package support;

import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.PrintStream;

import javax.xml.XMLConstants;
import javax.xml.transform.stream.StreamSource;
import javax.xml.validation.Schema;
import javax.xml.validation.SchemaFactory;
import javax.xml.validation.Validator;

import org.xml.sax.ErrorHandler;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;


public class XMLValidator implements ErrorHandler {

  private boolean withErrors = false;

  public XMLValidator() {

  }

  private static void println(PrintStream out, String msg) {
    out.println(msg);
    out.flush();
  }

  private static void logResult(String msg) {
    println(System.out, "result=" + msg);
  }

  private static void logError(String type, String msg) {
    println(System.err, String.format("[%s] %s", type, msg));
  }

  private static void logParseException(String type, SAXParseException e) {
    logError(
      type,
      String.format("%s (%d:%d)",
        e.getMessage(),
        e.getLineNumber(),
        e.getColumnNumber()
      )
    );
  }

  @Override
  public void warning(SAXParseException exception) throws SAXException {
    logParseException("warning", exception);

    withErrors = true;
  }

  @Override
  public void error(SAXParseException exception) throws SAXException {
    logParseException("error", exception);

    withErrors = true;
  }

  @Override
  public void fatalError(SAXParseException exception) throws SAXException {
    logParseException("fatal", exception);

    withErrors = true;
  }

  private static Schema loadSchema(String fileName, boolean insecure) throws Exception {

    SchemaFactory sf = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);

    if (insecure) {
      sf.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, false);
    }

    Schema schema = sf.newSchema(new File(fileName));

    return schema;
  }

  public static void main(String[] args) throws Exception {

    boolean readStdin = false;
    String fileName = null;
    String schemaFile = null;
    boolean insecure = false;

    for (String str: args) {
      if ("-insecure".equals(str)) {
        insecure = true;
      }

      if ("-stdin".equals(str)) {
        readStdin = true;
      } else
      if (str.startsWith("-file=")) {
        fileName = str.replaceFirst("-file=", "");
      } else
      if (str.startsWith("-schema=")) {
        schemaFile = str.replaceFirst("-schema=", "");
      }
    }

    if (schemaFile == null) {
      logError("error", "specify schema via -schema=[SCHEMA]");
      System.exit(1);
    }

    InputStream inputStream;

    if (readStdin) {
      inputStream = System.in;
    } else {
      inputStream = new FileInputStream(fileName);
    }

    XMLValidator handler = new XMLValidator();

    try {
      Schema schema = loadSchema(schemaFile, insecure);
      Validator validator = schema.newValidator();

      validator.setErrorHandler(handler);
      validator.validate(new StreamSource(inputStream));

      logResult(handler.withErrors ? "WITH_ERRORS" : "OK");

    } catch (Exception e) {
      logError("fatal", e.getMessage());
      logResult("FATAL_ERROR");

      handler.withErrors = true;
    }

    System.exit(handler.withErrors ? 1 : 0);
  }
}