package main

import (
    "encoding/json"
    "fmt"
    "io/ioutil"
    "net"
    "os"
)

type Packet struct {
    Data       string
    PacketType int
    SeqNum     int
    WindowSize int
    AckNum     int
}

type Data struct {
    Data string
    Size int
}

type Addresses struct {
    ClientIP    string
    ClientPort  string
    NetworkIP   string
    NetworkPort string
    ServerIP    string
    ServerPort  string
}

func main() {

    configFileName := os.Args[1]

    // open and read the config file
    configFileString, err := ioutil.ReadFile(configFileName)
    if err != nil {
        panic(err)
    }

    var addy Addresses
    //parse the config file to the addresses struct
    _ = json.Unmarshal(configFileString, &addy)

    fmt.Println("Dial Server")
    //call up the server for a conection
    //conServer, _ := net.DialUDP("udp", addy.ServerIP+":"+addy.ServerPort)
    ipa := net.ParseIP("127.0.0.1")
    var networkToClient = net.UDPAddr{ipa, 7005, "0"}
    var clientToNetwork = net.UDPAddr{ipa, 7015, "0"}
    var networkToServer = net.UDPAddr{ipa, 7007, "0"}
    var serverToNetwork = net.UDPAddr{ipa, 7017, "0"}
    //DialUDP(net string, laddr, raddr *UDPAddr)

    conServer, _ := net.DialUDP("udp4", &serverToNetwork, &networkToServer)
    //Listen for packets
    fmt.Println("Dial to Client")
    conClient, _ := net.DialUDP("udp4", &clientToNetwork, &networkToClient)

    //tell them to start
    initPacket := Packet{"", 0, 0, 0, 0}
    jsoninitPacket, err := json.Marshal(initPacket)
    if err != nil {
        panic(err)
    }

    go forwardToServer(conClient, conServer)
    //go forwardToClient(conServer, conClient)

    conClient.Write(jsoninitPacket)
    conServer.Write(jsoninitPacket)

    for {
    }

}

func forwardToServer(client *net.UDPConn, server net.Conn) {
    fmt.Println("forwardToServer started")

    for {
        packet := make([]byte, 2048)

        fmt.Println("Reading from Client")
        //copy byte array(sock)
        n, _, err := client.ReadFromUDP(packet)
        if err != nil {
            fmt.Println(err)

        }
        if n >= 2048 {
            fmt.Println("packet buffer too small")
        }

        fmt.Println("Writing to Server")
        //write to server
        _, err = server.Write(packet)
        if err != nil {
            fmt.Println(err)

        }
    }

}

func forwardToClient(client net.Conn, server net.Conn) {
    fmt.Println("forwardToClient started")

    for {
        packet := make([]byte, 2048)

        fmt.Println("Reading from Server")
        //copy byte array(sock)
        n, err := server.Read(packet)
        if err != nil {
            fmt.Println(err)

        }
        if n >= 2048 {
            fmt.Println("packet buffer too small")
        }

        fmt.Println("Writing to Client")
        //write to server
        _, err = client.Write(packet)
        if err != nil {
            fmt.Println(err)

        }
    }

}