// Copyright (c) 2017 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.

package main

import (
	"log"
	"time"

	"github.com/ligato/cn-infra/agent"
	"github.com/ligato/cn-infra/config"
	"github.com/ligato/cn-infra/infra"
	"github.com/ligato/cn-infra/logging"
)

// PluginName is injected as the plugin name.
// LocalFlavor.InfraDeps() will create and initialize a new flag used to make
// the plugin config file name configurable for the user (via dedicated CLI
// option and env. variable).
// The flag name is composed of the plugin name and the suffix config.FlagSuffix.
// The default (flag value) filename for the configuration file is the plugin
// name with the extension ".conf".
const PluginName = "example"

// *************************************************************************
// This file contains a PluginConfig show case:
// - plugin binds it's configuration to an example specific Conf structure
//   (see Init() to learn how the default configuration is set & how it can be
//    overridden via flags)
// - cn-infra helps by locating and parsing the configuration file
//
// ************************************************************************/

func main() {
	p := &ExamplePlugin{
		Deps: Deps{
			PluginName:   infra.PluginName(PluginName),
			Log:          logging.ForPlugin(PluginName),
			PluginConfig: config.ForPlugin(PluginName),
		},
		exampleFinished: make(chan struct{}),
	}
	a := agent.NewAgent(
		agent.AllPlugins(p),
		agent.QuitOnClose(p.exampleFinished),
	)
	if err := a.Run(); err != nil {
		log.Fatal(err)
	}
}

// ExamplePlugin demonstrates the use of injected Config plugin.
type ExamplePlugin struct {
	Deps

	Conf *Conf // it is possible to set config value programmatically (can be overridden)

	exampleFinished chan struct{}
}

// Deps defines dependencies for ExamplePlugin.
type Deps struct {
	infra.PluginName
	Log          logging.PluginLogger
	PluginConfig config.PluginConfig
}

// Conf - example config binding
type Conf struct {
	Field1 string
	Sleep  time.Duration
	// even nested fields are possible
}

func (conf *Conf) String() string {
	return "{Field1:" + conf.Field1 + ", Sleep:" + conf.Sleep.String() + "}"
}

// Init loads the configuration file assigned to ExamplePlugin (can be changed
// via the example-config flag).
// Loaded config is printed into the log file.
func (plugin *ExamplePlugin) Init() (err error) {
	plugin.Log.Info("Loading plugin config ", plugin.PluginConfig.GetConfigName())

	if plugin.Conf == nil {
		plugin.Conf = &Conf{Field1: "some default value"}
	}

	found, err := plugin.PluginConfig.LoadValue(plugin.Conf)
	if err != nil {
		plugin.Log.Error("Error loading config", err)
	} else if found {
		plugin.Log.Info("Loaded plugin config - found external configuration ", plugin.PluginConfig.GetConfigName())
	} else {
		plugin.Log.Info("Loaded plugin config - default")
	}
	plugin.Log.Info("Plugin Config ", plugin.Conf)

	time.Sleep(plugin.Conf.Sleep)
	close(plugin.exampleFinished)

	return nil
}

// Close closes the plugin.
func (plugin *ExamplePlugin) Close() (err error) {
	return nil
}

// Name returns name of the plugin.
func (plugin *ExamplePlugin) Name() string {
	return PluginName
}