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Advanced and thread-safe Java Redis client for synchronous, asynchronous, and reactive usage. Supports Cluster, Sentinel, Pipelining, Auto-Reconnect, Codecs and much more.

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/*
 * Copyright 2018-Present, Redis Ltd. and Contributors
 * All rights reserved.
 *
 * Licensed under the MIT License.
 *
 * This file contains contributions from third-party contributors
 * licensed 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
 *
 *      https://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 io.lettuce.core.output;

import io.lettuce.core.StringMatchResult;
import io.lettuce.core.codec.RedisCodec;
import io.lettuce.core.protocol.CommandKeyword;

import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;

import static io.lettuce.core.StringMatchResult.MatchedPosition;
import static io.lettuce.core.StringMatchResult.Position;

/**
 * Command output for {@code STRALGO} returning {@link StringMatchResult}.
 *
 * @author dengliming
 * @since 6.0
 */
public class StringMatchResultOutput extends CommandOutput {

    private static final ByteBuffer LEN = StandardCharsets.US_ASCII.encode(CommandKeyword.LEN.toString().toLowerCase());

    private String matchString;

    private int len;

    private List positions;

    private boolean readingLen = true;

    private final List matchedPositions = new ArrayList<>();

    public StringMatchResultOutput(RedisCodec codec) {
        super(codec, null);
    }

    @Override
    public void set(ByteBuffer bytes) {
        matchString = (String) codec.decodeKey(bytes);
        readingLen = LEN.equals(bytes);
    }

    @Override
    public void set(long integer) {
        if (readingLen) {
            this.len = (int) integer;
        } else {
            if (positions == null) {
                positions = new ArrayList<>();
            }
            positions.add(integer);
        }
        matchString = null;
    }

    @Override
    public void complete(int depth) {

        if (depth == 2) {
            matchedPositions.add(buildMatchedString(positions));
            positions = null;
        }

        if (depth == 0) {
            output = new StringMatchResult(matchString, matchedPositions, len);
        }
    }

    private static MatchedPosition buildMatchedString(List positions) {

        if (positions == null) {
            throw new IllegalStateException("No matched positions");
        }

        int size = positions.size();
        // not WITHMATCHLEN
        long matchLen = size % 2 == 0 ? 0L : positions.get(size - 1);
        return new MatchedPosition(new Position(positions.get(0), positions.get(1)),
                new Position(positions.get(2), positions.get(3)), matchLen);
    }

}