/*
  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.
*/
//////////////////////////////////////////////////////////////////////////////////////////////
// statement.cc: Implementation of the statement base class.
//
//
#include "statement.h"

ts::Metrics::Counter::AtomicType *hrw_stat_operators  = nullptr;
ts::Metrics::Counter::AtomicType *hrw_stat_conditions = nullptr;

void
init_hrw_work_stats()
{
  // createPtr() is idempotent and internally synchronized: it returns the existing counter when
  // one already has the given name. header_rewrite.so can be loaded both globally (TSPluginInit)
  // and as a remap plugin (TSRemapInit), so init runs more than once; every call resolves to the
  // same process-wide counter regardless of ordering or which thread runs it.
  if (nullptr == hrw_stat_operators) {
    hrw_stat_operators = ts::Metrics::Counter::createPtr("proxy.process.plugin.header_rewrite.operators");
  }
  if (nullptr == hrw_stat_conditions) {
    hrw_stat_conditions = ts::Metrics::Counter::createPtr("proxy.process.plugin.header_rewrite.conditions");
  }
}

void
Statement::append(Statement *stmt)
{
  Statement *tmp = this;

  TSReleaseAssert(stmt->_next == nullptr);
  while (tmp->_next) {
    tmp = tmp->_next;
  }
  tmp->_next = stmt;
}

ResourceIDs
Statement::get_resource_ids() const
{
  const Statement *stmt = this;
  ResourceIDs      ids  = RSRC_NONE;

  while (stmt) {
    ids  = static_cast<ResourceIDs>(ids | stmt->_rsrc);
    stmt = stmt->_next;
  }

  return ids;
}

bool
Statement::is_hook_valid(TSHttpHookID hook) const
{
  return std::find(_allowed_hooks.begin(), _allowed_hooks.end(), hook) != _allowed_hooks.end();
}

// This should be overridden for any Statement which only supports some hooks
void
Statement::initialize_hooks()
{
  add_allowed_hook(TS_HTTP_READ_RESPONSE_HDR_HOOK);
  add_allowed_hook(TS_HTTP_PRE_REMAP_HOOK);
  add_allowed_hook(TS_HTTP_READ_REQUEST_HDR_HOOK);
  add_allowed_hook(TS_HTTP_SEND_REQUEST_HDR_HOOK);
  add_allowed_hook(TS_HTTP_SEND_RESPONSE_HDR_HOOK);
  add_allowed_hook(TS_REMAP_PSEUDO_HOOK);
  add_allowed_hook(TS_HTTP_POST_REMAP_HOOK);
  add_allowed_hook(TS_HTTP_TXN_START_HOOK);
  add_allowed_hook(TS_HTTP_TXN_CLOSE_HOOK);
}

int
Statement::acquire_state_slot(TSUserArgType type)
{
  if (type == TS_USER_ARGS_SSN) {
    static int ssn_slot_index = []() -> int {
      int index = -1;
      if (TS_ERROR == TSUserArgIndexReserve(TS_USER_ARGS_SSN, PLUGIN_NAME, "HRW ssn variables", &index)) {
        TSError("[%s] failed to reserve ssn user arg index", PLUGIN_NAME);
      }
      return index;
    }();

    return ssn_slot_index;
  } else {
    static int txn_slot_index = []() -> int {
      int index = -1;
      if (TS_ERROR == TSUserArgIndexReserve(TS_USER_ARGS_TXN, PLUGIN_NAME, "HRW txn variables", &index)) {
        TSError("[%s] failed to reserve txn user arg index", PLUGIN_NAME);
      }
      return index;
    }();

    return txn_slot_index;
  }
}

int
Statement::acquire_txn_slot()
{
  return acquire_state_slot(TS_USER_ARGS_TXN);
}

int
Statement::acquire_ssn_slot()
{
  return acquire_state_slot(TS_USER_ARGS_SSN);
}

int
Statement::acquire_txn_private_slot()
{
  // Only call the index reservation once per plugin load
  static int txn_private_slot_index = []() -> int {
    int         index = -1;
    std::string name  = std::string(PLUGIN_NAME) + "_priv";

    if (TS_ERROR == TSUserArgIndexReserve(TS_USER_ARGS_TXN, name.c_str(), "HRW txn private variables", &index)) {
      TSError("[%s] failed to reserve user arg index", PLUGIN_NAME);
      return -1; // Fallback value
    }
    return index;
  }();

  return txn_private_slot_index;
}

// Parse NextHop qualifiers
NextHopQualifiers
Statement::parse_next_hop_qualifier(const std::string &q) const
{
  NextHopQualifiers qual = NEXT_HOP_NONE;

  if (q == "HOST") {
    qual = NEXT_HOP_HOST;
  } else if (q == "PORT") {
    qual = NEXT_HOP_PORT;
  } else if (q == "STRATEGY") {
    qual = NEXT_HOP_STRATEGY;
  } else {
    TSError("[%s] Invalid NextHop() qualifier: %s", PLUGIN_NAME, q.c_str());
  }

  return qual;
}

// Parse URL qualifiers, this one is special since it's used in a few places.
UrlQualifiers
Statement::parse_url_qualifier(const std::string &q) const
{
  UrlQualifiers qual = URL_QUAL_NONE;

  if (q == "HOST") {
    qual = URL_QUAL_HOST;
  } else if (q == "PORT") {
    qual = URL_QUAL_PORT;
  } else if (q == "PATH") {
    qual = URL_QUAL_PATH;
  } else if (q == "QUERY") {
    qual = URL_QUAL_QUERY;
  } else if (q == "SCHEME") {
    qual = URL_QUAL_SCHEME;
  } else if (q == "URL") {
    qual = URL_QUAL_URL;
  } else {
    TSError("[%s] Invalid URL() qualifier: %s", PLUGIN_NAME, q.c_str());
  }

  return qual;
}

// Parse HTTP CNTL qualifiers
TSHttpCntlType
Statement::parse_http_cntl_qualifier(const std::string &q) const
{
  TSHttpCntlType qual = TS_HTTP_CNTL_LOGGING_MODE;

  if (q == "LOGGING") {
    qual = TS_HTTP_CNTL_LOGGING_MODE;
  } else if (q == "INTERCEPT_RETRY") {
    qual = TS_HTTP_CNTL_INTERCEPT_RETRY_MODE;
  } else if (q == "RESP_CACHEABLE") {
    qual = TS_HTTP_CNTL_RESPONSE_CACHEABLE;
  } else if (q == "REQ_CACHEABLE") {
    qual = TS_HTTP_CNTL_REQUEST_CACHEABLE;
  } else if (q == "SERVER_NO_STORE") {
    qual = TS_HTTP_CNTL_SERVER_NO_STORE;
  } else if (q == "TXN_DEBUG") {
    qual = TS_HTTP_CNTL_TXN_DEBUG;
  } else if (q == "SKIP_REMAP") {
    qual = TS_HTTP_CNTL_SKIP_REMAPPING;
  } else {
    TSError("[%s] Invalid HTTP-CNTL() qualifier: %s", PLUGIN_NAME, q.c_str());
  }

  return qual;
}
