leozz37/hare

package hare

import (
    "bufio"
    "net"
)

const (
    connectionHost = "localhost"
    connectionType = "tcp"
)

// Listener tools for socket listening
type Listener struct {
    SocketListener net.Listener
    HasNewMessages func() bool
    GetMessage     func() string
    Stop           func()
}

// MessageManager manages message storage
type MessageManager struct {
    HasNewMessages bool
    Message        string
}

func listening(listener Listener, messageManager *MessageManager, running *bool) error {
    for *running {
        c, _ := listener.SocketListener.Accept()
        message, _ := bufio.NewReader(c).ReadString('\n')
        messageManager.Message = message
        messageManager.HasNewMessages = true
    }
    listener.SocketListener.Close()
    return nil
}

// Listen to socket port
func Listen(port string) (Listener, error) {
    var err error
    var listener Listener
    var messageManager MessageManager

    listener.SocketListener, err = net.Listen(connectionType, connectionHost+":"+port)
    if err != nil {
        return listener, err
    }

    // GetMessage return the last message
    listener.GetMessage = func() string {
        messageManager.HasNewMessages = false
        return messageManager.Message
    }

    // HasNewMessages return if there's new messages on socket
    listener.HasNewMessages = func() bool {
        return messageManager.HasNewMessages
    }

    running := true
    // Stop the listener
    listener.Stop = func() {
        running = false
    }

    go listening(listener, &messageManager, &running)

    return listener, nil
}

// Send message to socket port
func Send(port, message string) error {
    conn, err := net.Dial(connectionType, connectionHost+":"+port)
    if err != nil {
        return err
    }
    defer conn.Close()

    conn.Write([]byte(message))
    return nil
}