// This Source Code is in the Public Domain per: http://litesoft.org/License.txt
package org.litesoft.encryption.symmetric;

import org.litesoft.commonfoundation.typeutils.*;

import java.util.*;

public class SymmetricEncryptorManagerImpl implements SymmetricEncryptorManager
{
    private static final String SYMMETRIC_ENCRYPTOR_GET_IDENTIFIER_AND_VERSION = "SymmetricEncryptor.getIdentifierAndVersion()";

    private Map<String, SymmetricEncryptor> mSymmetricEncryptors = new HashMap<String, SymmetricEncryptor>();
    private SymmetricEncryptor mSymmetricEncryptor;

    /**
     * @return a non-null SHORT string with NO leading or trailing whitespace that contains an Idetifier
     *         for the Implementation and a Version Number (colons ':' are NOT allowed to be in this String)
     */
    private void validateSymmetricEncryptorID( String pIdentifierAndVersion )
    {
        Strings.assertNotNullNotEmpty( SYMMETRIC_ENCRYPTOR_GET_IDENTIFIER_AND_VERSION, pIdentifierAndVersion );
        Strings.assertNoLeadingOrTrailingWhiteSpace( SYMMETRIC_ENCRYPTOR_GET_IDENTIFIER_AND_VERSION, pIdentifierAndVersion );
        if ( pIdentifierAndVersion.indexOf( ':' ) != -1 )
        {
            throw new IllegalArgumentException( "Colon (':') not allowed in the " + SYMMETRIC_ENCRYPTOR_GET_IDENTIFIER_AND_VERSION );
        }
    }

    public SymmetricEncryptorManagerImpl()
    {
        setSymmetricEncryptor( BrainDeadSymmetricEncryptor.INSTANCE );
    }

    public synchronized void addDecryptor( SymmetricEncryptor pSymmetricEncryptor )
    {
        if ( pSymmetricEncryptor != null )
        {
            String zIdentifierAndVersion = pSymmetricEncryptor.getIdentifierAndVersion();
            validateSymmetricEncryptorID( zIdentifierAndVersion );
            mSymmetricEncryptors.put( zIdentifierAndVersion, pSymmetricEncryptor );
        }
    }

    public void setSymmetricEncryptor( SymmetricEncryptor pSymmetricEncryptor )
    {
        if ( pSymmetricEncryptor != null )
        {
            addDecryptor( pSymmetricEncryptor );
            mSymmetricEncryptor = pSymmetricEncryptor;
        }
    }

    public synchronized SymmetricEncryptor getSymmetricEncryptor()
    {
        return mSymmetricEncryptor;
    }

    public synchronized SymmetricEncryptor getSymmetricEncryptor( String pIdentifierAndVersion )
    {
        return pIdentifierAndVersion != null ? mSymmetricEncryptors.get( pIdentifierAndVersion ) : null;
    }
}