package org.testng.reporters;

import static java.nio.charset.StandardCharsets.UTF_8;
import static java.nio.file.Files.newBufferedWriter;

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.text.NumberFormat;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
import java.util.Optional;
import java.util.Set;
import java.util.stream.Collectors;
import org.testng.IReporter;
import org.testng.ISuite;
import org.testng.ISuiteResult;
import org.testng.ITestContext;
import org.testng.ITestResult;
import org.testng.Reporter;
import org.testng.annotations.CustomAttribute;
import org.testng.collections.Lists;
import org.testng.internal.Utils;
import org.testng.log4testng.Logger;
import org.testng.xml.XmlSuite;
import org.testng.xml.XmlSuite.ParallelMode;

/** Reporter that generates a single-page HTML report of the test results. */
public class EmailableReporter2 implements IReporter {
  private static final Logger LOG = Logger.getLogger(EmailableReporter2.class);

  protected PrintWriter writer;

  protected final List<SuiteResult> suiteResults = Lists.newArrayList();

  // Reusable buffer
  private final StringBuilder buffer = new StringBuilder();

  private String fileName = "emailable-report.html";

  public void setFileName(String fileName) {
    this.fileName = fileName;
  }

  public String getFileName() {
    return fileName;
  }

  @Override
  public void generateReport(
      List<XmlSuite> xmlSuites, List<ISuite> suites, String outputDirectory) {
    try {
      writer = createWriter(outputDirectory);
    } catch (IOException e) {
      LOG.error("Unable to create output file", e);
      return;
    }
    for (ISuite suite : suites) {
      suiteResults.add(new SuiteResult(suite));
    }

    writeDocumentStart();
    writeHead();
    writeBody();
    writeDocumentEnd();

    writer.close();
  }

  protected PrintWriter createWriter(String outdir) throws IOException {
    boolean ignored = new File(outdir).mkdirs();
    String jvmArg = RuntimeBehavior.getDefaultEmailableReport2Name();
    if (jvmArg != null && !jvmArg.trim().isEmpty()) {
      fileName = jvmArg;
    }
    return new PrintWriter(newBufferedWriter(new File(outdir, fileName).toPath(), UTF_8));
  }

  protected void writeDocumentStart() {
    writer.println(
        "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.1//EN\" \"https://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd\">");
    writer.println("<html xmlns=\"https://www.w3.org/1999/xhtml\">");
  }

  protected void writeHead() {
    writer.println("<head>");
    writer.println("<meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\"/>");
    writer.println("<title>TestNG Report</title>");
    writeStylesheet();
    writer.println("</head>");
  }

  protected void writeStylesheet() {
    writer.print("<style type=\"text/css\">");
    writer.print("table {margin-bottom:10px;border-collapse:collapse;empty-cells:show}");
    writer.print("th,td {border:1px solid #009;padding:.25em .5em}");
    writer.print("th {vertical-align:bottom}");
    writer.print("td {vertical-align:top}");
    writer.print("table a {font-weight:bold}");
    writer.print(".stripe td {background-color: #E6EBF9}");
    writer.print(".num {text-align:right}");
    writer.print(".passedodd td {background-color: #3F3}");
    writer.print(".passedeven td {background-color: #0A0}");
    writer.print(".skippedodd td {background-color: #DDD}");
    writer.print(".skippedeven td {background-color: #CCC}");
    writer.print(".failedodd td,.attn {background-color: #F33}");
    writer.print(".failedeven td,.stripe .attn {background-color: #D00}");
    writer.print(".stacktrace {white-space:pre;font-family:monospace}");
    writer.print(".totop {font-size:85%;text-align:center;border-bottom:2px solid #000}");
    writer.print(".invisible {display:none}");
    writer.println("</style>");
  }

  protected void writeBody() {
    writer.println("<body>");
    writeSuiteSummary();
    writeScenarioSummary();
    writeScenarioDetails();
    writer.println("</body>");
  }

  protected void writeDocumentEnd() {
    writer.println("</html>");
  }

  protected void writeSuiteSummary() {
    NumberFormat integerFormat = NumberFormat.getIntegerInstance();
    NumberFormat decimalFormat = NumberFormat.getNumberInstance();

    int totalPassedTests = 0;
    int totalSkippedTests = 0;
    int totalFailedTests = 0;
    int totalRetriedTests = 0;
    long totalDuration = 0;

    writer.println("<table>");
    writer.print("<tr>");
    writer.print("<th>Test</th>");
    writer.print("<th># Passed</th>");
    writer.print("<th># Skipped</th>");
    writer.print("<th># Retried</th>");
    writer.print("<th># Failed</th>");
    writer.print("<th>Time (ms)</th>");
    writer.print("<th>Included Groups</th>");
    writer.print("<th>Excluded Groups</th>");
    writer.println("</tr>");

    int testIndex = 0;
    for (SuiteResult suiteResult : suiteResults) {
      writer.print("<tr><th colspan=\"8\">");
      writer.print(Utils.escapeHtml(suiteResult.getSuiteName()));
      writer.println("</th></tr>");

      for (TestResult testResult : suiteResult.getTestResults()) {
        int passedTests = testResult.getPassedTestCount();
        int skippedTests = testResult.getSkippedTestCount();
        int failedTests = testResult.getFailedTestCount();
        int retriedTests = testResult.getRetriedTestCount();
        long duration = testResult.getDuration();

        writer.print("<tr");
        if ((testIndex % 2) == 1) {
          writer.print(" class=\"stripe\"");
        }
        writer.print(">");

        buffer.setLength(0);
        writeTableData(
            buffer
                .append("<a href=\"#t")
                .append(testIndex)
                .append("\">")
                .append(Utils.escapeHtml(testResult.getTestName()))
                .append("</a>")
                .toString());
        writeTableData(integerFormat.format(passedTests), "num");
        writeTableData(integerFormat.format(skippedTests), (skippedTests > 0 ? "num attn" : "num"));
        writeTableData(integerFormat.format(retriedTests), (retriedTests > 0 ? "num attn" : "num"));
        writeTableData(integerFormat.format(failedTests), (failedTests > 0 ? "num attn" : "num"));
        writeTableData(decimalFormat.format(duration), "num");
        writeTableData(testResult.getIncludedGroups());
        writeTableData(testResult.getExcludedGroups());

        writer.println("</tr>");

        totalPassedTests += passedTests;
        totalSkippedTests += skippedTests;
        totalFailedTests += failedTests;
        totalRetriedTests += retriedTests;
        totalDuration += duration;

        testIndex++;
      }
      boolean testsInParallel = XmlSuite.ParallelMode.TESTS.equals(suiteResult.getParallelMode());
      if (testsInParallel) {
        Optional<TestResult> maxValue =
            suiteResult.testResults.stream().max(Comparator.comparing(TestResult::getDuration));
        if (maxValue.isPresent()) {
          totalDuration = Math.max(totalDuration, maxValue.get().duration);
        }
      }
    }

    // Print totals if there was more than one test
    if (testIndex > 1) {
      writer.print("<tr>");
      writer.print("<th>Total</th>");
      writeTableHeader(integerFormat.format(totalPassedTests), "num");
      writeTableHeader(
          integerFormat.format(totalSkippedTests), (totalSkippedTests > 0 ? "num attn" : "num"));
      writeTableHeader(
          integerFormat.format(totalRetriedTests), (totalRetriedTests > 0 ? "num attn" : "num"));
      writeTableHeader(
          integerFormat.format(totalFailedTests), (totalFailedTests > 0 ? "num attn" : "num"));
      writeTableHeader(decimalFormat.format(totalDuration), "num");
      writer.print("<th colspan=\"2\"></th>");
      writer.println("</tr>");
    }

    writer.println("</table>");
  }

  /** Writes a summary of all the test scenarios. */
  protected void writeScenarioSummary() {
    writer.print("<table id='summary'>");
    writer.print("<thead>");
    writer.print("<tr>");
    writer.print("<th>Class</th>");
    writer.print("<th>Method</th>");
    writer.print("<th>Start</th>");
    writer.print("<th>Time (ms)</th>");
    writer.print("</tr>");
    writer.print("</thead>");

    int testIndex = 0;
    int scenarioIndex = 0;
    for (SuiteResult suiteResult : suiteResults) {
      writer.print("<tbody><tr><th colspan=\"4\">");
      writer.print(Utils.escapeHtml(suiteResult.getSuiteName()));
      writer.print("</th></tr></tbody>");

      for (TestResult testResult : suiteResult.getTestResults()) {
        writer.printf("<tbody id=\"t%d\">", testIndex);

        String testName = Utils.escapeHtml(testResult.getTestName());
        int startIndex = scenarioIndex;

        scenarioIndex +=
            writeScenarioSummary(
                testName + " &#8212; failed (configuration methods)",
                testResult.getFailedConfigurationResults(),
                "failed",
                scenarioIndex);
        scenarioIndex +=
            writeScenarioSummary(
                testName + " &#8212; failed",
                testResult.getFailedTestResults(),
                "failed",
                scenarioIndex);
        scenarioIndex +=
            writeScenarioSummary(
                testName + " &#8212; skipped (configuration methods)",
                testResult.getSkippedConfigurationResults(),
                "skipped",
                scenarioIndex);
        scenarioIndex +=
            writeScenarioSummary(
                testName + " &#8212; skipped",
                testResult.getSkippedTestResults(),
                "skipped",
                scenarioIndex);
        scenarioIndex +=
            writeScenarioSummary(
                testName + " &#8212; retried",
                testResult.getRetriedTestResults(),
                "retried",
                scenarioIndex);
        scenarioIndex +=
            writeScenarioSummary(
                testName + " &#8212; passed",
                testResult.getPassedTestResults(),
                "passed",
                scenarioIndex);

        if (scenarioIndex == startIndex) {
          writer.print("<tr><th colspan=\"4\" class=\"invisible\"/></tr>");
        }

        writer.println("</tbody>");

        testIndex++;
      }
    }

    writer.println("</table>");
  }

  /** Writes the scenario summary for the results of a given state for a single test. */
  private int writeScenarioSummary(
      String description,
      List<ClassResult> classResults,
      String cssClassPrefix,
      int startingScenarioIndex) {
    int scenarioCount = 0;
    if (!classResults.isEmpty()) {
      writer.print("<tr><th colspan=\"4\">");
      writer.print(description);
      writer.print("</th></tr>");

      int scenarioIndex = startingScenarioIndex;
      int classIndex = 0;
      for (ClassResult classResult : classResults) {
        String cssClass = cssClassPrefix + ((classIndex % 2) == 0 ? "even" : "odd");

        buffer.setLength(0);

        int scenariosPerClass = 0;
        int methodIndex = 0;
        for (MethodResult methodResult : classResult.getMethodResults()) {
          List<ITestResult> results = methodResult.getResults();
          if (results.isEmpty()) {
            throw new IllegalArgumentException("Should have found atleast 1 result");
          }
          int resultsCount = results.size();

          ITestResult firstResult = results.iterator().next();
          String methodName = Utils.escapeHtml(firstResult.getMethod().getMethodName());
          long start = firstResult.getStartMillis();
          long duration = firstResult.getEndMillis() - start;

          // The first method per class shares a row with the class
          // header
          if (methodIndex > 0) {
            buffer.append("<tr class=\"").append(cssClass).append("\">");
          }

          // Write the timing information with the first scenario per
          // method
          buffer
              .append("<td><a href=\"#m")
              .append(scenarioIndex)
              .append("\">")
              .append(methodName)
              .append("</a></td>")
              .append("<td rowspan=\"")
              .append(resultsCount)
              .append("\">")
              .append(getFormattedStartTime(start))
              .append("</td>")
              .append("<td rowspan=\"")
              .append(resultsCount)
              .append("\">")
              .append(duration)
              .append("</td></tr>");
          scenarioIndex++;

          // Write the remaining scenarios for the method
          for (int i = 1; i < resultsCount; i++) {
            buffer
                .append("<tr class=\"")
                .append(cssClass)
                .append("\">")
                .append("<td><a href=\"#m")
                .append(scenarioIndex)
                .append("\">")
                .append(methodName)
                .append("</a></td></tr>");
            scenarioIndex++;
          }

          scenariosPerClass += resultsCount;
          methodIndex++;
        }

        // Write the test results for the class
        writer.print("<tr class=\"");
        writer.print(cssClass);
        writer.print("\">");
        writer.print("<td rowspan=\"");
        writer.print(scenariosPerClass);
        writer.print("\">");
        writer.print(Utils.escapeHtml(classResult.getClassName()));
        writer.print("</td>");
        writer.print(buffer);

        classIndex++;
      }
      scenarioCount = scenarioIndex - startingScenarioIndex;
    }
    return scenarioCount;
  }

  protected String getFormattedStartTime(long startTimeInMillisFromEpoch) {
    return String.valueOf(startTimeInMillisFromEpoch);
  }

  /** Writes the details for all test scenarios. */
  protected void writeScenarioDetails() {
    int scenarioIndex = 0;
    for (SuiteResult suiteResult : suiteResults) {
      for (TestResult testResult : suiteResult.getTestResults()) {
        writer.print("<h2>");
        writer.print(Utils.escapeHtml(testResult.getTestName()));
        writer.print("</h2>");

        scenarioIndex +=
            writeScenarioDetails(testResult.getFailedConfigurationResults(), scenarioIndex);
        scenarioIndex += writeScenarioDetails(testResult.getFailedTestResults(), scenarioIndex);
        scenarioIndex +=
            writeScenarioDetails(testResult.getSkippedConfigurationResults(), scenarioIndex);
        scenarioIndex += writeScenarioDetails(testResult.getSkippedTestResults(), scenarioIndex);
        scenarioIndex += writeScenarioDetails(testResult.getRetriedTestResults(), scenarioIndex);
        scenarioIndex += writeScenarioDetails(testResult.getPassedTestResults(), scenarioIndex);
      }
    }
  }

  /** Writes the scenario details for the results of a given state for a single test. */
  private int writeScenarioDetails(List<ClassResult> classResults, int startingScenarioIndex) {
    int scenarioIndex = startingScenarioIndex;
    for (ClassResult classResult : classResults) {
      String className = classResult.getClassName();
      for (MethodResult methodResult : classResult.getMethodResults()) {
        List<ITestResult> results = methodResult.getResults();
        if (results.isEmpty()) {
          throw new IllegalStateException("There should have been at-least 1 test result");
        }

        String label =
            Utils.escapeHtml(
                className + "#" + results.iterator().next().getMethod().getMethodName());
        for (ITestResult result : results) {
          writeScenario(scenarioIndex, label, result);
          scenarioIndex++;
        }
      }
    }

    return scenarioIndex - startingScenarioIndex;
  }

  /** Writes the details for an individual test scenario. */
  private void writeScenario(int scenarioIndex, String label, ITestResult result) {
    writer.print("<h3 id=\"m");
    writer.print(scenarioIndex);
    writer.print("\">");
    writer.print(label);
    writer.print("</h3>");

    writer.print("<table class=\"result\">");

    // Write test parameters (if any)
    Object[] parameters = result.getParameters();
    boolean hasRows = dumpParametersInfo("Factory Parameter", result.getFactoryParameters());
    int parameterCount = (parameters == null ? 0 : parameters.length);
    hasRows = dumpParametersInfo("Parameter", result.getParameters());
    dumpAttributesInfo(result.getMethod().getAttributes());

    // Write reporter messages (if any)
    List<String> reporterMessages = Reporter.getOutput(result);
    if (!reporterMessages.isEmpty()) {
      writer.print("<tr><th");
      if (parameterCount > 1) {
        writer.printf(" colspan=\"%d\"", parameterCount);
      }
      writer.print(">Messages</th></tr>");

      writer.print("<tr><td");
      if (parameterCount > 1) {
        writer.printf(" colspan=\"%d\"", parameterCount);
      }
      writer.print(">");
      writeReporterMessages(reporterMessages);
      writer.print("</td></tr>");
      hasRows = true;
    }

    // Write exception (if any)
    Throwable throwable = result.getThrowable();
    if (throwable != null) {
      writer.print("<tr><th");
      if (parameterCount > 1) {
        writer.printf(" colspan=\"%d\"", parameterCount);
      }
      writer.print(">");
      writer.print(
          (result.getStatus() == ITestResult.SUCCESS ? "Expected Exception" : "Exception"));
      writer.print("</th></tr>");

      writer.print("<tr><td");
      if (parameterCount > 1) {
        writer.printf(" colspan=\"%d\"", parameterCount);
      }
      writer.print(">");
      writeStackTrace(throwable);
      writer.print("</td></tr>");
      hasRows = true;
    }

    if (!hasRows) {
      writer.print("<tr><th");
      if (parameterCount > 1) {
        writer.printf(" colspan=\"%d\"", parameterCount);
      }
      writer.print(" class=\"invisible\"/></tr>");
    }

    writer.print("</table>");
    writer.println("<p class=\"totop\"><a href=\"#summary\">back to summary</a></p>");
  }

  private boolean dumpParametersInfo(String prefix, Object[] parameters) {
    int parameterCount = (parameters == null ? 0 : parameters.length);
    if (parameterCount == 0) {
      return false;
    }
    writer.print("<tr class=\"param\">");
    for (int i = 1; i <= parameterCount; i++) {
      writer.print(String.format("<th>%s #", prefix));
      writer.print(i);
      writer.print("</th>");
    }
    writer.print("</tr><tr class=\"param stripe\">");
    for (Object parameter : parameters) {
      writer.print("<td>");
      writer.print(Utils.escapeHtml(Utils.toString(parameter)));
      writer.print("</td>");
    }
    writer.print("</tr>");
    return true;
  }

  private void dumpAttributesInfo(CustomAttribute[] attributes) {
    int parameterCount = (attributes == null ? 0 : attributes.length);
    if (parameterCount == 0) {
      return;
    }
    writer.print("<tr class=\"param\">");
    writer.print(String.format("<th colspan=3>%s</th>", "Attribute(s)"));
    writer.print("</tr>");
    writer.print("<tr class=\"param stripe\">");
    writer.print("<th>#</th><th>Name</th><th>Value(s)</th>");
    writer.print("</tr>");
    int i = 1;
    for (CustomAttribute attribute : attributes) {
      writer.print("<tr>");
      writer.print("<td>" + String.format("%02d.", (i++)) + "</td>");
      writer.print("<td>" + attribute.name() + "</td>");
      writer.print("<td>" + Utils.escapeHtml(Arrays.toString(attribute.values())) + "</td>");
      writer.print("</tr>");
    }
  }

  protected void writeReporterMessages(List<String> reporterMessages) {
    writer.print("<div class=\"messages\">");
    Iterator<String> iterator = reporterMessages.iterator();
    if (!iterator.hasNext()) {
      throw new IllegalStateException("There should have been at-least 1 message.");
    }
    if (Reporter.getEscapeHtml()) {
      writer.print(Utils.escapeHtml(iterator.next()));
    } else {
      writer.print(iterator.next());
    }
    while (iterator.hasNext()) {
      writer.print("<br/>");
      if (Reporter.getEscapeHtml()) {
        writer.print(Utils.escapeHtml(iterator.next()));
      } else {
        writer.print(iterator.next());
      }
    }
    writer.print("</div>");
  }

  protected void writeStackTrace(Throwable throwable) {
    writer.print("<div class=\"stacktrace\">");
    writer.print(Utils.shortStackTrace(throwable, true));
    writer.print("</div>");
  }

  /**
   * Writes a TH element with the specified contents and CSS class names.
   *
   * @param html the HTML contents
   * @param cssClasses the space-delimited CSS classes or null if there are no classes to apply
   */
  protected void writeTableHeader(String html, String cssClasses) {
    writeTag("th", html, cssClasses);
  }

  /**
   * Writes a TD element with the specified contents.
   *
   * @param html the HTML contents
   */
  protected void writeTableData(String html) {
    writeTableData(html, null);
  }

  /**
   * Writes a TD element with the specified contents and CSS class names.
   *
   * @param html the HTML contents
   * @param cssClasses the space-delimited CSS classes or null if there are no classes to apply
   */
  protected void writeTableData(String html, String cssClasses) {
    writeTag("td", html, cssClasses);
  }

  /**
   * Writes an arbitrary HTML element with the specified contents and CSS class names.
   *
   * @param tag the tag name
   * @param html the HTML contents
   * @param cssClasses the space-delimited CSS classes or null if there are no classes to apply
   */
  protected void writeTag(String tag, String html, String cssClasses) {
    writer.print("<");
    writer.print(tag);
    if (cssClasses != null) {
      writer.print(" class=\"");
      writer.print(cssClasses);
      writer.print("\"");
    }
    writer.print(">");
    writer.print(html);
    writer.print("</");
    writer.print(tag);
    writer.print(">");
  }

  /** Groups {@link TestResult}s by suite. */
  protected static class SuiteResult {
    private final String suiteName;
    private final List<TestResult> testResults = Lists.newArrayList();
    private final ParallelMode mode;

    public SuiteResult(ISuite suite) {
      suiteName = suite.getName();
      mode = suite.getXmlSuite().getParallel();
      for (ISuiteResult suiteResult : suite.getResults().values()) {
        testResults.add(new TestResult(suiteResult.getTestContext()));
      }
    }

    public String getSuiteName() {
      return suiteName;
    }

    /** @return the test results (possibly empty) */
    public List<TestResult> getTestResults() {
      return testResults;
    }

    public ParallelMode getParallelMode() {
      return mode;
    }
  }

  /** Groups {@link ClassResult}s by test, type (configuration or test), and status. */
  protected static class TestResult {
    /** Orders test results by class name and then by method name (in lexicographic order). */
    protected static final Comparator<ITestResult> RESULT_COMPARATOR =
        Comparator.comparing((ITestResult o) -> o.getTestClass().getName())
            .thenComparing(o -> o.getMethod().getMethodName());

    private final String testName;
    private final List<ClassResult> failedConfigurationResults;
    private final List<ClassResult> failedTestResults;
    private final List<ClassResult> skippedConfigurationResults;
    private final List<ClassResult> skippedTestResults;
    private final List<ClassResult> retriedTestResults;
    private final List<ClassResult> passedTestResults;
    private final int failedTestCount;
    private final int retriedTestCount;
    private final int skippedTestCount;
    private final int passedTestCount;
    private final long duration;
    private final String includedGroups;
    private final String excludedGroups;

    public TestResult(ITestContext context) {
      testName = context.getName();

      Set<ITestResult> failedConfigurations = context.getFailedConfigurations().getAllResults();
      Set<ITestResult> failedTests = context.getFailedTests().getAllResults();
      Set<ITestResult> skippedConfigurations = context.getSkippedConfigurations().getAllResults();
      Set<ITestResult> rawSkipped = context.getSkippedTests().getAllResults();
      Set<ITestResult> skippedTests = pruneSkipped(rawSkipped);
      Set<ITestResult> retriedTests = pruneRetried(rawSkipped);

      Set<ITestResult> passedTests = context.getPassedTests().getAllResults();

      failedConfigurationResults = groupResults(failedConfigurations);
      failedTestResults = groupResults(failedTests);
      skippedConfigurationResults = groupResults(skippedConfigurations);
      skippedTestResults = groupResults(skippedTests);
      retriedTestResults = groupResults(retriedTests);
      passedTestResults = groupResults(passedTests);

      failedTestCount = failedTests.size();
      retriedTestCount = retriedTests.size();
      skippedTestCount = skippedTests.size();
      passedTestCount = passedTests.size();

      duration = context.getEndDate().getTime() - context.getStartDate().getTime();

      includedGroups = formatGroups(context.getIncludedGroups());
      excludedGroups = formatGroups(context.getExcludedGroups());
    }

    private static Set<ITestResult> pruneSkipped(Set<ITestResult> results) {
      return results.stream().filter(result -> !result.wasRetried()).collect(Collectors.toSet());
    }

    private static Set<ITestResult> pruneRetried(Set<ITestResult> results) {
      return results.stream().filter(ITestResult::wasRetried).collect(Collectors.toSet());
    }

    /**
     * Groups test results by method and then by class.
     *
     * @param results All test results
     * @return Test result grouped by method and class
     */
    protected List<ClassResult> groupResults(Set<ITestResult> results) {
      List<ClassResult> classResults = Lists.newArrayList();
      if (!results.isEmpty()) {
        List<MethodResult> resultsPerClass = Lists.newArrayList();
        List<ITestResult> resultsPerMethod = Lists.newArrayList();

        List<ITestResult> resultsList = Lists.newArrayList(results);
        resultsList.sort(RESULT_COMPARATOR);
        Iterator<ITestResult> resultsIterator = resultsList.iterator();
        if (!resultsIterator.hasNext()) {
          throw new IllegalStateException("There should have been at-least 1 result");
        }

        ITestResult result = resultsIterator.next();
        resultsPerMethod.add(result);

        String previousClassName = result.getTestClass().getName();
        String previousMethodName = result.getMethod().getMethodName();
        while (resultsIterator.hasNext()) {
          result = resultsIterator.next();

          String className = result.getTestClass().getName();
          if (!previousClassName.equals(className)) {
            // Different class implies different method
            if (resultsPerMethod.isEmpty()) {
              throw new IllegalStateException("Results per method should NOT have been empty");
            }
            resultsPerClass.add(new MethodResult(resultsPerMethod));
            resultsPerMethod = Lists.newArrayList();

            classResults.add(new ClassResult(previousClassName, resultsPerClass));
            resultsPerClass = Lists.newArrayList();

            previousClassName = className;
            previousMethodName = result.getMethod().getMethodName();
          } else {
            String methodName = result.getMethod().getMethodName();
            if (!previousMethodName.equals(methodName)) {
              if (resultsPerMethod.isEmpty()) {
                throw new IllegalStateException("Results per method should NOT have been empty");
              }
              resultsPerClass.add(new MethodResult(resultsPerMethod));
              resultsPerMethod = Lists.newArrayList();

              previousMethodName = methodName;
            }
          }
          resultsPerMethod.add(result);
        }
        if (resultsPerMethod.isEmpty()) {
          throw new IllegalStateException("Results per method should NOT have been empty");
        }
        resultsPerClass.add(new MethodResult(resultsPerMethod));
        classResults.add(new ClassResult(previousClassName, resultsPerClass));
      }
      return classResults;
    }

    public String getTestName() {
      return testName;
    }

    /** @return the results for failed configurations (possibly empty) */
    public List<ClassResult> getFailedConfigurationResults() {
      return failedConfigurationResults;
    }

    /** @return the results for failed tests (possibly empty) */
    public List<ClassResult> getFailedTestResults() {
      return failedTestResults;
    }

    /** @return the results for skipped configurations (possibly empty) */
    public List<ClassResult> getSkippedConfigurationResults() {
      return skippedConfigurationResults;
    }

    /** @return the results for skipped tests (possibly empty) */
    public List<ClassResult> getSkippedTestResults() {
      return skippedTestResults;
    }

    public List<ClassResult> getRetriedTestResults() {
      return retriedTestResults;
    }

    /** @return the results for passed tests (possibly empty) */
    public List<ClassResult> getPassedTestResults() {
      return passedTestResults;
    }

    public int getFailedTestCount() {
      return failedTestCount;
    }

    public int getSkippedTestCount() {
      return skippedTestCount;
    }

    public int getRetriedTestCount() {
      return retriedTestCount;
    }

    public int getPassedTestCount() {
      return passedTestCount;
    }

    public long getDuration() {
      return duration;
    }

    public String getIncludedGroups() {
      return includedGroups;
    }

    public String getExcludedGroups() {
      return excludedGroups;
    }

    /**
     * Formats an array of groups for display.
     *
     * @param groups The groups
     * @return The String value of the groups
     */
    protected String formatGroups(String[] groups) {
      if (groups.length == 0) {
        return "";
      }

      StringBuilder builder = new StringBuilder();
      builder.append(groups[0]);
      for (int i = 1; i < groups.length; i++) {
        builder.append(", ").append(groups[i]);
      }
      return builder.toString();
    }
  }

  /** Groups {@link MethodResult}s by class. */
  protected static class ClassResult {
    private final String className;
    private final List<MethodResult> methodResults;

    /**
     * @param className the class name
     * @param methodResults the non-null, non-empty {@link MethodResult} list
     */
    public ClassResult(String className, List<MethodResult> methodResults) {
      this.className = className;
      this.methodResults = methodResults;
    }

    public String getClassName() {
      return className;
    }

    /** @return the non-null, non-empty {@link MethodResult} list */
    public List<MethodResult> getMethodResults() {
      return methodResults;
    }
  }

  /** Groups test results by method. */
  protected static class MethodResult {
    private final List<ITestResult> results;

    /** @param results the non-null, non-empty result list */
    public MethodResult(List<ITestResult> results) {
      this.results = results;
    }

    /** @return the non-null, non-empty result list */
    public List<ITestResult> getResults() {
      return results;
    }
  }
}
