package com.adhearsion.ruby_speech;

import org.jruby.Ruby;
import org.jruby.RubyClass;
import org.jruby.RubyModule;
import org.jruby.RubyObject;
import org.jruby.anno.JRubyClass;
import org.jruby.anno.JRubyMethod;
import org.jruby.runtime.Block;
import org.jruby.runtime.ObjectAllocator;
import org.jruby.runtime.ThreadContext;
import org.jruby.runtime.Visibility;
import org.jruby.runtime.builtin.IRubyObject;
import org.jruby.javasupport.util.RuntimeHelpers;

import java.util.regex.*;

@JRubyClass(name="RubySpeech::GRXML::Matcher")
public class RubySpeechGRXMLMatcher extends RubyObject {

  Pattern p;

  public RubySpeechGRXMLMatcher(final Ruby runtime, RubyClass rubyClass) {
    super(runtime, rubyClass);
  }

  @JRubyMethod(visibility=Visibility.PRIVATE)
  public IRubyObject compile_regex(ThreadContext context, IRubyObject regex) {
    Ruby runtime = context.getRuntime();
    p = Pattern.compile(regex.toString());
    return runtime.getNil();
  }

  @JRubyMethod(visibility=Visibility.PUBLIC)
  public IRubyObject find_match(ThreadContext context, IRubyObject buffer)
  {
    Ruby runtime = context.getRuntime();
    String string_buffer = buffer.toString();
    Matcher m = p.matcher(string_buffer);

    if (m.matches()) {
      if (is_max_match(string_buffer)) {
        return RuntimeHelpers.invoke(context, this, "match_for_buffer", buffer, runtime.getTrue());
      }
      return callMethod(context, "match_for_buffer", buffer);
    } else if (m.hitEnd()) {
      return getGRXMLType(runtime, "PotentialMatch").newInstance(context, Block.NULL_BLOCK);
    }
    return getGRXMLType(runtime, "NoMatch").newInstance(context, Block.NULL_BLOCK);
  }

  private boolean is_max_match(String buffer) {
    final int len = buffer.length();
    StringBuilder new_buffer = new StringBuilder(len + 1);
    new_buffer.append(buffer).append('\0');
    final String search_set = "0123456789#*ABCD";
    for (int i = 0; i < search_set.length(); i++) {
      new_buffer.setCharAt(len, search_set.charAt(i));
      if (p.matcher(new_buffer).matches()) return false;
    }
    return true;
  }

  private static RubyClass getGRXMLType(final Ruby runtime, final String name) {
    RubyModule grxml = (RubyModule) runtime.getModule("RubySpeech").getConstantAt("GRXML");
    return (RubyClass) grxml.getConstantAt(name);
  }

}