package net.i2p.router.web;

import java.io.File;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.List;
import java.util.StringTokenizer;

import net.i2p.I2PAppContext;
import net.i2p.crypto.TrustedUpdate;
import net.i2p.data.DataHelper;
import net.i2p.router.Router;
import net.i2p.router.RouterContext;
import net.i2p.router.RouterVersion;
import net.i2p.util.EepGet;
import net.i2p.util.I2PAppThread;
import net.i2p.util.Log;

/**
 * <p>Handles the request to update the router by firing off an
 * {@link net.i2p.util.EepGet} call to download the latest signed update file
 * and displaying the status to anyone who asks.
 * </p>
 * <p>After the download completes the signed update file is verified with
 * {@link net.i2p.crypto.TrustedUpdate}, and if it's authentic the payload
 * of the signed update file is unpacked and the router is restarted to complete
 * the update process.
 * </p>
 */
public class UpdateHandler {
    protected static UpdateRunner _updateRunner;
    protected RouterContext _context;
    protected Log _log;
    protected String _updateFile;
    private static String _status = "";
    private String _action;
    private String _nonce;
    
    protected static final String SIGNED_UPDATE_FILE = "i2pupdate.sud";
    static final String PROP_UPDATE_IN_PROGRESS = "net.i2p.router.web.UpdateHandler.updateInProgress";
    protected static final String PROP_LAST_UPDATE_TIME = "router.updateLastDownloaded";

    public UpdateHandler() {
        this(ContextHelper.getContext(null));
    }
    public UpdateHandler(RouterContext ctx) {
        _context = ctx;
        _log = ctx.logManager().getLog(UpdateHandler.class);
        _updateFile = (new File(ctx.getRouterDir(), SIGNED_UPDATE_FILE)).getAbsolutePath();
    }
    
    /**
     * Configure this bean to query a particular router context
     *
     * @param contextId beginning few characters of the routerHash, or null to pick
     *                  the first one we come across.
     */
    public void setContextId(String contextId) {
        try {
            _context = ContextHelper.getContext(contextId);
            _log = _context.logManager().getLog(UpdateHandler.class);
        } catch (Throwable t) {
            t.printStackTrace();
        }
    }
    
    /** these two can be set in either order, so call checkUpdateAction() twice */
    public void setUpdateAction(String val) {
        _action = val;
        checkUpdateAction();
    }
    
    public void setUpdateNonce(String nonce) { 
        _nonce = nonce;
        checkUpdateAction();
    }

    private void checkUpdateAction() { 
        if (_nonce == null || _action == null) return;
        if (_nonce.equals(System.getProperty("net.i2p.router.web.UpdateHandler.nonce")) ||
            _nonce.equals(System.getProperty("net.i2p.router.web.UpdateHandler.noncePrev"))) {
            if (_action.contains("Unsigned")) {
                // Not us, have NewsFetcher instantiate the correct class.
                NewsFetcher fetcher = NewsFetcher.getInstance(_context);
                fetcher.fetchUnsigned();
            } else {
                update();
            }
        }
    }

    public void update() {
        // don't block waiting for the other one to finish
        if ("true".equals(System.getProperty(PROP_UPDATE_IN_PROGRESS))) {
            _log.error("Update already running");
            return;
        }
        synchronized (UpdateHandler.class) {
            if (_updateRunner == null)
                _updateRunner = new UpdateRunner();
            if (_updateRunner.isRunning()) {
                return;
            } else {
                System.setProperty(PROP_UPDATE_IN_PROGRESS, "true");
                I2PAppThread update = new I2PAppThread(_updateRunner, "SignedUpdate");
                update.start();
            }
        }
    }
    
    public static String getStatus() {
        return _status;
    }
    
    public boolean isDone() {
        return false;
        // this needs to be fixed and tested
        //if(this._updateRunner == null)
        //    return true;
        //return this._updateRunner.isDone();
    }
    
    public class UpdateRunner implements Runnable, EepGet.StatusListener {
        protected boolean _isRunning;
        protected boolean done;
        protected EepGet _get;
        protected final DecimalFormat _pct = new DecimalFormat("0.0%");

        public UpdateRunner() { 
            _isRunning = false;
            this.done = false;
            updateStatus("<b>" + _("Updating") + "</b>");
        }
        public boolean isRunning() { return _isRunning; }
        public boolean isDone() {
            return this.done;
        }
        public void run() {
            _isRunning = true;
            update();
            System.setProperty(PROP_UPDATE_IN_PROGRESS, "false");
            _isRunning = false;
        }
        protected void update() {
            updateStatus("<b>" + _("Updating") + "</b>");
            // TODO:
            // Do a PartialEepGet on the selected URL, check for version we expect,
            // and loop if it isn't what we want.
            // This will allow us to do a release without waiting for the last host to install the update.
            // Alternative: In bytesTransferred(), Check the data in the output file after
            // we've received at least 56 bytes. Need a cancel() method in EepGet ?
            String updateURL = selectUpdateURL();
            if (_log.shouldLog(Log.DEBUG))
                _log.debug("Selected update URL: " + updateURL);
            boolean shouldProxy = Boolean.valueOf(_context.getProperty(ConfigUpdateHandler.PROP_SHOULD_PROXY, ConfigUpdateHandler.DEFAULT_SHOULD_PROXY)).booleanValue();
            String proxyHost = _context.getProperty(ConfigUpdateHandler.PROP_PROXY_HOST, ConfigUpdateHandler.DEFAULT_PROXY_HOST);
            int proxyPort = _context.getProperty(ConfigUpdateHandler.PROP_PROXY_PORT, ConfigUpdateHandler.DEFAULT_PROXY_PORT_INT);
            try {
                if (shouldProxy)
                    // 40 retries!!
                    _get = new EepGet(_context, proxyHost, proxyPort, 40, _updateFile, updateURL, false);
                else
                    _get = new EepGet(_context, 1, _updateFile, updateURL, false);
                _get.addStatusListener(UpdateRunner.this);
                _get.fetch();
            } catch (Throwable t) {
                _log.error("Error updating", t);
            }
        }
        
        public void attemptFailed(String url, long bytesTransferred, long bytesRemaining, int currentAttempt, int numRetries, Exception cause) {
            if (_log.shouldLog(Log.DEBUG))
                _log.debug("Attempt failed on " + url, cause);
            // ignored
        }
        public void bytesTransferred(long alreadyTransferred, int currentWrite, long bytesTransferred, long bytesRemaining, String url) {
            StringBuilder buf = new StringBuilder(64);
            buf.append("<b>").append(_("Updating")).append("</b> ");
            double pct = ((double)alreadyTransferred + (double)currentWrite) /
                         ((double)alreadyTransferred + (double)currentWrite + (double)bytesRemaining);
            synchronized (_pct) {
                buf.append(_pct.format(pct));
            }
            buf.append(":<br>\n");
            buf.append(_("{0}B transferred", DataHelper.formatSize2(currentWrite + alreadyTransferred)));
            updateStatus(buf.toString());
        }
        public void transferComplete(long alreadyTransferred, long bytesTransferred, long bytesRemaining, String url, String outputFile, boolean notModified) {
            updateStatus("<b>" + _("Update downloaded") + "</b>");
            TrustedUpdate up = new TrustedUpdate(_context);
            File f = new File(_updateFile);
            File to = new File(_context.getRouterDir(), Router.UPDATE_FILE);
            String err = up.migrateVerified(RouterVersion.VERSION, f, to);
            f.delete();
            if (err == null) {
                String policy = _context.getProperty(ConfigUpdateHandler.PROP_UPDATE_POLICY);
                this.done = true;
                // So unsigned update handler doesn't overwrite unless newer.
                String lastmod = _get.getLastModified();
                long modtime = 0;
                if (lastmod != null)
                    modtime = NewsFetcher.parse822Date(lastmod);
                if (modtime <= 0)
                    modtime = _context.clock().now();
                _context.router().setConfigSetting(PROP_LAST_UPDATE_TIME, "" + modtime);
                _context.router().saveConfig();
                if ("install".equals(policy)) {
                    _log.log(Log.CRIT, "Update was VERIFIED, restarting to install it");
                    updateStatus("<b>" + _("Update verified") + "</b><br>" + _("Restarting"));
                    restart();
                } else {
                    _log.log(Log.CRIT, "Update was VERIFIED, will be installed at next restart");
                    StringBuilder buf = new StringBuilder(64);
                    buf.append("<b>").append(_("Update downloaded")).append("<br>");
                    if (System.getProperty("wrapper.version") != null)
                        buf.append(_("Click Restart to install"));
                    else
                        buf.append(_("Click Shutdown and restart to install"));
                    if (up.newVersion() != null)
                        buf.append(' ').append(_("Version {0}", up.newVersion()));
                    buf.append("</b>");
                    updateStatus(buf.toString());
                }
            } else {
                _log.log(Log.CRIT, err + " from " + url);
                updateStatus("<b>" + err + ' ' + _("from {0}", url) + " </b>");
            }
        }
        public void transferFailed(String url, long bytesTransferred, long bytesRemaining, int currentAttempt) {
            // don't display bytesTransferred as it is meaningless
            _log.log(Log.CRIT, "Update from " + url + " did not download completely (" +
                               bytesRemaining + " remaining after " + currentAttempt + " tries)");

            updateStatus("<b>" + _("Transfer failed") + "</b>");
        }
        public void headerReceived(String url, int attemptNum, String key, String val) {}
        public void attempting(String url) {}
    }
    
    protected void restart() {
        _context.addShutdownTask(new ConfigServiceHandler.UpdateWrapperManagerTask(Router.EXIT_GRACEFUL_RESTART));
        _context.router().shutdownGracefully(Router.EXIT_GRACEFUL_RESTART);
    }

    private String selectUpdateURL() {
        String URLs = _context.getProperty(ConfigUpdateHandler.PROP_UPDATE_URL, ConfigUpdateHandler.DEFAULT_UPDATE_URL);
        StringTokenizer tok = new StringTokenizer(URLs, " ,\r\n");
        List URLList = new ArrayList();
        while (tok.hasMoreTokens())
            URLList.add(tok.nextToken().trim());
        int size = URLList.size();
        //_log.log(Log.DEBUG, "Picking update source from " + size + " candidates.");
        if (size <= 0) {
            _log.log(Log.CRIT, "Update source list is empty - cannot download update");
            return null;
        }
        int index = I2PAppContext.getGlobalContext().random().nextInt(size);
        _log.log(Log.DEBUG, "Picked update source " + index + ".");
        return (String) URLList.get(index);
    }
    
    protected void updateStatus(String s) {
        _status = s;
    }

    /** translate a string */
    protected String _(String s) {
        return Messages.getString(s, _context);
    }

    /**
     *  translate a string with a parameter
     *  This is a lot more expensive than _(s), so use sparingly.
     *
     *  @param s string to be translated containing {0}
     *    The {0} will be replaced by the parameter.
     *    Single quotes must be doubled, i.e. ' -> '' in the string.
     *  @param o parameter, not translated.
     *    To tranlslate parameter also, use _("foo {0} bar", _("baz"))
     *    Do not double the single quotes in the parameter.
     *    Use autoboxing to call with ints, longs, floats, etc.
     */
    protected String _(String s, Object o) {
        return Messages.getString(s, o, _context);
    }

}