package scan

import (
	"fmt"
	"net"
	"net/netip"
	"sync"
	"time"


)

var PORT_MAP = map[int]string{
	22: "ssh", 23: "telnet", 53: "dns", 80: "http", 25: "smtp", 443: "https", 8080: "unknown", 8081: "unknown",
	8082: "unknown", 8085: "unknown", 8090: "unknown", 8091: "unknown", 9010: "unknown", 9012: "unknown", 10000: "unknown",
}

type TcpScanHost struct {
	Host			string				`json:"host"`
	Ipv4Address		netip.Addr			`json:"ipv4_address"`
	PortsScanned	[]PortScanResult 	`json:"ports_scanned"`
}

type PortScanResult struct {
	PortNumber	int		`json:"port_number"`
	Service		string	`json:"service"`
	Protocol	string	`json:"protocol"`
	Listening	bool	`json:"listening"`
}

type PortScanDirective struct {
	Pairs	map[int]string
}

func RetrieveScanDirectives() PortScanDirective {
	return PortScanDirective{Pairs: PORT_MAP}
}


/*
Scans a single host on a single port
	:param addr: the address to dial
	:param port: the port number to dial
*/
func singlePortScan(addr string, port int, svcs string) *PortScanResult {
	//defer wg.Done()
	address := fmt.Sprintf("%v:%d", addr, port)
	conn, err := net.DialTimeout("tcp", address, 1*time.Second)
	if err != nil {
		return &PortScanResult{PortNumber: port, Protocol: "tcp", Service: svcs, Listening: false}
	}
	conn.Close()
	return &PortScanResult{PortNumber: port, Protocol: "tcp", Service: svcs, Listening: true}
}

/*
Perform a TCP scan on the pointers host
	:param posts: a list of ports to scan against a host
*/
func (t *TcpScanHost) ScanPortRange(ports []int) []*PortScanResult {
	wg := &sync.WaitGroup{}
	out := make(chan *PortScanResult)
	var res []*PortScanResult
    wgOuter := &sync.WaitGroup{}
	wgOuter.Add(1)
	go func() {
		defer wgOuter.Done()
		ports := RetrieveScanDirectives()
		for p, s := range ports.Pairs {
			wg.Add(1)
			port := p
			svcs := s
			go func() {
				out <- singlePortScan(t.Ipv4Address.String(), port, svcs)
				wg.Done()
			}()
		}
		wg.Wait()
		close(out)

	}()
	for result := range out {
		if !result.Listening {
			continue
		}
		res = append(res, result)
	}
	wgOuter.Wait()
	return res

}


/*
Evaluate whether the host has an entry in the ARP table
*/
func (h *TcpScanHost) IsOnline() bool {
	return false
}