package main

import (
	"encoding/json"
	"fmt"
	mqtt "github.com/eclipse/paho.mqtt.golang"
	"github.com/gin-gonic/gin"
	"github.com/jinzhu/gorm"
	_ "github.com/jinzhu/gorm/dialects/mysql"
	"io/ioutil"
	"log"
	"math/rand"
	"net/http"
	"strconv"
	"time"
)
var client mqtt.Client
var db *gorm.DB
var conf Config

type DeviceInfo struct {
	ID        		int64   	`json:"id"`
	DevEui      	string 		`json:"devEUI"`
	DevAddr			string 		`json:"devAddr"`
	Username		string 		`json:"username"`
	CreateAt		time.Time 	`json:"createAt"`
}

type Config struct {
	Server struct {
		Port string
	}
	DB struct {
		Host string
		Port int
		User string
		Password string
		Name     string
		LogMode  bool
	}
	MQTT struct {
		Server string
		Topic  string
	}
}

func loadConfig(filename string, c *Config) error {
	data, err := ioutil.ReadFile(filename)
	if err != nil {
		return nil
	}
	err = json.Unmarshal(data, c)
	if err != nil {
		return err
	}
	return nil
}
func Krand(size int, kind int) []byte {
	ikind, kinds, result := kind, [][]int{[]int{10, 48}, []int{26, 97}, []int{26, 65}}, make([]byte, size)
	is_all := kind > 2 || kind < 0
	for i :=0; i < size; i++ {
		if is_all { // random ikind
			ikind = rand.Intn(3)
		}
		scope, base := kinds[ikind][0], kinds[ikind][1]
		result[i] = uint8(base+rand.Intn(scope))
	}
	return result
}

func Setup(c *Config)  {
	var err error
	dsn := fmt.Sprintf("%s:%s@(%s:%d)/%s?charset=utf8&parseTime=True&loc=Local", c.DB.User, c.DB.Password, c.DB.Host, c.DB.Port,c.DB.Name)
	db, err = gorm.Open("mysql", dsn)
	if err != nil {
		panic(err)
	}
	db.LogMode(c.DB.LogMode)
	db.AutoMigrate(&DeviceInfo{})
	db.Model(&DeviceInfo{}).AddUniqueIndex("idx_dev_eui","dev_eui")
	db.Model(&DeviceInfo{}).AddUniqueIndex("idx_dev_addr", "dev_addr")
	db.Model(&DeviceInfo{}).AddIndex("idx_create_at", "create_at")
	opts := mqtt.NewClientOptions().AddBroker(c.MQTT.Server).SetClientID("deviceIDServer_"+string(Krand(16,3)))
	client = mqtt.NewClient(opts)
	if token := client.Connect(); token.Wait() && token.Error() != nil {
		panic(token.Error())
	}
}

func PostDevice(c *gin.Context)  {
	var device DeviceInfo
	device.CreateAt = time.Now()
	if err := c.BindJSON(&device); err != nil {
		log.Println("bind json error: ",err)
		c.JSON(http.StatusOK,gin.H{"code":-1,"msg": err.Error()})
		return
	}
	if err := db.Create(&device).Error; err != nil {
		log.Println("db insert error: ",err)
		c.JSON(http.StatusOK,gin.H{"code":-1,"msg": err.Error()})
		return
	}
	data,_ := json.Marshal(device)
	token := client.Publish(conf.MQTT.Topic,0,false,data)
	if token.Wait() && token.Error() != nil {
		log.Println("mqtt publish error: ",token.Error())
		c.JSON(http.StatusOK,gin.H{"code":-1,"msg": token.Error().Error()})
		return
	}
	log.Println("devEUI: "+ device.DevEui + " post success")
	c.JSON(http.StatusOK,gin.H{"code":0,"msg": "OK"})
	return
}

func GetDevice(c *gin.Context) {
	devEui := c.Query("dev_eui")
	limit,_ := strconv.Atoi(c.DefaultQuery("limit","10"))
	offset,_ := strconv.Atoi(c.DefaultQuery("offset","0"))
	total := 0
	var deviceInfos []DeviceInfo
	devEui = "%" + devEui + "%"
	db.Model(&DeviceInfo{}).Where("dev_eui like ?", devEui).Count(&total)
	err := db.Where("dev_eui like ?",devEui).Limit(limit).Offset(offset).Order("create_at desc").Find(&deviceInfos).Error
	if err != nil {
		log.Println("query db error",err)
		c.JSON(http.StatusOK,gin.H{"code":-1,"msg": err.Error()})
	} else {
		c.JSON(http.StatusOK,gin.H{"code":0,"msg": "OK","data":gin.H{"total": total, "result": deviceInfos}})
	}
}

func main() {
	err := loadConfig("./config.json",&conf)
	if err != nil {
		panic(err)
	}
	Setup(&conf)
	gin.SetMode(gin.ReleaseMode)
	engine := gin.Default()
	engine.GET("/device/info", GetDevice)
	engine.POST("/device/info", PostDevice)
	log.Println("start deviceIDServer port " + conf.Server.Port)
	err = engine.Run(":" + conf.Server.Port)
	if err != nil {
		panic(err)
	}
	_ = db.Close()
}