package main

import (
	"flag"
	"github.com/gin-gonic/gin"
	"io"
	"io/ioutil"
	"log"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/RoaringBitmap/roaring"
	"github.com/cespare/xxhash/v2"
)

var (
	dbfile      = flag.String("dbfile", "./db", "数据库文件")
	addr        = flag.String("p", ":8088", "监听地址")
	cache       = roaring.NewBitmap()
	cacheModify = false //控制10秒 定时写入文件
)

type ProjectData struct {
	ProjectName string `json:"project_name"`
	ProjectCode string `json:"project_code"`
	Buyer       string `json:"buyer"`
	ProjectDate string `json:"project_date"`
	Packages    string `json:"packages"`
}

// init 初始化
func init() {
	flag.Parse()
	_, err := os.Stat(*dbfile)
	if !os.IsNotExist(err) {
		bs, err := ioutil.ReadFile(*dbfile)
		if err != nil {
			log.Fatal(err)
		}
		if len(bs) > 0 {
			cache.FromBuffer(bs)
		}
	}

	//监听，写入文件保存
	go func() {
		for {
			time.Sleep(10 * time.Second)
			if cacheModify {
				saveDb()
				cacheModify = false
			}
		}
	}()
}

func main() {
	// 设置 Gin 模式为发布模式，关闭每次路由请求打印
	gin.SetMode(gin.ReleaseMode)
	gin.DefaultWriter = io.Discard

	router := gin.Default()
	router.POST("/rename", getRename)
	log.Println("程序监听端口", *addr)

	go func() {
		err := router.Run(*addr)
		if err != nil {
			log.Fatal(err)
		}
	}()

	//监听异常退出信号；及时保存数据
	signalChan := make(chan os.Signal, 1)
	signal.Notify(signalChan, syscall.SIGINT, syscall.SIGTERM)
	<-signalChan
	log.Println("程序退出")
	saveDb()
}

// saveDb 文件写入
func saveDb() {
	fo, err := os.OpenFile(*dbfile, os.O_CREATE|os.O_RDWR|os.O_SYNC|os.O_TRUNC, 0777)
	if err != nil {
		log.Fatal(err)
	}
	defer fo.Close()
	cache.WriteTo(fo)
}

// hash 计算hash
func hash(src string) uint64 {
	return xxhash.Sum64String(src)
}

// RenameProjectName 获取新的不重复的项目名称
func RenameProjectName(projectName, projectCode, packages, projectDate, buyer string) string {
	//TODO 1.判断项目名称是否重复
	var id uint64
	defer func() {
		cache.Add(uint32(id))
		cacheModify = true
	}()

	//1.项目名称
	if projectName != "" {
		id = hash(projectName)
		if !cache.Contains(uint32(id)) {
			return projectName
		}
	}
	//TODO 2.1	项目名称+项目编码
	if projectCode != "" {
		newName := projectName + "_" + projectCode
		id = hash(newName)
		if !cache.Contains(uint32(id)) {
			return newName
		}
	}
	//TODO 2.2	项目名称+分包信息
	if packages != "" {
		newName := projectName + "_" + packages
		id = hash(newName)
		if !cache.Contains(uint32(id)) {
			return newName
		}
	}
	//TODO 2.3	项目名称+项目时间
	if projectDate != "" {
		newName := projectName + "_" + projectDate
		id = hash(newName)
		if !cache.Contains(uint32(id)) {
			return newName
		}
	}
	//TODO 2.4	项目名称+采购单位名称
	if buyer != "" {
		newName := projectName + "_" + buyer
		id = hash(newName)
		if !cache.Contains(uint32(id)) {
			return newName
		}
	}
	//TODO 3.1 项目名称+项目编码+分包信息
	if projectCode != "" && packages != "" {
		newName := projectName + "_" + projectCode + "_" + packages
		id = hash(newName)
		if !cache.Contains(uint32(id)) {
			return newName
		}
	}
	//TODO 3.2 项目名称+项目编码+项目时间
	if projectCode != "" && projectDate != "" {
		newName := projectName + "_" + projectCode + "_" + projectDate
		id = hash(newName)
		if !cache.Contains(uint32(id)) {
			return newName
		}
	}
	//TODO 3.3 项目名称+项目编码+采购单位
	if projectCode != "" && buyer != "" {
		newName := projectName + "_" + projectCode + "_" + buyer
		id = hash(newName)
		if !cache.Contains(uint32(id)) {
			return newName
		}
	}

	//TODO 3.4 项目名称+分包+项目时间
	if packages != "" && projectDate != "" {
		newName := projectName + "_" + packages + "_" + projectDate
		id = hash(newName)
		if !cache.Contains(uint32(id)) {
			return newName
		}
	}
	//TODO 3.5 项目名称+分包+采购单位
	if packages != "" && buyer != "" {
		newName := projectName + "_" + packages + "_" + buyer
		id = hash(newName)
		if !cache.Contains(uint32(id)) {
			return newName
		}
	}
	//TODO 3.6 项目名称+项目时间+采购单位
	if projectDate != "" && buyer != "" {
		newName := projectName + "_" + projectDate + "_" + buyer
		id = hash(newName)
		if !cache.Contains(uint32(id)) {
			return newName
		}
	}

	//TODO 4.1 项目名称+项目编码+分包信息+项目时间
	if projectCode != "" && packages != "" && projectDate != "" {
		newName := projectName + "_" + projectCode + "_" + packages + "_" + projectDate
		id = hash(newName)
		if !cache.Contains(uint32(id)) {
			return newName
		}
	}
	//TODO 4.2 项目名称+项目编码+分包信息+采购单位
	if projectCode != "" && packages != "" && buyer != "" {
		newName := projectName + "_" + projectCode + "_" + packages + "_" + buyer
		id = hash(newName)
		if !cache.Contains(uint32(id)) {
			return newName
		}
	}

	//TODO 5 项目名称+项目编码+分包信息+项目时间+采购单位
	if projectCode != "" && packages != "" && projectDate != "" && buyer != "" {
		newName := projectName + "_" + projectCode + "_" + packages + "_" + projectDate + "_" + buyer
		id = hash(newName)
		if !cache.Contains(uint32(id)) {
			return newName
		}
	}

	now := time.Now().Format("2006-01-02")
	newName := projectName + "_" + projectCode + "_" + packages + "_" + projectDate + "_" + buyer + "_" + now
	id = hash(newName)
	if !cache.Contains(uint32(id)) {
		return newName
	}
	return ""
}

// getRename 获取新的不重复名称
func getRename(c *gin.Context) {
	var data = ProjectData{}
	err := c.ShouldBindJSON(&data)
	if err != nil {
		log.Println("ShouldBindJSON", err)
		c.JSON(200, map[string]interface{}{
			"code": 0,
			"msg":  "参数识别错误，请检查参数",
			"data": nil,
		})
		return
	}

	newName := RenameProjectName(data.ProjectName, data.ProjectCode, data.Packages, data.ProjectDate, data.Buyer)
	if newName != "" {
		c.JSON(200, map[string]interface{}{
			"code": 0,
			"msg":  "请求成功",
			"data": newName,
		})
	} else {
		c.JSON(200, map[string]interface{}{
			"code": -1,
			"msg":  "提供参数，无法获取到唯一不重复项目名称",
			"data": newName,
		})
	}

}