/**
 * Copyright (c) 2021 OceanBase
 * OceanBase CE is licensed under Mulan PubL v2.
 * You can use this software according to the terms and conditions of the Mulan PubL v2.
 * You may obtain a copy of Mulan PubL v2 at:
 *          http://license.coscl.org.cn/MulanPubL-2.0
 * THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
 * EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
 * MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
 * See the Mulan PubL v2 for more details.
 */

#define USING_LOG_PREFIX SQL_ENG
#include <string.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <net/if.h>
#include "sql/engine/expr/ob_expr_uuid.h"
using namespace oceanbase::common;
using namespace oceanbase::sql;

namespace oceanbase {
namespace sql {

int ObBigEndian::put_uint16(unsigned char* b, uint16_t v)
{
  int ret = OB_SUCCESS;
  if (OB_ISNULL(b)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_ERROR("unexpected error. pointer is null", K(ret), K(b));
  } else {
    b[0] = static_cast<unsigned char>(v >> 8);
    b[1] = static_cast<unsigned char>(v);
  }
  return ret;
}
int ObBigEndian::put_uint32(unsigned char* b, uint32_t v)
{
  int ret = OB_SUCCESS;
  if (OB_ISNULL(b)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_ERROR("unexpected error. pointer is null", K(ret), K(b));
  } else {
    b[0] = static_cast<unsigned char>(v >> 24);
    b[1] = static_cast<unsigned char>(v >> 16);
    b[2] = static_cast<unsigned char>(v >> 8);
    b[3] = static_cast<unsigned char>(v);
  }
  return ret;
}

ObUUIDNode::ObUUIDNode()
{
  is_inited_ = false;
  (void)init();
}

/*
 * get and set mac address
 *
 */
int ObUUIDNode::init()
{
  int ret = OB_SUCCESS;
  struct ifreq ifr;
  struct ifconf ifc;
  char buf[1024];
  is_inited_ = false;
  int sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
  if (sock == -1) {
    ret = OB_ERR_UNEXPECTED;
    LOG_ERROR("socket failed", K(ret), K(errno));
  } else {
    ifc.ifc_len = sizeof(buf);
    ifc.ifc_buf = buf;
    if (ioctl(sock, SIOCGIFCONF, &ifc) < 0) {
      ret = OB_ERR_UNEXPECTED;
      LOG_WARN("unexpected error. ioctl failed", K(ret), K(errno));
    } else {
      ifreq* it = ifc.ifc_req;
      ifreq* end = it + (ifc.ifc_len / sizeof(ifreq));
      bool mac_addr_found = false;
      for (; it != end && OB_SUCC(ret); ++it) {
        if (OB_ISNULL(it) || OB_ISNULL(it->ifr_name) || OB_ISNULL(ifr.ifr_name)) {
          continue;
        } else {
          strncpy(ifr.ifr_name, it->ifr_name, IFNAMSIZ - 1);
          if (ioctl(sock, SIOCGIFFLAGS, &ifr) == 0) {
            if (!(ifr.ifr_flags & IFF_LOOPBACK)) {
              if (ioctl(sock, SIOCGIFHWADDR, &ifr) == 0) {
                MEMCPY(mac_addr_, ifr.ifr_hwaddr.sa_data, 6);
                mac_addr_found = true;
                break;
              }
            }
          }
        }
      }  // end for
      if (OB_FAIL(ret)) {
      } else if (!mac_addr_found) {
        ret = OB_ERR_UNEXPECTED;
        LOG_WARN("unexpected error. can not get mac address", K(ret), K(errno));
      } else {
        is_inited_ = true;
      }
    }
    close(sock);
  }
  return ret;
}

int ObUUIDTime::get_time(uint64_t& time, uint16_t& seq)
{
  int ret = OB_SUCCESS;
  ObLatchWGuard guard(lock_, ObLatchIds::DEFAULT_MUTEX);
  uint64_t now = 0;
  if (OB_FAIL(time_now(now))) {
    LOG_WARN("get time failed", K(ret));
  } else {
    if (clock_seq_ == 0) {
      reset_clock_seq();
    }
    now = (now / uint64_t(100)) + G1582NS100;
    if (now <= lasttime_) {
      clock_seq_ = static_cast<uint16_t>(((clock_seq_ + 1) & 0x3fff) | 0x8000);
    }
    lasttime_ = now;
    time = now;
    seq = clock_seq_;
  }
  return ret;
}

int ObUUIDTime::time_now(uint64_t& now)
{
  int ret = OB_SUCCESS;
  struct timespec ts;
  int tmpret = clock_gettime(CLOCK_REALTIME, &ts);
  if (tmpret != 0) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("get clock time failed", K(ret), K(errno));
  } else {
    now = uint64_t(ts.tv_sec) * uint64_t(1000000000) + uint64_t(ts.tv_nsec);
  }
  return ret;
}

void ObUUIDTime::reset_clock_seq()
{
  uint8_t b[2] = {0, 0};
  srandom(static_cast<unsigned int>(time(NULL)));
  b[0] = static_cast<uint8_t>(random());
  b[1] = static_cast<uint8_t>(random());
  uint16_t seq = static_cast<uint16_t>(uint16_t(b[0] << 8) | uint16_t(b[1]));
  clock_seq_ = static_cast<uint16_t>((seq & 0x3fff) | 0x8000);
}

ObExprUuid::ObExprUuid(ObIAllocator& alloc) : ObFuncExprOperator(alloc, T_FUN_SYS_UUID, N_UUID, 0, NOT_ROW_DIMENSION)
{}

ObExprUuid::ObExprUuid(
    ObIAllocator& alloc, ObExprOperatorType type, const char* name, int32_t param_num, int32_t dimension)
    : ObFuncExprOperator(alloc, type, name, param_num, dimension)
{}

ObExprUuid::~ObExprUuid()
{}

int ObExprUuid::calc_result0(ObObj& result, ObExprCtx& expr_ctx) const
{
  int ret = OB_SUCCESS;
  char* buffer = NULL;
  unsigned char scratch[ObExprUuid::LENGTH_UUID];
  if (OB_ISNULL(expr_ctx.calc_buf_)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("allocator is null", K(ret), K(expr_ctx.calc_buf_));
  } else if (OB_UNLIKELY(NULL == (buffer = static_cast<char*>(expr_ctx.calc_buf_->alloc(ObExprUuid::LENGTH_UUID))))) {
    ret = OB_ALLOCATE_MEMORY_FAILED;
    LOG_ERROR("allocate memory failed", K(ret));
  } else if (OB_FAIL(calc(scratch))) {
    LOG_WARN("calc failed", K(ret));
  } else {
    // to string
    char* start = buffer;
    for (int64_t i = 0; i < 16; ++i) {
      if (4 == i || 6 == i || 8 == i || 10 == i) {
        sprintf(buffer++, "-");
      }
      sprintf(buffer, "%02x", scratch[i]);
      buffer += 2;
    }
    result.set_varchar(start, ObExprUuid::LENGTH_UUID);
    result.set_collation(result_type_);
  }
  return ret;
}

int ObExprUuid::init()
{
  // will be inited once when and only when server starts
  // so, please do not worry too much about the contention even we use ob_malloc here.
  int ret = OB_SUCCESS;
  ObMemAttr mem_attr;
  mem_attr.label_ = ObModIds::OB_SQL_EXPR;
  uuid_node = static_cast<ObUUIDNode*>(ob_malloc(sizeof(ObUUIDNode), mem_attr));
  if (OB_UNLIKELY(NULL == uuid_node)) {
    ret = OB_ALLOCATE_MEMORY_FAILED;
    LOG_ERROR("allocate memory failed", K(ret));
  } else if (OB_FAIL(uuid_node->init())) {
    LOG_WARN("init uuid node failed", K(ret));
    ob_free(uuid_node);  // very important ! do not forget this !
    uuid_node = NULL;    // very important ! do not forget this !
  }
  return ret;
}

int ObExprUuid::calc(unsigned char* scratch)
{
  int ret = OB_SUCCESS;
  if (OB_ISNULL(scratch)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_ERROR("unexpected error. pointer is null", K(ret), K(scratch));
  } else if (OB_ISNULL(uuid_node) || OB_UNLIKELY(!(uuid_node->is_inited_))) {
    ret = OB_ERR_UNEXPECTED;
    LOG_ERROR("unexpected error. uuid node is not inited", K(ret), K(uuid_node));
  } else {
    unsigned char* mac_addr = uuid_node->mac_addr_;
    uint64_t time = 0;
    uint16_t seq = 0;
    if (OB_FAIL(ObUUIDTime::get_time(time, seq))) {
      LOG_WARN("get time failed", K(ret));
    } else {
      uint32_t time_low = static_cast<uint32_t>(time);
      uint16_t time_mid = static_cast<uint16_t>(time >> 32);
      uint16_t time_hi = static_cast<uint16_t>((time >> 48) & 0x0fff);
      time_hi |= 0x1000;
      /*faint. really ugly. 4 if(ob_fail)s here, not efficient at all*/
      /*may I omit the tests for NULL on scratch ? */
      if (OB_FAIL(ObBigEndian::put_uint32(scratch, time_low))) {
        LOG_WARN("put uint32 failed", K(ret));
      } else if (OB_FAIL(ObBigEndian::put_uint16(scratch + 4, time_mid))) {
        LOG_WARN("put uint16 failed", K(ret));
      } else if (OB_FAIL(ObBigEndian::put_uint16(scratch + 6, time_hi))) {
        LOG_WARN("put uint16 failed", K(ret));
      } else if (OB_FAIL(ObBigEndian::put_uint16(scratch + 8, seq))) {
        LOG_WARN("put uint16 failed", K(ret));
      } else {
        MEMCPY(scratch + 10, mac_addr, 6);
      }
    }
  }
  return ret;
}

uint64_t ObUUIDTime::lasttime_ = 0;
uint16_t ObUUIDTime::clock_seq_ = 0;
ObLatch ObUUIDTime::lock_;

ObUUIDNode* ObExprUuid::uuid_node = NULL;

int ObExprUuid::eval_uuid(const ObExpr& expr, ObEvalCtx& ctx, ObDatum& expr_datum)
{
  int ret = OB_SUCCESS;
  UNUSED(expr);
  unsigned char scratch[ObExprUuid::LENGTH_UUID] = {0};
  if (OB_FAIL(calc(scratch))) {
    LOG_WARN("calc failed", K(ret));
  } else {
    char* buf = expr.get_str_res_mem(ctx, LENGTH_UUID);
    int64_t pos = 0;
    if (OB_ISNULL(buf)) {
      ret = OB_ERR_UNEXPECTED;
      SERVER_LOG(WARN, "buff is null", K(ret));
    } else {
      // to string
      const char* HEXCHARS = "0123456789abcdef";
      for (int64_t i = 0; pos < LENGTH_UUID && i < 16; ++i) {
        if (4 == i || 6 == i || 8 == i || 10 == i) {
          buf[pos++] = '-';
        }
        buf[pos++] = HEXCHARS[scratch[i] >> 4 & 0xF];
        buf[pos++] = HEXCHARS[scratch[i] & 0xF];
      }
      if (OB_SUCC(ret)) {
        expr_datum.set_string(buf, LENGTH_UUID);
      }
    }
  }
  return ret;
}

int ObExprUuid::cg_expr(ObExprCGCtx& op_cg_ctx, const ObRawExpr& raw_expr, ObExpr& rt_expr) const
{
  UNUSED(raw_expr);
  UNUSED(op_cg_ctx);
  rt_expr.eval_func_ = ObExprUuid::eval_uuid;
  return OB_SUCCESS;
}

ObExprSysGuid::ObExprSysGuid(ObIAllocator& alloc) : ObExprUuid(alloc, T_FUN_SYS_GUID, N_SYS_GUID, 0, NOT_ROW_DIMENSION)
{}

ObExprSysGuid::~ObExprSysGuid()
{}

int ObExprSysGuid::calc_result0(ObObj& result, ObExprCtx& expr_ctx) const
{
  int ret = OB_SUCCESS;
  unsigned char* buffer = NULL;
  CK(OB_NOT_NULL(expr_ctx.calc_buf_));
  if (OB_SUCC(ret) &&
      OB_ISNULL(buffer = static_cast<unsigned char*>(expr_ctx.calc_buf_->alloc(ObExprUuid::LENGTH_UUID)))) {
    ret = OB_ALLOCATE_MEMORY_FAILED;
    LOG_WARN("allocate memory for sys guid failed", K(ret));
  }
  OZ(calc(buffer));
  OX(result.set_raw(reinterpret_cast<char*>(buffer), ObExprSysGuid::LENGTH_SYS_GUID));
  OX(result.set_collation(result_type_));
  return ret;
}

int ObExprSysGuid::eval_sys_guid(const ObExpr& expr, ObEvalCtx& ctx, ObDatum& expr_datum)
{
  int ret = OB_SUCCESS;
  unsigned char* buf = reinterpret_cast<unsigned char*>(expr.get_str_res_mem(ctx, LENGTH_UUID));
  if (OB_ISNULL(buf)) {
    ret = OB_ALLOCATE_MEMORY_FAILED;
    LOG_WARN("buff is null", K(ret));
  } else if (OB_FAIL(calc(buf))) {
    LOG_WARN("calc uuid failed", K(ret));
  } else {
    expr_datum.set_string(reinterpret_cast<char*>(buf), LENGTH_SYS_GUID);
  }
  return ret;
}

}  // namespace sql
}  // namespace oceanbase