/*
 * Copyright (C) 2010-2021 Structr GmbH
 *
 * This file is part of Structr <http://structr.org>.
 *
 * Structr is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * Structr is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Structr.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.structr.core.function;

import org.structr.common.error.ArgumentCountException;
import org.structr.common.error.ArgumentNullException;
import org.structr.common.error.FrameworkException;
import org.structr.schema.action.ActionContext;

public class GetenvFunction extends CoreFunction {

    public static final String ERROR_MESSAGE_GETENV    = "Usage: ${getenv()}. Example: ${getenv('JAVA_HOME')}";
    public static final String ERROR_MESSAGE_GETENV_JS = "Usage: ${{ $.getenv() }. Example: ${{ $.getenv('JAVA_HOME'); }}";

    @Override
    public String getName() {
        return "getenv";
    }

    @Override
    public String getSignature() {
        return "[variable]";
    }

    @Override
    public Object apply(final ActionContext ctx, final Object caller, final Object[] sources) throws FrameworkException {

        try {

            assertArrayHasMinLengthAndMaxLengthAndAllElementsNotNull(sources, 0, 1);

            if (sources.length == 1) {

                return System.getenv(sources[0].toString());

            } else {

                return System.getenv();
            }

        } catch (SecurityException se) {

            logException(se, "SecurityException encountered for parameters: {}", sources);

        } catch (ArgumentNullException pe) {

            // silently ignore null arguments

        } catch (ArgumentCountException pe) {

            logParameterError(caller, sources, pe.getMessage(), ctx.isJavaScriptContext());
        }

        return "";
    }

    @Override
    public String usage(boolean inJavaScriptContext) {
        return inJavaScriptContext ? ERROR_MESSAGE_GETENV_JS : ERROR_MESSAGE_GETENV;
    }

    @Override
    public String shortDescription() {
        return "Returns the value of the specified environment variable. If no value is specified, all environment variables are returned as a map. An environment variable is a system-dependent external named value.";
    }
}
