package com.oracle.avatar.util;

import java.io.IOException;
import java.net.URL;
import java.net.URLConnection;

import jdk.nashorn.internal.runtime.Source;

/**
 * A map that supports {@link Class} storage and lookup by either {@link URL} or {@link Source}.
 * @author Bryan Atsatt. Copyright (c) 2013 <a href="http://oracle.com">Oracle</a>.
 * @since 7/29/13
 */
public interface ClassMap {

    /**
     * A ClassMap entry.
     */
    public static class Entry {
        private final Source src;
        private final Class cls;
        private final long last;

        /**
         * Constructor.
         * @param source The {@link Source}.
         * @param cls The {@link Class};
         */
        Entry(final Source source, final Class cls) {
            this.src = source;
            this.cls = cls;
            final URL u = source.getURL();
            long lastMod = -1;
            if (u != null) {
                final URLConnection c = connectionFor(u);
                if (c != null) {
                    lastMod = c.getLastModified();
                }
            }
            this.last = lastMod;
        }

        /**
         * Test if this entry represents the same content
         * as that of the specified {@code URL}. The default
         * implementation compares only content length and
         * last modified time, not the actual content.
         * @param other The {@code URL} to compare against.
         * @return {@code true} if equivalent.
         */
        public boolean equals(final URL other) {
            final URL ours = src.getURL();
            if (ours != null && other != null) {
                if (ours == other) {
                    return true;
                } else if (ours.sameFile(other)) {
                    final URLConnection otherConn = connectionFor(other);
                    if (otherConn != null) {
                        if (src.getLength() == otherConn.getContentLength()) {
                            if (last == otherConn.getLastModified()) {
                                return true;
                            }
                        }
                    }
                }
            }
            return false;
        }

        /**
         * Returns the {@code URL}.
         * @return the URL, or {@code null} if none.
         */
        public URL toURL() {
            return src.getURL();
        }

        /**
         * Returns the {@link Source}.
         * @return The source.
         */
        public Source toSource() {
            return src;
        }

        /**
         * Returns the {@link Source}.
         * @return The source.
         */
        public Class toClass() {
            return cls;
        }

        private static URLConnection connectionFor(URL url) {
            try {
                return url.openConnection();
            } catch (IOException e) {
                return null;
            }
        }
    }

    /**
     * Lookup an entry by {@code URL}.
     * @param key The url.
     * @return The entry or {@code null} if not found.
     */
    public Entry get(final URL key);

    /**
     * Lookup an entry by {@link Source}.
     * @param key The source.
     * @return The entry or {@code null} if none.
     */
    public Entry get(final Source key);

    /**
     * Add an entry.
     * @param source The {@link Source}.
     * @param cls The {@link Class};
     * @return Any previous {@link Entry}.
     */
    public Entry put(final Source source, final Class cls);

    /**
     * Return the current size.
     * @return The size.
     */
    public int size();
}