package nodes

import (
	"encoding/json"
	"fmt"
	MQTT "git.eclipse.org/gitroot/paho/org.eclipse.paho.mqtt.golang.git"
	"github.com/gogf/gf/util/guid"
	"html/template"
	"sparrow/pkg/protocol"
	"sparrow/pkg/ruleEngine"
	"strings"
	"time"
)

const defaultTopicTemp = "/device_message/{{.VendorId}}/{{.DeviceId}}/{{.SubDeviceId}}"
const defaultTimeout = 5

// MQTTBrokerNode Publish incoming message payload to the topic of the configured MQTT broker with QoS AT_LEAST_ONCE.
// In case of successful message publishing, original Message will be passed to the next nodes via Success chain,
//otherwise Failure chain is used.
type MQTTBrokerNode struct {
	mqttClient *MQTT.Client
	config     *MQTTBrokerNodeCfg
}

type MQTTBrokerNodeCfg struct {
	// can be a static string, or pattern that is resolved using Message Metadata properties. .
	// default topic device_message/{{.VendorId}}/{{.DeviceId}}
	TopicPattern string `json:"topic_pattern"`
	// MQTT broker host.
	Host string `json:"host"`
	// MQTT broker port.
	Port int `json:"port"`
	//  timeout in seconds for connecting to MQTT broker.
	Timeout int `json:"timeout"`
	//  optional client identifier used for connecting to MQTT broker. If not specified, default generated clientId will be used.
	ClientId string `json:"client_id"`
	// establishes a non persistent connection with the broker when enabled.
	ClearSession bool `json:"clear_session"`
	// enable/disable secure communication.
	SSLEnable bool `json:"ssl_enable"`
	// MQTT connection credentials. Can be either Anonymous, Basic or PEM.
	Credentials string `json:"credentials"` // Anonymous, Basic, PEM
	/*
		If PEM credentials type is selected, the following configuration should be provided:

		CA certificate file
		Certificate file
		Private key file
		Private key password
	*/
	UserName string `json:"user_name"`
	Password string `json:"password"`
}

func (M *MQTTBrokerNode) Init(ctx ruleEngine.Context, config string) error {
	if config != "" {
		c := new(MQTTBrokerNodeCfg)
		err := json.Unmarshal([]byte(config), c)
		if err != nil {
			return err
		}
		M.config = c
	}
	if M.config.Timeout == 0 {
		M.config.Timeout = defaultTimeout
	}

	var opt MQTT.ClientOptions
	opt.ClientID = "MQTT_NODE_" + guid.S()
	opt.CleanSession = M.config.ClearSession
	opt.KeepAlive = time.Second * 30
	opt.ConnectTimeout = time.Duration(M.config.Timeout) * time.Second
	switch M.config.Credentials {
	case "Basic":
		opt.Username = M.config.UserName
		opt.Password = M.config.Password
	default:

	}
	if M.config.ClientId != "" {
		opt.ClientID = M.config.ClientId
	}
	opt.AutoReconnect = true
	opt.MaxReconnectInterval = 10
	opt.AddBroker(fmt.Sprintf("tcp://%s:%d", M.config.Host, M.config.Port))
	c := MQTT.NewClient(&opt)
	M.mqttClient = c
	go func() {
		if token := c.Connect(); token.Wait() && token.Error() != nil {
			fmt.Println(token.Error().Error())
			return
		}
	}()
	return nil
}

type MeteData struct {
	VendorId    string
	DeviceId    string
	SubDeviceId string
}

func (M *MQTTBrokerNode) OnMessage(ctx ruleEngine.Context, message *protocol.Message) error {
	var meteData MeteData
	if v, ok := message.MetaData["vendor_id"]; ok {
		meteData.VendorId = v.(string)
	}
	if v, ok := message.MetaData["device_id"]; ok {
		meteData.DeviceId = v.(string)
	}
	if v, ok := message.MetaData["sub_device_id"]; ok {
		meteData.SubDeviceId = v.(string)
	}
	tpl, err := template.New("topic").Parse(defaultTopicTemp)
	if err != nil {
		return err
	}
	stringBuf := new(strings.Builder)
	if err = tpl.Execute(stringBuf, &meteData); err != nil {
		return nil
	}
	topic := stringBuf.String()
	token := M.mqttClient.Publish(topic, 0, false, message.Data)
	if token.Error() != nil {
		ctx.TellNext(message, protocol.Failure)
	} else {
		ctx.TellNext(message, protocol.Success)
	}

	return nil
}