package tfm.arcs.pdg;

import org.jgrapht.io.Attribute;
import org.jgrapht.io.DefaultAttribute;
import tfm.arcs.Arc;
import tfm.graphs.pdg.PDG;
import tfm.graphs.sdg.SDG;

import java.util.Map;
import java.util.Objects;

/**
 * An arc used in the {@link PDG} and {@link SDG},
 * representing the declaration of some data linked to its usage (of that value).
 * There is data dependency between two nodes if and only if (1) the source <it>may</it>
 * declare a variable, (2) the destination <it>may</it> use it, and (3) there is a
 * path between the nodes where the variable is not redefined.
 */
public class DataDependencyArc extends Arc {
    private final String variable;

    public DataDependencyArc(String variable) {
        super();
        this.variable = variable;
    }

    @Override
    public String getLabel() {
        return variable;
    }

    @Override
    public Map<String, Attribute> getDotAttributes() {
        Map<String, Attribute> map = super.getDotAttributes();
        map.put("style", DefaultAttribute.createAttribute("dashed"));
        map.put("color", DefaultAttribute.createAttribute("red"));
        return map;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }

        if (!(o instanceof DataDependencyArc)) {
            return false;
        }

        DataDependencyArc other = (DataDependencyArc) o;

        return Objects.equals(variable, other.variable)
                && Objects.equals(getSource(), other.getSource())
                && Objects.equals(getTarget(), other.getTarget());
    }

    @Override
    public int hashCode() {
        return Objects.hash(variable, getSource(), getTarget());
    }
}