source: TraumaOntologies/src/main/java/tudelft/healthpsychology/traumaontologies/answerstate/OntologyAnswerState.java@ 4

package tudelft.healthpsychology.traumaontologies.answerstate;

import java.util.Collection;
import java.util.List;
import java.util.Optional;
import java.util.stream.Collectors;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;

import tudelft.healthpsychology.traumaontologies.questiontypes.QuestionType;
import tudelft.healthpsychology.traumaontologies.questiontypes.SelectFromList;
import tudelft.utilities.tree.Tree;

/**
 * This AnswerState searches the ontology class that is the best match to what
 * the user has in mind. It tries to get as close as possible to the leaf nodes
 * in the ontology, offering the user to choose between children nodes
 * repeatedly.
 * 
 * The state transitioning works as follows. The idea is that the initial state
 * is with the most abstract {@link OntologyNode} fitting the expectations
 * (typically "object" or "person").
 * 
 * {@link #getOptions()} returns a set of more accurate ontology nodes that are
 * children of the current node. By calling {@link #with(String)} with one of
 * these nodes, the new state is that selected node. If tnat selected node is a
 * leaf node, the state is final and the process is done.
 * 
 * If with() is called with null it means "anders"/"other", which indicates the
 * answer is not in the node set. If that is selected:
 * <ul>
 * <li>user did not yet select anything else and we are at depth >1. Then we
 * decrease depth by 1.
 * <li>user previously selected a child or we are at depth 1. Then we select the
 * currently current node.
 * </ul>
 * immutable.
 */
public class OntologyAnswerState implements AnswerState {
        /**
         * Max nr of options given to the user to choose from
         */
        private static final int MAX_OPTIONS = 15;
        private static final String OTHER = "anders";
        private static final String IT = "het";

        private final String nodelabel;
        private final int depth;
        private final boolean isFocused;
        private final boolean isFinal;
        private final String nameOfObject;

        /**
         * 
         * @param qnodelabel the {@link OntologyNode} that needs to be more precise.
         * @param depth      the depth at which the options are selected. 1 means
         *                   direct children, 2 means children of the children, etc.
         *                   This can be shallower than the maximum depth if user
         *                   selects "other" indicating his choice is not in the
         *                   exact list.
         * @param isFocused  true iff the user made a focusing step - he selected
         *                   something else than "other" at some point.
         * @param isfinal    true iff this is a final state where the user made his
         *                   choice. This can be either due to selecting a leaf
         *                   node, or due to selecting other and then again the same
         *                   subtype, and therefore has to be recorded separately.
         * @pram nameOfObject a name of the object, to make the question to the user
         *       more specific which is especially relevant if this is part of a
         *       breath-first and the user entered some name or so some time before.
         *       If null, "het" ("it") is used.
         */

        @JsonCreator
        public OntologyAnswerState(@JsonProperty("nodelabel") String qnodelabel,
                        @JsonProperty("depth") int depth,
                        @JsonProperty("isFocused") boolean isFocused,
                        @JsonProperty("isFinal") boolean isfinal,
                        @JsonProperty("nameOfObject") String nameOfObject) {
                if (qnodelabel == null) {
                        throw new IllegalArgumentException("node must be not null");
                }
                this.nodelabel = qnodelabel;
                this.depth = depth;
                this.isFinal = isfinal;
                this.isFocused = isFocused;
                this.nameOfObject = nameOfObject == null ? IT : nameOfObject;
        }

        /**
         * Convenience constructor that sets depth to maximum for initial state.
         * 
         * @param qnode the node to create a new AnswerState for. This is initially
         *              the most abstract OntologyNode that fits the range of
         *              possibilities, eg #Persoon. The answer process gradually
         *              focuses on more detailed children of this node, and qnode
         *              will then change to this more detailed choice.
         * 
         *              The depth is set to the maximum possible depth with
         *              {@link #MAX_OPTIONS} answers.
         * @pram nameOfObject a name of the object, to make the question to the user
         *       more specific which is especially relevant if this is part of a
         *       breath-first and the user entered some name or so some time before.
         *       If null, "het" ("it") is used.
         */
        public OntologyAnswerState(OntologyNode qnode, String nameOfObject) {
                this(qnode.getLabel(), maximumDepth(qnode), false, false, nameOfObject);
        }

        @Override
        public QuestionType getOptions(
                        Tree<String, Collection<Property>, OntologyNode> tree) {
                if (isFinal)
                        return null;
                OntologyNode node = tree.get(nodelabel);
                List<String> optionstrings = node.getChildren(depth).stream()
                                .map(child -> child.getLabel()).collect(Collectors.toList());
                optionstrings.add(OTHER);
                String optionstring = optionstrings.toString().replace("[", "{")
                                .replace("]", "}");

                return new SelectFromList(
                                "Kan U " + (isFocused ? "nog specifieker " : "")
                                                + "aangeven: wat voor soort " + nodelabel + " was "
                                                + nameOfObject + "? " + optionstring,
                                optionstrings, node.getLabel());
        }

        @Override
        public OntologyAnswerState with(String answer,
                        Tree<String, Collection<Property>, OntologyNode> tree) {
                if (OTHER.equals(answer)) {
                        return with((OntologyNode) null, tree);
                }
                OntologyNode root = tree.get(nodelabel);

                Optional<OntologyNode> selection = root.getChildren(depth).stream()
                                .filter(node -> answer.equals(node.getLabel())).findFirst();
                if (!selection.isPresent()) {
                        throw new IllegalArgumentException(
                                        "Antwoord " + answer + " is geen optie");
                }
                return with(selection.get(), tree);

        }

        /**
         * 
         * @param choice the {@link OntologyAnswerState} state that advances this to
         *               the next state. If null, it means the user could not make a
         *               choice ("other"). <br>
         *               The returned state is created as follows.
         *               <ol>
         *               <li>if choice=null:
         *               <ol>
         *               <li>if parent=null: new state = this and is final.
         *               <li>else new state = parent, depth =1
         *               </ol>
         * 
         *               <li>if choice is a leaf node: new state=choice and is final
         *               <li>if choice=node we just came from : new state=choice and
         *               final.
         *               <li>else new state = choice, depth = maximum with 15-node
         *               limit
         *               </ol>
         * @return new {@link OntologyAnswerState} reflecting that the choice was
         *         made. The explanation is cleared, assuming that the user has read
         *         and understood the explanation after he gave an answer.
         * @throws IllegalStateException if {@link #isFinal()}
         */
        public OntologyAnswerState with(OntologyNode choice,
                        Tree<String, Collection<Property>, OntologyNode> tree) {
                if (isFinal) {
                        throw new IllegalStateException("state is final");
                }
                OntologyNode node = tree.get(nodelabel);
                if (choice == null) {
                        if (depth <= 1 || isFocused) {
                                // take the current node as answer
                                return new OntologyAnswerState(nodelabel, depth, isFocused,
                                                true, nameOfObject);
                        }
                        // zoom out
                        return new OntologyAnswerState(nodelabel, depth - 1, false, false,
                                        nameOfObject);
                }

                // if choice has no children then this choice is also final.
                return new OntologyAnswerState(choice.getLabel(), depth, true,
                                choice.getChildren().isEmpty(), nameOfObject);
        }

        /**
         * @return the specific node label that was reached at this point.
         */
        public String getNode() {
                return nodelabel;
        }

        /**
         * 
         * @return the depth at which the options are selected. This can be
         *         shallower than the maximum depth, indicating we are restricting
         *         the user's answer options to non-leaf (more abstract) nodes.
         */
        public int getDepth() {
                return depth;
        }

        @Override
        public String toString() {
                return "OntologyAnswerState[" + nodelabel + "," + isFocused + ","
                                + depth + "," + isFinal + "," + nameOfObject + "]";
        }

        /**
         * @return the maximum depth achievable with at most MAX_ANSWERS. Assumes
         *         depth 1 and 2 exist and that #children <MAX_ANSWERS at depth 1.
         */
        private static int maximumDepth(OntologyNode node) {
                List<OntologyNode> nodes = node.getChildren(1);
                // assume at least 1 more child per depth step to put some upper limit
                // invariant: up to given depth, there are less than MAX_OPTIONS
                for (int depth = 1; depth < MAX_OPTIONS; depth++) {
                        List<OntologyNode> newnodes = node.getChildren(depth + 1);
                        // equals if we are effectively at the bottom of the tree.
                        if (newnodes.size() > MAX_OPTIONS || newnodes.equals(nodes))
                                return depth;
                        nodes = newnodes;
                }
                return MAX_OPTIONS;
        }

        @Override
        public int hashCode() {
                final int prime = 31;
                int result = 1;
                result = prime * result + depth;
                result = prime * result + (isFinal ? 1231 : 1237);
                result = prime * result + (isFocused ? 1231 : 1237);
                result = prime * result
                                + ((nameOfObject == null) ? 0 : nameOfObject.hashCode());
                result = prime * result
                                + ((nodelabel == null) ? 0 : nodelabel.hashCode());
                return result;
        }

        @Override
        public boolean equals(Object obj) {
                if (this == obj)
                        return true;
                if (obj == null)
                        return false;
                if (getClass() != obj.getClass())
                        return false;
                OntologyAnswerState other = (OntologyAnswerState) obj;
                if (depth != other.depth)
                        return false;
                if (isFinal != other.isFinal)
                        return false;
                if (isFocused != other.isFocused)
                        return false;
                if (nameOfObject == null) {
                        if (other.nameOfObject != null)
                                return false;
                } else if (!nameOfObject.equals(other.nameOfObject))
                        return false;
                if (nodelabel == null) {
                        if (other.nodelabel != null)
                                return false;
                } else if (!nodelabel.equals(other.nodelabel))
                        return false;
                return true;
        }

}