// Copyright 2000-2005 the Contributors, as shown in the revision logs.
// Licensed under the Apache Public Source License 2.0 ("the License").
// You may not use this file except in compliance with the License.

package org.ibex.js; 

import org.ibex.util.*; 
import org.ibex.io.*;
import java.io.*;

// FEATURE: support for move
// FEATURE: support for bytestreams
// FEATURE: cache directories so we can do equality checking on them?
// FEATURE: autoconvert "true" to true and "0.3" to 0.3 on readback

/** 
 * A crude mechanism for using a filesystem as object storage.
 *
 *  This object represents a directory; writing a string, number, or
 *  boolean to any of its properties will create a file with the
 *  (encoded) property name as its filename and the "stringified"
 *  value as its contents.
 *
 *  Writing 'null' to one of this object's properties will
 *  [recursively if necessary] delete the corresponding directory
 *  entry.
 *  
 *  Writing any other object to one of this object's properties will
 *  create a new Directory object and copy the other object's keys()
 *  into the new Directory.  This means that assigning one directory
 *  to a property of another directory will <i>copy</i> the directory,
 *  not move it.  There is currently no way to move directories.
 *
 *  If an object is written to a property that already has an entry,
 *  the old one is deleted (equivalent to writing 'null') first.
 * 
 *  WARNING: when instantiating a Directory object with a file
 *  argument that points to a non-directory File, this class will
 *  delete that file and create a directory!
 */
public class Directory extends JS.Immutable {

    File f;

    /** 
     *  Create the directory object.  Existing directories will be
     *  preserved; if a file is present it will be obliterated.
     */ 

    public Directory(File f) throws IOException {
        this.f = f;
        if (!f.exists()) new Directory(new File(f.getParent()));
        if (!f.isDirectory()) destroy(f);
        f.mkdirs();
    }

    private static void destroy(File f) throws IOException {
        if (!f.exists()) return;
        if (f.isDirectory()) {
            String[] entries = f.list();
            for(int i=0; i<entries.length; i++) destroy(new File(f.getAbsolutePath() + File.separatorChar + entries[i]));
        }
        f.delete();
    }

    public void put(JS key0, JS val) throws JSExn {
        try {
            if (key0 == null) return;
            String key = JSU.toString(key0);
            File f2 = new File(f.getAbsolutePath() + File.separatorChar + Encode.toFilename(key));
            destroy(f2);
            if (val == null) return;
            if (val instanceof org.ibex.io.Fountain) {
                Stream stream = ((org.ibex.io.Fountain)val).getStream();
                Stream out = new Stream(null, new FileOutputStream(f2));
                stream.transcribe(out);
                out.close();
            } else if (val instanceof JSPrimitive) {
                OutputStream out = new FileOutputStream(f2);
                Writer w = new OutputStreamWriter(out);
                w.write(JSU.toString(val));
                w.flush();
                out.close();
            } else {
                Directory d2 = new Directory(f2);
                JS.Enumeration e = val.keys();
                while(e.hasNext()) {
                    JS k = e.next();
                    JS v = val.get(k);
                    d2.put(k, v);
                }
            }
        } catch (IOException ioe) {
            throw new JSExn.IO(ioe);
        }
    }

    public JS get(JS key0) throws JSExn {
        try {
            if (key0 == null) return null;
            String key = JSU.toString(key0);
            File f2 = new File(f.getAbsolutePath() + File.separatorChar + Encode.toFilename(key));
            if (!f2.exists()) return null;
            if (f2.isDirectory()) return new Directory(f2);
            char[] chars = new char[((int)f2.length()) * 4 + 10];
            int numchars = 0;
            Reader r = new InputStreamReader(new FileInputStream(f2));
            while(true) {
                int numread = r.read(chars, numchars, chars.length - numchars);
                if (numread == -1) return JSU.S(new String(chars, 0, numchars));
                numchars += numread;
            }
        } catch (IOException ioe) {
            throw new JSExn.IO(ioe);
        }
    }

    public JS.Enumeration keys() {
        final String[] elements = f.list();
        return new JS.Enumeration(null) {
                int i = 0;
                public boolean _hasNext() { return i < elements.length; }
                public JS _next() { return JSU.S(Encode.fromFilename(elements[i++])); }
            };
    }
}