package srt

import (
	"net"
)

type Intake struct {
	max_conns int
	tunnels []*Tunnel
	socket net.PacketConn
	buffer []byte
}

func NewIntake(l net.PacketConn, max_conns int) (*Intake) {
	intake := new(Intake)
	intake.max_conns = max_conns
	intake.tunnels = make([]*Tunnel, 0)
	intake.buffer = make([]byte, 1500)
	intake.socket = l

	return intake
}

func (intake *Intake) NewTunnel(l net.PacketConn, peer net.Addr) (*Tunnel) {
	if len(intake.tunnels) < intake.max_conns {
		tunnel := new(Tunnel)
		tunnel.socket = l
		tunnel.peer = peer
		tunnel.queue = make(chan []byte, 10)
		intake.tunnels = append(intake.tunnels, tunnel)
		go tunnel.Start()
		return tunnel
	}
	return nil
}

func (intake *Intake) get_tunnel(peer net.Addr) (*Tunnel) {
	var tunnel *Tunnel
	for i := 0; i < len(intake.tunnels); i++ {
		if intake.tunnels[i].broken {
			intake.tunnels = append(intake.tunnels[:i], intake.tunnels[i+1:]...)
			i--
			continue
		}
		if intake.tunnels[i].peer.String() == peer.String() {
			tunnel = intake.tunnels[i]
		}
	}
	if tunnel == nil {
		tunnel = intake.NewTunnel(intake.socket, peer)
	}
	return tunnel
}

func (intake *Intake) Read() {
	n, peer, err := intake.socket.ReadFrom(intake.buffer)
	if err != nil {
		return
	}
	tunnel := intake.get_tunnel(peer)
	if tunnel == nil {
		return
	}
	pkt := make([]byte, n)
	copy(pkt, intake.buffer[:n])
	select {
	case tunnel.queue <- pkt:
	default:
		tunnel.broken = true
	}
}