/*
Copyright (c) 2017 OpenStack Foundation.

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 plugins

import (
	"fmt"
	"sync"

	"github.com/containernetworking/cni/pkg/types/current"
	"github.com/golang/glog"
	"github.com/gophercloud/gophercloud/openstack/networking/v2/ports"
)

type PluginInterface interface {
	SetupInterface(podName, podInfraContainerID string, port *ports.Port, ipcidr, gateway, ifName, netns string) (*current.Interface, *current.Interface, error)
	DestroyInterface(podName, podInfraContainerID string, port *ports.Port) error
	Init(integrationBridge string) error
}

// Factory is a function that returns a networkplugin.Interface.
// The config parameter provides an io.Reader handler to the factory in
// order to load specific configurations. If no configuration is provided
// the parameter is nil.
type Factory func() (PluginInterface, error)

// All registered network plugins.
var pluginsMutex sync.Mutex
var plugins = make(map[string]Factory)

// RegisterNetworkPlugin registers a networkplugin.Factory by name.  This
// is expected to happen during app startup.
func RegisterNetworkPlugin(name string, networkPlugin Factory) {
	pluginsMutex.Lock()
	defer pluginsMutex.Unlock()
	if _, found := plugins[name]; found {
		glog.Fatalf("Network plugin %q was registered twice", name)
	}
	glog.V(1).Infof("Registered network plugin %q", name)
	plugins[name] = networkPlugin
}

// GetNetworkPlugin creates an instance of the named network plugin, or nil if
// the name is not known.  The error return is only used if the named plugin
// was known but failed to initialize.
func GetNetworkPlugin(name string) (PluginInterface, error) {
	pluginsMutex.Lock()
	defer pluginsMutex.Unlock()
	f, found := plugins[name]
	if !found {
		return nil, nil
	}
	return f()
}

// InitNetworkPlugin creates an instance of the named networkPlugin plugin.
func InitNetworkPlugin(name string) (PluginInterface, error) {
	var networkPlugin PluginInterface

	if name == "" {
		glog.Info("No network plugin specified.")
		return nil, nil
	}

	var err error
	networkPlugin, err = GetNetworkPlugin(name)

	if err != nil {
		return nil, fmt.Errorf("could not init networkPlugin plugin %q: %v", name, err)
	}
	if networkPlugin == nil {
		return nil, fmt.Errorf("unknown networkPlugin plugin %q", name)
	}

	return networkPlugin, nil
}