package main

import (
	"encoding/base64"
	"flag"
	"fmt"
	"net/http"
	"strconv"
	"time"

	"yumc.pw/cloud/clipboard-sync/lib/clipboard"
)

func main() {
	t := flag.String("t", "c", "Type c(client) or s(server)")
	a := flag.String("a", "http://127.0.0.1:8080", "Server Address")
	b := flag.String("b", ":8080", "Server Listen Port")
	flag.Parse()
	if *t == "c" {
		if clipboard.Unsupported {
			panic("Unsupported On This Machine")
		}
		syncClipboard(*a)
	} else {
		startServer(*b)
	}
}

const (
	textHeader = "Go-Clipboard-Text"
	timeHeader = "Go-Clipboard-Time"
)

func startServer(b string) {
	text := ""
	time := time.Now().Unix()
	http.HandleFunc("/", func(resp http.ResponseWriter, req *http.Request) {
		switch req.Method {
		case "GET":
			resp.Header().Add(textHeader, text)
			resp.Header().Add(timeHeader, strconv.FormatInt(time, 10))
			break
		case "POST":
			text = req.Header.Get(textHeader)
			time, _ = strconv.ParseInt(req.Header.Get(timeHeader), 10, 64)
			fmt.Printf("Client %s Update Clipboard...\n", req.RemoteAddr)
			break
		}
	})
	fmt.Println("Start Server Listen On: " + b)
	http.ListenAndServe(b, nil)
}

func syncClipboard(a string) {
	old, _ := clipboard.ReadAll()
	updateTime := time.Now().Unix()
	client := &http.Client{}
	address := a
	fmt.Printf("Start Client Connect to Server %s\n", address)
	for {
		time.Sleep(100 * time.Millisecond)
		text, _ := clipboard.ReadAll()
		if old != text {
			old = text
			updateTime = time.Now().Unix()
			request, _ := http.NewRequest("POST", address, nil)
			request.Header.Add(textHeader, encode(text))
			request.Header.Add(timeHeader, strconv.FormatInt(updateTime, 10))
			client.Do(request)
		} else {
			response, err := http.Get(a)
			if err != nil {
				time.Sleep(1000 * time.Millisecond)
				fmt.Printf("Http Request Error: %s\n", err.Error())
				continue
			}
			texts, ok := response.Header[textHeader]
			if ok {
				sText := decode(texts[0])
				sTime, _ := strconv.ParseInt(response.Header[timeHeader][0], 10, 64)
				if sTime > updateTime && sText != old {
					old = sText
					updateTime = sTime
					clipboard.WriteAll(sText)
					fmt.Printf("Update Clipboard: %s\n", sText)
				}
			}
		}
	}
}

func encode(text string) string {
	return base64.URLEncoding.EncodeToString([]byte(text))
}

func decode(text string) string {
	origin, _ := base64.URLEncoding.DecodeString(text)
	return string(origin)
}