// FIXEME
// Copyright 2003 Adam Megacz, see the COPYING file for licensing [GPL]
package org.xwt;

import java.io.*;
import java.util.*;
import java.util.zip.*;
import org.xwt.js.*;
import org.xwt.util.*;
import org.bouncycastle.util.encoders.Base64;


/** Base class for XWT resources */
public abstract class Res extends JS {

    /** return a resource for a given url */
    public static final Res fromURL(String url) throws JSExn {
        if (url.startsWith("http://")) return new Res.HTTP(url);
        else if (url.startsWith("https://")) return new Res.HTTP(url);
        else if (url.startsWith("data:")) return new Res.ByteArray(Base64.decode(url.substring(5)), null);
        else if (url.startsWith("utf8:")) return new Res.ByteArray(url.substring(5).getBytes(), null);
        throw new JSExn("invalid resource specifier " + url);
    }

    // Base Class //////////////////////////////////////////////////////////////////////

    public String typeName() { return "resource"; }

    /** so that we get the same subresource each time */
    private Hash refCache = null;

    public Template t = null;

    public final InputStream getInputStream() throws IOException { return getInputStream(""); }
    public abstract InputStream getInputStream(String path) throws IOException;

    public Res addExtension(String extension) { return new Ref(this, extension); }

    public Object get(Object key) throws JSExn {
        if ("".equals(key)) {
            try {
                Template t = Template.getTemplate(addExtension(".xwt"));
                return t == null ? null : t.getStatic(null);  /** FIXME VERY BAD! */
            } catch (Exception e) {
                Log.info(this, e);
                return null;
            }
        }
        Object ret = refCache == null ? null : refCache.get(key);
        if (ret != null) return ret;
        ret = new Ref(this, key);
        if (refCache == null) refCache = new Hash();
        refCache.put(key, ret);
        return ret;
    }



    // Caching //////////////////////////////////////////////////////////////////////

    public static class NotCacheableException extends Exception { }
    public static NotCacheableException notCacheable = new NotCacheableException();

    /** if it makes sense to cache a resource, the resource must return a unique key */
    public String getCacheKey() throws NotCacheableException { throw notCacheable; }

    /** subclass from this if you want a CachedInputStream for each path */
    public static class CachedRes extends Res {
        private Res parent;
        private boolean disk = false;
        private String key;
        public String getCacheKey() throws NotCacheableException { return key; }
        public String toString() { return key; }
        private Hash cachedInputStreams = new Hash();
        public CachedRes(Res p, String s, boolean d) throws NotCacheableException {
            this.parent = p; this.disk = d; this.key = p.getCacheKey();
        }
        public InputStream getInputStream(String path) throws IOException {
            CachedInputStream cis = (CachedInputStream)cachedInputStreams.get(path);
            if (cis == null) {
                if (disk) {
                    java.io.File f = LocalStorage.Cache.getCacheFileForKey(key);
                    if (f.exists()) return new FileInputStream(f);
                    cis = new CachedInputStream(parent.getInputStream(path), f);
                } else {
                    cis = new CachedInputStream(parent.getInputStream(path));
                }
                cachedInputStreams.put(path, cis);
            }
            return cis.getInputStream();
        }
    }


    // Useful Subclasses //////////////////////////////////////////////////////////////////////

    /** HTTP or HTTPS resource */
    public static class HTTP extends Res {
        private String url;
        HTTP(String url) { while (url.endsWith("/")) url = url.substring(0, url.length() - 1); this.url = url; }
        public String toString() { return url; }
        public String getCacheKey() throws NotCacheableException { return url; }
        public InputStream getInputStream(String path) throws IOException { return new org.xwt.HTTP(url + path).GET(); }
    }

    /** byte arrays */
    public static class ByteArray extends Res {
        private byte[] bytes;
        private String cacheKey = null;
        ByteArray(byte[] bytes, String cacheKey) { this.bytes = bytes; this.cacheKey = cacheKey; }
        public String toString() { return "byte[]"; }
        public String getCacheKey() throws NotCacheableException { return cacheKey; }
        public InputStream getInputStream(String path) throws IOException {
            if (!"".equals(path)) throw new IOException("can't get subresources of a byte[] resource");
            return new ByteArrayInputStream(bytes);
        }
    }

    /** a file */
    public static class File extends Res {
        private String path;
        File(String path) {
            while (path.endsWith(java.io.File.separatorChar + "")) path = path.substring(0, path.length() - 1);
            this.path = path;
        }
        public String toString() { return "file:" + path; }
        public String getCacheKey() throws NotCacheableException { throw notCacheable; }  // already on the disk!
        public InputStream getInputStream(String rest) throws IOException {
            return new FileInputStream((path + rest).replace('/', java.io.File.separatorChar)); }
    }

    /** "unwrap" a Zip archive */
    public static class Zip extends Res {
        private Res parent;
        Zip(Res parent) { this.parent = parent; }
        public String toString() { return parent.toString() + "!zip"; }
        public String getCacheKey() throws NotCacheableException { return parent.getCacheKey() + "!zip:"; }
        public InputStream getInputStream(String path) throws IOException {
            if (path.startsWith("/")) path = path.substring(1);
            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 Res {
        private Res parent;
        Cab(Res parent) { this.parent = parent; }
        public String toString() { return parent.toString() + "!cab"; }
        public String getCacheKey() throws NotCacheableException { return parent.getCacheKey() + "!cab:"; }
        public InputStream getInputStream(String path) throws IOException {
            if (path.startsWith("/")) path = path.substring(1);
            return new org.xwt.translators.MSPack(parent.getInputStream()).getInputStream(path);
        }
    }

    /** the Builtin resource */
    public static class Builtin extends Res {
        public Builtin() { };
        public String getCacheKey() throws NotCacheableException { throw notCacheable; }    // not cacheable
        public String toString() { return "builtin:"; }
        public InputStream getInputStream(String path) throws IOException {
            if (!path.equals("")) throw new IOException("the builtin resource has no subresources");
            return Platform.getBuiltinInputStream();
        }
    }

    /** what you get when you reference a subresource */
    public static class Ref extends Res {
        Res parent;
        Object key;
        public String toString() { return parent.toString() + "/" + key; }
        Ref(Res parent, Object key) { this.parent = parent; this.key = key; }
        public String getCacheKey() throws NotCacheableException { return parent.getCacheKey() + "/" + key; }
        public Res addExtension(String extension) {
            return ((String)key).endsWith(extension) ? this : new Ref(parent, key + extension); }
        public InputStream getInputStream(String path) throws IOException { return parent.getInputStream("/" + key + path); }
    }

    /** provides redirection of a specified key */
    public static class Graft extends Res {
        Res graftee;
        ObjectObjectreplaced_keyreplaced_val       Graft(Res graftee, Object key, Object val) { this.graftee = graftee; this.replaced_key = key; this.replaced_val = val; }
        public boolean equals(Object o) { return this == o || graftee.equals(o); }
        public int hashCode() { return graftee.hashCode(); }
        public InputStream getInputStream(String s) throws IOException { return graftee.getInputStream(s); }
        public Object get(Object key) throws JSExn { return replaced_key.equals(key) ? replaced_val : graftee.get(key); }
        public Object callMethod(Object name, Object a, Object b, Object c, Object[] rest, int nargs) throws JSExn {
            if (replaced_key.equals(name)) {
                if (replaced_val instanceof JS) return ((JS)replaced_val).call(a, b, c, rest, nargs);
                else throw new JSExn("attempted to call non-function (class="+replaced_val.getClass()+")");
            } else {
                return graftee.callMethod(name, a, b, c, rest, nargs);
            }
        }
        public Number coerceToNumber() { return graftee.coerceToNumber(); }
        public String coerceToString() { return graftee.coerceToString(); }
        public boolean coerceToBoolean() { return graftee.coerceToBoolean(); }
        public String typeName() { return graftee.typeName(); }
    }

    /** shadow resource which replaces the graft */
    public static class ProgressWatcher extends Res {
        final Res watchee;
        JSFunction callback;
        ProgressWatcher(Res watchee, JSFunction callback) { this.watchee = watchee; this.callback = callback; }
        public String toString() { return watchee.toString(); }
        public String getCacheKey() throws NotCacheableException { return watchee.getCacheKey(); }
        public InputStream getInputStream(String s) throws IOException {
            final InputStream is = watchee.getInputStream(s);
            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;
                        Scheduler.add(new Scheduler.Task() { public void perform() throws Exception {
                            callback.call(N(bytesDownloaded),
                                          N(is instanceof KnownLength ? ((KnownLength)is).getLength() : 0), null, null, 2);
                        } });
                        return ret;
                    }
                };
        }
    }
}