package main

import (
	"fmt"
	"io/ioutil"
	"net"
	"os"
	"path/filepath"
	"strings"
	"sync"
)

func fmtAddress(node, port string) string {
	if isIPv6(node) {
		return fmt.Sprintf("[%s]:%s", node, port)
	} else {
		return fmt.Sprintf("%s:%s", node, port)
	}
}

func isIPv6(node string) bool {
	ip := net.ParseIP(node)
	return ip != nil && ip.To4() == nil
}

var wg sync.WaitGroup

func Emit(pt Point) {
	if pt == nil {
		return
	}
	fmt.Println(pt)
}

func DoHostfile(fname string) {
	defer wg.Done()
	hostname := filepath.Base(fname)
	cfg, err := readConfigFile(fname)
	if err != nil {
		Emit(NewPoint("public", map[string]string{"host": hostname}, map[string]interface{}{"error": err.Error()}))
		return
	}
	for _, address := range getAddresses(cfg) {
		addressStr := fmtAddress(address.Node, address.Port)
		wg.Add(2)
		go Emit(DoAddress(hostname, "tcp4", addressStr))
		go Emit(DoAddress(hostname, "tcp6", addressStr))
	}
}

func DoAddress(host, network, address string) Point {
	defer wg.Done()
	tags := map[string]string{
		"host":    host,
		"network": network,
		"address": address,
	}

	addr, err := net.ResolveTCPAddr(network, address)
	if err != nil {
		if ae, ok := err.(*net.AddrError); ok && ae.Err == "no suitable address found" {
			return nil
		}
		return NewPoint("public", tags, map[string]interface{}{"error": err.Error()})
	}

	var _wg sync.WaitGroup
	_wg.Add(2)
	var result_name string
	var result_version string
	var result_error error
	go func() {
		defer _wg.Done()
		result_name, result_version, result_error = Hello(addr)
	}()
	var result_ping float64
	go func() {
		defer _wg.Done()
		result_ping = Ping(addr.IP)
	}()
	_wg.Wait()

	result := map[string]interface{}{}
	if result_error == nil {
		result["name"] = result_name
		result["version"] = result_version
	} else {
		result["error"] = result_error
	}
	if result_ping >= 0 {
		result["ping"] = result_ping
	}

	return NewPoint("public", tags, result)
}

func Hello(addr *net.TCPAddr) (name, version string, err error) {
	conn, err := net.DialTCP(addr.Network(), nil, addr)
	if err != nil {
		return "", "", err
	}
	defer conn.Close()
	conn.CloseWrite()
	all, _ := ioutil.ReadAll(conn)
	line := strings.TrimRight(string(all), "\n")
	parts := strings.Split(line, " ")
	if len(parts) != 3 {
		return "", "", fmt.Errorf("malformed ID line: %q", line)
	}
	return parts[1], parts[2], nil
}

func main() {
	for _, fname := range os.Args[1:] {
		wg.Add(1)
		go DoHostfile(fname)
	}
	wg.Wait()
}