/**
 * 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 "lib/oblog/ob_log.h"
#include "sql/engine/expr/ob_expr_initcap.h"
#include "objit/common/ob_item_type.h"
#include "common/data_buffer.h"
#include "sql/session/ob_sql_session_info.h"
#include "sql/engine/expr/ob_expr_lob_utils.h"

namespace oceanbase
{
using namespace common;
namespace sql
{

ObExprInitcap::ObExprInitcap(ObIAllocator &alloc)
    : ObExprInitcapCommon(alloc, T_FUN_SYS_INITCAP, N_INITCAP, 1)
{
}

ObExprInitcap::~ObExprInitcap()
{
}

int ObExprInitcap::calc_result_type1(ObExprResType &type,
                                     ObExprResType &text,
                                     ObExprTypeCtx &type_ctx) const
{
  int ret = OB_SUCCESS;
  const ObBasicSessionInfo *session = type_ctx.get_session();
  ObSEArray<ObExprResType*, 1, ObNullAllocator> params;

  CK(OB_NOT_NULL(session));
  OZ(params.push_back(&text));
  OZ(aggregate_string_type_and_charset_oracle(*session, params, type, PREFER_VAR_LEN_CHAR));
  OZ(deduce_string_param_calc_type_and_charset(*session, type, params));
  if (OB_SUCC(ret)) {
    common::ObLength result_len = text.get_calc_length();
    if (OB_UNLIKELY(!ObCharset::is_valid_collation(type.get_collation_type()))) {
      ret = OB_INVALID_ARGUMENT;
      LOG_WARN("invalid charset", K(type), K(ret));
    } else {
      result_len *= ObCharset::get_charset(type.get_collation_type())->caseup_multiply;
      type.set_length(result_len);
    }
  }
  return ret;
}

// last_has_first_letter is used to assign has_first_letter at the beginning, and return last state of text
int ObExprInitcapCommon::initcap_string(const ObString &text,
                                  const ObCollationType cs_type,
                                  ObIAllocator *allocator,
                                  ObString &res_str,
                                  bool &last_has_first_letter)
{
  int ret = OB_SUCCESS;

  if (OB_ISNULL(allocator)) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("allocator is null", K(ret));
  } else {

    int64_t case_multiply = std::max(ObCharset::get_charset(cs_type)->caseup_multiply,
                                     ObCharset::get_charset(cs_type)->casedn_multiply);
    int64_t buf_len = case_multiply * text.length();
    char *buf = static_cast<char *>(allocator->alloc(buf_len));
    int64_t pos = 0;

    if (OB_ISNULL(buf)) {
      ret = OB_ALLOCATE_MEMORY_FAILED;
      LOG_WARN("alloc memory failed", K(text.length()), K(case_multiply), K(cs_type), K(ret));
    } else {
      ObStringScanner scanner(text, cs_type);
      ObString cur_letter;
      int32_t wchar = 0;
      bool has_first_letter = last_has_first_letter;

      if (1 == case_multiply) {
        MEMCPY(buf, text.ptr(), text.length());
      }

      while (OB_SUCC(ret)) {
        if (OB_ITER_END == (ret = scanner.next_character(cur_letter, wchar))) {
          ret = OB_SUCCESS;
          break;
        } else if (OB_FAIL(ret)) {
          LOG_WARN("fail to get next character", K(ret), K(scanner));
        } else {
          bool is_alphanumeric =
              (wchar <= INT8_MAX
               && ob_isalnum(ObCharset::get_charset(CS_TYPE_UTF8MB4_GENERAL_CI), wchar));
          if (is_alphanumeric) {
            char *src_ptr = (1 == case_multiply) ? buf + pos : cur_letter.ptr();
            int64_t buf_remain = cur_letter.length() * case_multiply;
            int64_t write_len = has_first_letter ?
                  ObCharset::casedn(cs_type, src_ptr, cur_letter.length(), buf + pos, buf_remain)
                : ObCharset::caseup(cs_type, src_ptr, cur_letter.length(), buf + pos, buf_remain);
            if (OB_UNLIKELY(0 == write_len)) {
              ret = OB_ERR_UNEXPECTED;
            } else {
              pos += write_len;
            }
            has_first_letter = true;
          } else {
            has_first_letter = false;
            MEMCPY(buf + pos, cur_letter.ptr(), cur_letter.length());
            pos += cur_letter.length();
          }
        }
      }
      if (OB_SUCC(ret)) {
        last_has_first_letter = has_first_letter;
        res_str.assign_ptr(buf, pos);
      }
    }
  }

  return ret;
}

int calc_initcap_expr(const ObExpr &expr, ObEvalCtx &ctx, ObDatum &res_datum)
{
  int ret = OB_SUCCESS;
  ObDatum *arg_datum = NULL;
  ObString res_str;
  char *res_buf = NULL;
  ObCollationType cs_type = expr.args_[0]->datum_meta_.cs_type_;
  int64_t case_multiply = std::max(ObCharset::get_charset(cs_type)->caseup_multiply,
                                   ObCharset::get_charset(cs_type)->casedn_multiply);
  if (OB_FAIL(expr.args_[0]->eval(ctx, arg_datum))) {
    LOG_WARN("eval arg 0 failed", K(ret), K(expr));
  } else if (arg_datum->is_null()) {
    res_datum.set_null();
  } else {
    if (!ob_is_text_tc(expr.args_[0]->datum_meta_.type_)) {
      if (OB_ISNULL(res_buf = expr.get_str_res_mem(ctx, arg_datum->len_ * case_multiply))) {
        ret = OB_ALLOCATE_MEMORY_FAILED;
        LOG_WARN("allocate memory failed", K(ret));
      } else {
        ObDataBuffer buf_alloc(res_buf, arg_datum->len_ * case_multiply);
        bool last_has_first_letter = false;
        if (OB_FAIL(ObExprInitcap::initcap_string(arg_datum->get_string(),
                                                  cs_type,
                                                  &buf_alloc,
                                                  res_str,
                                                  last_has_first_letter))) {
          LOG_WARN("initcap string failed", K(ret), K(arg_datum->get_string()));
        }
      }
    } else { // text tc
      ObEvalCtx::TempAllocGuard alloc_guard(ctx);
      ObIAllocator &calc_alloc = alloc_guard.get_allocator();
      ObTextStringIter input_iter(expr.args_[0]->datum_meta_.type_, cs_type,
                                  arg_datum->get_string(),
                                  expr.args_[0]->obj_meta_.has_lob_header());
      ObTextStringDatumResult output_result(expr.datum_meta_.type_, &expr, &ctx, &res_datum);
      int64_t input_byte_len = 0;
      int64_t buf_size = 0;
      if (OB_FAIL(input_iter.init(0, NULL, &calc_alloc))) {
        LOG_WARN("init input_iter failed ", K(ret), K(input_iter));
      } else if (OB_FAIL(input_iter.get_byte_len(input_byte_len))) {
        LOG_WARN("get input byte len failed");
      } else if (OB_FAIL(output_result.init(input_byte_len * case_multiply))) {
        LOG_WARN("init stringtext result failed");
      } else if (input_byte_len == 0) {
        // do nothing, let res_str become empty string
        res_str.assign_ptr(NULL, 0);
      } else if (OB_FAIL(output_result.get_reserved_buffer(res_buf, buf_size))) {
        LOG_WARN("stringtext result reserve buffer failed");
      } else {
        ObTextStringIterState state;
        ObString input_data;
        bool last_has_first_letter = false;
        while (OB_SUCC(ret)
              && buf_size > 0
              && (state = input_iter.get_next_block(input_data)) == TEXTSTRING_ITER_NEXT) {
          ObDataBuffer buf_alloc(res_buf, buf_size);
          if (OB_FAIL(ObExprInitcap::initcap_string(input_data,
                                                    cs_type,
                                                    &buf_alloc,
                                                    res_str,
                                                    last_has_first_letter))) {
            LOG_WARN("initcap string failed", K(ret), K(input_data));
          } else if (OB_FAIL(output_result.lseek(res_str.length(), 0))) {
            LOG_WARN("result lseek failed", K(ret));
          } else {
            res_buf = res_buf + res_str.length();
            buf_size = buf_size - res_str.length();
          }
        }
        output_result.get_result_buffer(res_str);
      }
    }
    if (OB_SUCC(ret)) {
      if (0 == res_str.length()) {
        // initcap is only for oracle mode. set res be null when string length is 0.
        res_datum.set_null();
      } else {
        res_datum.set_string(res_str);
      }
    }
  }
  return ret;
}

int ObExprInitcap::cg_expr(ObExprCGCtx &expr_cg_ctx, const ObRawExpr &raw_expr,
                           ObExpr &rt_expr) const
{
  int ret = OB_SUCCESS;
  UNUSED(expr_cg_ctx);
  UNUSED(raw_expr);
  rt_expr.eval_func_ = calc_initcap_expr;
  return ret;
}

ObExprNlsInitCap::ObExprNlsInitCap(ObIAllocator &alloc)
    : ObExprInitcapCommon(alloc, T_FUN_SYS_NLS_INITCAP, N_NLS_INITCAP, PARAM_NUM_UNKNOWN)
{
}

int ObExprNlsInitCap::calc_result_typeN(ObExprResType &type,
                                        ObExprResType *texts,
                                        int64_t param_num,
                                        ObExprTypeCtx &type_ctx) const
{
  int ret = OB_SUCCESS;
  const ObBasicSessionInfo *session = type_ctx.get_session();
  if (OB_ISNULL(session)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("session is NULL", K(ret));
  } else if (param_num <= 0) {
    ret = OB_ERR_NOT_ENOUGH_ARGS_FOR_FUN;
    LOG_WARN("nls_initcap require at least one parameter", K(ret), K(param_num));
  } else if (param_num > 2) {
    ret = OB_ERR_TOO_MANY_ARGS_FOR_FUN;
    LOG_WARN("nls_initcap require at most two parameters", K(ret), K(param_num));
  } else if (OB_ISNULL(texts)) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("Invalid argument", K(ret), K(param_num), K(texts));
  } else {
    ObSEArray<ObExprResType*, 1, ObNullAllocator> params;
    CK(OB_NOT_NULL(session));
    if (OB_FAIL(params.push_back(&texts[0]))) {
      LOG_WARN("fail to push back param", K(ret));
    } else if OB_FAIL(aggregate_string_type_and_charset_oracle(*session, params, type, true)) {
      LOG_WARN("fail to aggregrate string type and charset", K(ret));
    } else if (ObVarcharType != type.get_type() && ObNVarchar2Type != type.get_type()) {
      type.set_varchar();
    }
    if (OB_SUCC(ret)) {
      if (OB_FAIL(deduce_string_param_calc_type_and_charset(*session, type, params))) {
        LOG_WARN("fail to deduce string param type", K(ret));
      } else {
        const ObCharsetInfo * cs_info = NULL;
        if (OB_ISNULL(cs_info = ObCharset::get_charset(type.get_collation_type()))) {
          ret = OB_ERR_UNEXPECTED;
          LOG_WARN("fail to get charset info", K(ret), K(texts[0]));
        } else {
          int64_t len = texts[0].get_calc_length();
          len = len * cs_info->mbmaxlen;
          type.set_length(len > OB_MAX_ORACLE_VARCHAR_LENGTH ?
                          OB_MAX_ORACLE_VARCHAR_LENGTH : len);
        }
      }
    }
  }
  return ret;
}

int ObExprNlsInitCap::cg_expr(ObExprCGCtx &expr_cg_ctx, const ObRawExpr &raw_expr,
                           ObExpr &rt_expr) const
{
  int ret = OB_SUCCESS;
  UNUSED(expr_cg_ctx);
  UNUSED(raw_expr);
  rt_expr.eval_func_ = calc_nls_initcap_expr;
  if ((1 == rt_expr.arg_cnt_ && rt_expr.args_[0]->is_batch_result())
      || (2 == rt_expr.arg_cnt_
          && rt_expr.args_[0]->is_batch_result()
          && !rt_expr.args_[1]->is_batch_result())) {
    rt_expr.eval_batch_func_ = calc_nls_initcap_batch;
  }
  return ret;
}

int ObExprNlsInitCap::calc_nls_initcap_expr(const ObExpr &expr, ObEvalCtx &ctx, ObDatum &res_datum)
{
  int ret = OB_SUCCESS;
  ObCollationType cs_type = expr.args_[0]->datum_meta_.cs_type_;
  bool is_null_result = false;
  int64_t case_multiply = 1;
  ObDatum *arg_datum = NULL;
  if (OB_UNLIKELY(expr.arg_cnt_ <= 0 || expr.arg_cnt_ > 2)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("unexpected param number", K(ret), K(expr.arg_cnt_));
  } else if (OB_FAIL(expr.args_[0]->eval(ctx, arg_datum))) {
    LOG_WARN("eval arg 0 failed", K(ret), K(expr));
  } else if (arg_datum->is_null()) {
    res_datum.set_null();
    is_null_result = true;
  } else if (expr.arg_cnt_ == 2) {
    ObDatum *param_datum = NULL;
    if (OB_ISNULL(expr.args_[1])) {
      ret = OB_ERR_UNEXPECTED;
      LOG_WARN("failed to get nls parameter", K(ret));
    } else if (OB_FAIL(expr.args_[1]->eval(ctx, param_datum))) {
      LOG_WARN("eval nls parameter failed", K(ret));
    } else if (param_datum->is_null()) {
      // Second param_datum is null, set result null as well.
      res_datum.set_null();
      is_null_result = true;
    } else {
      const ObString &m_param = param_datum->get_string();
      if (OB_UNLIKELY(!ObExprOperator::is_valid_nls_param(m_param))) {
        ret = OB_ERR_INVALID_NLS_PARAMETER_STRING;
        LOG_WARN("invalid nls parameter", K(ret), K(m_param));
      } else {
        // Should set cs_type here, but for now, we do nothing
        // since nls parameter only support BINARY
      }
    }
  }
  if (OB_SUCC(ret) && !is_null_result) {
    const ObCharsetInfo * cs_info = NULL;
    if (OB_ISNULL(cs_info = ObCharset::get_charset(cs_type))) {
      ret = OB_ERR_UNEXPECTED;
      LOG_WARN("fail to get charset info", K(ret), K(cs_type));
    } else {
      case_multiply = std::max(cs_info->caseup_multiply, cs_info->casedn_multiply);
    }
  }
  if (OB_SUCC(ret) && !is_null_result) {
    char *res_buf = NULL;
    if (OB_ISNULL(res_buf = expr.get_str_res_mem(ctx, arg_datum->len_ * case_multiply))) {
      ret = OB_ALLOCATE_MEMORY_FAILED;
      LOG_WARN("allocate memory failed", K(ret));
    } else {
      ObDataBuffer buf_alloc(res_buf, arg_datum->len_ * case_multiply);
      ObString res_str;
      bool last_has_first_letter = false;
      if (OB_FAIL(initcap_string(arg_datum->get_string(),
                                  expr.args_[0]->datum_meta_.cs_type_,
                                  &buf_alloc, res_str, last_has_first_letter))) {
        LOG_WARN("initcap string failed", K(ret), K(arg_datum->get_string()));
      } else if (0 == res_str.length()) {
        // nls_initcap is only for oracle mode. set res be null when string length is 0.
        res_datum.set_null();
      } else {
        res_datum.set_string(res_str);
      }
    }
  }
  return ret;
}

int ObExprNlsInitCap::calc_nls_initcap_batch(const ObExpr &expr, ObEvalCtx &ctx, const ObBitVector &skip, const int64_t batch_size) {
  int ret = OB_SUCCESS;
  ObDatum *results = expr.locate_batch_datums(ctx);
  if (OB_ISNULL(results)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("expr results frame is not init", K(ret));
  } else if (OB_UNLIKELY(expr.arg_cnt_ <= 0 || expr.arg_cnt_ > 2)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("unexpected param number", K(ret), K(expr.arg_cnt_));
  } else {
    ObBitVector &eval_flags = expr.get_evaluated_flags(ctx);
    ObDatum *nlsparam_datum = NULL;
    bool is_result_all_null = false;
    ObCollationType cs_type = expr.args_[0]->datum_meta_.cs_type_;
    int64_t case_multiply = 1;
    ObDatum *datum_array = NULL;
    if (OB_FAIL(expr.args_[0]->eval_batch(ctx, skip, batch_size))) {
      LOG_WARN("failed to eval batch result args0", K(ret));
    } else {
      datum_array = expr.args_[0]->locate_batch_datums(ctx);
    }
    if (2 == expr.arg_cnt_) {
      if (OB_FAIL(expr.args_[1]->eval(ctx, nlsparam_datum))) {
        LOG_WARN("eval fmt_datum failed", K(ret));
      } else if (nlsparam_datum->is_null()) {
        is_result_all_null = true;
      } else {
        const ObString &m_param = nlsparam_datum->get_string();
        if (OB_UNLIKELY(!ObExprOperator::is_valid_nls_param(m_param))) {
          for (int64_t i = 0; OB_SUCC(ret) && i < batch_size; ++i) {
            if (skip.at(i) || eval_flags.at(i)) {
              continue;
            } else if (!datum_array[i].is_null()) {
              ret = OB_ERR_INVALID_NLS_PARAMETER_STRING;
              LOG_WARN("invalid nls parameter", K(ret), K(m_param));
            }
          }
          if (OB_SUCC(ret)) {
            //if the nls_sort param is not valid, return null instead of an error when the param is null
            is_result_all_null = true;
          }
        } else {
          // Should set cs_type here, but for now, we do nothing
          // since nls parameter only support BINARY=
        }
      }
    }
    if (OB_SUCC(ret) && !is_result_all_null) {
      const ObCharsetInfo * cs_info = NULL;
      if (OB_ISNULL(cs_info = ObCharset::get_charset(cs_type))) {
        ret = OB_ERR_UNEXPECTED;
        LOG_WARN("fail to get charset info", K(ret), K(cs_type));
      } else {
        case_multiply = std::max(cs_info->caseup_multiply, cs_info->casedn_multiply);
      }
    }
    if (OB_SUCC(ret)) {
      for (int64_t i = 0; OB_SUCC(ret) && i < batch_size; ++i) {
        char *res_buf = NULL;
        if (skip.at(i) || eval_flags.at(i)) {
          continue;
        } else if (is_result_all_null || datum_array[i].is_null()) {
          results[i].set_null();
          eval_flags.set(i);
        } else if (OB_ISNULL(res_buf = expr.get_str_res_mem(ctx, datum_array[i].len_ * case_multiply, i))) {
          ret = OB_ALLOCATE_MEMORY_FAILED;
          LOG_WARN("allocate memory failed", K(ret));
        } else {
          ObDataBuffer buf_alloc(res_buf, datum_array[i].len_ * case_multiply);
          ObString res_str;
          bool last_has_first_letter = false;
          if (OB_FAIL(initcap_string(datum_array[i].get_string(),
                                    cs_type,
                                    &buf_alloc, res_str, last_has_first_letter))) {
            LOG_WARN("initcap string failed", K(ret), K(datum_array[i].get_string()));
          } else if (0 == res_str.length()) {
            // nls_initcap is only for oracle mode. set res be null when string length is 0.
            results[i].set_null();
            eval_flags.set(i);
          } else {
            results[i].set_string(res_str);
            eval_flags.set(i);
          }
        }
      }
    }
  }
  return ret;
}

} /* sql */
} /* oceanbase */