/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [http://neo4j.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.adversaries.fs;

import java.io.IOException;
import java.io.Reader;
import java.nio.BufferOverflowException;
import java.nio.CharBuffer;
import org.neo4j.adversaries.Adversary;

@SuppressWarnings("unchecked")
public class AdversarialReader extends Reader {
    private final Reader reader;
    private final Adversary adversary;

    public AdversarialReader(Reader reader, Adversary adversary) {
        this.reader = reader;
        this.adversary = adversary;
    }

    @Override
    public int read(CharBuffer target) throws IOException {
        if (adversary.injectFailureOrMischief(
                IOException.class, BufferOverflowException.class, IndexOutOfBoundsException.class)) {
            CharBuffer dup = target.duplicate();
            dup.limit(Math.max(target.limit() / 2, 1));
            return reader.read(dup);
        }
        return reader.read(target);
    }

    @Override
    public int read() throws IOException {
        adversary.injectFailure(IOException.class);
        return reader.read();
    }

    @Override
    public int read(char[] cbuf) throws IOException {
        if (adversary.injectFailureOrMischief(IOException.class)) {
            char[] dup = new char[Math.max(cbuf.length / 2, 1)];
            int read = reader.read(dup);
            System.arraycopy(dup, 0, cbuf, 0, read);
            return read;
        }
        return reader.read(cbuf);
    }

    @Override
    public int read(char[] cbuf, int off, int len) throws IOException {
        if (adversary.injectFailureOrMischief(IOException.class)) {
            return reader.read(cbuf, off, Math.max(len / 2, 1));
        }
        return reader.read(cbuf, off, len);
    }

    @Override
    public long skip(long n) throws IOException {
        adversary.injectFailure(IllegalArgumentException.class, IOException.class);
        return reader.skip(n);
    }

    @Override
    public boolean ready() throws IOException {
        adversary.injectFailure(IOException.class);
        return reader.ready();
    }

    @Override
    public boolean markSupported() {
        adversary.injectFailure();
        return reader.markSupported();
    }

    @Override
    public void mark(int readAheadLimit) throws IOException {
        adversary.injectFailure(IOException.class);
        reader.mark(readAheadLimit);
    }

    @Override
    public void reset() throws IOException {
        adversary.injectFailure(IOException.class);
        reader.reset();
    }

    @Override
    public void close() throws IOException {
        adversary.injectFailure(IOException.class);
        reader.close();
    }
}
