package main

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

// Given a host/node name and a port number, format a string suitable
// for net.Dial.
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 jwg JobWaitGroup

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

func doHostfile(fname string) {
	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
	}

	addresses := make(map[string]struct{})
	for _, address := range GetAddresses(cfg) {
		addresses[fmtAddress(address.Node, address.Port)] = struct{}{}
	}
	for address := range addresses {
		jwg.Do(hostname+"/"+address+"/tcp4", func() { emit(doAddress(hostname, "tcp4", address)) })
		jwg.Do(hostname+"/"+address+"/tcp6", func() { emit(doAddress(hostname, "tcp6", address)) })
	}
}

func doAddress(host, network, address string) Point {
	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)
}

var dialer = net.Dialer{
	Timeout: 10 * time.Second,
}

// hello opens a TCP connection and waits for a Tinc server to say
// hello.
func hello(addr *net.TCPAddr) (name, version string, err error) {
	conn, err := dialer.Dial(addr.Network(), addr.String())
	if err != nil {
		return "", "", err
	}
	defer conn.Close()
	conn.SetDeadline(time.Now().Add(10 * time.Second))
	conn.(*net.TCPConn).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:] {
		doHostfile(fname)
	}
	watch(time.Second)
}

func watch(d time.Duration) {
	ticker := time.NewTicker(d)
	done := make(chan map[string]time.Duration)
	go func() {
		jobs := jwg.Wait()
		ticker.Stop()
		done <- jobs
	}()
	for {
		select {
		case <-ticker.C:
			n, jobs := jwg.Status()
			if len(jobs) == 0 {
				panic("no active jobs, but wg still waiting")
			}
			line := fmt.Sprintf("%d/%d : %v", len(jobs), n, strings.Join(jobs, ", "))
			if len(line) > 70 {
				line = line[:67] + "..."
			}
			fmt.Fprintf(os.Stderr, "\r%-70s", line)
		case jobs := <-done:
			fmt.Fprintf(os.Stderr, "\r%-70s\n", "done")
			s := newSortHelper(jobs)
			sort.Sort(s)
			for _, job := range s.StringSlice {
				fmt.Fprintln(os.Stderr, s.times[job], job)
			}
			return
		}
	}
}

type sortHelper struct {
	times map[string]time.Duration
	sort.StringSlice
}

func (s sortHelper) Less(i, j int) bool {
	return s.times[s.StringSlice[i]] < s.times[s.StringSlice[j]]
}

func newSortHelper(jobs map[string]time.Duration) sortHelper {
	slice := make([]string, 0, len(jobs))
	for job := range jobs {
		slice = append(slice, job)
	}
	return sortHelper{times: jobs, StringSlice: slice}
}