package aQute.bnd.make.coverage;

import java.io.*;
import java.lang.reflect.*;
import java.util.*;

import aQute.lib.osgi.*;
import aQute.lib.osgi.Clazz.*;

/**
 * This class can create a coverage table between two classspaces. The
 * destination class space is used to create a table of methods. All source
 * methods that refer to a specific dest are then filled into the table.
 * 
 */
public class Coverage {

    /**
     * Create a cross reference table from source to dest.
     * 
     * @param source
     *            The methods that refer to dest
     * @param dest
     *            The methods that are being referred to
     * @return A mapping of source methods to destination methods.
     * @throws IOException
     */
    public static Map<MethodDef, List<MethodDef>> getCrossRef(
            Collection<Clazz> source, Collection<Clazz> dest)
            throws Exception {
        final Map<MethodDef, List<MethodDef>> catalog = buildCatalog(dest);
        crossRef(source, catalog);
        return catalog;
    }

    private static void crossRef(Collection<Clazz> source,
            final Map<MethodDef, List<MethodDef>> catalog) throws Exception {
        for (final Clazz clazz : source) {
            clazz.parseClassFileWithCollector(new ClassDataCollector() {
                MethodDef source;

                public void implementsInterfaces(String names[]) {
                    MethodDef def = new MethodDef(0, clazz.getFQN(),
                            "<implements>", "()V");
                    for (String interfaceName : names) {
                        interfaceName = Clazz.internalToFqn(interfaceName);
                        for (Map.Entry<MethodDef, List<MethodDef>> entry : catalog
                                .entrySet()) {
                            String catalogClass = entry.getKey().clazz;
                            List<MethodDef> references = entry.getValue();

                            if (catalogClass.equals(interfaceName)) {
                                references.add(def);
                            }
                        }
                    }
                }

                // Method definitions
                public void method(MethodDef source) {
                    this.source = source;
                }

                public void reference(MethodDef reference) {
                    List<MethodDef> references = catalog.get(reference);
                    if (references != null) {
                        references.add(source);
                    }
                }
            });
        }
    }

    private static Map<MethodDef, List<MethodDef>> buildCatalog(
            Collection<Clazz> sources) throws Exception {
        final Map<MethodDef, List<MethodDef>> catalog = new TreeMap<MethodDef, List<MethodDef>>();
        for (final Clazz clazz : sources) {
            clazz.parseClassFileWithCollector(new ClassDataCollector() {

                public boolean classStart(int access, String name) {
                    return clazz.isPublic();
                }

                public void method(MethodDef source) {
                    if (java.lang.reflect.Modifier.isPublic(source.access)
                            || Modifier.isProtected(source.access))
                        catalog.put(source, new ArrayList<MethodDef>());
                }

            });
        }
        return catalog;
    }

}