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package org.jruby.ext.zlib;

import com.jcraft.jzlib.Deflater;
import com.jcraft.jzlib.GZIPException;
import com.jcraft.jzlib.GZIPOutputStream;
import com.jcraft.jzlib.JZlib;
import org.jcodings.specific.ASCIIEncoding;
import org.joda.time.DateTime;
import org.jruby.Ruby;
import org.jruby.RubyClass;
import org.jruby.RubyKernel;
import org.jruby.RubyNumeric;
import org.jruby.RubyObject;
import org.jruby.RubyString;
import org.jruby.RubyTime;
import org.jruby.anno.JRubyClass;
import org.jruby.anno.JRubyMethod;
import org.jruby.ext.stringio.StringIO;
import org.jruby.runtime.Block;
import org.jruby.runtime.Helpers;
import org.jruby.runtime.ObjectAllocator;
import org.jruby.runtime.ThreadContext;
import org.jruby.runtime.builtin.IRubyObject;
import org.jruby.util.ByteList;
import org.jruby.util.IOOutputStream;
import org.jruby.util.TypeConverter;
import org.jruby.util.io.EncodingUtils;

import java.io.IOException;

import static org.jruby.runtime.Visibility.PRIVATE;

/**
 *
 */
@JRubyClass(name = "Zlib::GzipWriter", parent = "Zlib::GzipFile")
public class JZlibRubyGzipWriter extends RubyGzipFile {
    protected static final ObjectAllocator GZIPWRITER_ALLOCATOR = new ObjectAllocator() {
        @Override
        public IRubyObject allocate(Ruby runtime, RubyClass klass) {
            return new JZlibRubyGzipWriter(runtime, klass);
        }
    };

    @JRubyMethod(name = "new", rest = true, meta = true)
    public static IRubyObject newInstance(ThreadContext context, IRubyObject recv, IRubyObject[] args, Block block) {
        JZlibRubyGzipWriter result = newInstance(recv, args);

        return RubyGzipFile.wrapBlock(context, result, block);
    }

    public static JZlibRubyGzipWriter newInstance(IRubyObject recv, IRubyObject[] args) {
        RubyClass klass = (RubyClass) recv;
        JZlibRubyGzipWriter result = (JZlibRubyGzipWriter) klass.allocate();

        result.callInit(args, Block.NULL_BLOCK);

        return result;
    }

    @JRubyMethod(name = "open", required = 1, optional = 3, meta = true)
    public static IRubyObject open19(ThreadContext context, IRubyObject recv, IRubyObject[] args, Block block) {
        Ruby runtime = recv.getRuntime();
        
        args[0] = Helpers.invoke(context, runtime.getFile(), "open", args[0], runtime.newString("wb"));
        
        JZlibRubyGzipWriter gzio = newInstance(recv, args);
        
        return RubyGzipFile.wrapBlock(context, gzio, block);
    }

    public JZlibRubyGzipWriter(Ruby runtime, RubyClass type) {
        super(runtime, type);
    }

    public IRubyObject initialize(IRubyObject[] args) {
        return initialize19(getRuntime().getCurrentContext(), args, Block.NULL_BLOCK);
    }

    @JRubyMethod(name = "initialize", rest = true, visibility = PRIVATE)
    public IRubyObject initialize19(ThreadContext context, IRubyObject[] args, Block block) {
        Ruby runtime = context.getRuntime();
        IRubyObject opt = context.nil;
        
        int argc = args.length;
        if (argc > 1) {
            opt = TypeConverter.checkHashType(runtime, opt);
            if (!opt.isNil()) argc--;
        }
        
        level = processLevel(argc, args, runtime);
        
        // unused; could not figure out how to get JZlib to take this right
        /*int strategy = */processStrategy(argc, args);
        
        initializeCommon(args[0], level);
        
        ecopts(context, opt);
        
        return this;
    }

    private int processStrategy(int argc, IRubyObject[] args) {
        return argc < 3 ? JZlib.Z_DEFAULT_STRATEGY : RubyZlib.FIXNUMARG(args[2], JZlib.Z_DEFAULT_STRATEGY);
    }

    private int processLevel(int argc, IRubyObject[] args, Ruby runtime) {
        int level = argc < 2 ? JZlib.Z_DEFAULT_COMPRESSION : RubyZlib.FIXNUMARG(args[1], JZlib.Z_DEFAULT_COMPRESSION);

        checkLevel(runtime, level);

        return level;
    }

    private IRubyObject initializeCommon(IRubyObject stream, int level) {
        realIo = (RubyObject) stream;
        try {
            // the 15+16 here is copied from a Deflater default constructor
            Deflater deflater = new Deflater(level, 15+16, false);
            final IOOutputStream ioOutputStream = new IOOutputStream(realIo, false, false) {
                
Customize IOOutputStream#write(byte[], int, int) to create a defensive copy of the byte array
that GZIPOutputStream hands us.
That byte array is a reference to one of GZIPOutputStream's internal byte buffers.
The base IOOutputStream#write(byte[], int, int) uses the bytes it is handed to back a
copy-on-write ByteList.  So, without this defensive copy, those two classes overwrite each
other's bytes, corrupting our output.
/**
                 * Customize IOOutputStream#write(byte[], int, int) to create a defensive copy of the byte array
                 * that GZIPOutputStream hands us.
                 *
                 * That byte array is a reference to one of GZIPOutputStream's internal byte buffers.
                 * The base IOOutputStream#write(byte[], int, int) uses the bytes it is handed to back a
                 * copy-on-write ByteList.  So, without this defensive copy, those two classes overwrite each
                 * other's bytes, corrupting our output.
                 */
                @Override
                public void write(byte[] bytes, int off, int len) throws IOException {
                    byte[] bytesCopy = new byte[len];
                    System.arraycopy(bytes, off, bytesCopy, 0, len);
                    super.write(bytesCopy, 0, len);
                }
            };

            io = new GZIPOutputStream(ioOutputStream, deflater, 512, false);
            return this;
        } catch (IOException ioe) {
            throw getRuntime().newIOErrorFromException(ioe);
        }
    }
    
    private static void checkLevel(Ruby runtime, int level) {
        if (level != JZlib.Z_DEFAULT_COMPRESSION && (level < JZlib.Z_NO_COMPRESSION || level > JZlib.Z_BEST_COMPRESSION)) {
            throw RubyZlib.newStreamError(runtime, "stream error: invalid level");
        }
    }


    @Override
    @JRubyMethod(name = "close")
    public IRubyObject close() {
        if (!closed) {
            try {
                io.close();
                if (realIo.respondsTo("close")) {
                    realIo.callMethod(realIo.getRuntime().getCurrentContext(), "close");
                }
            } catch (IOException ioe) {
                throw getRuntime().newIOErrorFromException(ioe);
            }
        }
        
        this.closed = true;
        
        return realIo;
    }

    @JRubyMethod(name = {"append", "<<"}, required = 1)
    public IRubyObject append(IRubyObject p1) {
        this.write(p1);
        
        return this;
    }

    @JRubyMethod(name = "printf", required = 1, rest = true)
    public IRubyObject printf(ThreadContext context, IRubyObject[] args) {
        write(RubyKernel.sprintf(context, this, args));
        
        return context.getRuntime().getNil();
    }

    @JRubyMethod(name = "print", rest = true)
    public IRubyObject print(IRubyObject[] args) {
        if (args.length != 0) {
            for (int i = 0, j = args.length; i < j; i++) {
                write(args[i]);
            }
        }

        IRubyObject sep = getRuntime().getGlobalVariables().get("$\\");
        if (!sep.isNil()) write(sep);

        return getRuntime().getNil();
    }

    @JRubyMethod(name = {"pos", "tell"})
    public IRubyObject pos() {
        return RubyNumeric.int2fix(getRuntime(), io.getTotalIn());
    }

    @JRubyMethod(name = "orig_name=", required = 1)
    public IRubyObject set_orig_name(IRubyObject obj) {
        nullFreeOrigName = obj.convertToString().strDup(getRuntime());
        ensureNonNull(nullFreeOrigName);
        
        try {
            io.setName(nullFreeOrigName.toString());
        } catch (GZIPException e) {
            throw RubyZlib.newGzipFileError(getRuntime(), "header is already written");
        }
        
        return obj;
    }

    @JRubyMethod(name = "comment=", required = 1)
    public IRubyObject set_comment(IRubyObject obj) {
        nullFreeComment = obj.convertToString().strDup(getRuntime());
        ensureNonNull(nullFreeComment);
        
        try {
            io.setComment(nullFreeComment.toString());
        } catch (GZIPException e) {
            throw RubyZlib.newGzipFileError(getRuntime(), "header is already written");
        }
        
        return obj;
    }

    private void ensureNonNull(RubyString obj) {
        String str = obj.toString();
        
        if (str.indexOf('\0') >= 0) {
            String trim = str.substring(0, str.indexOf('\0'));
            obj.setValue(new ByteList(trim.getBytes()));
        }
    }

    @JRubyMethod(name = "putc", required = 1)
    public IRubyObject putc(IRubyObject p1) {
        try {
            io.write(RubyNumeric.num2chr(p1));
            
            return p1;
        } catch (IOException ioe) {
            throw getRuntime().newIOErrorFromException(ioe);
        }
    }

    @JRubyMethod(name = "puts", rest = true)
    public IRubyObject puts(ThreadContext context, IRubyObject[] args) {
        final RubyClass StringIO = context.runtime.getClass("StringIO");
        StringIO sio = (StringIO) StringIO.newInstance(context, IRubyObject.NULL_ARRAY, Block.NULL_BLOCK);
        
        sio.puts(context, args);
        write(sio.string(context));

        return context.nil;
    }

    @Override
    public IRubyObject finish() {
        if (!finished) {
            try {
                io.finish();
            } catch (IOException ioe) {
                throw getRuntime().newIOErrorFromException(ioe);
            }
        }
        
        finished = true;
        
        return realIo;
    }

    @JRubyMethod(name = "flush", optional = 1)
    public IRubyObject flush(IRubyObject[] args) {
        int flush = JZlib.Z_SYNC_FLUSH;
        
        if (args.length > 0 && !args[0].isNil()) {
            flush = RubyNumeric.fix2int(args[0]);
        }
        
        boolean tmp = io.getSyncFlush();
        try {
            if (flush != 0 /*
                     * NO_FLUSH
                     */) {
                io.setSyncFlush(true);
            }
            io.flush();
        } catch (IOException ioe) {
            throw getRuntime().newIOErrorFromException(ioe);
        } finally {
            io.setSyncFlush(tmp);
        }
        
        return getRuntime().getNil();
    }

    @JRubyMethod(name = "mtime=", required = 1)
    public IRubyObject set_mtime(IRubyObject arg) {
        if (arg instanceof RubyTime) {
            this.mtime = ((RubyTime) arg);
        } else if (arg.isNil()) {
            // ...nothing
        } else {
            this.mtime.setDateTime(new DateTime(RubyNumeric.fix2long(arg) * 1000));
        }
        
        try {
            io.setModifiedTime(this.mtime.to_i().getLongValue());
        } catch (GZIPException e) {
            throw RubyZlib.newGzipFileError(getRuntime(), "header is already written");
        }
        
        return getRuntime().getNil();
    }

    @Override
    @JRubyMethod(name = "crc")
    public IRubyObject crc() {
        long crc = 0L;
        
        try {
            crc = io.getCRC();
        } catch (GZIPException e) {
            // not calculated yet
        }
        
        return getRuntime().newFixnum(crc);
    }

    @JRubyMethod(name = "write", required = 1)
    public IRubyObject write(IRubyObject p1) {
        Ruby runtime = getRuntime();
        RubyString str = p1.asString();

        if (enc2 != null
                && enc2 != ASCIIEncoding.INSTANCE) {
            str = EncodingUtils.strConvEncOpts(runtime.getCurrentContext(), str, str.getEncoding(),
                    enc2, 0, runtime.getNil());
        
        }
        
        try {
            // TODO: jzlib-1.1.0.jar throws IndexOutOfBoundException for zero length buffer.
            if (str.size() > 0) {
                io.write(str.getByteList().getUnsafeBytes(), str.getByteList().begin(), str.getByteList().length());
            }
            
            return runtime.newFixnum(str.getByteList().length());
        } catch (IOException ioe) {
            throw runtime.newIOErrorFromException(ioe);
        }
    }

    @Override
    @JRubyMethod
    public IRubyObject set_sync(IRubyObject arg) {
        IRubyObject s = super.set_sync(arg);
        
        io.setSyncFlush(sync);
        
        return s;
    }
    
    private GZIPOutputStream io;
}