/**
 * ============LICENSE_START=======================================================
 * org.onap.aai
 * ================================================================================
 * Copyright © 2017-2018 AT&T Intellectual Property. All rights reserved.
 * ================================================================================
 * 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.
 * ============LICENSE_END=========================================================
 */

package org.onap.aai.extensions;

import java.lang.reflect.Method;

import org.onap.aai.exceptions.AAIException;
import org.onap.aai.util.AAIConfig;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ExtensionController {

    private static final Logger LOGGER = LoggerFactory.getLogger(ExtensionController.class);

    /**
     * Run extension.
     *
     * @param apiVersion the api version
     * @param namespace the namespace
     * @param resourceName the resource name
     * @param methodName the method name
     * @param aaiExtMap the aai ext map
     * @param isPreExtension the is pre extension
     * @throws AAIException the AAI exception
     */
    public void runExtension(String apiVersion, String namespace, String resourceName, String methodName,
            AAIExtensionMap aaiExtMap, boolean isPreExtension) throws AAIException {
        String extensionClassName = "org.onap.aai.extensions." + apiVersion.toLowerCase() + "." + namespace + "."
                + resourceName + "Extension";
        String defaultErrorCallback = resourceName + "ExtensionErrorCallback";

        String configOption = "aai.extensions." + apiVersion.toLowerCase() + "." + namespace.toLowerCase() + "."
                + resourceName.toLowerCase() + ".enabled";

        try {

            String extensionEnabled = AAIConfig.get(configOption, "true");
            if (extensionEnabled.equalsIgnoreCase("false")) {
                return;
            }

            Class<?> clazz = Class.forName(extensionClassName);

            Method extension = clazz.getMethod(methodName, new Class[] {AAIExtensionMap.class});
            if (extension != null) {

                Object ret = extension.invoke(clazz.getDeclaredConstructor().newInstance(), aaiExtMap);

                if (ret instanceof Integer) {
                    Exception e = null;

                    if (isPreExtension == true) {
                        e = aaiExtMap.getPreExtException();
                    } else {
                        e = aaiExtMap.getPostExtException();
                    }

                    boolean failOnError = true;
                    if (isPreExtension == true) {
                        failOnError = aaiExtMap.getPreExtFailOnError();
                    } else {
                        failOnError = aaiExtMap.getPostExtFailOnError();
                    }

                    if (e != null) {
                        boolean handleException = true;
                        if (isPreExtension == true) {
                            if (aaiExtMap.getPreExtSkipErrorCallback() == true) {
                                handleException = false;
                            }
                        } else {
                            if (aaiExtMap.getPostExtSkipErrorCallback() == true) {
                                handleException = false;
                            }
                        }
                        if (handleException == true) {
                            Method errorCallback = null;
                            if (isPreExtension == true) {
                                errorCallback = aaiExtMap.getPreExtErrorCallback();
                            } else {
                                errorCallback = aaiExtMap.getPostExtErrorCallback();
                            }

                            if (errorCallback != null) {
                                errorCallback.invoke(clazz.getDeclaredConstructor().newInstance(), aaiExtMap);
                            } else {
                                Method defaultErrorCallbackExtension =
                                        clazz.getMethod(defaultErrorCallback, new Class[] {AAIExtensionMap.class});
                                defaultErrorCallbackExtension.invoke(clazz.getDeclaredConstructor().newInstance(),
                                        aaiExtMap);
                            }
                        }
                    }

                    if (failOnError == true && e != null) {
                        throw e;
                    } else if (failOnError == false && e != null) { // in this
                                                                    // case, we
                                                                    // just note
                                                                    // the error
                                                                    // without
                                                                    // stopping
                        LOGGER.warn("Error while processing extension - " + aaiExtMap.getMessage());
                    }
                }
            }
        } catch (ClassNotFoundException ex) {
            LOGGER.debug("Extension class not found: " + extensionClassName + ", method: " + methodName + ".");
        } catch (NoSuchMethodException e) {
            LOGGER.debug("Method " + methodName + " does not exist for class " + extensionClassName);
        } catch (AAIException e) {
            throw e;
        } catch (Exception e) {
            throw new AAIException("AAI_5105", e);
        }
    }
}