// 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 java.io.*;
import java.util.zip.*;
import org.ibex.js.*;
import org.ibex.util.*;
import org.ibex.net.*;

/**
 *   Essentiall an InputStream "factory".  You can repeatedly ask a
 *   Fountain for an InputStream, and each InputStream you get back will
 *   be totally independent of the others (ie separate stream position
 *   and state) although they draw from the same data source.
 */
public abstract class Fountain extends JS.Obj implements JS.Cloneable {

    // Public Interface //////////////////////////////////////////////////////////////////////////////

    public static InputStream getInputStream(Object js) throws IOException { return ((Fountain)((JS)js).unclone()).getInputStream();}
    public static class NotCacheableException extends Exception { }

    // streams are "sealed" by default to prevent accidental object leakage
    private Cache getCache = new Cache(100, true);
    protected JS _get(JS key) throws JSExn { return null; }
    public final JS get(JS key) throws JSExn {
        JS ret = (JS)getCache.get(key);
        if (ret == null) getCache.put(key, ret = _get(key));
        return ret;
    }

    // Private Interface //////////////////////////////////////////////////////////////////////////////

    public abstract InputStream getInputStream() throws IOException;
    protected String getCacheKey() throws NotCacheableException { throw new NotCacheableException(); }

    /** HTTP or HTTPS resource */
    public static class HTTP extends Fountain {
        private String url;
        //public String toString() { return "Fountain.HTTP:" + url; }
        public HTTP(String url) { while (url.endsWith("/")) url = url.substring(0, url.length() - 1); this.url = url; }
        public JS _get(JS key) throws JSExn { return new HTTP(url + "/" + JSU.toString(key)); }
        public String getCacheKey(Vec path) throws NotCacheableException { return url; }
        public InputStream getInputStream() throws IOException { return new org.ibex.net.HTTP(url).GET(null, null); }
    }

    /** byte arrays */
    public static class ByteArray extends Fountain {
        private byte[] bytes;
        private String cacheKey;
        public ByteArray(byte[] bytes, String cacheKey) { this.bytes = bytes; this.cacheKey = cacheKey; }
        public String getCacheKey() throws NotCacheableException {
            if (cacheKey == null) throw new NotCacheableException(); return cacheKey; }
        public InputStream getInputStream() throws IOException { return new ByteArrayInputStream(bytes); }
    }

    /** a file */
    public static class File extends Fountain {
        private String path;
        public File(String path) { this.path = path; }
        //public String toString() { return "file:" + path; }
        public String getCacheKey() throws NotCacheableException { throw new NotCacheableException(); /* already on disk */ }
        public InputStream getInputStream() throws IOException { return new FileInputStream(path); }
        public JS _get(JS key) throws JSExn { return new File(path + java.io.File.separatorChar + JSU.toString(key)); }
    }

    /** "unwrap" a Zip archive */
    public static class Zip extends Fountain {
        private Fountain parent;
        private String path;
        public Zip(Fountain parent) { this(parent, null); }
        public Zip(Fountain parent, String path) {
            while(path != null && path.startsWith("/")) path = path.substring(1);
            this.parent = parent;
            this.path = path;
        }
        public String getCacheKey() throws NotCacheableException { return parent.getCacheKey() + "!zip:"; }
        public JS _get(JS key) throws JSExn { return new Zip(parent, path==null?JSU.toString(key):path+'/'+JSU.toString(key)); }
        public InputStream getInputStream() throws IOException {
            InputStream pis = parent.getInputStream();
            ZipInputStream zis = new ZipInputStream(pis);
            ZipEntry ze = zis.getNextEntry();
            while(ze != null && !ze.getName().equals(path)) ze = zis.getNextEntry();
            if (ze == null) throw new IOException("requested file (" + path + ") not found in archive");
            return new KnownLength.KnownLengthInputStream(zis, (int)ze.getSize());
        }
    }

    /** "unwrap" a Cab archive */
    /*
    public static class Cab extends Fountain {
        private Fountain parent;
        private String path;
        public Cab(Fountain parent) { this(parent, null); }
        public Cab(Fountain parent, String path) { this.parent = parent; this.path = path; }
        public String getCacheKey() throws NotCacheableException { return parent.getCacheKey() + "!cab:"; }
        public JS _get(JS key) throws JSExn { return new Cab(parent, path==null?(String)key:path+'/'+(String)key); }
        public InputStream getInputStream() throws IOException { return new MSPack(parent.getInputStream()).getInputStream(path); }
    }
    */

    public static class FromInputStream extends Fountain {
        private final InputStream is;
        public FromInputStream(InputStream is) { this.is = is; }
        public String getCacheKey() throws NotCacheableException { throw new NotCacheableException(); }
        public InputStream getInputStream() throws IOException { return is; }
    }

    /** shadow resource which replaces the graft */
    public static class ProgressWatcher extends Fountain {
        private final JS[] callargs = new JS[2];
        final Fountain watchee;
        Callable callback;
        public ProgressWatcher(Fountain watchee, Callable callback) { this.watchee = watchee; this.callback = callback; }
        public String getCacheKey() throws NotCacheableException { return watchee.getCacheKey(); }
        public InputStream getInputStream() throws IOException {
            final InputStream is = watchee.getInputStream();
            return new FilterInputStream(is) {
                    int bytesDownloaded = 0;
                    public int read() throws IOException {
                        int ret = super.read();
                        if (ret != -1) bytesDownloaded++;
                        return ret;
                    }
                    public int read(byte[] b, int off, int len) throws IOException {
                        int ret = super.read(b, off, len);
                        if (ret != 1) bytesDownloaded += ret;
                        callargs[0] = JSU.N(bytesDownloaded);
                        callargs[1] = JSU.N(is instanceof KnownLength.KnownLengthInputStream ?
                                            ((KnownLength.KnownLengthInputStream)is).getLength() : 0);
                        try {
                            callback.run(callargs);
                        } catch (Exception e) {
                            Log.warn(ProgressWatcher.class, e);
                        }
                        return ret;
                    }
                };
        }
    }

    /** subclass from this if you want a CachedInputStream for each path */
    /*
    public static class CachedFountain extends Fountain {
        private Fountain parent;
        private boolean disk = false;
        private String key;
        public String getCacheKey() throws NotCacheableException { return key; }
        CachedInputStream cis = null;
        public CachedFountain(Fountain p, String s, boolean d) throws NotCacheableException {
            this.parent = p; this.disk = d; this.key = p.getCacheKey();
        }
        public InputStream getInputStream() throws IOException {
            if (cis != null) return cis.getInputStream();
            if (!disk) {
                cis = new CachedInputStream(parent.getInputStream());
            } else {
                java.io.File f = org.ibex.plat.Platform.LocalStorage.Cache.getCacheFileForKey(key);
                if (f.exists()) return new FileInputStream(f);
                cis = new CachedInputStream(parent.getInputStream(), f);
            }
            return cis.getInputStream();
        }
    }
    */
}