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package org.tinymediamanager.core;

import java.util.Collection;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.builder.ReflectionToStringBuilder;
import org.apache.commons.lang3.builder.ToStringStyle;

public class RecursiveToStringStyle extends ToStringStyle {

  private static final long                   serialVersionUID = 1L;
  private static final RecursiveToStringStyle INSTANCE         = new RecursiveToStringStyle(13);

  public static ToStringStyle getInstance() {
    return INSTANCE;
  }

  public static String toString(Object value) {
    final StringBuffer sb = new StringBuffer(512);
    INSTANCE.appendDetail(sb, null, value);
    return sb.toString();
  }

  private final int                   maxDepth;
  private final String                tabs;

  // http://stackoverflow.com/a/16934373/603516
  private ThreadLocal depth = ThreadLocal.withInitial(() -> new MutableInteger(0));


  public RecursiveToStringStyle(int maxDepth) {
    this.maxDepth = maxDepth;
    tabs = StringUtils.repeat("\t", maxDepth);

    setUseShortClassName(true);
    setUseIdentityHashCode(false);
    setContentStart(" {");
    setFieldSeparator(System.lineSeparator());
    setFieldSeparatorAtStart(true);
    setFieldNameValueSeparator(" = ");
    setContentEnd("}");
  }

  private int getDepth() {
    return depth.get().get();
  }

  private void padDepth(StringBuffer buffer) {
    buffer.append(tabs, 0, getDepth());
  }

  private StringBuffer appendTabified(StringBuffer buffer, String value) {
    // return buffer.append(String.valueOf(value).replace("\n", "\n" + tabs.substring(0, getDepth())));
    Matcher matcher = Pattern.compile("\n").matcher(value);
    String replacement = "\n" + tabs.substring(0, getDepth());
    while (matcher.find()) {
      matcher.appendReplacement(buffer, replacement);
    }
    matcher.appendTail(buffer);
    return buffer;
  }

  @Override
  protected void appendFieldSeparator(StringBuffer buffer) {
    buffer.append(getFieldSeparator());
    padDepth(buffer);
  }

  @Override
  public void appendStart(StringBuffer buffer, Object object) {
    depth.get().increment();
    super.appendStart(buffer, object);
  }

  @Override
  public void appendEnd(StringBuffer buffer, Object object) {
    super.appendEnd(buffer, object);
    buffer.setLength(buffer.length() - getContentEnd().length());
    buffer.append(System.lineSeparator());
    depth.get().decrement();
    padDepth(buffer);
    appendContentEnd(buffer);
  }

  @Override
  protected void removeLastFieldSeparator(StringBuffer buffer) {
    int len = buffer.length();
    int sepLen = getFieldSeparator().length() + getDepth();
    if (len > 0 && sepLen > 0 && len >= sepLen) {
      buffer.setLength(len - sepLen);
    }
  }

  private boolean noReflectionNeeded(Object value) {
    try {
      return value != null
          && (value.getClass().getName().startsWith("java.lang.") || value.getClass().getMethod("toString").getDeclaringClass() != Object.class);
    }
    catch (NoSuchMethodException e) {
      throw new IllegalStateException(e);
    }
  }

  @Override
  protected void appendDetail(StringBuffer buffer, String fieldName, Object value) {
    if (getDepth() >= maxDepth || noReflectionNeeded(value)) {
      appendTabified(buffer, String.valueOf(value));
    }
    else {
      new ReflectionToStringBuilder(value, this, buffer, null, false, false).toString();
    }
  }

  // another helpful method, for collections:
  @Override
  protected void appendDetail(StringBuffer buffer, String fieldName, Collection coll) {
    buffer.append(ReflectionToStringBuilder.toString(coll.toArray(), this, true, true));
  }

  static class MutableInteger {
    private int value;

    MutableInteger(int value) {
      this.value = value;
    }

    public final int get() {
      return value;
    }

    public final void increment() {
      ++value;
    }

    public final void decrement() {
      --value;
    }
  }
}