content: /*
   * 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.
   */
  package com.datastax.oss.driver.internal.core.type.codec.extras.array;
  
  import com.datastax.oss.driver.api.core.type.DataType;
  import com.datastax.oss.driver.api.core.type.ListType;
  import com.datastax.oss.driver.api.core.type.codec.TypeCodec;
  import com.datastax.oss.driver.api.core.type.reflect.GenericType;
  import com.datastax.oss.driver.internal.core.type.codec.ParseUtils;
  import edu.umd.cs.findbugs.annotations.NonNull;
  import edu.umd.cs.findbugs.annotations.Nullable;
  import java.lang.reflect.Array;
  import java.util.Objects;
  
  /**
   * Base class for all codecs dealing with Java arrays. This class aims to reduce the amount of code
   * required to create such codecs.
   *
   * @param <ArrayT> The Java array type this codec handles
   */
  public abstract class AbstractListToArrayCodec<ArrayT> implements TypeCodec<ArrayT> {
  
    @NonNull protected final ListType cqlType;
    @NonNull protected final GenericType<ArrayT> javaType;
  
    /**
     * @param cqlType The CQL type. Must be a list type.
     * @param arrayType The Java type. Must be an array class.
     */
    protected AbstractListToArrayCodec(
        @NonNull ListType cqlType, @NonNull GenericType<ArrayT> arrayType) {
      this.cqlType = Objects.requireNonNull(cqlType, "cqlType cannot be null");
      this.javaType = Objects.requireNonNull(arrayType, "arrayType cannot be null");
      if (!arrayType.isArray()) {
        throw new IllegalArgumentException("Expecting Java array class, got " + arrayType);
      }
    }
  
    @NonNull
    @Override
    public GenericType<ArrayT> getJavaType() {
      return javaType;
    }
  
    @NonNull
    @Override
    public DataType getCqlType() {
      return cqlType;
    }
  
    @NonNull
    @Override
    public String format(@Nullable ArrayT array) {
      if (array == null) {
        return "NULL";
      }
      int length = Array.getLength(array);
      StringBuilder sb = new StringBuilder();
      sb.append('[');
      for (int i = 0; i < length; i++) {
        if (i != 0) {
          sb.append(",");
        }
        formatElement(sb, array, i);
      }
      sb.append(']');
      return sb.toString();
    }
  
    @Nullable
    @Override
    public ArrayT parse(@Nullable String value) {
      if (value == null || value.isEmpty() || value.equalsIgnoreCase("NULL")) {
        return null;
      }
      int idx = skipSpaces(value, 0);
      idx = skipOpeningBracket(value, idx);
      idx = skipSpaces(value, idx);
      if (value.charAt(idx) == ']') {
        return newInstance(0);
      }
      // first pass: determine array length
      int length = getArrayLength(value, idx);
      // second pass: parse elements
      ArrayT array = newInstance(length);
      int i = 0;
      for (; idx < value.length(); i++) {
        int n = skipLiteral(value, idx);
        parseElement(value.substring(idx, n), array, i);
        idx = skipSpaces(value, n);
        if (value.charAt(idx) == ']') {
          return array;
        }
        idx = skipComma(value, idx);
        idx = skipSpaces(value, idx);
      }
      throw new IllegalArgumentException(
          String.format("Malformed list value \"%s\", missing closing ']'", value));
    }
  
    /**
     * Creates a new array instance with the given size.
     *
     * @param size The size of the array to instantiate.
     * @return a new array instance with the given size.
     */
    @NonNull
    protected abstract ArrayT newInstance(int size);
  
    /**
     * Formats the {@code index}th element of {@code array} to {@code output}.
     *
     * @param output The StringBuilder to write to.
     * @param array The array to read from.
     * @param index The element index.
     */
    protected abstract void formatElement(
        @NonNull StringBuilder output, @NonNull ArrayT array, int index);
  
    /**
     * Parses the {@code index}th element of {@code array} from {@code input}.
     *
     * @param input The String to read from.
     * @param array The array to write to.
     * @param index The element index.
     */
    protected abstract void parseElement(@NonNull String input, @NonNull ArrayT array, int index);
  
    private int getArrayLength(String value, int idx) {
      int length = 1;
      for (; idx < value.length(); length++) {
        idx = skipLiteral(value, idx);
        idx = skipSpaces(value, idx);
        if (value.charAt(idx) == ']') {
          break;
        }
        idx = skipComma(value, idx);
        idx = skipSpaces(value, idx);
      }
      return length;
    }
  
    private int skipComma(String value, int idx) {
      if (value.charAt(idx) != ',') {
        throw new IllegalArgumentException(
            String.format(
                "Cannot parse list value from \"%s\", at character %d expecting ',' but got '%c'",
                value, idx, value.charAt(idx)));
      }
      return idx + 1;
    }
  
    private int skipOpeningBracket(String value, int idx) {
      if (value.charAt(idx) != '[') {
        throw new IllegalArgumentException(
            String.format(
                "cannot parse list value from \"%s\", at character %d expecting '[' but got '%c'",
                value, idx, value.charAt(idx)));
      }
      return idx + 1;
    }
  
    private int skipSpaces(String value, int idx) {
      try {
        return ParseUtils.skipSpaces(value, idx);
      } catch (IllegalArgumentException e) {
        throw new IllegalArgumentException(
            String.format(
                "Cannot parse list value from \"%s\", at character %d expecting space but got '%c'",
                value, idx, value.charAt(idx)),
            e);
      }
    }
  
    private int skipLiteral(String value, int idx) {
      try {
        return ParseUtils.skipCQLValue(value, idx);
      } catch (IllegalArgumentException e) {
        throw new IllegalArgumentException(
            String.format(
                "Cannot parse list value from \"%s\", invalid CQL value at character %d", value, idx),
            e);
      }
    }
  }
  