/*
 * Copyright (C) 2009 JavaRosa
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

package org.odk.collect.android.logic;

import android.util.Log;

import org.javarosa.core.model.FormDef;
import org.javarosa.core.model.FormIndex;
import org.javarosa.core.model.GroupDef;
import org.javarosa.core.model.IDataReference;
import org.javarosa.core.model.IFormElement;
import org.javarosa.core.model.SubmissionProfile;
import org.javarosa.core.model.condition.EvaluationContext;
import org.javarosa.core.model.data.IAnswerData;
import org.javarosa.core.model.data.StringData;
import org.javarosa.core.model.instance.FormInstance;
import org.javarosa.core.model.instance.TreeElement;
import org.javarosa.core.services.IPropertyManager;
import org.javarosa.core.services.PrototypeManager;
import org.javarosa.core.services.transport.payload.ByteArrayPayload;
import org.javarosa.form.api.FormEntryCaption;
import org.javarosa.form.api.FormEntryController;
import org.javarosa.form.api.FormEntryModel;
import org.javarosa.form.api.FormEntryPrompt;
import org.javarosa.model.xform.XFormSerializingVisitor;
import org.javarosa.model.xform.XFormsModule;
import org.javarosa.model.xform.XPathReference;
import org.javarosa.xform.parse.XFormParser;
import org.javarosa.xpath.XPathParseTool;
import org.javarosa.xpath.expr.XPathExpression;
import org.odk.collect.android.exception.JavaRosaException;
import org.odk.collect.android.views.ODKView;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Vector;

/**
 * This class is a wrapper for Javarosa's FormEntryController. In theory, if you wanted to replace javarosa as the form
 * engine, you should only need to replace the methods in this file. Also, we haven't wrapped every method provided by
 * FormEntryController, only the ones we've needed so far. Feel free to add more as necessary.
 *
 * @author carlhartung
 */
public class FormController {

  private static final String t = "FormController";

  public static final boolean STEP_INTO_GROUP = true;
  public static final boolean STEP_OVER_GROUP = false;

  /**
   * OpenRosa metadata tag names.
   */
  private static final String INSTANCE_ID = "instanceID";
  private static final String INSTANCE_NAME = "instanceName";

  /**
   * OpenRosa metadata of a form instance.
   *
   * Contains the values for the required metadata fields and nothing else.
   *
   * @author mitchellsundt@gmail.com
   */
  public static final class InstanceMetadata {
    public final String instanceId;
    public final String instanceName;

    InstanceMetadata(String instanceId, String instanceName) {
      this.instanceId = instanceId;
      this.instanceName = instanceName;
    }
  }

  ;

  /**
   * Classes needed to serialize objects. Need to put anything from JR in here.
   */
  private final static String[] SERIALIABLE_CLASSES = {
      "org.javarosa.core.services.locale.ResourceFileDataSource", // JavaRosaCoreModule
      "org.javarosa.core.services.locale.TableLocaleSource", // JavaRosaCoreModule
      "org.javarosa.core.model.FormDef",
      "org.javarosa.core.model.SubmissionProfile", // CoreModelModule
      "org.javarosa.core.model.QuestionDef", // CoreModelModule
      "org.javarosa.core.model.GroupDef", // CoreModelModule
      "org.javarosa.core.model.instance.FormInstance", // CoreModelModule
      "org.javarosa.core.model.data.BooleanData", // CoreModelModule
      "org.javarosa.core.model.data.DateData", // CoreModelModule
      "org.javarosa.core.model.data.DateTimeData", // CoreModelModule
      "org.javarosa.core.model.data.DecimalData", // CoreModelModule
      "org.javarosa.core.model.data.GeoPointData", // CoreModelModule
      "org.javarosa.core.model.data.GeoShapeData", // CoreModelModule
      "org.javarosa.core.model.data.GeoTraceData", // CoreModelModule
      "org.javarosa.core.model.data.IntegerData", // CoreModelModule
      "org.javarosa.core.model.data.LongData", // CoreModelModule
      "org.javarosa.core.model.data.MultiPointerAnswerData", // CoreModelModule
      "org.javarosa.core.model.data.PointerAnswerData", // CoreModelModule
      "org.javarosa.core.model.data.SelectMultiData", // CoreModelModule
      "org.javarosa.core.model.data.SelectOneData", // CoreModelModule
      "org.javarosa.core.model.data.StringData", // CoreModelModule
      "org.javarosa.core.model.data.TimeData", // CoreModelModule
      "org.javarosa.core.model.data.UncastData", // CoreModelModule
      "org.javarosa.core.model.data.helper.BasicDataPointer", // CoreModelModule
      "org.javarosa.core.model.Action", // CoreModelModule
      "org.javarosa.core.model.actions.SetValueAction" // CoreModelModule
  };

  private static boolean isJavaRosaInitialized = false;

  /**
   * Isolate the initialization of JavaRosa into one method, called first by the Collect Application.  Called
   * subsequently whenever the Preferences dialogs are exited (to potentially update username and email fields).
   *
   * @param mgr
   */
  public static synchronized void initializeJavaRosa(IPropertyManager mgr) {
    if (!isJavaRosaInitialized) {
      // need a list of classes that formdef uses
      // unfortunately, the JR registerModule() functions do more than this.
      // register just the classes that would have been registered by:
      // new JavaRosaCoreModule().registerModule();
      // new CoreModelModule().registerModule();
      // replace with direct call to PrototypeManager
      PrototypeManager.registerPrototypes(SERIALIABLE_CLASSES);
      new XFormsModule().registerModule();

      isJavaRosaInitialized = true;
    }

    // needed to override rms property manager
    org.javarosa.core.services.PropertyManager
        .setPropertyManager(mgr);
  }

  private File mMediaFolder;
  private File mInstancePath;
  private FormEntryController mFormEntryController;
  private FormIndex mIndexWaitingForData = null;

  public FormController(File mediaFolder, FormEntryController fec, File instancePath) {
    mMediaFolder = mediaFolder;
    mFormEntryController = fec;
    mInstancePath = instancePath;
  }

  public FormDef getFormDef() {
    return mFormEntryController.getModel().getForm();
  }

  public File getMediaFolder() {
    return mMediaFolder;
  }

  public File getInstancePath() {
    return mInstancePath;
  }

  public void setInstancePath(File instancePath) {
    mInstancePath = instancePath;
  }

  public void setIndexWaitingForData(FormIndex index) {
    mIndexWaitingForData = index;
  }

  public FormIndex getIndexWaitingForData() {
    return mIndexWaitingForData;
  }

  /**
   * For logging purposes...
   *
   * @param index
   *
   * @return xpath value for this index
   */
  public String getXPath(FormIndex index) {
    String value;
    switch (getEvent()) {
      case FormEntryController.EVENT_BEGINNING_OF_FORM:
        value = "beginningOfForm";
        break;
      case FormEntryController.EVENT_END_OF_FORM:
        value = "endOfForm";
        break;
      case FormEntryController.EVENT_GROUP:
        value = "group." + index.getReference().toString();
        break;
      case FormEntryController.EVENT_QUESTION:
        value = "question." + index.getReference().toString();
        break;
      case FormEntryController.EVENT_PROMPT_NEW_REPEAT:
        value = "promptNewRepeat." + index.getReference().toString();
        break;
      case FormEntryController.EVENT_REPEAT:
        value = "repeat." + index.getReference().toString();
        break;
      case FormEntryController.EVENT_REPEAT_JUNCTURE:
        value = "repeatJuncture." + index.getReference().toString();
        break;
      default:
        value = "unexpected";
        break;
    }
    return value;
  }

  public FormIndex getIndexFromXPath(String xPath) {
    if (xPath.equals("beginningOfForm")) {
      return FormIndex.createBeginningOfFormIndex();
    } else if (xPath.equals("endOfForm")) {
      return FormIndex.createEndOfFormIndex();
    } else if (xPath.equals("unexpected")) {
      Log.e(t, "Unexpected string from XPath");
      throw new IllegalArgumentException("unexpected string from XPath");
    } else {
      FormIndex returned = null;
      FormIndex saved = getFormIndex();
      // the only way I know how to do this is to step through the entire form
      // until the XPath of a form entry matches that of the supplied XPath
      try {
        jumpToIndex(FormIndex.createBeginningOfFormIndex());
        int event = stepToNextEvent(true);
        while (event != FormEntryController.EVENT_END_OF_FORM) {
          String candidateXPath = getXPath(getFormIndex());
          // Log.i(t, "xpath: " + candidateXPath);
          if (candidateXPath.equals(xPath)) {
            returned = getFormIndex();
            break;
          }
          event = stepToNextEvent(true);
        }
      } finally {
        jumpToIndex(saved);
      }
      return returned;
    }
  }

  /**
   * returns the event for the current FormIndex.
   *
   * @return
   */
  public int getEvent() {
    return mFormEntryController.getModel().getEvent();
  }


  /**
   * returns the event for the given FormIndex.
   *
   * @param index
   *
   * @return
   */
  public int getEvent(FormIndex index) {
    return mFormEntryController.getModel().getEvent(index);
  }


  /**
   * @return current FormIndex.
   */
  public FormIndex getFormIndex() {
    return mFormEntryController.getModel().getFormIndex();
  }


  /**
   * Return the langauges supported by the currently loaded form.
   *
   * @return Array of Strings containing the languages embedded in the XForm.
   */
  public String[] getLanguages() {
    return mFormEntryController.getModel().getLanguages();
  }


  /**
   * @return A String containing the title of the current form.
   */
  public String getFormTitle() {
    return mFormEntryController.getModel().getFormTitle();
  }


  /**
   * @return the currently selected language.
   */
  public String getLanguage() {
    return mFormEntryController.getModel().getLanguage();
  }

  public String getBindAttribute(String attributeNamespace, String attributeName) {
    return getBindAttribute(getFormIndex(), attributeNamespace, attributeName);
  }

  public String getBindAttribute(FormIndex idx, String attributeNamespace, String attributeName) {
    return mFormEntryController.getModel().getForm().getMainInstance().resolveReference(
        idx.getReference()).getBindAttributeValue(attributeNamespace, attributeName);
  }

  /**
   * @return an array of FormEntryCaptions for the current FormIndex. This is how we get group information Group 1 >
   * Group 2> etc... The element at [size-1] is the current question text, with group names decreasing in hierarchy
   * until array element at [0] is the root
   */
  private FormEntryCaption[] getCaptionHierarchy() {
    return mFormEntryController.getModel().getCaptionHierarchy();
  }

  /**
   * @param index
   *
   * @return an array of FormEntryCaptions for the supplied FormIndex. This is how we get group information Group 1 >
   * Group 2> etc... The element at [size-1] is the current question text, with group names decreasing in hierarchy
   * until array element at [0] is the root
   */
  private FormEntryCaption[] getCaptionHierarchy(FormIndex index) {
    return mFormEntryController.getModel().getCaptionHierarchy(index);
  }

  /**
   * Returns a caption prompt for the given index. This is used to create a multi-question per screen view.
   *
   * @param index
   *
   * @return
   */
  public FormEntryCaption getCaptionPrompt(FormIndex index) {
    return mFormEntryController.getModel().getCaptionPrompt(index);
  }


  /**
   * Return the caption for the current FormIndex. This is usually used for a repeat prompt.
   *
   * @return
   */
  public FormEntryCaption getCaptionPrompt() {
    return mFormEntryController.getModel().getCaptionPrompt();
  }


  /**
   * This fires off the jr:preload actions and events to save values like the end time of a form.
   *
   * @return
   */
  public boolean postProcessInstance() {
    return mFormEntryController.getModel().getForm().postProcessInstance();
  }


  /**
   * TODO: We need a good description of what this does, exactly, and why.
   *
   * @return
   */
  private FormInstance getInstance() {
    return mFormEntryController.getModel().getForm().getInstance();
  }


  /**
   * A convenience method for determining if the current FormIndex is in a group that is/should be displayed as a
   * multi-question view. This is useful for returning from the formhierarchy view to a selected index.
   *
   * @param index
   *
   * @return
   */
  private boolean groupIsFieldList(FormIndex index) {
    // if this isn't a group, return right away
    IFormElement element = mFormEntryController.getModel().getForm().getChild(index);
    if (!(element instanceof GroupDef)) {
      return false;
    }

    GroupDef gd = (GroupDef) element; // exceptions?
    return (ODKView.FIELD_LIST.equalsIgnoreCase(gd.getAppearanceAttr()));
  }

  private boolean repeatIsFieldList(FormIndex index) {
    // if this isn't a group, return right away
    IFormElement element = mFormEntryController.getModel().getForm().getChild(index);
    if (!(element instanceof GroupDef)) {
      return false;
    }

    GroupDef gd = (GroupDef) element; // exceptions?
    return (ODKView.FIELD_LIST.equalsIgnoreCase(gd.getAppearanceAttr()));
  }

  /**
   * Tests if the FormIndex 'index' is located inside a group that is marked as a "field-list"
   *
   * @param index
   *
   * @return true if index is in a "field-list". False otherwise.
   */
  private boolean indexIsInFieldList(FormIndex index) {
    int event = getEvent(index);
    if (event == FormEntryController.EVENT_QUESTION) {
      // caption[0..len-1]
      // caption[len-1] == the question itself
      // caption[len-2] == the first group it is contained in.
      FormEntryCaption[] captions = getCaptionHierarchy(index);
      if (captions.length < 2) {
        // no group
        return false;
      }
      FormEntryCaption grp = captions[captions.length - 2];
      return groupIsFieldList(grp.getIndex());
    } else if (event == FormEntryController.EVENT_GROUP) {
      return groupIsFieldList(index);
    } else if (event == FormEntryController.EVENT_REPEAT) {
      return repeatIsFieldList(index);
    } else {
      // right now we only test Questions and Groups. Should we also handle
      // repeats?
      return false;
    }

  }

  public boolean currentPromptIsQuestion() {
    return (getEvent() == FormEntryController.EVENT_QUESTION
        || ((getEvent() == FormEntryController.EVENT_GROUP ||
        getEvent() == FormEntryController.EVENT_REPEAT)
        && indexIsInFieldList()));
  }

  /**
   * Tests if the current FormIndex is located inside a group that is marked as a "field-list"
   *
   * @return true if index is in a "field-list". False otherwise.
   */
  public boolean indexIsInFieldList() {
    return indexIsInFieldList(getFormIndex());
  }


  /**
   * Attempts to save answer at the current FormIndex into the data model.
   *
   * @param data
   *
   * @return
   */
  private int answerQuestion(IAnswerData data) {
    return mFormEntryController.answerQuestion(data);
  }


  /**
   * Attempts to save answer into the given FormIndex into the data model.
   *
   * @param index
   * @param data
   *
   * @return
   */
  public int answerQuestion(FormIndex index, IAnswerData data) throws JavaRosaException {
    try {
      return mFormEntryController.answerQuestion(index, data);
    } catch (Exception e) {
      throw new JavaRosaException(e);
    }
  }

  /**
   * Goes through the entire form to make sure all entered answers comply with their constraints. Constraints are
   * ignored on 'jump to', so answers can be outside of constraints. We don't allow saving to disk, though, until all
   * answers conform to their constraints/requirements.
   *
   * @param markCompleted
   *
   * @return ANSWER_OK and leave index unchanged or change index to bad value and return error type.
   */
  public int validateAnswers(Boolean markCompleted) {
    FormEntryController formEntryController = this.mFormEntryController;
    FormEntryModel formEntryModel = formEntryController.getModel();

    FormEntryModel formEntryModelToBeValidated = new FormEntryModel(formEntryModel.getForm());
    FormEntryController formEntryControllerToBeValidated = new FormEntryController(formEntryModelToBeValidated);
    FormController formControllerToBeValidated = new FormController(this.getMediaFolder(),
        formEntryControllerToBeValidated, this.getInstancePath());

    formControllerToBeValidated.jumpToIndex(FormIndex.createBeginningOfFormIndex());

    int event;
    while ((event =
        formControllerToBeValidated.stepToNextEvent(FormController.STEP_INTO_GROUP)) != FormEntryController
        .EVENT_END_OF_FORM) {
      if (event != FormEntryController.EVENT_QUESTION) {
        continue;
      } else {
        FormIndex formControllerToBeValidatedFormIndex = formControllerToBeValidated.getFormIndex();

        int saveStatus = formControllerToBeValidated.answerQuestion(formControllerToBeValidated.getQuestionPrompt()
            .getAnswerValue());
        if (markCompleted && saveStatus != FormEntryController.ANSWER_OK) {
          // jump to the error
          this.jumpToIndex(formControllerToBeValidatedFormIndex);
          return saveStatus;
        }
      }
    }

    return FormEntryController.ANSWER_OK;
  }


  /**
   * saveAnswer attempts to save the current answer into the data model without doing any constraint checking. Only use
   * this if you know what you're doing. For normal form filling you should always use answerQuestion or
   * answerCurrentQuestion.
   *
   * @param index
   * @param data
   *
   * @return true if saved successfully, false otherwise.
   */
  public boolean saveAnswer(FormIndex index, IAnswerData data) throws JavaRosaException {
    try {
      return mFormEntryController.saveAnswer(index, data);
    } catch (Exception e) {
      throw new JavaRosaException(e);
    }
  }


  /**
   * saveAnswer attempts to save the current answer into the data model without doing any constraint checking. Only use
   * this if you know what you're doing. For normal form filling you should always use answerQuestion().
   *
   * @param data
   *
   * @return true if saved successfully, false otherwise.
   */
  public boolean saveAnswer(IAnswerData data) throws JavaRosaException {
    try {
      return mFormEntryController.saveAnswer(data);
    } catch (Exception e) {
      throw new JavaRosaException(e);
    }
  }


  /**
   * Navigates forward in the form.
   *
   * @return the next event that should be handled by a view.
   */
  public int stepToNextEvent(boolean stepIntoGroup) {
    if ((getEvent() == FormEntryController.EVENT_GROUP ||
        getEvent() == FormEntryController.EVENT_REPEAT)
        && indexIsInFieldList() && !stepIntoGroup) {
      return stepOverGroup();
    } else {
      return mFormEntryController.stepToNextEvent();
    }
  }


  /**
   * If using a view like HierarchyView that doesn't support multi-question per screen, step over the group represented
   * by the FormIndex.
   *
   * @return
   */
  private int stepOverGroup() {
    ArrayList<FormIndex> indicies = new ArrayList<>();
    GroupDef gd =
        (GroupDef) mFormEntryController.getModel().getForm()
            .getChild(getFormIndex());
    FormIndex idxChild =
        mFormEntryController.getModel().incrementIndex(
            getFormIndex(), true); // descend into group
    for (int i = 0; i < gd.getChildren().size(); i++) {
      indicies.add(idxChild);
      // don't descend
      idxChild = mFormEntryController.getModel().incrementIndex(idxChild, false);
    }

    // jump to the end of the group
    mFormEntryController.jumpToIndex(indicies.get(indicies.size() - 1));
    return stepToNextEvent(STEP_OVER_GROUP);
  }

  /**
   * used to go up one level in the formIndex. That is, if you're at 5_0, 1 (the second question in a repeating group),
   * this method will return a FormInex of 5_0 (the start of the repeating group). If your at index 16 or 5_0, this will
   * return null;
   *
   * @param index
   *
   * @return index
   */
  public FormIndex stepIndexOut(FormIndex index) {
    if (index.isTerminal()) {
      return null;
    } else {
      return new FormIndex(stepIndexOut(index.getNextLevel()), index);
    }
  }

  /**
   * Move the current form index to the index of the previous question in the form. Step backward out of repeats and
   * groups as needed. If the resulting question is itself within a field-list, move upward to the group or repeat
   * defining that field-list.
   *
   * @return
   */
  public int stepToPreviousScreenEvent() throws JavaRosaException {
    try {
      if (getEvent() != FormEntryController.EVENT_BEGINNING_OF_FORM) {
        int event = stepToPreviousEvent();

        while (event == FormEntryController.EVENT_REPEAT_JUNCTURE ||
            event == FormEntryController.EVENT_PROMPT_NEW_REPEAT ||
            (event == FormEntryController.EVENT_QUESTION && indexIsInFieldList()) ||
            ((event == FormEntryController.EVENT_GROUP
                || event == FormEntryController.EVENT_REPEAT) && !indexIsInFieldList())) {
          event = stepToPreviousEvent();
        }

        // Work-around for broken field-list handling from 1.1.7 which breaks either
        // build-generated forms or XLSForm-generated forms.  If the current group
        // is a GROUP with field-list and it is nested within a group or repeat with just
        // this containing group, and that is also a field-list, then return the parent group.
        if (getEvent() == FormEntryController.EVENT_GROUP) {
          FormIndex currentIndex = getFormIndex();
          IFormElement element = mFormEntryController.getModel().getForm().getChild(currentIndex);
          if (element instanceof GroupDef) {
            GroupDef gd = (GroupDef) element;
            if (ODKView.FIELD_LIST.equalsIgnoreCase(gd.getAppearanceAttr())) {
              // OK this group is a field-list... see what the parent is...
              FormEntryCaption[] fclist = this.getCaptionHierarchy(currentIndex);
              if (fclist.length > 1) {
                FormEntryCaption fc = fclist[fclist.length - 2];
                GroupDef pd = (GroupDef) fc.getFormElement();
                if (pd.getChildren().size() == 1 &&
                    ODKView.FIELD_LIST.equalsIgnoreCase(pd.getAppearanceAttr())) {
                  mFormEntryController.jumpToIndex(fc.getIndex());
                }
              }
            }
          }
        }
      }
      return getEvent();
    } catch (RuntimeException e) {
      throw new JavaRosaException(e);
    }
  }

  /**
   * Move the current form index to the index of the next question in the form. Stop if we should ask to create a new
   * repeat group or if we reach the end of the form. If we enter a group or repeat, return that if it is a field-list
   * definition. Otherwise, descend into the group or repeat searching for the first question.
   *
   * @return
   */
  public int stepToNextScreenEvent() throws JavaRosaException {
    try {
      if (getEvent() != FormEntryController.EVENT_END_OF_FORM) {
        int event;
        group_skip:
        do {
          event = stepToNextEvent(FormController.STEP_OVER_GROUP);
          switch (event) {
            case FormEntryController.EVENT_QUESTION:
            case FormEntryController.EVENT_END_OF_FORM:
              break group_skip;
            case FormEntryController.EVENT_PROMPT_NEW_REPEAT:
              break group_skip;
            case FormEntryController.EVENT_GROUP:
            case FormEntryController.EVENT_REPEAT:
              if (indexIsInFieldList()
                  && getQuestionPrompts().length != 0) {
                break group_skip;
              }
              // otherwise it's not a field-list group, so just skip it
              break;
            case FormEntryController.EVENT_REPEAT_JUNCTURE:
              Log.i(t, "repeat juncture: "
                  + getFormIndex().getReference());
              // skip repeat junctures until we implement them
              break;
            default:
              Log.w(t,
                  "JavaRosa added a new EVENT type and didn't tell us... shame on them.");
              break;
          }
        } while (event != FormEntryController.EVENT_END_OF_FORM);
      }
      return getEvent();
    } catch (RuntimeException e) {
      throw new JavaRosaException(e);
    }
  }


  /**
   * Move the current form index to the index of the first enclosing repeat or to the start of the form.
   *
   * @return
   */
  public int stepToOuterScreenEvent() {
    FormIndex index = stepIndexOut(getFormIndex());
    int currentEvent = getEvent();

    // Step out of any group indexes that are present.
    while (index != null
        && getEvent(index) == FormEntryController.EVENT_GROUP) {
      index = stepIndexOut(index);
    }

    if (index == null) {
      jumpToIndex(FormIndex.createBeginningOfFormIndex());
    } else {
      if (currentEvent == FormEntryController.EVENT_REPEAT) {
        // We were at a repeat, so stepping back brought us to then previous level
        jumpToIndex(index);
      } else {
        // We were at a question, so stepping back brought us to either:
        // The beginning. or The start of a repeat. So we need to step
        // out again to go passed the repeat.
        index = stepIndexOut(index);
        if (index == null) {
          jumpToIndex(FormIndex.createBeginningOfFormIndex());
        } else {
          jumpToIndex(index);
        }
      }
    }
    return getEvent();
  }


  public static class FailedConstraint {
    public final FormIndex index;
    public final int status;

    FailedConstraint(FormIndex index, int status) {
      this.index = index;
      this.status = status;
    }
  }

  /**
   * @param answers
   * @param evaluateConstraints
   *
   * @return FailedConstraint of first failed constraint or null if all questions were saved.
   */
  public FailedConstraint saveAllScreenAnswers(LinkedHashMap<FormIndex, IAnswerData> answers, boolean
      evaluateConstraints) throws JavaRosaException {
    if (currentPromptIsQuestion()) {
      Iterator<FormIndex> it = answers.keySet().iterator();
      while (it.hasNext()) {
        FormIndex index = it.next();
        // Within a group, you can only save for question events
        if (getEvent(index) == FormEntryController.EVENT_QUESTION) {
          int saveStatus;
          IAnswerData answer = answers.get(index);
          if (evaluateConstraints) {
            saveStatus = answerQuestion(index, answer);
            if (saveStatus != FormEntryController.ANSWER_OK) {
              return new FailedConstraint(index, saveStatus);
            }
          } else {
            saveAnswer(index, answer);
          }
        } else {
          Log.w(t,
              "Attempted to save an index referencing something other than a question: "
                  + index.getReference());
        }
      }
    }
    return null;
  }


  /**
   * Navigates backward in the form.
   *
   * @return the event that should be handled by a view.
   */
  public int stepToPreviousEvent() {
        /*
         * Right now this will always skip to the beginning of a group if that group is represented
         * as a 'field-list'. Should a need ever arise to step backwards by only one step in a
         * 'field-list', this method will have to be updated.
         */

    mFormEntryController.stepToPreviousEvent();

    // If after we've stepped, we're in a field-list, jump back to the beginning of the group
    //

    if (indexIsInFieldList()
        && getEvent() == FormEntryController.EVENT_QUESTION) {
      // caption[0..len-1]
      // caption[len-1] == the question itself
      // caption[len-2] == the first group it is contained in.
      FormEntryCaption[] captions = getCaptionHierarchy();
      FormEntryCaption grp = captions[captions.length - 2];
      int event = mFormEntryController.jumpToIndex(grp.getIndex());
      // and test if this group or at least one of its children is relevant...
      FormIndex idx = grp.getIndex();
      if (!mFormEntryController.getModel().isIndexRelevant(idx)) {
        return stepToPreviousEvent();
      }
      idx = mFormEntryController.getModel().incrementIndex(idx, true);
      while (FormIndex.isSubElement(grp.getIndex(), idx)) {
        if (mFormEntryController.getModel().isIndexRelevant(idx)) {
          return event;
        }
        idx = mFormEntryController.getModel().incrementIndex(idx, true);
      }
      return stepToPreviousEvent();
    } else if (indexIsInFieldList() && getEvent() == FormEntryController.EVENT_GROUP) {
      FormIndex grpidx = mFormEntryController.getModel().getFormIndex();
      int event = mFormEntryController.getModel().getEvent();
      // and test if this group or at least one of its children is relevant...
      if (!mFormEntryController.getModel().isIndexRelevant(grpidx)) {
        return stepToPreviousEvent(); // shouldn't happen?
      }
      FormIndex idx = mFormEntryController.getModel().incrementIndex(grpidx, true);
      while (FormIndex.isSubElement(grpidx, idx)) {
        if (mFormEntryController.getModel().isIndexRelevant(idx)) {
          return event;
        }
        idx = mFormEntryController.getModel().incrementIndex(idx, true);
      }
      return stepToPreviousEvent();
    }

    return getEvent();

  }


  /**
   * Jumps to a given FormIndex.
   *
   * @param index
   *
   * @return EVENT for the specified Index.
   */
  public int jumpToIndex(FormIndex index) {
    return mFormEntryController.jumpToIndex(index);
  }


  /**
   * Creates a new repeated instance of the group referenced by the current FormIndex.
   *
   * @param questionIndex
   */
  public void newRepeat() {
    mFormEntryController.newRepeat();
  }


  /**
   * If the current FormIndex is within a repeated group, will find the innermost repeat, delete it, and jump the
   * FormEntryController to the previous valid index. That is, if you have group1 (2) > group2 (3) and you call
   * deleteRepeat, it will delete the 3rd instance of group2.
   */
  public void deleteRepeat() {
    FormIndex fi = mFormEntryController.deleteRepeat();
    mFormEntryController.jumpToIndex(fi);
  }


  /**
   * If the current FormIndex is within a repeated group, will find the innermost repeat, delete it, and jump the
   * FormEntryController to the previous valid index. That is, if you have group1 (2) > group2 (3) and you call
   * deleteRepeat, it will delete the 3rd instance of group2.
   */
  public void deleteRepeat(final int index) {
    final FormEntryModel model = mFormEntryController.getModel();
    final FormIndex formIndex = model.getForm().descendIntoRepeat(model.getFormIndex(), 0);
    final FormIndex fi = mFormEntryController.deleteRepeat(model.getForm().descendIntoRepeat(model.getFormIndex(),
        index));
    mFormEntryController.jumpToIndex(fi);
  }


  /**
   * Sets the current language.
   *
   * @param language
   */
  public void setLanguage(String language) {
    mFormEntryController.setLanguage(language);
  }


  /**
   * Returns an array of question promps.
   *
   * @return
   * @throws RuntimeException
   *     if an error occurs.
   */
  public FormEntryPrompt[] getQuestionPrompts() throws RuntimeException {

    ArrayList<FormIndex> indicies = new ArrayList<>();
    FormIndex currentIndex = getFormIndex();

    // For questions, there is only one.
    // For groups, there could be many, but we set that below
    FormEntryPrompt[] questions = new FormEntryPrompt[1];

    IFormElement element = mFormEntryController.getModel().getForm().getChild(currentIndex);
    if (element instanceof GroupDef) {
      GroupDef gd = (GroupDef) element;
      // descend into group
      FormIndex idxChild = mFormEntryController.getModel().incrementIndex(currentIndex, true);

      if (gd.getChildren().size() == 1 && getEvent(idxChild) == FormEntryController.EVENT_GROUP) {
        // if we have a group definition within a field-list attribute group, and this is the
        // only child in the group, check to see if it is also a field-list appearance.
        // If it is, then silently recurse into it to pick up its elements.
        // Work-around for the inconsistent treatment of field-list groups and repeats in 1.1.7 that
        // either breaks forms generated by build or breaks forms generated by XLSForm.
        IFormElement nestedElement = mFormEntryController.getModel().getForm().getChild(idxChild);
        if (nestedElement instanceof GroupDef) {
          GroupDef nestedGd = (GroupDef) nestedElement;
          if (ODKView.FIELD_LIST.equalsIgnoreCase(nestedGd.getAppearanceAttr())) {
            gd = nestedGd;
            idxChild = mFormEntryController.getModel().incrementIndex(idxChild, true);
          }
        }
      }

      for (int i = 0; i < gd.getChildren().size(); i++) {
        indicies.add(idxChild);
        // don't descend
        idxChild = mFormEntryController.getModel().incrementIndex(idxChild, false);
      }

      // we only display relevant questions
      ArrayList<FormEntryPrompt> questionList = new ArrayList<FormEntryPrompt>();
      for (int i = 0; i < indicies.size(); i++) {
        FormIndex index = indicies.get(i);

        if (getEvent(index) != FormEntryController.EVENT_QUESTION) {
          String errorMsg =
              "Only questions are allowed in 'field-list'.  Bad node is: "
                  + index.getReference().toString(false);
          RuntimeException e = new RuntimeException(errorMsg);
          Log.e(t, errorMsg);
          throw e;
        }

        // we only display relevant questions
        if (mFormEntryController.getModel().isIndexRelevant(index)) {
          questionList.add(getQuestionPrompt(index));
        }
        questions = new FormEntryPrompt[questionList.size()];
        questionList.toArray(questions);
      }
    } else {
      // We have a quesion, so just get the one prompt
      questions[0] = getQuestionPrompt();
    }

    return questions;
  }


  public FormEntryPrompt getQuestionPrompt(FormIndex index) {
    return mFormEntryController.getModel().getQuestionPrompt(index);
  }


  public FormEntryPrompt getQuestionPrompt() {
    return mFormEntryController.getModel().getQuestionPrompt();
  }

  public String getQuestionPromptConstraintText(FormIndex index) {
    return mFormEntryController.getModel().getQuestionPrompt(index).getConstraintText();
  }

  public String getQuestionPromptRequiredText(FormIndex index) {
    // look for the text under the requiredMsg bind attribute
    String constraintText = getBindAttribute(index, XFormParser.NAMESPACE_JAVAROSA, "requiredMsg");
    if (constraintText != null) {
      XPathExpression xPathRequiredMsg;
      try {
        xPathRequiredMsg = XPathParseTool.parseXPath("string(" + constraintText + ")");
      } catch (Exception e) {
        // Expected in probably most cases.
        // This is a string literal, so no need to evaluate anything.
        return constraintText;
      }

      if (xPathRequiredMsg != null) {
        try {
          FormDef form = mFormEntryController.getModel().getForm();
          TreeElement mTreeElement = form.getMainInstance().resolveReference(index.getReference());
          EvaluationContext ec = new EvaluationContext(form.exprEvalContext, mTreeElement.getRef());
          Object value = xPathRequiredMsg.eval(form.getMainInstance(), ec);
          if (value != "") {
            return (String) value;
          }
          return null;
        } catch (Exception e) {
          Log.e(t, "Error evaluating a valid-looking required xpath ", e);
          return constraintText;
        }
      } else {
        return constraintText;
      }
    }
    return null;
  }

  /**
   * Returns an array of FormEntryCaptions for current FormIndex.
   *
   * @return
   */
  public FormEntryCaption[] getGroupsForCurrentIndex() {
    // return an empty array if you ask for something impossible
    if (!(getEvent() == FormEntryController.EVENT_QUESTION
        || getEvent() == FormEntryController.EVENT_PROMPT_NEW_REPEAT
        || getEvent() == FormEntryController.EVENT_GROUP
        || getEvent() == FormEntryController.EVENT_REPEAT)) {
      return new FormEntryCaption[0];
    }

    // the first caption is the question, so we skip it if it's an EVENT_QUESTION
    // otherwise, the first caption is a group so we start at index 0
    int lastquestion = 1;
    if (getEvent() == FormEntryController.EVENT_PROMPT_NEW_REPEAT
        || getEvent() == FormEntryController.EVENT_GROUP
        || getEvent() == FormEntryController.EVENT_REPEAT) {
      lastquestion = 0;
    }

    FormEntryCaption[] v = getCaptionHierarchy();
    FormEntryCaption[] groups = new FormEntryCaption[v.length - lastquestion];
    for (int i = 0; i < v.length - lastquestion; i++) {
      groups[i] = v[i];
    }
    return groups;
  }


  /**
   * This is used to enable/disable the "Delete Repeat" menu option.
   *
   * @return
   */
  public boolean indexContainsRepeatableGroup() {
    FormEntryCaption[] groups = getCaptionHierarchy();
    if (groups.length == 0) {
      return false;
    }
    for (int i = 0; i < groups.length; i++) {
      if (groups[i].repeats()) {
        return true;
      }
    }
    return false;
  }


  /**
   * The count of the closest group that repeats or -1.
   */
  public int getLastRepeatedGroupRepeatCount() {
    FormEntryCaption[] groups = getCaptionHierarchy();
    if (groups.length > 0) {
      for (int i = groups.length - 1; i > -1; i--) {
        if (groups[i].repeats()) {
          return groups[i].getMultiplicity();

        }
      }
    }
    return -1;
  }


  /**
   * The name of the closest group that repeats or null.
   */
  public String getLastRepeatedGroupName() {
    FormEntryCaption[] groups = getCaptionHierarchy();
    // no change
    if (groups.length > 0) {
      for (int i = groups.length - 1; i > -1; i--) {
        if (groups[i].repeats()) {
          return groups[i].getLongText();
        }
      }
    }
    return null;
  }


  /**
   * The closest group the prompt belongs to.
   *
   * @return FormEntryCaption
   */
  private FormEntryCaption getLastGroup() {
    FormEntryCaption[] groups = getCaptionHierarchy();
    if (groups == null || groups.length == 0) {
      return null;
    } else {
      return groups[groups.length - 1];
    }
  }


  /**
   * The repeat count of closest group the prompt belongs to.
   */
  public int getLastRepeatCount() {
    if (getLastGroup() != null) {
      return getLastGroup().getMultiplicity();
    }
    return -1;

  }


  /**
   * The text of closest group the prompt belongs to.
   */
  public String getLastGroupText() {
    if (getLastGroup() != null) {
      return getLastGroup().getLongText();
    }
    return null;
  }

  /**
   * Find the portion of the form that is to be submitted
   *
   * @return
   */
  private IDataReference getSubmissionDataReference() {
    FormDef formDef = mFormEntryController.getModel().getForm();
    // Determine the information about the submission...
    SubmissionProfile p = formDef.getSubmissionProfile();
    if (p == null || p.getRef() == null) {
      return new XPathReference("/");
    } else {
      return p.getRef();
    }
  }

  /**
   * Once a submission is marked as complete, it is saved in the submission format, which might be a fragment of the
   * original form or might be a SMS text string, etc.
   *
   * @return true if the submission is the entire form.  If it is, then the submission can be re-opened for editing
   * after it was marked-as-complete (provided it has not been encrypted).
   */
  public boolean isSubmissionEntireForm() {
    IDataReference sub = getSubmissionDataReference();
    return (getInstance().resolveReference(sub) == null);
  }

  /**
   * Constructs the XML payload for a filled-in form instance. This payload enables a filled-in form to be re-opened and
   * edited.
   *
   * @return
   * @throws IOException
   */
  public ByteArrayPayload getFilledInFormXml() throws IOException {
    // assume no binary data inside the model.
    FormInstance datamodel = getInstance();
    XFormSerializingVisitor serializer = new XFormSerializingVisitor();
    ByteArrayPayload payload =
        (ByteArrayPayload) serializer.createSerializedPayload(datamodel);

    return payload;
  }

  /**
   * Extract the portion of the form that should be uploaded to the server.
   *
   * @return
   * @throws IOException
   */
  public ByteArrayPayload getSubmissionXml() throws IOException {
    FormInstance instance = getInstance();
    XFormSerializingVisitor serializer = new XFormSerializingVisitor();
    ByteArrayPayload payload =
        (ByteArrayPayload) serializer.createSerializedPayload(instance,
            getSubmissionDataReference());
    return payload;
  }

  /**
   * Traverse the submission looking for the first matching tag in depth-first order.
   *
   * @param parent
   * @param name
   *
   * @return
   */
  private TreeElement findDepthFirst(TreeElement parent, String name) {
    int len = parent.getNumChildren();
    for (int i = 0; i < len; ++i) {
      TreeElement e = parent.getChildAt(i);
      if (name.equals(e.getName())) {
        return e;
      } else if (e.getNumChildren() != 0) {
        TreeElement v = findDepthFirst(e, name);
        if (v != null) {
          return v;
        }
      }
    }
    return null;
  }

  /**
   * Get the OpenRosa required metadata of the portion of the form beng submitted
   *
   * @return
   */
  public InstanceMetadata getSubmissionMetadata() {
    FormDef formDef = mFormEntryController.getModel().getForm();
    TreeElement rootElement = formDef.getInstance().getRoot();

    TreeElement trueSubmissionElement;
    // Determine the information about the submission...
    SubmissionProfile p = formDef.getSubmissionProfile();
    if (p == null || p.getRef() == null) {
      trueSubmissionElement = rootElement;
    } else {
      IDataReference ref = p.getRef();
      trueSubmissionElement = formDef.getInstance().resolveReference(ref);
      // resolveReference returns null if the reference is to the root element...
      if (trueSubmissionElement == null) {
        trueSubmissionElement = rootElement;
      }
    }

    // and find the depth-first meta block in this...
    TreeElement e = findDepthFirst(trueSubmissionElement, "meta");

    String instanceId = null;
    String instanceName = null;

    if (e != null) {
      Vector<TreeElement> v;

      // instance id...
      v = e.getChildrenWithName(INSTANCE_ID);
      if (v.size() == 1) {
        StringData sa = (StringData) v.get(0).getValue();
        if (sa != null) {
          instanceId = (String) sa.getValue();
        }
      }

      // instance name...
      v = e.getChildrenWithName(INSTANCE_NAME);
      if (v.size() == 1) {
        StringData sa = (StringData) v.get(0).getValue();
        if (sa != null) {
          instanceName = (String) sa.getValue();
        }
      }
    }

    return new InstanceMetadata(instanceId, instanceName);
  }

}
