsyncTxnAction.hpp"

#include <boost/algorithm/string.hpp>

using grpc::Channel;

namespace etcd {
namespace detail {

static bool dns_resolve(std::string const &target, std::vector<std::string> &endpoints) {
  struct addrinfo hints = {}, *addrs;
  hints.ai_family = AF_INET;
  hints.ai_socktype = SOCK_STREAM;
  hints.ai_protocol = IPPROTO_TCP;

  std::vector<std::string> target_parts;
  boost::split(target_parts, target, boost::is_any_of(":"));
  if (target_parts.size() != 2) {
    std::cerr << "warn: invalid URL: " << target << std::endl;
    return false;
  }

#if defined(_WIN32)
  {
    // Use the MAKEWORD(lowbyte, highbyte) macro declared in Windef.h.
    WORD wVersionRequested = MAKEWORD(2, 2);
    WSADATA wsaData;

    int err = WSAStartup(wVersionRequested, &wsaData);
    if (err != 0) {
      // Tell the user that we could not find a usable Winsock DLL.                                  */
      std::cerr << "WSAStartup failed with error: %d" << err << std::endl;
      return false;
    }
  }
#endif

  int r = getaddrinfo(target_parts[0].c_str(), target_parts[1].c_str(), &hints, &addrs);
  if (r != 0) {
    std::cerr << "warn: getaddrinfo() failed for endpoint " << target
              << " with error: " << r << std::endl;
    return false;
  }

  char host[16] = {'\0'};
  for (struct addrinfo* addr = addrs; addr != nullptr; addr = addr->ai_next) {
    memset(host, '\0', sizeof(host));
    getnameinfo(addr->ai_addr, addr->ai_addrlen, host, sizeof(host), NULL, 0, NI_NUMERICHOST);
    endpoints.emplace_back(std::string(host) + ":" + target_parts[1]);
  }
  freeaddrinfo(addrs);
  return true;
}

const std::string strip_and_resolve_addresses(std::string const &address) {
  std::vector<std::string> addresses;
  boost::algorithm::split(addresses, address, boost::algorithm::is_any_of(",;"));
  std::string stripped_address;
  {
    std::vector<std::string> stripped_addresses;
    std::string substr("://");
    for (auto const &addr: addresses) {
      std::string::size_type idx = addr.find(substr);
      std::string target = idx == std::string::npos ? addr : addr.substr(idx + substr.length());
      etcd::detail::dns_resolve(target, stripped_addresses);
    }
    stripped_address = boost::algorithm::join(stripped_addresses, ",");
  }
  return "ipv4:///" + stripped_address;
}

const bool authenticate(std::shared_ptr<grpc::Channel> const &channel,
                        std::string const &username,
                        std::string const &password,
                        std::string &token_or_message) {
  // run a round of auth
  auto auth_stub = Auth::NewStub(channel);
  ClientContext context;
  etcdserverpb::AuthenticateRequest auth_request;
  etcdserverpb::AuthenticateResponse auth_response;
  auth_request.set_name(username);
  auth_request.set_password(password);
  auto status = auth_stub->Authenticate(&context, auth_request, &auth_response);
  if (status.ok()) {
    token_or_message = auth_response.token();
    return true;
  } else {
    token_or_message = status.error_message();
    return false;
  }
}

}
}

etcd::Client::Client(std::string const & address,
                     const unsigned int& timeout, 
                     std::string const & load_balancer)
{
  // create channels
  std::string const addresses = etcd::detail::strip_and_resolve_addresses(address);
  grpc::ChannelArguments grpc_args;
  grpc_args.SetMaxSendMessageSize(std::numeric_limits<int>::max());
  grpc_args.SetMaxReceiveMessageSize(std::numeric_limits<int>::max());
  std::shared_ptr<grpc::ChannelCredentials> creds = grpc::InsecureChannelCredentials();
  grpc_args.SetLoadBalancingPolicyName(load_balancer);
  this->channel = grpc::CreateCustomChannel(addresses, creds, grpc_args);

  // create stubs
  kvServiceStub = KV::NewStub(this->channel);
  watchServiceStub= Watch::NewStub(this->channel);
  leaseServiceStub= Lease::NewStub(this->channel);
  lockServiceStub = Lock::NewStub(this->channel);
  this->timeout = timeout;
}

etcd::Client::Client(std::string const & address,
                     std::string const & username,
                     std::string const & password,
                     const unsigned int& timeout,
                     std::string const & load_balancer)
{
  // create channels
  std::string const addresses = etcd::detail::strip_and_resolve_addresses(address);
  grpc::ChannelArguments grpc_args;
  grpc_args.SetMaxSendMessageSize(std::numeric_limits<int>::max());
  grpc_args.SetMaxReceiveMessageSize(std::numeric_limits<int>::max());
  std::shared_ptr<grpc::ChannelCredentials> creds = grpc::InsecureChannelCredentials();
  grpc_args.SetLoadBalancingPolicyName(load_balancer);
  this->channel = grpc::CreateCustomChannel(addresses, creds, grpc_args);

  // auth
  std::string token_or_message;
  if (!etcd::detail::authenticate(this->channel, username, password, token_or_message)) {
    throw std::invalid_argument("Etcd authentication failed: " + token_or_message);
  }
  this->auth_token = token_or_message;

  // setup stubs
  kvServiceStub = KV::NewStub(this->channel);
  watchServiceStub= Watch::NewStub(this->channel);
  leaseServiceStub= Lease::NewStub(this->channel);
  lockServiceStub = Lock::NewStub(this->channel);
  this->timeout = timeout;
}

pplx::task<etcd::Response> etcd::Client::get(std::string const & key)
{
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.key.assign(key);
  params.withPrefix = false;
  params.kv_stub = kvServiceStub .get();
  params.timeout = this->timeout;
  std::shared_ptr<etcdv3::AsyncGetAction> call(new etcdv3::AsyncGetAction(params));
  return Response::create(call);
}

pplx::task<etcd::Response> etcd::Client::set(std::string const & key, std::string const & value, int ttl)
{
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.key.assign(key);
  params.value.assign(value);
  params.kv_stub = kvServiceStub .get();
  params.timeout = this->timeout;
  if(ttl > 0)
  {
    auto res = leasegrant(ttl).get();
    if(!res.is_ok()) 
    {
      return pplx::task<etcd::Response>([res]()
      {
        return etcd::Response(res.error_code(), res.error_message().c_str());    
      });
    }
    else
    {
      params.lease_id = res.value().lease();
    }
  }

  std::shared_ptr<etcdv3::AsyncSetAction> call(new etcdv3::AsyncSetAction(params));
  return Response::create(call);
}

pplx::task<etcd::Response> etcd::Client::set(std::string const & key, std::string const & value, int64_t leaseid)
{
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.key.assign(key);
  params.value.assign(value);
  params.lease_id = leaseid;
  params.kv_stub = kvServiceStub .get();
  params.timeout = this->timeout;
  std::shared_ptr<etcdv3::AsyncSetAction> call(new etcdv3::AsyncSetAction(params));
  return Response::create(call);
}


pplx::task<etcd::Response> etcd::Client::add(std::string const & key, std::string const & value, int ttl)
{
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.key.assign(key);
  params.value.assign(value);
  params.kv_stub = kvServiceStub .get();
  params.timeout = this->timeout;
  if(ttl > 0)
  {
    auto res = leasegrant(ttl).get();
    if(!res.is_ok()) 
    {
      return pplx::task<etcd::Response>([res]()
      {
        return etcd::Response(res.error_code(), res.error_message().c_str());    
      });
    }
    else
    {
      params.lease_id = res.value().lease();
    }
  }
  std::shared_ptr<etcdv3::AsyncSetAction> call(new etcdv3::AsyncSetAction(params,true));
  return Response::create(call);
}

pplx::task<etcd::Response> etcd::Client::add(std::string const & key, std::string const & value, int64_t leaseid)
{
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.key.assign(key);
  params.value.assign(value);
  params.lease_id = leaseid;
  params.kv_stub = kvServiceStub .get();
  params.timeout = this->timeout;
  std::shared_ptr<etcdv3::AsyncSetAction> call(new etcdv3::AsyncSetAction(params,true));
  return Response::create(call);
}


pplx::task<etcd::Response> etcd::Client::modify(std::string const & key, std::string const & value, int ttl)
{
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.key.assign(key);
  params.value.assign(value);
  params.kv_stub = kvServiceStub .get();
  params.timeout = this->timeout;
  if(ttl > 0)
  {
    auto res = leasegrant(ttl).get();
    if(!res.is_ok()) 
    {
      return pplx::task<etcd::Response>([res]()
      {
        return etcd::Response(res.error_code(), res.error_message().c_str());    
      });
    }
    else
    {
      params.lease_id = res.value().lease();
    }
  }
  std::shared_ptr<etcdv3::AsyncUpdateAction> call(new etcdv3::AsyncUpdateAction(params));
  return Response::create(call);
}

pplx::task<etcd::Response> etcd::Client::modify(std::string const & key, std::string const & value, int64_t leaseid)
{
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.key.assign(key);
  params.value.assign(value);
  params.lease_id = leaseid;
  params.kv_stub = kvServiceStub .get();
  params.timeout = this->timeout;
  std::shared_ptr<etcdv3::AsyncUpdateAction> call(new etcdv3::AsyncUpdateAction(params));
  return Response::create(call);
}


pplx::task<etcd::Response> etcd::Client::modify_if(std::string const & key, std::string const & value, std::string const & old_value, int ttl)
{
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.key.assign(key);
  params.value.assign(value);
  params.old_value.assign(old_value);
  params.kv_stub = kvServiceStub .get();
  params.timeout = this->timeout;
  if(ttl > 0)
  {
    auto res = leasegrant(ttl).get();
    if(!res.is_ok()) 
    {
      return pplx::task<etcd::Response>([res]()
      {
        return etcd::Response(res.error_code(), res.error_message().c_str());    
      });
    }
    else
    {
      params.lease_id = res.value().lease();
    }
  }
  std::shared_ptr<etcdv3::AsyncCompareAndSwapAction> call(new etcdv3::AsyncCompareAndSwapAction(params,etcdv3::Atomicity_Type::PREV_VALUE));
  return Response::create(call);
}

pplx::task<etcd::Response> etcd::Client::modify_if(std::string const & key, std::string const & value, std::string const & old_value, int64_t leaseid)
{
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.key.assign(key);
  params.value.assign(value);
  params.old_value.assign(old_value);
  params.lease_id = leaseid;
  params.kv_stub = kvServiceStub .get();
  params.timeout = this->timeout;
  std::shared_ptr<etcdv3::AsyncCompareAndSwapAction> call(new etcdv3::AsyncCompareAndSwapAction(params,etcdv3::Atomicity_Type::PREV_VALUE));
  return Response::create(call);
}

pplx::task<etcd::Response> etcd::Client::modify_if(std::string const & key, std::string const & value, int old_index, int ttl)
{
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.key.assign(key);
  params.value.assign(value);
  params.old_revision = old_index;
  params.kv_stub = kvServiceStub.get();
  params.timeout = this->timeout;
  if(ttl > 0)
  {
    auto res = leasegrant(ttl).get();
    if(!res.is_ok()) 
    {
      return pplx::task<etcd::Response>([res]()
      {
        return etcd::Response(res.error_code(), res.error_message().c_str());    
      });
    }
    else
    {
      params.lease_id = res.value().lease();
    }
  }
  std::shared_ptr<etcdv3::AsyncCompareAndSwapAction> call(new etcdv3::AsyncCompareAndSwapAction(params,etcdv3::Atomicity_Type::PREV_INDEX));
  return Response::create(call);
}

pplx::task<etcd::Response> etcd::Client::modify_if(std::string const & key, std::string const & value, int old_index, int64_t leaseid)
{
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.key.assign(key);
  params.value.assign(value);
  params.lease_id = leaseid;
  params.old_revision = old_index;
  params.kv_stub = kvServiceStub .get();
  params.timeout = this->timeout;
  std::shared_ptr<etcdv3::AsyncCompareAndSwapAction> call(new etcdv3::AsyncCompareAndSwapAction(params,etcdv3::Atomicity_Type::PREV_INDEX));
  return Response::create(call);
}


pplx::task<etcd::Response> etcd::Client::rm(std::string const & key)
{
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.key.assign(key);
  params.withPrefix = false;
  params.kv_stub = kvServiceStub.get();
  params.timeout = this->timeout;
  std::shared_ptr<etcdv3::AsyncDeleteAction> call(new etcdv3::AsyncDeleteAction(params));
  return Response::create(call);
}


pplx::task<etcd::Response> etcd::Client::rm_if(std::string const & key, std::string const & old_value)
{
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.key.assign(key);
  params.old_value.assign(old_value);
  params.kv_stub = kvServiceStub.get();
  params.timeout = this->timeout;
  std::shared_ptr<etcdv3::AsyncCompareAndDeleteAction> call(new etcdv3::AsyncCompareAndDeleteAction(params,etcdv3::Atomicity_Type::PREV_VALUE));
  return Response::create(call);
}

pplx::task<etcd::Response> etcd::Client::rm_if(std::string const & key, int old_index)
{
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.key.assign(key);
  params.old_revision = old_index;
  params.kv_stub = kvServiceStub.get();
  params.timeout = this->timeout;
  std::shared_ptr<etcdv3::AsyncCompareAndDeleteAction> call(new etcdv3::AsyncCompareAndDeleteAction(params, etcdv3::Atomicity_Type::PREV_INDEX));;
  return Response::create(call);

}

pplx::task<etcd::Response> etcd::Client::rmdir(std::string const & key, bool recursive)
{
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.key.assign(key);
  params.withPrefix = recursive;
  params.kv_stub = kvServiceStub .get();
  params.timeout = this->timeout;
  std::shared_ptr<etcdv3::AsyncDeleteAction> call(new etcdv3::AsyncDeleteAction(params));
  return Response::create(call);
}

pplx::task<etcd::Response> etcd::Client::ls(std::string const & key)
{
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.key.assign(key);
  params.withPrefix = true;
  params.limit = 0;  // default no limit.
  params.kv_stub = kvServiceStub .get();
  params.timeout = this->timeout;
  std::shared_ptr<etcdv3::AsyncGetAction> call(new etcdv3::AsyncGetAction(params));
  return Response::create(call);
}

pplx::task<etcd::Response> etcd::Client::ls(std::string const & key, size_t const limit)
{
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.key.assign(key);
  params.withPrefix = true;
  params.limit = limit;
  params.kv_stub = kvServiceStub .get();
  params.timeout = this->timeout;
  std::shared_ptr<etcdv3::AsyncGetAction> call(new etcdv3::AsyncGetAction(params));
  return Response::create(call);
}

pplx::task<etcd::Response> etcd::Client::watch(std::string const & key, bool recursive)
{
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.key.assign(key);
  params.withPrefix = recursive;
  params.watch_stub = watchServiceStub.get();
  params.timeout = this->timeout;
  std::shared_ptr<etcdv3::AsyncWatchAction> call(new etcdv3::AsyncWatchAction(params));
  return Response::create(call);
}

pplx::task<etcd::Response> etcd::Client::watch(std::string const & key, int fromIndex, bool recursive)
{
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.key.assign(key);
  params.withPrefix = recursive;
  params.revision = fromIndex;
  params.watch_stub = watchServiceStub.get();
  params.timeout = this->timeout;
  std::shared_ptr<etcdv3::AsyncWatchAction> call(new etcdv3::AsyncWatchAction(params));
  return Response::create(call);
}

pplx::task<etcd::Response> etcd::Client::leasegrant(int ttl)
{
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.ttl = ttl;
  params.lease_stub = leaseServiceStub.get();
  params.timeout = this->timeout;
  std::shared_ptr<etcdv3::AsyncLeaseGrantAction> call(new etcdv3::AsyncLeaseGrantAction(params));
  return Response::create(call);
}

pplx::task<etcd::Response> etcd::Client::leaserevoke(int64_t lease_id)
{
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.lease_id = lease_id;
  params.lease_stub = leaseServiceStub.get();
  params.timeout = this->timeout;
  std::shared_ptr<etcdv3::AsyncLeaseRevokeAction> call(new etcdv3::AsyncLeaseRevokeAction(params));
  return Response::create(call);
}

pplx::task<etcd::Response> etcd::Client::leasetimetolive(int64_t lease_id)
{
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.lease_id = lease_id;
  params.lease_stub = leaseServiceStub.get();
  params.timeout = this->timeout;
  std::shared_ptr<etcdv3::AsyncLeaseTimeToLiveAction> call(new etcdv3::AsyncLeaseTimeToLiveAction(params));
  return Response::create(call);
}

pplx::task<etcd::Response> etcd::Client::lock(std::string const &key) {
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.timeout = this->timeout;
  static const int DEFAULT_LEASE_TTL_FOR_LOCK = 10;

  // routines in lock usually will be fast, less than 10 seconds.
  //
  // (base on our experiences in vineyard and GraphScope).
  auto resp = this->leasegrant(DEFAULT_LEASE_TTL_FOR_LOCK).get();
  int64_t lease_id = resp.value().lease();
  {
    std::lock_guard<std::mutex> lexical_scope_lock(mutex_for_keepalives);
    this->keep_alive_for_locks[lease_id].reset(
      new KeepAlive(*this, DEFAULT_LEASE_TTL_FOR_LOCK, lease_id));
  }
  params.key = key;
  params.lease_id = lease_id;
  params.lock_stub = lockServiceStub.get();
  std::shared_ptr<etcdv3::AsyncLockAction> call(new etcdv3::AsyncLockAction(params));
  return Response::create(call).then(
    [this, lease_id](pplx::task<etcd::Response> const &resp_task) -> etcd::Response {
      auto const& resp = resp_task.get();
      {
        std::lock_guard<std::mutex> lexical_scope_lock(mutex_for_keepalives);
        if (resp.is_ok()) {
          this->leases_for_locks[resp.lock_key()] = lease_id;
        } else {
          this->keep_alive_for_locks.erase(lease_id);
        }
      }
      return resp;
    }
  );
}

pplx::task<etcd::Response> etcd::Client::lock(std::string const &key,
                                              int64_t lease_id) {
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.key = key;
  params.lease_id = lease_id;
  params.lock_stub = lockServiceStub.get();
  params.timeout = this->timeout;
  std::shared_ptr<etcdv3::AsyncLockAction> call(new etcdv3::AsyncLockAction(params));
  return Response::create(call);
}

pplx::task<etcd::Response> etcd::Client::unlock(std::string const &lock_key) {
  // cancel the KeepAlive first, it exists
  {
    std::lock_guard<std::mutex> lexical_scope_lock(mutex_for_keepalives);
    auto p_leases = this->leases_for_locks.find(lock_key);
    if (p_leases != this->leases_for_locks.end()) {
      auto p_keeps_alive = this->keep_alive_for_locks.find(p_leases->second);
      if (p_keeps_alive != this->keep_alive_for_locks.end()) {
        this->keep_alive_for_locks.erase(p_keeps_alive);
      }
      this->leases_for_locks.erase(p_leases);
    }
  }

  // issue a "unlock" request
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.key = lock_key;
  params.lock_stub = lockServiceStub.get();
  params.timeout = this->timeout;
  std::shared_ptr<etcdv3::AsyncUnlockAction> call(new etcdv3::AsyncUnlockAction(params));
  return Response::create(call);
}

pplx::task<etcd::Response> etcd::Client::txn(etcdv3::Transaction const &txn) {
  etcdv3::ActionParameters params;
  params.auth_token.assign(this->auth_token);
  params.kv_stub = kvServiceStub .get();
  params.timeout = this->timeout;
  std::shared_ptr<etcdv3::AsyncTxnAction> call(new etcdv3::AsyncTxnAction(params, txn));
  return Response::create(call);
}