package nokogiri;

import static nokogiri.XmlNode.setDocumentAndDecorate;
import static nokogiri.internals.NokogiriHelpers.getNokogiriClass;
import static nokogiri.internals.NokogiriHelpers.nodeListToRubyArray;

import java.util.Arrays;

import org.jruby.Ruby;
import org.jruby.RubyArray;
import org.jruby.RubyClass;
import org.jruby.RubyFixnum;
import org.jruby.RubyObject;
import org.jruby.RubyRange;
import org.jruby.anno.JRubyClass;
import org.jruby.anno.JRubyMethod;
import org.jruby.runtime.ThreadContext;
import org.jruby.runtime.Visibility;
import org.jruby.runtime.builtin.IRubyObject;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

/**
 * Class for Nokogiri::XML::NodeSet
 *
 * @author sergio
 * @author Yoko Harada <yokolet@gmail.com>
 */
@JRubyClass(name = "Nokogiri::XML::NodeSet")
public class XmlNodeSet extends RubyObject implements NodeList
{
  private static final long serialVersionUID = 1L;

  IRubyObject[] nodes;

  public
  XmlNodeSet(Ruby ruby, RubyClass klazz)
  {
    super(ruby, klazz);
    nodes = IRubyObject.NULL_ARRAY;
  }

  XmlNodeSet(Ruby ruby, RubyClass klazz, IRubyObject[] nodes)
  {
    super(ruby, klazz);
    this.nodes = nodes;
  }

  public static XmlNodeSet
  newEmptyNodeSet(ThreadContext context, XmlNodeSet docOwner)
  {
    final Ruby runtime = context.runtime;
    XmlNodeSet set = new XmlNodeSet(runtime, getNokogiriClass(runtime, "Nokogiri::XML::NodeSet"));
    set.initializeFrom(context, docOwner);
    return set;
  }

  public static XmlNodeSet
  newEmptyNodeSet(ThreadContext context, XmlNode docOwner)
  {
    final Ruby runtime = context.runtime;
    XmlNodeSet set = new XmlNodeSet(runtime, getNokogiriClass(runtime, "Nokogiri::XML::NodeSet"));
    set.initialize(runtime, docOwner);
    return set;
  }

  public static XmlNodeSet
  newNodeSet(Ruby runtime, IRubyObject[] nodes)
  {
    XmlNodeSet xmlNodeSet = new XmlNodeSet(runtime, getNokogiriClass(runtime, "Nokogiri::XML::NodeSet"));
    xmlNodeSet.setNodes(nodes);
    return xmlNodeSet;
  }

  public static XmlNodeSet
  newNodeSet(Ruby runtime, IRubyObject[] nodes, XmlNode docOwner)
  {
    XmlNodeSet set = new XmlNodeSet(runtime, getNokogiriClass(runtime, "Nokogiri::XML::NodeSet"), nodes);
    set.initialize(runtime, docOwner);
    return set;
  }

  /**
   * Create and return a copy of this object.
   *
   * @return a clone of this object
   */
  @Override
  public Object
  clone() throws CloneNotSupportedException
  {
    return super.clone();
  }

  private void
  setNodes(IRubyObject[] array)
  {
    this.nodes = array;

    IRubyObject first = array.length > 0 ? array[0] : null;
    initialize(getRuntime(), first);
  }

  private void
  initializeFrom(ThreadContext context, XmlNodeSet ref)
  {
    IRubyObject document = ref.getInstanceVariable("@document");
    if (document != null && !document.isNil()) {
      initialize(context, (XmlDocument) document);
    }
  }

  final void
  initialize(Ruby runtime, IRubyObject refNode)
  {
    if (refNode instanceof XmlNode) {
      XmlDocument doc = ((XmlNode) refNode).document(runtime);
      setDocumentAndDecorate(runtime.getCurrentContext(), this, doc);
    }
  }

  private void
  initialize(ThreadContext context, XmlDocument doc)
  {
    setDocumentAndDecorate(context, this, doc);
  }

  public int
  length()
  {
    return nodes == null ? 0 : nodes.length;
  }

  @JRubyMethod(name = "&")
  public IRubyObject
  op_and(ThreadContext context, IRubyObject nodeSet)
  {
    IRubyObject[] otherNodes = getNodes(context, nodeSet);

    if (otherNodes == null || otherNodes.length == 0) {
      return newEmptyNodeSet(context, this);
    }

    if (nodes == null || nodes.length == 0) {
      return newEmptyNodeSet(context, this);
    }

    IRubyObject[] curr = nodes;
    IRubyObject[] other = getNodes(context, nodeSet);
    IRubyObject[] result = new IRubyObject[nodes.length];

    int last = 0;
    outer:
    for (int i = 0; i < curr.length; i++) {
      IRubyObject n = curr[i];

      for (int j = 0; j < other.length; j++) {
        if (other[j] == n) {
          result[last++] = n;
          continue outer;
        }
      }
    }

    XmlNodeSet newSet = newNodeSet(context.runtime, Arrays.copyOf(result, last));
    newSet.initializeFrom(context, this);
    return newSet;
  }

  @JRubyMethod
  public IRubyObject
  delete (ThreadContext context, IRubyObject node_or_namespace)
  {
    IRubyObject nodeOrNamespace = asXmlNodeOrNamespace(context, node_or_namespace);

    if (nodes.length == 0) {
      return context.nil;
    }

    IRubyObject[] orig = nodes;
    IRubyObject[] result = new IRubyObject[nodes.length];

    int last = 0;

    for (int i = 0; i < orig.length; i++) {
      IRubyObject n = orig[i];

      if (n == nodeOrNamespace) {
        continue;
      }

      result[last++] = n;
    }

    nodes = Arrays.copyOf(result, last);

    if (nodes.length < orig.length) {
      // if we found the node return it
      return nodeOrNamespace;
    }

    return context.nil;
  }

  public IRubyObject
  dup(ThreadContext context)
  {
    XmlNodeSet dup = newNodeSet(context.runtime, nodes.clone());
    dup.initializeFrom(context, this);
    return dup;
  }

  @JRubyMethod(visibility = Visibility.PROTECTED)
  public IRubyObject
  initialize_copy(ThreadContext context, IRubyObject other)
  {
    setNodes(getNodes(context, other));
    initializeFrom(context, (XmlNodeSet)other);
    return this;
  }

  @JRubyMethod(name = "include?")
  public IRubyObject
  include_p(ThreadContext context, IRubyObject node_or_namespace)
  {
    for (int i = 0; i < nodes.length; i++) {
      if (nodes[i] == node_or_namespace) {
        return context.tru;
      }
    }

    return context.fals;
  }

  @JRubyMethod(name = {"length", "size"})
  public IRubyObject
  length(ThreadContext context)
  {
    return context.runtime.newFixnum(nodes.length);
  }

  @JRubyMethod(name = "-")
  public IRubyObject
  op_diff(ThreadContext context, IRubyObject nodeSet)
  {
    IRubyObject[] otherNodes = getNodes(context, nodeSet);

    if (otherNodes.length == 0) {
      return dup(context);
    }

    if (nodes.length == 0) {
      return newEmptyNodeSet(context, this);
    }

    IRubyObject[] curr = nodes;
    IRubyObject[] other = getNodes(context, nodeSet);
    IRubyObject[] result = new IRubyObject[nodes.length];

    int last = 0;
    outer:
    for (int i = 0; i < curr.length; i++) {
      IRubyObject n = curr[i];

      for (int j = 0; j < other.length; j++) {
        if (other[j] == n) {
          continue outer;
        }
      }

      result[last++] = n;
    }

    XmlNodeSet newSet = newNodeSet(context.runtime, Arrays.copyOf(result, last));
    newSet.initializeFrom(context, this);
    return newSet;
  }

  @JRubyMethod(name = {"|", "+"})
  public IRubyObject
  op_or(ThreadContext context, IRubyObject nodeSet)
  {
    IRubyObject[] otherNodes = getNodes(context, nodeSet);

    if (nodes.length == 0) {
      return ((XmlNodeSet) nodeSet).dup(context);
    }

    if (otherNodes.length == 0) {
      return dup(context);
    }

    IRubyObject[] curr = nodes;
    IRubyObject[] other = getNodes(context, nodeSet);
    IRubyObject[] result = Arrays.copyOf(curr, curr.length + other.length);

    int last = curr.length;
    outer:
    for (int i = 0; i < other.length; i++) {
      IRubyObject n = other[i];

      for (int j = 0; j < curr.length; j++) {
        if (curr[j] == n) {
          continue outer;
        }
      }

      result[last++] = n;
    }

    XmlNodeSet newSet = newNodeSet(context.runtime, Arrays.copyOf(result, last));
    newSet.initializeFrom(context, this);
    return newSet;
  }

  @JRubyMethod(name = {"push", "<<"})
  public IRubyObject
  push(ThreadContext context, IRubyObject node_or_namespace)
  {
    nodes = Arrays.copyOf(nodes, nodes.length + 1);
    nodes[nodes.length - 1] = node_or_namespace;
    return this;
  }

  //  replace with
  //  https://github.com/jruby/jruby/blame/13a3ec76d883a162b9d46c374c6e9eeea27b3261/core/src/main/java/org/jruby/RubyRange.java#L974
  //  once we upgraded the min JRuby version to >= 9.2
  private static IRubyObject
  rangeBeginLength(ThreadContext context, IRubyObject rangeMaybe, int len, long[] begLen)
  {
    RubyRange range = (RubyRange) rangeMaybe;
    long min = range.begin(context).convertToInteger().getLongValue();
    long max = range.end(context).convertToInteger().getLongValue();

    if (min < 0) {
      min += len;
      if (min < 0) {
        return context.nil;
      }
    }

    if (max < 0) {
      max += len;
    }

    if (!range.isExcludeEnd()) {
      max++;
    }

    begLen[0] = min;
    begLen[1] = max;
    return context.tru;
  }


  @JRubyMethod(name = {"[]", "slice"})
  public IRubyObject
  slice(ThreadContext context, IRubyObject indexOrRange)
  {
    if (indexOrRange instanceof RubyFixnum) {
      return slice(context, ((RubyFixnum) indexOrRange).getLongValue());
    }
    if (indexOrRange instanceof RubyRange) {
      long[] begLen = new long[2];
      if (rangeBeginLength(context, indexOrRange, nodes.length, begLen).isNil()) {
        return context.nil;
      }
      long min = begLen[0];
      long max = begLen[1];
      return subseq(context, min, max - min);
    }
    throw context.runtime.newTypeError("index must be an Integer or a Range");
  }

  IRubyObject
  slice(ThreadContext context, long idx)
  {
    if (idx < 0) {
      idx += nodes.length;
    }

    if (idx >= nodes.length || idx < 0) {
      return context.nil;
    }

    return nodes[(int) idx];
  }

  @JRubyMethod(name = {"[]", "slice"})
  public IRubyObject
  slice(ThreadContext context, IRubyObject start, IRubyObject length)
  {
    long s = ((RubyFixnum) start).getLongValue();
    long l = ((RubyFixnum) length).getLongValue();

    if (s < 0) {
      s += nodes.length;
    }

    return subseq(context, s, l);
  }

  public IRubyObject
  subseq(ThreadContext context, long start, long length)
  {
    if (start < 0 || length < 0 || start > nodes.length) {
      return context.nil;
    }

    long end = start + Math.min(length, nodes.length - start);

    return newNodeSet(context.runtime, Arrays.copyOfRange(nodes, (int) start, (int) end));
  }

  @JRubyMethod(name = {"to_a", "to_ary"})
  public RubyArray<?>
  to_a(ThreadContext context)
  {
    return context.runtime.newArrayNoCopy(nodes);
  }

  @JRubyMethod(name = {"unlink", "remove"})
  public IRubyObject
  unlink(ThreadContext context)
  {
    for (int i = 0; i < nodes.length; i++) {
      if (nodes[i] instanceof XmlNode) {
        ((XmlNode) nodes[i]).unlink(context);
      }
    }
    return this;
  }

  private static IRubyObject
  asXmlNodeOrNamespace(ThreadContext context, IRubyObject possibleNode)
  {
    if (possibleNode instanceof XmlNode || possibleNode instanceof XmlNamespace) {
      return possibleNode;
    }
    throw context.getRuntime().newArgumentError("node must be a Nokogiri::XML::Node or Nokogiri::XML::Namespace");
  }

  private static IRubyObject[]
  getNodes(ThreadContext context, IRubyObject possibleNodeSet)
  {
    if (possibleNodeSet instanceof XmlNodeSet) {
      return ((XmlNodeSet) possibleNodeSet).nodes;
    }
    throw context.getRuntime().newArgumentError("node must be a Nokogiri::XML::NodeSet");
  }

  public int
  getLength()
  {
    return nodes.length;
  }

  public Node
  item(int index)
  {
    Object n = nodes[index];
    if (n instanceof XmlNode) { return ((XmlNode) n).node; }
    if (n instanceof XmlNamespace) { return ((XmlNamespace) n).getNode(); }
    return null;
  }
}
