/**
  Licensed to the Apache Software Foundation (ASF) under one
  or more contributor license agreements.  See the NOTICE file
  distributed with this work for additional information
  regarding copyright ownership.  The ASF licenses this file
  to you 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.
 */

/**
 * @file Transaction.cc
 */

#include <memory>
#include <cstdlib>
#include <cstring>
#include <map>
#include <string>
#include <utility>

#include "tscpp/api/Transaction.h"
#include "tscore/ink_memory.h"
#include "logging_internal.h"
#include "utils_internal.h"
#include "tscpp/api/noncopyable.h"

using std::map;
using std::string;
using namespace atscppapi;

/**
 * @private
 */
struct atscppapi::TransactionState : noncopyable {
  TSHttpTxn                                               txn_;
  TSEvent                                                 event_; ///< Current event being dispatched.
  std::list<TransactionPlugin *>                          plugins_;
  TSMBuffer                                               client_request_hdr_buf_;
  TSMLoc                                                  client_request_hdr_loc_;
  ClientRequest                                           client_request_;
  TSMBuffer                                               server_request_hdr_buf_;
  TSMLoc                                                  server_request_hdr_loc_;
  Request                                                 server_request_;
  TSMBuffer                                               server_response_hdr_buf_;
  TSMLoc                                                  server_response_hdr_loc_;
  Response                                                server_response_;
  TSMBuffer                                               client_response_hdr_buf_;
  TSMLoc                                                  client_response_hdr_loc_;
  Response                                                client_response_;
  TSMBuffer                                               cached_response_hdr_buf_;
  TSMLoc                                                  cached_response_hdr_loc_;
  Response                                                cached_response_;
  TSMBuffer                                               cached_request_hdr_buf_;
  TSMLoc                                                  cached_request_hdr_loc_;
  Request                                                 cached_request_;
  map<string, std::shared_ptr<Transaction::ContextValue>> context_values_;

  TransactionState(TSHttpTxn txn, TSMBuffer client_request_hdr_buf, TSMLoc client_request_hdr_loc)
    : txn_(txn),
      event_(TS_EVENT_NONE),
      client_request_hdr_buf_(client_request_hdr_buf),
      client_request_hdr_loc_(client_request_hdr_loc),
      client_request_(txn, client_request_hdr_buf, client_request_hdr_loc),
      server_request_hdr_buf_(nullptr),
      server_request_hdr_loc_(nullptr),
      server_response_hdr_buf_(nullptr),
      server_response_hdr_loc_(nullptr),
      client_response_hdr_buf_(nullptr),
      client_response_hdr_loc_(nullptr),
      cached_response_hdr_buf_(nullptr),
      cached_response_hdr_loc_(nullptr),
      cached_request_hdr_buf_(nullptr),
      cached_request_hdr_loc_(nullptr){};
};

Transaction::Transaction(void *raw_txn)
{
  TSHttpTxn txn = static_cast<TSHttpTxn>(raw_txn);
  TSMBuffer hdr_buf;
  TSMLoc    hdr_loc;
  (void)TSHttpTxnClientReqGet(txn, &hdr_buf, &hdr_loc);
  if (!hdr_buf || !hdr_loc) {
    LOG_ERROR("TSHttpTxnClientReqGet tshttptxn=%p returned a null hdr_buf=%p or hdr_loc=%p.", txn, hdr_buf, hdr_loc);
  }

  state_ = std::make_unique<TransactionState>(txn, hdr_buf, hdr_loc);
  LOG_DEBUG("Transaction tshttptxn=%p constructing Transaction object %p, client req hdr_buf=%p, client req hdr_loc=%p", txn, this,
            hdr_buf, hdr_loc);
}

Transaction::~Transaction()
{
  LOG_DEBUG("Transaction tshttptxn=%p destroying Transaction object %p", state_->txn_, this);
}

void
Transaction::setEvent(TSEvent event)
{
  state_->event_ = event;
}

bool
Transaction::configIntSet(TSOverridableConfigKey conf, int value)
{
  return TS_SUCCESS == TSHttpTxnConfigIntSet(state_->txn_, conf, static_cast<TSMgmtInt>(value));
}
bool
Transaction::configIntGet(TSOverridableConfigKey conf, int *value)
{
  return TS_SUCCESS == TSHttpTxnConfigIntGet(state_->txn_, conf, reinterpret_cast<TSMgmtInt *>(value));
}

bool
Transaction::configFloatSet(TSOverridableConfigKey conf, float value)
{
  return TS_SUCCESS == TSHttpTxnConfigFloatSet(state_->txn_, conf, static_cast<TSMgmtFloat>(value));
}

bool
Transaction::configFloatGet(TSOverridableConfigKey conf, float *value)
{
  return TS_SUCCESS == TSHttpTxnConfigFloatGet(state_->txn_, conf, value);
}

bool
Transaction::configStringSet(TSOverridableConfigKey conf, std::string const &value)
{
  return TS_SUCCESS == TSHttpTxnConfigStringSet(state_->txn_, conf, const_cast<TSMgmtString>(value.data()), value.length());
}

bool
Transaction::configStringGet(TSOverridableConfigKey conf, std::string &value)
{
  const char *svalue;
  int         length;
  bool        zret = TS_SUCCESS == TSHttpTxnConfigStringGet(state_->txn_, conf, &svalue, &length);
  if (zret) {
    value.assign(svalue, length);
  } else {
    value.clear();
  }
  return zret;
}

bool
Transaction::configFind(std::string const &name, TSOverridableConfigKey *conf, TSRecordDataType *type)
{
  return TS_SUCCESS == TSHttpTxnConfigFind(name.data(), name.length(), conf, type);
}

void
Transaction::resume()
{
  TSHttpTxnReenable(state_->txn_, static_cast<TSEvent>(TS_EVENT_HTTP_CONTINUE));
}

void
Transaction::error()
{
  LOG_DEBUG("Transaction tshttptxn=%p reenabling to error state", state_->txn_);
  TSHttpTxnReenable(state_->txn_, static_cast<TSEvent>(TS_EVENT_HTTP_ERROR));
}

void
Transaction::error(const std::string &page)
{
  setErrorBody(page);
  error(); // finally, reenable with HTTP_ERROR
}

void
Transaction::setErrorBody(const std::string &page)
{
  LOG_DEBUG("Transaction tshttptxn=%p setting error body page length: %lu", state_->txn_, page.length());
  char *body = static_cast<char *>(TSmalloc(page.length()));
  memcpy(body, page.data(), page.length());
  TSHttpTxnErrorBodySet(state_->txn_, body, page.length(), nullptr); // Default to text/html
}

void
Transaction::setErrorBody(const std::string &page, const std::string &mimetype)
{
  LOG_DEBUG("Transaction tshttptxn=%p setting error body page length: %lu", state_->txn_, page.length());
  char *body = static_cast<char *>(TSmalloc(page.length()));
  memcpy(body, page.data(), page.length());
  TSHttpTxnErrorBodySet(state_->txn_, body, page.length(), TSstrdup(mimetype.c_str()));
}

void
Transaction::setStatusCode(HttpStatus code)
{
  LOG_DEBUG("Transaction tshttptxn=%p setting status code: %d", state_->txn_, code);
  TSHttpTxnStatusSet(state_->txn_, static_cast<TSHttpStatus>(code), "tscpp");
}

bool
Transaction::isInternalRequest() const
{
  return (0 != TSHttpTxnIsInternal(state_->txn_));
}

void *
Transaction::getAtsHandle() const
{
  return static_cast<void *>(state_->txn_);
}

const std::list<atscppapi::TransactionPlugin *> &
Transaction::getPlugins() const
{
  return state_->plugins_;
}

void
Transaction::addPlugin(TransactionPlugin *plugin)
{
  LOG_DEBUG("Transaction tshttptxn=%p registering new TransactionPlugin %p.", state_->txn_, plugin);
  state_->plugins_.push_back(plugin);
}

std::shared_ptr<Transaction::ContextValue>
Transaction::getContextValue(const std::string &key)
{
  std::shared_ptr<Transaction::ContextValue>                        return_context_value;
  map<string, std::shared_ptr<Transaction::ContextValue>>::iterator iter = state_->context_values_.find(key);
  if (iter != state_->context_values_.end()) {
    return_context_value = iter->second;
  }

  return return_context_value;
}

void
Transaction::setContextValue(const std::string &key, std::shared_ptr<Transaction::ContextValue> value)
{
  state_->context_values_[key] = std::move(value);
}

ClientRequest &
Transaction::getClientRequest()
{
  return state_->client_request_;
  ;
}

string
Transaction::getEffectiveUrl()
{
  string ret_val;
  int    length = 0;
  char  *buf    = TSHttpTxnEffectiveUrlStringGet(state_->txn_, &length);
  if (buf && length) {
    ret_val.assign(buf, length);
  }

  if (buf) {
    TSfree(buf);
  }

  return ret_val;
}

bool
Transaction::setCacheUrl(const string &cache_url)
{
  TSReturnCode res = TSCacheUrlSet(state_->txn_, cache_url.c_str(), cache_url.length());
  return (res == TS_SUCCESS);
}

void
Transaction::setSkipRemapping(int flag)
{
  TSHttpTxnCntlSet(state_->txn_, TS_HTTP_CNTL_SKIP_REMAPPING, flag);
}

const sockaddr *
Transaction::getIncomingAddress() const
{
  return TSHttpTxnIncomingAddrGet(state_->txn_);
}

const sockaddr *
Transaction::getClientAddress() const
{
  return TSHttpTxnClientAddrGet(state_->txn_);
}

const sockaddr *
Transaction::getNextHopAddress() const
{
  return TSHttpTxnNextHopAddrGet(state_->txn_);
}

const sockaddr *
Transaction::getServerAddress() const
{
  return TSHttpTxnServerAddrGet(state_->txn_);
}

bool
Transaction::setServerAddress(const sockaddr *sockaddress)
{
  return TSHttpTxnServerAddrSet(state_->txn_, sockaddress) == TS_SUCCESS;
}

bool
Transaction::setIncomingPort(uint16_t port)
{
  TSHttpTxnClientIncomingPortSet(state_->txn_, port);
  return true; // In reality TSHttpTxnClientIncomingPortSet should return SUCCESS or ERROR.
}

/*
 * Note: The following methods cannot be attached to a Response
 * object because that would require the Response object to
 * know that it's a server or client response because of the
 * TS C api which is TSHttpTxnServerRespBodyBytesGet.
 */
size_t
Transaction::getServerResponseBodySize()
{
  return static_cast<size_t>(TSHttpTxnServerRespBodyBytesGet(state_->txn_));
}

size_t
Transaction::getServerResponseHeaderSize()
{
  return static_cast<size_t>(TSHttpTxnServerRespHdrBytesGet(state_->txn_));
}

size_t
Transaction::getClientResponseBodySize()
{
  return static_cast<size_t>(TSHttpTxnClientRespBodyBytesGet(state_->txn_));
}

size_t
Transaction::getClientResponseHeaderSize()
{
  return static_cast<size_t>(TSHttpTxnClientRespHdrBytesGet(state_->txn_));
}

void
Transaction::setTimeout(Transaction::TimeoutType type, int time_ms)
{
  switch (type) {
  case TIMEOUT_DNS:
    TSHttpTxnDNSTimeoutSet(state_->txn_, time_ms);
    break;
  case TIMEOUT_CONNECT:
    TSHttpTxnConnectTimeoutSet(state_->txn_, time_ms);
    break;
  case TIMEOUT_NO_ACTIVITY:
    TSHttpTxnNoActivityTimeoutSet(state_->txn_, time_ms);
    break;
  case TIMEOUT_ACTIVE:
    TSHttpTxnActiveTimeoutSet(state_->txn_, time_ms);
    break;
  default:
    break;
  }
}

Transaction::CacheStatus
Transaction::getCacheStatus()
{
  int obj_status = TS_ERROR;

  if (TSHttpTxnCacheLookupStatusGet(state_->txn_, &obj_status) == TS_ERROR) {
    return CACHE_LOOKUP_NONE;
  }

  switch (obj_status) {
  case TS_CACHE_LOOKUP_MISS:
    return CACHE_LOOKUP_MISS;
  case TS_CACHE_LOOKUP_HIT_STALE:
    return CACHE_LOOKUP_HIT_STALE;
  case TS_CACHE_LOOKUP_HIT_FRESH:
    return CACHE_LOOKUP_HIT_FRESH;
  case TS_CACHE_LOOKUP_SKIPPED:
    return CACHE_LOOKUP_SKIPPED;
  default:
    return CACHE_LOOKUP_NONE;
  }
}

void
Transaction::redirectTo(std::string const &url)
{
  // Must re-alloc the string locally because ownership is transferred to the transaction.
  char *const buffer = static_cast<char *>(TSmalloc(url.size() + 1));
  memcpy(buffer, url.c_str(), url.size());
  buffer[url.size()] = '\0';
  TSHttpTxnRedirectUrlSet(state_->txn_, buffer, url.size());
}

namespace
{
/**
 * initializeHandles is a convenience functor that takes a pointer to a TS Function that
 * will return the TSMBuffer and TSMLoc for a given server request/response or client/request response
 *
 * @param constructor takes a function pointer of type GetterFunction
 * @param txn a TSHttpTxn
 * @param hdr_buf the address where the hdr buf will be stored
 * @param hdr_loc the address where the mem loc will be stored
 * @param name name of the entity - used for logging
 */
class initializeHandles
{
public:
  using GetterFunction = TSReturnCode (*)(TSHttpTxn, TSMBuffer *, TSMLoc *);
  initializeHandles(GetterFunction getter) : getter_(getter) {}
  bool
  operator()(TSHttpTxn txn, TSMBuffer &hdr_buf, TSMLoc &hdr_loc, const char *handles_name)
  {
    hdr_buf = nullptr;
    hdr_loc = nullptr;
    if (getter_(txn, &hdr_buf, &hdr_loc) == TS_SUCCESS) {
      return true;
    } else {
      LOG_ERROR("Could not get %s", handles_name);
    }
    return false;
  }

private:
  GetterFunction getter_;
};

} // anonymous namespace

Request &
Transaction::getServerRequest()
{
  static initializeHandles initializeServerRequestHandles(TSHttpTxnServerReqGet);
  if (nullptr == state_->server_request_hdr_buf_) {
    initializeServerRequestHandles(state_->txn_, state_->server_request_hdr_buf_, state_->server_request_hdr_loc_,
                                   "server request");
    LOG_DEBUG("Initializing server request, event %d", state_->event_);
    state_->server_request_.init(state_->server_request_hdr_buf_, state_->server_request_hdr_loc_);
  }
  return state_->server_request_;
}

Response &
Transaction::getServerResponse()
{
  static initializeHandles initializeServerResponseHandles(TSHttpTxnServerRespGet);
  if (nullptr == state_->server_response_hdr_buf_) {
    initializeServerResponseHandles(state_->txn_, state_->server_response_hdr_buf_, state_->server_response_hdr_loc_,
                                    "server response");
    LOG_DEBUG("Initializing server response, event %d", state_->event_);
    state_->server_response_.init(state_->server_response_hdr_buf_, state_->server_response_hdr_loc_);
  }
  return state_->server_response_;
}

Response &
Transaction::getClientResponse()
{
  static initializeHandles initializeClientResponseHandles(TSHttpTxnClientRespGet);
  if (nullptr == state_->client_response_hdr_buf_) {
    initializeClientResponseHandles(state_->txn_, state_->client_response_hdr_buf_, state_->client_response_hdr_loc_,
                                    "client response");
    LOG_DEBUG("Initializing client response, event %d", state_->event_);
    state_->client_response_.init(state_->client_response_hdr_buf_, state_->client_response_hdr_loc_);
  }
  return state_->client_response_;
}

Request &
Transaction::getCachedRequest()
{
  static initializeHandles initializeCachedRequestHandles(TSHttpTxnCachedReqGet);

  if (state_->event_ == TS_EVENT_HTTP_TXN_CLOSE) {
    // CachedRequest is destroyed in tunnel_handler_cache_read
    state_->cached_request_.reset();
    LOG_DEBUG("Reset cached request, event %d", state_->event_);
  } else {
    if (nullptr == state_->cached_request_hdr_buf_) {
      initializeCachedRequestHandles(state_->txn_, state_->cached_request_hdr_buf_, state_->cached_request_hdr_loc_,
                                     "cached request");
      LOG_DEBUG("Initializing cached request, event %d", state_->event_);
      state_->cached_request_.init(state_->cached_request_hdr_buf_, state_->cached_request_hdr_loc_);
    }
  }
  return state_->cached_request_;
}

Response &
Transaction::getCachedResponse()
{
  static initializeHandles initializeCachedResponseHandles(TSHttpTxnCachedRespGet);
  if (nullptr == state_->cached_response_hdr_buf_) {
    initializeCachedResponseHandles(state_->txn_, state_->cached_response_hdr_buf_, state_->cached_response_hdr_loc_,
                                    "cached response");
    LOG_DEBUG("Initializing cached response, event %d", state_->event_);
    state_->cached_response_.init(state_->cached_response_hdr_buf_, state_->cached_response_hdr_loc_);
  }
  return state_->cached_response_;
}

void
Transaction::resetHandles()
{
  state_->cached_request_hdr_buf_  = nullptr;
  state_->cached_request_hdr_loc_  = nullptr;
  state_->cached_response_hdr_buf_ = nullptr;
  state_->cached_response_hdr_loc_ = nullptr;

  state_->client_response_hdr_buf_ = nullptr;
  state_->client_response_hdr_loc_ = nullptr;

  state_->server_request_hdr_buf_  = nullptr;
  state_->server_request_hdr_loc_  = nullptr;
  state_->server_response_hdr_buf_ = nullptr;
  state_->server_response_hdr_loc_ = nullptr;
}