package net.i2p.router.web;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.Reader;

import net.i2p.data.DataHelper;
import net.i2p.router.RouterContext;
import net.i2p.router.update.ConsoleUpdateManager;
import static net.i2p.update.UpdateType.*;

/**
 *  If news file does not exist, use file from the initialNews directory
 *  in $I2P
 *
 *  @since 0.8.2
 */
public class NewsHelper extends ContentHelper {
    
    public static final String PROP_LAST_UPDATE_TIME = "router.updateLastDownloaded";
    /** @since 0.8.12 */
    private static final String PROP_LAST_HIDDEN = "routerconsole.newsLastHidden";
    /** @since 0.9.4 */
    public static final String PROP_LAST_CHECKED = "routerconsole.newsLastChecked";
    /** @since 0.9.4 */
    public static final String PROP_LAST_UPDATED = "routerconsole.newsLastUpdated";
    /** @since 0.9.55 */
    public static final String PROP_LAST_NEW_ENTRY = "routerconsole.newsLastNewEntry";
    /** @since 0.9.62 */
    public static final String PROP_LAST_LANG = "routerconsole.newsLastLanguage";
    /**
     * Default true
     * @since 0.9.21
     */
    public static final String PROP_TRANSLATE = "routerconsole.newsTranslate";
    public static final String NEWS_FILE = "docs/news.xml";

    /**
     *  If ANY update is in progress.
     *  @since 0.9.4 was stored in system properties
     */
    public static boolean isAnyUpdateInProgress() {
        ConsoleUpdateManager mgr = ConsoleUpdateManager.getInstance();
        if (mgr == null) return false;
        return mgr.isUpdateInProgress();
    }

    /**
     *  If a signed or unsigned router update is in progress.
     *  Does NOT cover plugins, news, etc.
     *  @since 0.9.4 was stored in system properties
     */
    public static boolean isUpdateInProgress() {
        ConsoleUpdateManager mgr = ConsoleUpdateManager.getInstance();
        if (mgr == null) return false;
        return mgr.isUpdateInProgress(ROUTER_SIGNED) ||
               mgr.isUpdateInProgress(ROUTER_SIGNED_SU3) ||
               mgr.isUpdateInProgress(ROUTER_UNSIGNED) ||
               mgr.isUpdateInProgress(ROUTER_DEV_SU3) ||
               mgr.isUpdateInProgress(TYPE_DUMMY);
    }

    /**
     *  Release update only.
     *  Will be false if already downloaded.
     *  @since 0.9.4 moved from NewsFetcher
     */
    public static boolean isUpdateAvailable() {
        ConsoleUpdateManager mgr = ConsoleUpdateManager.getInstance();
        if (mgr == null) return false;
        return mgr.getUpdateAvailable(ROUTER_SIGNED) != null ||
               mgr.getUpdateAvailable(ROUTER_SIGNED_SU3) != null;
    }

    /**
     *  A router update had been downloaded and handled by an UpdatePostProcessor.
     *  It will provide wrapper-like function to install the update and restart after shutdown.
     *
     *  @since 0.9.51
     */
    public static boolean isExternalRestartPending() {
        ConsoleUpdateManager mgr = ConsoleUpdateManager.getInstance();
        if (mgr == null) return false;
        return mgr.isExternalRestartPending();
    }

    /**
     *  Release update only.
     *  Available version, will be null if already downloaded.
     *  @return null if none
     *  @since 0.9.4 moved from NewsFetcher
     */
    public static String updateVersion() {
        ConsoleUpdateManager mgr = ConsoleUpdateManager.getInstance();
        if (mgr == null) return null;
        String rv = mgr.getUpdateAvailable(ROUTER_SIGNED_SU3);
        if (rv != null)
            return rv;
        return mgr.getUpdateAvailable(ROUTER_SIGNED);
    }

    /**
     *  Release update only.
     *  Translated message about new version available but constrained
     *  @return null if none
     *  @since 0.9.9
     */
    public static String updateConstraint() {
        ConsoleUpdateManager mgr = ConsoleUpdateManager.getInstance();
        if (mgr == null) return null;
        return mgr.getUpdateConstraint(ROUTER_SIGNED, "");
    }

    /**
     *  Translated message about new version available but constrained
     *  @return null if none
     *  @since 0.9.23
     */
    public static String unsignedUpdateConstraint() {
        ConsoleUpdateManager mgr = ConsoleUpdateManager.getInstance();
        if (mgr == null) return null;
        return mgr.getUpdateConstraint(ROUTER_UNSIGNED, "");
    }

    /**
     *  Translated message about new version available but constrained
     *  @return null if none
     *  @since 0.9.23
     */
    public static String devSU3UpdateConstraint() {
        ConsoleUpdateManager mgr = ConsoleUpdateManager.getInstance();
        if (mgr == null) return null;
        return mgr.getUpdateConstraint(ROUTER_DEV_SU3, "");
    }

    /**
     *  Release update only.
     *  Already downloaded but not installed version.
     *  @return null if none
     *  @since 0.9.4
     */
    public static String updateVersionDownloaded() {
        ConsoleUpdateManager mgr = ConsoleUpdateManager.getInstance();
        if (mgr == null) return null;
        String rv = mgr.getUpdateDownloaded(ROUTER_SIGNED_SU3);
        if (rv != null)
            return rv;
        return mgr.getUpdateDownloaded(ROUTER_SIGNED);
    }

    /**
     *  Will be false if already downloaded or if dev update disabled.
     *  @since 0.9.4 moved from NewsFetcher
     */
    public static boolean isUnsignedUpdateAvailable(RouterContext ctx) {
        ConsoleUpdateManager mgr = ConsoleUpdateManager.getInstance();
        if (mgr == null) return false;
        return mgr.getUpdateAvailable(ROUTER_UNSIGNED) != null &&
               ctx.getBooleanProperty(ConfigUpdateHandler.PROP_UPDATE_UNSIGNED);
    }

    /**
     *  @return null if none
     *  @since 0.9.4 moved from NewsFetcher
     */
    public static String unsignedUpdateVersion() {
        ConsoleUpdateManager mgr = ConsoleUpdateManager.getInstance();
        if (mgr == null) return null;
        return formatUnsignedVersion(mgr.getUpdateAvailable(ROUTER_UNSIGNED));
    }

    /**
     *  Already downloaded but not installed version
     *  @return null if none
     *  @since 0.9.4
     */
    public static String unsignedVersionDownloaded() {
        ConsoleUpdateManager mgr = ConsoleUpdateManager.getInstance();
        if (mgr == null) return null;
        return formatUnsignedVersion(mgr.getUpdateDownloaded(ROUTER_UNSIGNED));
    }

    /**
     *  Will be false if already downloaded or if dev update disabled.
     *  @since 0.9.20
     */
    public static boolean isDevSU3UpdateAvailable(RouterContext ctx) {
        ConsoleUpdateManager mgr = ConsoleUpdateManager.getInstance();
        if (mgr == null) return false;
        return mgr.getUpdateAvailable(ROUTER_DEV_SU3) != null &&
               ctx.getBooleanProperty(ConfigUpdateHandler.PROP_UPDATE_DEV_SU3);
    }

    /**
     *  @return null if none
     *  @since 0.9.20
     */
    public static String devSU3UpdateVersion() {
        ConsoleUpdateManager mgr = ConsoleUpdateManager.getInstance();
        if (mgr == null) return null;
        return mgr.getUpdateAvailable(ROUTER_DEV_SU3);
    }

    /**
     *  Already downloaded but not installed version
     *  @return null if none
     *  @since 0.9.20
     */
    public static String devSU3VersionDownloaded() {
        ConsoleUpdateManager mgr = ConsoleUpdateManager.getInstance();
        if (mgr == null) return null;
        return mgr.getUpdateDownloaded(ROUTER_DEV_SU3);
    }

    /**
     *  Convert long date stamp to
     *  date/time in the system locale, local time zone
     *  @return null if ver = null
     *  @since 0.9.4 moved from NewsFetcher
     */
    private static String formatUnsignedVersion(String ver) {
        if (ver != null) {
            try {
                long modtime = Long.parseLong(ver);
                return DataHelper.formatTime(modtime);
            } catch (NumberFormatException nfe) {}
        }
        return null;
    }

    /**
     *  @return "" if none
     *  @since 0.9.4 moved from UpdateHelper
     */
    public static String getUpdateStatus() {
        ConsoleUpdateManager mgr = ConsoleUpdateManager.getInstance();
        if (mgr == null) return "";
        return mgr.getStatus();
    }

    /**
     *  If we haven't downloaded news yet, use the translated initial news file
     */
    @Override
    public String getContent() {
        // show a min of 1, max of 3, none older than 60 days over min
        return NewsFeedHelper.getEntries(_context, 0, 3, 60*24*60*60*1000L);
    }

    /**
     *  Is the news newer than the last time it was hidden?
     *  @since 0.8.12
     */
    public boolean shouldShowNews() {
        return shouldShowNews(_context);
    }

    /**
     *  @since 0.9.4
     */
    public static boolean shouldShowNews(RouterContext ctx) {
        long lastUpdated = lastNewEntry(ctx);
        if (lastUpdated <= 0)
            return true;
        long last = ctx.getProperty(PROP_LAST_HIDDEN, 0L);
        return lastUpdated > last;
    }

    /**
     *  Save config with the timestamp of the current news to hide, or 0 to show
     *  @since 0.8.12
     */
    public void showNews(boolean yes) {
        showNews(_context, yes);
    }

    /**
     *  Save config with the timestamp of the current news to hide, or 0 to show
     *  @since 0.9.4
     */
    public static void showNews(RouterContext ctx, boolean yes) {
        long stamp = yes ? 0 : lastNewEntry(ctx);
        ctx.router().saveConfig(PROP_LAST_HIDDEN, Long.toString(stamp));
    }

    /**
     *  @return HTML
     *  @since 0.9.4 moved from NewsFetcher
     */
    public String status() {
        return status(_context);
    }

    /**
     *  @return HTML
     *  @since 0.9.4 moved from NewsFetcher
     */
    public static String status(RouterContext ctx) {
         StringBuilder buf = new StringBuilder(128);
         long now = ctx.clock().now();
         buf.append("<span id=\"newsStatus\"><i>");
         long lastUpdated = lastUpdated(ctx);
         long lastFetch = lastChecked(ctx);
         if (lastUpdated > 0) {
             buf.append(Messages.getString("News last updated {0} ago.",
                                           DataHelper.formatDuration2(now - lastUpdated),
                                           ctx))
                .append('\n');
         }
         if (lastFetch > lastUpdated) {
             buf.append(Messages.getString("News last checked {0} ago.",
                                           DataHelper.formatDuration2(now - lastFetch),
                                           ctx));
         }
         buf.append("</i></span><span id=\"newsDisplay\">");
         String consoleNonce = CSSHelper.getNonce();
         if (lastUpdated > 0 && consoleNonce != null) {
             if (shouldShowNews(ctx)) {
                 buf.append(" <a href=\"/?news=0&amp;consoleNonce=").append(consoleNonce).append("\">")
                    .append(Messages.getString("Hide news", ctx));
             } else {
                 buf.append(" <a href=\"/?news=1&amp;consoleNonce=").append(consoleNonce).append("\">")
                    .append(Messages.getString("Show news", ctx));
             }
             buf.append("</a>" +
                        " | <a href=\"/news\">")
                .append(Messages.getString("Show all news", ctx))
                .append("</a></span>");
         }
         return buf.toString();
    }
    
    /**
     *  @since 0.9.4 moved from NewsFetcher
     */
    public static boolean dontInstall(RouterContext ctx) {
        return isUpdateDisabled(ctx) || isBaseReadonly(ctx);
    }
    
    /**
     *  @since 0.9.9
     */
    public static boolean isUpdateDisabled(RouterContext ctx) {
        return ctx.getBooleanProperty(ConfigUpdateHandler.PROP_UPDATE_DISABLED);
    }
    
    /**
     *  @since 0.9.9
     */
    public static boolean isBaseReadonly(RouterContext ctx) {
        File test = new File(ctx.getBaseDir(), "history.txt");
        boolean readonly = ((test.exists() && !test.canWrite()) || (!ctx.getBaseDir().canWrite()));
        return readonly;
    }

    /**
     *  @since 0.9.4
     */
    public static long lastChecked(RouterContext ctx) {
        return ctx.getProperty(PROP_LAST_CHECKED, 0L);
    }

    /**
     *  When the news was last downloaded
     *  @since 0.9.4
     */
    public static long lastUpdated(RouterContext ctx) {
        long rv = ctx.getProperty(PROP_LAST_UPDATED, 0L);
        if (rv > 0)
            return rv;
        File newsFile = new File(ctx.getRouterDir(), NEWS_FILE);
        rv = newsFile.lastModified();
        ctx.router().saveConfig(PROP_LAST_UPDATED, Long.toString(rv));
        return rv;
    }

    /**
     *  When we last got a new news entry
     *  @since 0.9.55
     */
    private static long lastNewEntry(RouterContext ctx) {
        long rv = ctx.getProperty(PROP_LAST_NEW_ENTRY, 0L);
        if (rv > 0)
            return rv;
        rv = lastUpdated(ctx);
        ctx.router().saveConfig(PROP_LAST_NEW_ENTRY, Long.toString(rv));
        return rv;
    }
}
