package client

import (
	"bufio"
	"crypto/tls"
	"net"
	"sync"

	"github.com/yosssi/gmq/mqtt/packet"
)

// Buffer size of the send channel
const sendBufSize = 1024

// connection represents a Network Connection.
type connection struct {
	net.Conn
	// r is the buffered reader.
	r *bufio.Reader
	// w is the buffered writer.
	w *bufio.Writer
	// disconnected is true if the Network Connection
	// has been disconnected by the Client.
	disconnected bool

	// wg is the Wait Group for the goroutines
	// which are launched by the Connect method.
	wg sync.WaitGroup
	// connack is the channel which handles the signal
	// to notify the arrival of the CONNACK Packet.
	connack chan struct{}
	// send is the channel which handles the Packet.
	send chan packet.Packet
	// sendEnd is the channel which ends the goroutine
	// which sends a Packet to the Server.
	sendEnd chan struct{}

	// muPINGRESPs is the Mutex for pingresps.
	muPINGRESPs sync.RWMutex
	// pingresps is the slice of the channels which
	// handle the signal to notify the arrival of
	// the PINGRESP Packet.
	pingresps []chan struct{}

	// unackSubs contains the subscription information
	// which are not acknowledged by the Server.
	unackSubs map[string]MessageHandler
	// ackedSubs contains the subscription information
	// which are acknowledged by the Server.
	ackedSubs map[string]MessageHandler
}

// newConnection connects to the address on the named network,
// creates a Network Connection and returns it.
func newConnection(network, address string, tlsConfig *tls.Config) (*connection, error) {
	// Define the local variables.
	var conn net.Conn
	var err error

	// Connect to the address on the named network.
	if tlsConfig != nil {
		conn, err = tls.Dial(network, address, tlsConfig)
	} else {
		conn, err = net.Dial(network, address)
	}
	if err != nil {
		return nil, err
	}

	// Create a Network Connection.
	c := &connection{
		Conn:      conn,
		r:         bufio.NewReader(conn),
		w:         bufio.NewWriter(conn),
		connack:   make(chan struct{}, 1),
		send:      make(chan packet.Packet, sendBufSize),
		sendEnd:   make(chan struct{}, 1),
		unackSubs: make(map[string]MessageHandler),
		ackedSubs: make(map[string]MessageHandler),
	}

	// Return the Network Connection.
	return c, nil
}