/**
 * 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.
 */

// This file contains implementation for json_remove.
#define USING_LOG_PREFIX SQL_ENG
#include "ob_expr_json_remove.h"
#include "ob_expr_json_func_helper.h"

using namespace oceanbase::common;
using namespace oceanbase::sql;
namespace oceanbase
{
namespace sql
{
ObExprJsonRemove::ObExprJsonRemove(ObIAllocator &alloc)
    : ObFuncExprOperator(alloc, T_FUN_SYS_JSON_REMOVE, N_JSON_REMOVE, MORE_THAN_ONE, NOT_ROW_DIMENSION)
{
}

ObExprJsonRemove::~ObExprJsonRemove()
{
}

int ObExprJsonRemove::calc_result_typeN(ObExprResType& type,
                                        ObExprResType* types_stack,
                                        int64_t param_num,
                                        ObExprTypeCtx& type_ctx) const
{
  UNUSED(type_ctx);
  int ret = OB_SUCCESS;

  // json doc
  if (OB_FAIL(ObJsonExprHelper::is_valid_for_json(types_stack, 0, N_JSON_REMOVE))) {
    LOG_WARN("wrong type for json doc.", K(ret), K(types_stack[0].get_type()));
  }
  // json path
  for (int64_t i = 1; OB_SUCC(ret) && i < param_num; i++) {
    if (OB_FAIL(ObJsonExprHelper::is_valid_for_path(types_stack, i))) {
      LOG_WARN("wrong type for json path.", K(ret), K(types_stack[i].get_type()));
    }
  }
  type.set_json();
  return ret;
}

static int remove_from_json(ObJsonPath *path_node, ObIJsonBase *parent)
{
  INIT_SUCC(ret);
  // remove item in hits
  ObJsonPathBasicNode* last_node = path_node->last_path_node();
  // get node to be removed
  ObJsonNodeType type = parent->json_type();
  if (type == ObJsonNodeType::J_OBJECT && last_node->get_node_type() == JPN_MEMBER) {
    ObPathMember member = last_node->get_object();
    ObString key(member.len_, member.object_name_);
    if (OB_FAIL(parent->object_remove(key))) {
      LOG_WARN("fail to remove json_object node", K(ret));
    }
  } else if (type == ObJsonNodeType::J_ARRAY && last_node->get_node_type() == JPN_ARRAY_CELL) {
    ObJsonArrayIndex array_index;
    if (OB_FAIL(last_node->get_first_array_index(parent->element_count(), array_index))) {
      LOG_WARN("error, get array index failed", K(ret));
    } else if (array_index.is_within_bounds() && OB_FAIL(parent->array_remove(array_index.get_array_index()))) {
      LOG_WARN("fail to remove json_array node", K(ret));
    }
  }
  return ret;
}

int ObExprJsonRemove::calc_resultN(common::ObObj &result,
                                   const common::ObObj *params,
                                   int64_t param_num,
                                   common::ObExprCtx &expr_ctx) const
{
  INIT_SUCC(ret);
  ObIAllocator *allocator = expr_ctx.calc_buf_;
  
  if (OB_ISNULL(allocator)) { // check allocator
    ret = OB_NOT_INIT;
    LOG_WARN("varchar buffer not init", K(ret));
  } else if (result_type_.get_collation_type() != CS_TYPE_UTF8MB4_BIN) {
    ret = OB_ERR_INVALID_JSON_CHARSET;
    LOG_WARN("invalid out put charset", K(ret), K(result_type_));
  } else {
    ObIJsonBase *json_doc = NULL;
    bool is_null_result = false;
    if (OB_FAIL(ObJsonExprHelper::get_json_doc(params, allocator, 0,
                                               json_doc, is_null_result))) {
      LOG_WARN("get_json_doc failed", K(ret));
    }

    ObJsonPathCache ctx_cache(allocator);
    ObJsonPathCache* path_cache = &ctx_cache;
    ObJsonBaseVector hits;
    if (!is_null_result && OB_SUCC(ret)) {
      for (int64_t i = 1; OB_SUCC(ret) && i < param_num; i++) {
        hits.clear();
        ObObjType val_type = params[i].get_type();
        if (val_type == ObNullType || params[i].is_null()) {
          is_null_result = true;
          break;
        } else {
          ObString path_val = params[i].get_string();
          ObJsonPath *json_path;
          if (OB_FAIL(ObJsonExprHelper::find_and_add_cache(path_cache, json_path, path_val, i, false))) {
            LOG_WARN("json parse failed or path illegal", K(path_val), K(ret));
          } else if (json_path->path_node_cnt() == 0) {
            ret = OB_ERR_JSON_VACUOUS_PATH;
            LOG_USER_ERROR(OB_ERR_JSON_VACUOUS_PATH); 
          } else if (OB_FAIL(json_doc->seek(*json_path, json_path->path_node_cnt() - 1, true, false, hits))) {
            LOG_WARN("json seek failed", K(path_val), K(ret));
          } else if (hits.size() == 0){
            continue;
          } else if (hits.size() > 1){
            ret = OB_INVALID_ERROR;
            LOG_WARN("Expect only one result", K(ret));
          } else {
            if (OB_FAIL(remove_from_json(json_path, hits[0]))) {
              LOG_WARN("remove_from_json failed", K(ret));
            } 
          }
        }
      }
    }

    // set result
    if (OB_UNLIKELY(OB_FAIL(ret))) {
      LOG_WARN("json_remove failed", K(ret));
    } else if (is_null_result) {
      result.set_null();
    } else {
      ObString raw_bin;
      if (OB_FAIL(json_doc->get_raw_binary(raw_bin, allocator))) {
        LOG_WARN("json_remove get result binary failed", K(ret));
      } else {
        result.set_collation_type(CS_TYPE_UTF8MB4_BIN);
        result.set_string(ObJsonType, raw_bin.ptr(), raw_bin.length());
      }
    }
  }
  return ret;
}

int ObExprJsonRemove::eval_json_remove(const ObExpr &expr, ObEvalCtx &ctx, ObDatum &res)
{
  int ret = OB_SUCCESS;
  ObIJsonBase *json_doc = NULL;

  bool is_null_result = false;
  common::ObArenaAllocator &temp_allocator = ctx.get_reset_tmp_alloc();
  if (expr.datum_meta_.cs_type_ != CS_TYPE_UTF8MB4_BIN) {
    ret = OB_ERR_INVALID_JSON_CHARSET;
    LOG_WARN("invalid out put charset", K(ret), K(expr.datum_meta_.cs_type_));
  } else if (OB_FAIL(ObJsonExprHelper::get_json_doc(expr, ctx, temp_allocator, 0,
                                                    json_doc, is_null_result))) {
    LOG_WARN("get_json_doc failed", K(ret));
  }

  ObJsonPathCache ctx_cache(&temp_allocator);
  ObJsonPathCache* path_cache = NULL;
  if (OB_SUCC(ret) && !is_null_result) {
    path_cache = ObJsonExprHelper::get_path_cache_ctx(expr.expr_ctx_id_, &ctx.exec_ctx_);
    path_cache = ((path_cache != NULL) ? path_cache : &ctx_cache);
  }
  
  ObJsonBaseVector hits;
  for (int64_t i = 1; OB_SUCC(ret) && !is_null_result && i < expr.arg_cnt_; i++) {
    hits.clear();
    ObDatum *path_data = NULL;
    if (expr.args_[i]->datum_meta_.type_ == ObNullType) {
      is_null_result = true;
    } else if (OB_FAIL(expr.args_[i]->eval(ctx, path_data))) {
      ret = OB_ERR_INVALID_JSON_PATH;
      LOG_USER_ERROR(OB_ERR_INVALID_JSON_PATH);
    } else {
      ObString path_val = path_data->get_string();
      ObJsonPath *json_path;
      if (OB_FAIL(ObJsonExprHelper::find_and_add_cache(path_cache, json_path, path_val, i, false))) {
        LOG_WARN("parse text to path failed", K(path_data->get_string()), K(ret));
      } else if (json_path->path_node_cnt() == 0) {
        ret = OB_ERR_JSON_VACUOUS_PATH;
        LOG_USER_ERROR(OB_ERR_JSON_VACUOUS_PATH); 
      } else if (OB_FAIL(json_doc->seek(*json_path, json_path->path_node_cnt() - 1, true, false, hits))) {
        LOG_WARN("json seek failed", K(path_data->get_string()), K(ret));
      } else if (hits.size() == 0){
        continue;
      } else if (hits.size() > 1){
        ret = OB_INVALID_ERROR;
        LOG_WARN("More than one results after seek with only_need_one mode.", K(ret));
      } else {
        if (OB_FAIL(remove_from_json(json_path, hits[0]))) {
          LOG_WARN("remove_from_json failed", K(ret));
        }
      }
    }
  }

  // set result
  if (OB_FAIL(ret)) {
    LOG_WARN("json_remove failed", K(ret));
  } else if (is_null_result) {
    res.set_null();
  } else {
    ObString str;
    if (OB_FAIL(json_doc->get_raw_binary(str, &temp_allocator))) {
      LOG_WARN("json_remove get result binary failed", K(ret));
    } else {
      char *buf = expr.get_str_res_mem(ctx, str.length());
      if (OB_ISNULL(buf)){
        ret = OB_ALLOCATE_MEMORY_FAILED;
        LOG_WARN("json_remove alloc jsonString failed", K(ret), K(str.length()));
      } else {
        MEMCPY(buf, str.ptr(), str.length());
        res.set_string(buf, str.length());
      }
    }
  }

  return ret;
}

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

}
}