//   Copyright 2012 Georg-August-Universität Göttingen, Germany
//
//   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 de.ugoe.cs.autoquest.usability.evaluation.rule.evaluator;

import static de.ugoe.cs.autoquest.usability.tasktree.filter.EventTypeFilter.TEXT_INPUT;

import com.google.common.base.Optional;
import com.google.common.base.Predicate;
import com.google.common.collect.Iterables;

import de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskTree;
import de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskTreeNode;
import de.ugoe.cs.autoquest.usability.evaluation.result.UsabilityDefectSeverityLevel;
import de.ugoe.cs.autoquest.usability.evaluation.rule.set.UsabilityRule;
import de.ugoe.cs.autoquest.usability.tasktree.filter.FilterStatistic;
import de.ugoe.cs.autoquest.usability.tasktree.filter.IterativeDFSFilterStrategy;
import de.ugoe.cs.autoquest.usability.tasktree.filter.TaskTreeFilter;

/**
 * <p>
 * TODO comment
 * </p>
 * 
 * @author Alexander Deicke
 */
public class TextInputRatioEvaluator extends RuleEvaluator {

    public TextInputRatioEvaluator(UsabilityRule evaluatedUsabilityRule, ITaskTree taskTree) {
        super(evaluatedUsabilityRule, taskTree);
    }

    @Override
    protected FilterStatistic nodesUnderEvaluation(ITaskTree taskTree) {
        Optional<FilterStatistic> cachedNodes = loadFromCache(TEXT_INPUT);
        return cachedNodes.isPresent() ? cachedNodes.get() : cacheAndReturnNodes(taskTree,
                                                                                 TEXT_INPUT);
    }

    @Override
    protected FilterStatistic extractNodesFromTaskTree(ITaskTree taskTree) {
        return new TaskTreeFilter(new IterativeDFSFilterStrategy()).filterByEventType(TEXT_INPUT)
            .from(taskTree);
    }

    @Override
    protected float calculateEvaluationMetric() {
        float textInputEvents = this.filteredNodes.nrOfNodesMatchedFilter();
        float nonTextInputEvents = nrOfEventNodesNotMatchedFilter();
        return textInputEvents / (textInputEvents + nonTextInputEvents);
    }

    private int nrOfEventNodesNotMatchedFilter() {
        return Iterables.size(Iterables.filter(this.filteredNodes.nodesNotMatchedFilter(),
                                               new Predicate<ITaskTreeNode>() {

                                                   @Override
                                                   public boolean apply(ITaskTreeNode node) {
                                                       return (node.getChildren() == null) ||
                                                           (node.getChildren().size() == 0);
                                                   }
                                               }));
    }

    @Override
    protected Optional<UsabilityDefectSeverityLevel> determineSeverityLevel(float evaluationMetric)
    {
        Optional<UsabilityDefectSeverityLevel> recommendationSeverityLevel = Optional.absent();
        if (evaluationMetric > 0.9) {
            recommendationSeverityLevel = Optional.of(UsabilityDefectSeverityLevel.HIGH);
        }
        else if (evaluationMetric > 0.7) {
            recommendationSeverityLevel = Optional.of(UsabilityDefectSeverityLevel.MEDIUM);
        }
        else if (evaluationMetric > 0.5) {
            recommendationSeverityLevel = Optional.of(UsabilityDefectSeverityLevel.LOW);
        }
        else if (evaluationMetric > 0.3) {
            recommendationSeverityLevel = Optional.of(UsabilityDefectSeverityLevel.INFO);
        }
        return recommendationSeverityLevel;
    }

}