/*
 * Copyright (C) 2018 "IoT.bzh"
 * Author Sebastien Douheret <sebastien@iot.bzh>
 *
 * 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 (
	"fmt"
	"sync"

	"gerrit.automotivelinux.org/gerrit/src/xds/xds-agent.git/lib/xaapiv1"

	socketio_client "github.com/sebd71/go-socket.io-client"
)

// Disconnection Channel used to notify XDS Server disconnection
type Disconnection struct {
	error   string
	code    int
	svrConf xaapiv1.ServerCfg
}

// IOSockClient .
type IOSockClient struct {
	URL             string
	Conn            *socketio_client.Client
	Options         *socketio_client.Options
	EmitMutex       *sync.Mutex
	Connected       bool
	ServerDiscoChan chan Disconnection
	EscapeKeys      []byte
}

// NewIoSocketClient Create a new IOSockClient
func NewIoSocketClient(url, clientID string) (*IOSockClient, error) {

	var err error

	sCli := &IOSockClient{
		URL:       url,
		EmitMutex: &sync.Mutex{},
		Options: &socketio_client.Options{
			Transport: "websocket",
			Header:    make(map[string][]string),
		},
		ServerDiscoChan: make(chan Disconnection, 1),
	}
	sCli.Options.Header["XDS-AGENT-SID"] = []string{clientID}

	sCli.Conn, err = socketio_client.NewClient(url, sCli.Options)
	if err != nil {
		return nil, fmt.Errorf("IO.socket connection error: " + err.Error())
	}

	sCli.Conn.On("connection", func() {
		sCli.Connected = true
	})

	sCli.Conn.On("disconnection", func(err error) {
		Log.Debugf("WS disconnection event with err: %v\n", err)
		sCli.Connected = false
	})

	args := xaapiv1.EventRegisterArgs{Name: xaapiv1.EVTServerConfig}
	if err := HTTPCli.Post("/events/register", args, nil); err != nil {
		return sCli, err
	}

	sCli.Conn.On(xaapiv1.EVTServerConfig, func(ev xaapiv1.EventMsg) {
		svrCfg, err := ev.DecodeServerCfg()
		if err == nil && !svrCfg.Connected {
			sCli.ServerDiscoChan <- Disconnection{
				error:   "\nXDS Server (id " + svrCfg.ID + ") disconnected !",
				code:    1,
				svrConf: svrCfg,
			}
		}
	})

	return sCli, nil
}

// On record a callback on a specific message
func (c *IOSockClient) On(message string, f interface{}) (err error) {
	return c.Conn.On(message, f)
}

// Emit send a message
func (c *IOSockClient) Emit(message string, args ...interface{}) (err error) {
	c.EmitMutex.Lock()
	defer c.EmitMutex.Unlock()
	return c.Conn.Emit(message, args...)
}