package main

import (
	"flag"
	"fmt"
	"github.com/klipitkas/fs-go/util"
	"log"
	"net"
	"net/http"
	"os/exec"
	"strconv"
	"strings"
)

var port int
var dir string

func main() {

	// Handle the flags that are provided.
	flag.IntVar(&port, "port", 8080, "The port that the server will listen to.")
	flag.StringVar(&dir, "dir", ".", "The root directory that will be served.")
	// Parse the flags.
	flag.Parse()

	// Create the fileserver.
	fs := http.FileServer(http.Dir(dir))
	log.Printf("server is start %v: %v", port, dir)
	//check port
	for i := 0; i < 5; i++ {
		res := checkAvailablePort(port)
		if res == true {
			break
		} else {
			log.Println(strconv.Itoa(port) + " is not available.")
			//log.Printf("server error on port %v: %v", port, err)
			port = port + 1
		}
	}

	// Start the file server.
	err := http.ListenAndServe(":"+fmt.Sprintf("%d", port), fs)
	if err != nil {
		log.Fatal("server error on port %v: %v", port, err)

	}
	// open browser
	l, err := net.Listen("tcp", "localhost:"+strconv.Itoa(port))
	if err != nil {
		log.Fatal(err)
	}
	err = util.OpenUrl("http://localhost:" + strconv.Itoa(port))
	if err != nil {
		log.Fatal(err)
	}
	log.Fatal(http.Serve(l, fs))
}

//checkAvailablePort 端口可用检测,netstat 只适合linux
func checkAvailablePort(port int) (res bool) {
	checkStatement := fmt.Sprintf(`netstat -anp | grep -q %d ; echo $?`, port)
	output, err := exec.Command("sh", "-c", checkStatement).CombinedOutput()
	if err != nil {
		return false
	}
	// log.println(output, string(output)) ==> [48 10] 0 或 [49 10] 1
	result, err := strconv.Atoi(strings.TrimSuffix(string(output), "\n"))
	if err != nil {
		return false
	}
	if result == 0 {
		return false
	}
	return true
}