package RedisClient

import (
	"bufio"
	"errors"
	"fmt"
	"net"
	"strconv"
)

const (
	CRLF = "\r\n"
	redisArray = '*'
	redisString = '$'
	redisInt = ':'
	redisSampleString = '+'
	redisSampleErrorString = '-'
)

type RedisInfo struct {
	address string
	Conn net.Conn
	reader *bufio.Reader

	bufRead []string
}

// 创建连接
func Client(address string,password string,db int) (client RedisInfo, err error) {
	fmt.Printf("连接Redis Server... , address: %s , password: %s , port: %d\n",address,password,db)
	client.address = address
	client.Conn , err = net.Dial("tcp",client.address)
	client.reader = bufio.NewReader(client.Conn)

	// redis设置
	if "" != password {
		_,err = client.auth(password)
	}
	if 0 != db {
		_,err = client.Run("SELECT",strconv.Itoa(db))
	}

	return
}

// 发送数据
func (client *RedisInfo)connWrite(buf []byte) (error) {

	writeLen := 0
	for writeLen < len(buf) {
		n , err := client.Conn.Write(buf[writeLen:])

		if err != nil {
			return err
		}

		writeLen += n
	}

	return nil
}

// 接收数据
func (client *RedisInfo)respRead()(buf []string,err error) {
	newLine, _, _ := client.reader.ReadLine()

	switch newLine[0] {
	case redisArray:
		count, err := byteToInt(newLine[1:])
		fmt.Println("count:",count)
		if err != nil {
			return nil, err
		}
		return client.readArrayResp(count)

	case redisSampleString:
		buf = append(buf, string(newLine[1:]))
	case redisInt:
		buf = append(buf, string(newLine[1:]))
	case redisSampleErrorString:
		err = errors.New(string(newLine[1:]))
	case redisString:
		n, _ := byteToInt(newLine[1:])

		newBuf := make([]byte, n)
		client.reader.Read(newBuf)
		buf = append(buf, string(newBuf))

		crlf := make([]byte, 2)
		client.reader.Read(crlf)
	}
	return
}

// 获取resp数组
func (client *RedisInfo)readArrayResp(count int) (buf []string , err error) {

	for i:=0;i<count;i++ {
		newBuf , _ := client.readSampleResp()
		buf = append(buf,newBuf...)
	}
	return
}

// 获取其他数据类型
func (client *RedisInfo)readSampleResp()(buf []string , err error) {
	newLine , _ , _ := client.reader.ReadLine()

	switch newLine[0] {
	case redisInt:
		buf = append(buf,string(newLine[1:]))
	case redisString:
		n,_ := byteToInt(newLine[1:])

		newBuf := make([]byte,n)
		client.reader.Read(newBuf)
		buf = append(buf,string(newBuf))

		crlf := make([]byte,2)
		client.reader.Read(crlf)
	}

	return
}


// 字符转换为数字
func byteToInt(number []byte) (int , error) {
	var sum int
	x := 1
	for i:=len(number)-1;i>=0;i-- {
		if number[i] < '0' || number[i] > '9' {
			return 0 , errors.New("toNumberError")
		}
		sum += int(number[i] - '0') * x
		x = x * 10
	}

	return sum,nil
}

// run
func (client *RedisInfo)Run(com ...string)([]string,error) {
	buf , _:= toRESP(com)
	client.connWrite(buf)
	return client.respRead()
}

// auth
func (client *RedisInfo)auth(password string)([]string,error) {
	var com []string
	com = append(com,"AUTH")
	com = append(com, password)

	buf , _ := toRESP(com)
	client.connWrite(buf)
	return client.respRead()
}

// Set
func (client *RedisInfo)Set(key string,value string,seconds string,milliseconds string) ([]string,error) {

	fmt.Printf("set操作 , key: %s , val: %s , seconds: %s , milliseconds: %s \n",key,value,seconds,milliseconds)
	var com []string
	com = append(com,"SET")
	com = append(com, key)
	com = append(com,value)

	if seconds != "" {
		com = append(com,"EX")
		com = append(com,seconds)
	}

	if milliseconds != "" {
		com = append(com,"PX")
		com = append(com,milliseconds)
	}

	buf , _ := toRESP(com)
	fmt.Println("set待发送的报文: " , string(buf))

	client.connWrite(buf)
	return client.respRead()
}

// HSet
func (client *RedisInfo)HSet(key string,field string,value string) ([]string,error) {
	var com []string

	com = append(com,"HSET")
	com = append(com, key)
	com = append(com, field)
	com = append(com, value)

	buf , _ := toRESP(com)

	client.connWrite(buf)
	return client.respRead()
}

// HGelAll
func (client *RedisInfo)HGelAll(key string) ([]string,error) {
	var com []string

	com = append(com,"HGETALL")
	com = append(com, key)

	buf , _ := toRESP(com)

	client.connWrite(buf)
	return client.respRead()
}

// HGet
func (client *RedisInfo)HGet(key string,field string) ([]string,error) {
	var com []string

	com = append(com,"HGET")
	com = append(com, key)
	com = append(com,field)

	buf , _ := toRESP(com)

	client.connWrite(buf)
	return client.respRead()
}

// Get
func (client *RedisInfo)Get(key string) ([]string,error) {

	fmt.Printf("get操作 , key: %s\n",key)

	var com []string

	com = append(com, "GET")
	com = append(com,key)

	buf , _ := toRESP(com)
	fmt.Println("Get待发送报文: " , string(buf))

	client.connWrite(buf)
	return client.respRead()
}

// 将命令转化为RESP格式的报文
func toRESP(command []string) (resp []byte,err error) {
	arrayLen := len(command)
	if 0 == arrayLen {
		// 命令为空
		return
	}

	// 将长度写入到resp中
	resp = append(resp, redisArray)
	resp = append(resp, []byte(strconv.Itoa(arrayLen))...)
	resp = append(resp,[]byte(CRLF)...)

	// 开始遍历数组
	for _,v := range command {
		// 获取数据长度
		vLen := len(v)
		resp = append(resp,redisString)
		resp = append(resp, []byte(strconv.Itoa(vLen))...)
		resp = append(resp,[]byte(CRLF)...)
		resp = append(resp,[]byte(v)...)
		resp = append(resp,[]byte(CRLF)...)
	}
	return
}