/**
 * Yobi, Project Hosting SW
 *
 * Copyright 2014 NAVER Corp.
 * http://yobi.io
 *
 * @Author Yi EungJun
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package utils;

import org.apache.commons.lang3.exception.ExceptionUtils;

import javax.annotation.Nonnull;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;

abstract public class Diagnostic {

    private final static List<Diagnostic> diagnostics = new CopyOnWriteArrayList<>();

    /**
     * Register a diagnostic.
     *
     * Registered diagnostics are run when someone open Site Management >
     * Diagnostics page.
     *
     * @param diagnostic
     */
    public static void register(@Nonnull Diagnostic diagnostic) {
        diagnostics.add(diagnostic);
    }

    @Nonnull
    public static List<String> checkAll() {
        List<String> errors = new ArrayList<>();

        for (Diagnostic diagnostic : diagnostics) {
            try {
                errors.addAll(diagnostic.check());
            } catch (Exception e) {
                errors.add("Failed to diagnose: "
                        + ExceptionUtils.getStackTrace(e));
            }
        }

        return errors;
    }

    @Nonnull
    abstract public List<String> check();
}
