// This Source Code is in the Public Domain per: http://unlicense.org
package org.litesoft.filesinksource;

import org.litesoft.codec.*;
import org.litesoft.commonfoundation.base.*;

import java.io.*;

public abstract class FileSinkAndSourceFactory {
    public final FileSink createFileSink( String pName )
            throws IOException {
        if ( (pName.indexOf( '\\' ) != -1) || (pName.indexOf( '/' ) != -1) ) {
            throw new IllegalArgumentException( "Invalid File Name, found Path Sep in: " + pName );
        }
        return LLcreateFileSink( pName );
    }

    protected abstract FileSink LLcreateFileSink( String pName )
            throws IOException;

    public abstract FileSource createFileSource( String pOpaqueHandle )
            throws IOException;

    private static FileSinkAndSourceFactory sInstance = Null.INSTANCE;

    public static FileSinkAndSourceFactory getInstance() {
        return sInstance;
    }

    public static void setInstance( FileSinkAndSourceFactory pInstance ) {
        sInstance = (pInstance != null) ? pInstance : Null.INSTANCE;
    }

    public static class Null extends FileSinkAndSourceFactory {
        public static final FileSinkAndSourceFactory INSTANCE = new Null();

        private Null() {
        }

        @Override
        protected FileSink LLcreateFileSink( String pName )
                throws IOException {
            throw new RuntimeException( "Null" );
        }

        @Override
        public FileSource createFileSource( String pOpaqueHandle )
                throws IOException {
            throw new RuntimeException( "Null" );
        }
    }

    protected static abstract class AbstractFileSink implements FileSink {
        protected final String mDesiredFileName;

        protected AbstractFileSink( String pDesiredFileName ) {
            mDesiredFileName = Confirm.significant( "DesiredFileName", pDesiredFileName );
        }
    }

    protected static abstract class AbstractFileSource implements FileSource {
        protected final String mOpaqueHandle;

        protected AbstractFileSource( String pOpaqueHandle ) {
            mOpaqueHandle = Confirm.significant( "OpaqueHandle", pOpaqueHandle );
        }
    }

    protected static abstract class AbstractFileSourceInfo implements FileSourceInfo {
        private final String mDesiredFileName;

        protected AbstractFileSourceInfo( String pDesiredFileName ) {
            mDesiredFileName = Confirm.significant( "DesiredFileName", pDesiredFileName );
        }

        @Override
        public String getName() {
            return mDesiredFileName;
        }

        @Override
        public InputStream getInputStream()
                throws IOException {
            return null;
        }
    }

    protected static abstract class AbstractOpaqueHandle {
        protected final String mDesiredFileName;

        protected AbstractOpaqueHandle( String pDesiredFileName ) {
            mDesiredFileName = Confirm.significant( "DesiredFileName", pDesiredFileName );
        }

        public String getDesiredFileName() {
            return mDesiredFileName;
        }

        protected String toString( String pHandlePrefix, String pOpaquePart ) {
            return pHandlePrefix + HexStringCodec.encode( pOpaquePart ) + "/" + mDesiredFileName;
        }

        /**
         * @return String pair - 1st = OpaquePart, 2nd = DesiredFileName
         */
        protected static String[] parse( String pHandlePrefix, String pOpaqueHandleToString ) {
            if ( pOpaqueHandleToString.startsWith( pHandlePrefix ) ) {
                String zRest = pOpaqueHandleToString.substring( pHandlePrefix.length() );
                int slashAt = zRest.lastIndexOf( '/' );
                if ( slashAt != -1 ) {
                    String zOpaquePart = ConstrainTo.significantOrNull( HexStringCodec.decode( zRest.substring( 0, slashAt ).trim() ) );
                    String zDesiredFileName = ConstrainTo.significantOrNull( zRest.substring( slashAt + 1 ) );
                    if ( (zOpaquePart != null) && (zDesiredFileName != null) ) {
                        return new String[]{zOpaquePart, zDesiredFileName};
                    }
                }
            }
            return null;
        }
    }
}