package edu.washington.cs.oneswarm.watchdir;

import java.io.File;
import java.io.FilenameFilter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.logging.Logger;

import org.gudy.azureus2.core3.util.Constants;

import edu.uw.cse.netlab.reputation.GloballyAwareOneHopUnchoker;

public class UpdatingFileTree {

    public static final long IDLE_THRESHOLD = 60 * 1000; // 1 minute without
                                                         // mods

    private static Logger logger = Logger.getLogger(UpdatingFileTree.class.getName());

    List<UpdatingFileTree> children = Collections
            .synchronizedList(new ArrayList<UpdatingFileTree>());
    File thisFile = null;
    long lastRefreshed = 0;
    boolean gone = false;
    private UpdatingFileTreeListener mSpawn;
    boolean mHasDirectoryChildren = false;
    String mRelativePath = null;

    public UpdatingFileTree(File root) {
        this(root, new UpdatingFileTreeListener() {
            public void broadcastChange(UpdatingFileTree path, boolean isDelete) {
            }
        }, Integer.MAX_VALUE);
    }

    public UpdatingFileTree(File root, UpdatingFileTreeListener spawn) {
        this(root, spawn, Integer.MAX_VALUE);
    }

    public UpdatingFileTree(File root, UpdatingFileTreeListener spawn, int maxDepth) {
        thisFile = root;

        mSpawn = spawn;

        lastRefreshed = thisFile.lastModified();

        if (thisFile.isDirectory()) {
            File[] files = thisFile.listFiles(new FilenameFilter() {
                public boolean accept(File dir, String name) {
                    /**
                     * We don't want to hash trash on windows
                     */
                    if (name.toLowerCase().equals("recycler") && Constants.isWindows)
                        return false;

                    return name.startsWith(".") == false; // skip hidden files
                }
            });
            if (files != null && maxDepth > 0) {
                List<UpdatingFileTree> children = new ArrayList<UpdatingFileTree>(files.length);
                for (int i = 0; i < files.length; i++) {

                    UpdatingFileTree c = new UpdatingFileTree(files[i], mSpawn);
                    if (c != null) // we might not have perms everywhere...
                    {
                        if (c.thisFile.lastModified() + IDLE_THRESHOLD < System.currentTimeMillis()) {
                            children.add(c);
                            if (c.isDirectory()) {
                                mHasDirectoryChildren = true;
                            }
                        } else {
                            logger.fine("skipping fresh child: " + c.thisFile.getAbsolutePath());
                        }
                    }
                }

                this.children = children;
            } else {
                gone = true;
            }
        }
    }

    public long getLastModified() {
        return lastRefreshed;
    }

    /**
     * so we get directories before their files...
     */
    public void broadcast() {
        mSpawn.broadcastChange(this, false);
        for (UpdatingFileTree c : children)
            c.broadcast();
    }

    public boolean isDirectory() {
        return thisFile.isDirectory();
    }

    public void update() {
        logger.finest("update of: " + this.getThisFile().getAbsolutePath());
        if (thisFile.lastModified() != lastRefreshed || mHasDirectoryChildren) {
            if (thisFile.exists() == false) {
                this.gone = true;
            }

            /**
             * 1. check if children still there
             */
            mHasDirectoryChildren = false;
            if (children != null) {
                for (UpdatingFileTree c : children.toArray(new UpdatingFileTree[0])) {
                    if (c.gone) {
                        children.remove(c);
                        logger.finest("child gone this pass: " + c.getThisFile().getAbsolutePath());
                    } else {
                        c.update();
                        if (c.isDirectory()) {
                            mHasDirectoryChildren = true;
                        }
                    }
                }
            }

            /**
             * 2. Check if there are new children
             */
            File[] files = thisFile.listFiles(new FilenameFilter() {
                public boolean accept(File dir, String name) {
                    return name.startsWith(".") == false; // skip hidden files
                }
            });
            if (files != null) {
                for (int i = 0; i < files.length; i++) {
                    boolean newFile = true;
                    for (UpdatingFileTree c : children) {
                        if (c.thisFile.equals(files[i]) == true) {
                            newFile = false;
                            break;
                        }
                    }
                    if (newFile) {
                        UpdatingFileTree neu = new UpdatingFileTree(files[i], mSpawn);
                        long thresh = neu.thisFile.lastModified() + IDLE_THRESHOLD;
                        if (thresh < System.currentTimeMillis()) {
                            children.add(neu);
                            if (neu.isDirectory()) {
                                mHasDirectoryChildren = true;
                            }
                            neu.broadcast();
                        } else {
                            logger.fine("skipping too-fresh file: "
                                    + neu.thisFile.getAbsolutePath() + " "
                                    + (thresh - System.currentTimeMillis()) + "s left");
                        }
                    }
                }
            } else if (thisFile.exists() == false) {
                logger.finest(getThisFile().getAbsolutePath() + " will be gone next pass");
                gone = true; // will get removed during the next pass
                mSpawn.broadcastChange(this, true);
            }
        } else if (thisFile.exists() == false) {
            logger.finest(getThisFile().getAbsolutePath() + " will be gone next pass");
            gone = true; // will get removed during the next pass
            mSpawn.broadcastChange(this, true);
        }
    }

    public List<UpdatingFileTree> getDirectoryChildren() {
        if (mHasDirectoryChildren == false) {
            return new ArrayList<UpdatingFileTree>(0);
        } else {
            List<UpdatingFileTree> out = new ArrayList<UpdatingFileTree>();
            for (UpdatingFileTree u : children) {
                if (u.isDirectory() && !u.gone)
                    out.add(u);
            }
            return out;
        }
    }

    public List<UpdatingFileTree> getFileChildren() {
        List<UpdatingFileTree> out = new ArrayList<UpdatingFileTree>();
        for (UpdatingFileTree u : children) {
            if (u.isDirectory() == false && !u.gone)
                out.add(u);
        }
        return out;
    }

    public List<UpdatingFileTree> getChildren() {
        return children;
    }

    public String toString() {
        return thisFile.getName()
                + (isDirectory() && children != null ? " (" + children.size() + " children)" : "");
    }

    public File getThisFile() {
        return thisFile;
    }

    public long modifiedChecksum() {
        long sum = getLastModified();
        for (UpdatingFileTree k : children) {
            sum += k.modifiedChecksum();
        }
        return sum;
    }
}