/**
 * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
 */

package net.sourceforge.pmd.lang.symboltable;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 * Base class for any {@link Scope}. Provides useful default implementations.
 */
public abstract class AbstractScope implements Scope {

    private Scope parent;
    /** Stores the name declaration already sorted by class. */
    private Map<Class<? extends NameDeclaration>, Map<NameDeclaration, List<NameOccurrence>>> nameDeclarations = new LinkedHashMap<>();

    @Override
    public Scope getParent() {
        return parent;
    }

    @Override
    public void setParent(Scope parent) {
        this.parent = parent;
    }

    @Override
    public Map<NameDeclaration, List<NameOccurrence>> getDeclarations() {
        Map<NameDeclaration, List<NameOccurrence>> result = new LinkedHashMap<>();
        for (Map<NameDeclaration, List<NameOccurrence>> e : nameDeclarations.values()) {
            result.putAll(e);
        }
        return result;
    }

    @Override
    public <T extends NameDeclaration> Map<T, List<NameOccurrence>> getDeclarations(Class<T> clazz) {
        @SuppressWarnings("unchecked")
        Map<T, List<NameOccurrence>> result = (Map<T, List<NameOccurrence>>) nameDeclarations.get(clazz);
        if (result == null) {
            result = Collections.emptyMap();
        }
        return result;
    }

    @Override
    public boolean contains(NameOccurrence occ) {
        for (NameDeclaration d : getDeclarations().keySet()) {
            if (d.getImage().equals(occ.getImage())) {
                return true;
            }
        }
        return false;
    }

    @Override
    public void addDeclaration(NameDeclaration declaration) {
        Map<NameDeclaration, List<NameOccurrence>> declarationsPerClass = nameDeclarations.get(declaration.getClass());
        if (declarationsPerClass == null) {
            declarationsPerClass = new LinkedHashMap<>();
            nameDeclarations.put(declaration.getClass(), declarationsPerClass);
        }
        declarationsPerClass.put(declaration, new ArrayList<NameOccurrence>());
    }

    @SuppressWarnings("unchecked")
    @Override
    public <T extends Scope> T getEnclosingScope(Class<T> clazz) {
        Scope current = this;
        while (current != null) {
            if (clazz.isAssignableFrom(current.getClass())) {
                return (T) current;
            }
            current = current.getParent();
        }
        return null;
    }

    @Override
    public Set<NameDeclaration> addNameOccurrence(NameOccurrence occurrence) {
        Set<NameDeclaration> result = new HashSet<>();
        for (Map.Entry<NameDeclaration, List<NameOccurrence>> e : getDeclarations().entrySet()) {
            if (e.getKey().getImage().equals(occurrence.getImage())) {
                result.add(e.getKey());
                e.getValue().add(occurrence);
            }
        }
        return result;
    }
}