#!/usr/bin/env python2
#
# Copyright (c) 2016,2018 Cisco and/or its affiliates.
# 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.
from string import Template

from jvpp_model import is_control_ping, is_control_ping_reply, is_dump, is_request


def generate_notifications(work_dir, model, logger):
    """ Generates notification registry interface and implementation """
    logger.debug("Generating Notification interfaces and implementation for %s" % model.json_api_files)
    messages = filter(_notification_filter, model.messages)
    _generate_global_event_callback(work_dir, model, messages)
    _generate_event_registry(work_dir, model, messages)
    _generate_event_registry_impl(work_dir, model, messages)
    _generate_event_registry_provider(work_dir, model)


def _notification_filter(msg):
    # Generate callbacks for all messages except for dumps and requests (handled by vpp, not client).
    # Also skip control ping managed by jvpp registry.
    return (not is_control_ping(msg)) and \
           (not is_control_ping_reply(msg)) and \
           (not is_dump(msg)) and \
           (not is_request(msg))


def _generate_event_registry(work_dir, model, messages):
    plugin_name = model.plugin_java_name
    plugin_package = model.plugin_package

    register_callback_methods = []
    for msg in messages:
        name = _callback_name(msg)
        fqn_name = _fqn_callback_name(plugin_package, name)
        # TODO create NotificationListenerRegistration and return that instead of AutoCloseable to better indicate
        # that the registration should be closed
        register_callback_methods.append("    java.lang.AutoCloseable register%s(%s callback);" % (name, fqn_name))

    with open("%s/%sEventRegistry.java" % (work_dir, plugin_name), "w") as f:
        f.write(_EVENT_REGISTRY_TEMPLATE.substitute(
            plugin_package=plugin_package,
            plugin_name=plugin_name,
            json_filename=model.json_api_files,
            register_callback_methods="\n".join(register_callback_methods)
        ))

_EVENT_REGISTRY_TEMPLATE = Template("""
package $plugin_package.notification;

/**
 * <p>Registry for notification callbacks defined in ${plugin_name}.
 * <br>It was generated by notification_gen.py based on $json_filename.
 */
public interface ${plugin_name}EventRegistry extends io.fd.jvpp.notification.EventRegistry {

$register_callback_methods

    @Override
    void close();
}
""")


def _generate_event_registry_impl(work_dir, model, messages):
    plugin_name = model.plugin_java_name
    plugin_package = model.plugin_package

    register_callback_methods = []
    handler_methods = []
    for msg in messages:
        notification = msg.java_name_upper
        callback = "%sCallback" % notification
        register_callback_methods.append(_REGISTER_CALLBACK_IMPL_TEMPLATE.substitute(
            plugin_package=plugin_package,
            notification=notification,
            callback=callback
        ))
        handler_methods.append(_HANDLER_IMPL_TEMPLATE.substitute(
            plugin_package=plugin_package,
            notification=notification,
            callback=callback
        ))

    with open("%s/%sEventRegistryImpl.java" % (work_dir, plugin_name), "w") as f:
        f.write(_EVENT_REGISTRY_IMPL_TEMPLATE.substitute(
            plugin_package=plugin_package,
            plugin_name=plugin_name,
            json_filename=model.json_api_files,
            register_callback_methods="".join(register_callback_methods),
            handler_methods="".join(handler_methods)
        ))

_REGISTER_CALLBACK_IMPL_TEMPLATE = Template("""
    public java.lang.AutoCloseable register$callback(final $plugin_package.callback.$callback callback){
        if(null != registeredCallbacks.putIfAbsent($plugin_package.dto.$notification.class, callback)){
            throw new IllegalArgumentException("Callback for " + $plugin_package.dto.$notification.class +
                "notification already registered");
        }
        return () -> registeredCallbacks.remove($plugin_package.dto.$notification.class);
    }
""")

_HANDLER_IMPL_TEMPLATE = Template("""
    @Override
    public void on$notification(
        final $plugin_package.dto.$notification notification) {
        if (LOG.isLoggable(java.util.logging.Level.FINE)) {
            LOG.fine(java.lang.String.format("Received $notification event message: %s", notification));
        }
        final io.fd.jvpp.callback.JVppCallback jVppCallback = registeredCallbacks.get($plugin_package.dto.$notification.class);
        if (null != jVppCallback) {
            (($plugin_package.callback.$callback) registeredCallbacks
                .get($plugin_package.dto.$notification.class))
                .on$notification(notification);
        }
    }
""")

_EVENT_REGISTRY_IMPL_TEMPLATE = Template("""
package $plugin_package.notification;

/**
 * <p>Notification registry delegating notification processing to registered callbacks.
 * <br>It was generated by notification_gen.py based on $json_filename.
 */
public final class ${plugin_name}EventRegistryImpl implements ${plugin_name}EventRegistry, Global${plugin_name}EventCallback {

    // TODO add a special NotificationCallback interface and only allow those to be registered
    private final java.util.concurrent.ConcurrentMap<Class<?>, io.fd.jvpp.callback.JVppCallback> registeredCallbacks =
        new java.util.concurrent.ConcurrentHashMap<>();
    private static java.util.logging.Logger LOG = java.util.logging.Logger.getLogger(${plugin_name}EventRegistryImpl.class.getName());

    $register_callback_methods
    $handler_methods

    @Override
    public void close() {
        registeredCallbacks.clear();
    }

    @Override
    public void onError(io.fd.jvpp.VppCallbackException ex) {
        java.util.logging.Logger LOG = java.util.logging.Logger.getLogger(${plugin_name}EventRegistryImpl.class.getName());
        LOG.log(java.util.logging.Level.WARNING, java.lang.String.format("Received onError exception: call=%s, context=%d, retval=%d%n", ex.getMethodName(),
            ex.getCtxId(), ex.getErrorCode()), ex);
    }
}
""")


def _generate_global_event_callback(work_dir, model, messages):
    plugin_name = model.plugin_java_name
    plugin_package = model.plugin_package

    callbacks = ""
    callback_list = []
    for msg in messages:
        fqn_name = _fqn_callback_name(plugin_package, _callback_name(msg))
        callback_list.append(fqn_name)

    if callback_list:
        callbacks = " extends %s" % ", ".join(callback_list)

    with open("%s/Global%sEventCallback.java" % (work_dir, plugin_name), "w") as f:
        f.write(_GLOBAL_EVENT_CALLBACK_TEMPLATE.substitute(
            plugin_package=plugin_package,
            plugin_name=plugin_name,
            json_filename=model.json_api_files,
            callbacks=callbacks
        ))

_GLOBAL_EVENT_CALLBACK_TEMPLATE = Template("""
package $plugin_package.notification;

/**
 * <p>Aggregated callback interface for notifications only.
 * <br>It was generated by notification_gen.py based on $json_filename.
 */
public interface Global${plugin_name}EventCallback$callbacks {

}
""")


def _generate_event_registry_provider(work_dir, model):
    plugin_name = model.plugin_java_name
    with open("%s/%sEventRegistryProvider.java" % (work_dir, plugin_name), "w") as f:
        f.write(_EVENT_REGISTRY_PROVIDER_TEMPLATE.substitute(
            plugin_package=model.plugin_package,
            plugin_name=plugin_name,
            json_filename=model.json_api_files
        ))

_EVENT_REGISTRY_PROVIDER_TEMPLATE = Template("""
package $plugin_package.notification;

 /**
 * Provides ${plugin_name}EventRegistry.
 * <br>The file was generated by notification_gen.py based on $json_filename.
 */
public interface ${plugin_name}EventRegistryProvider extends io.fd.jvpp.notification.EventRegistryProvider {

    @Override
    public ${plugin_name}EventRegistry getEventRegistry();
}
""")


def _callback_name(msg):
    return "%sCallback" % msg.java_name_upper


def _fqn_callback_name(plugin_package, callback_name):
    return "%s.callback.%s" % (plugin_package, callback_name)