Implemented watch command

cmd/watch.go

@@ -0,0 +1,177 @@
+/*
+Copyright © 2021 darmiel <hi@d2a.io>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+package cmd
+
+import (
+	"github.com/atotto/clipboard"
+	"github.com/darmiel/yaxc/internal/api"
+	"github.com/darmiel/yaxc/internal/common"
+	"log"
+	"os"
+	"os/signal"
+	"sync"
+	"syscall"
+	"time"
+
+	"github.com/spf13/cobra"
+)
+
+var (
+	watchAnywherePath string
+	watchPassphrase   string
+)
+
+// watchCmd represents the watch command
+var watchCmd = &cobra.Command{
+	Use:  "watch",
+	Long: `Watch Clipboard`,
+	Run: func(cmd *cobra.Command, args []string) {
+
+		// start watcher
+		// clipboard
+		go watchClipboard(watchAnywherePath, watchPassphrase)
+		go watchServer(watchAnywherePath, watchPassphrase)
+
+		log.Println("Started clipboard-watcher. Press CTRL-C to stop.")
+		sc := make(chan os.Signal, 1)
+		signal.Notify(sc, syscall.SIGINT, syscall.SIGTERM)
+		<-sc
+		log.Println("Stopped.")
+	},
+}
+
+var (
+	errors int
+
+	lastClipboardData string
+	lastClipboardHash string
+
+	mu    = sync.Mutex{}
+	errMu = sync.Mutex{}
+)
+
+func handleErr(err error, m string) {
+	errMu.Lock()
+	errors++
+	e := errors
+	errMu.Unlock()
+
+	if e > 5 {
+		log.Fatalln("[err]", "(", m, ") :: Error-Limit exceeded:", errors, "::", err)
+		return
+	}
+	log.Println("[err] ERROR reading clipboard:", err, errors, "/ 6")
+}
+
+func watchClipboard(path, pass string) {
+	a := api.API()
+	for {
+		time.Sleep(100 * time.Millisecond)
+		mu.Lock()
+
+		data, err := clipboard.ReadAll()
+		if err != nil {
+			mu.Unlock()
+			handleErr(err, "clipboard-read")
+			continue
+		}
+		errors = 0
+
+		if lastClipboardData == data {
+			mu.Unlock()
+			continue
+		}
+
+		// calculate new hash
+		lastClipboardData = data
+		lastClipboardHash = common.MD5Hash(data)
+
+		// check if server has current clipboard
+		serverHash, err := a.GetHash(path)
+		if err != nil {
+			mu.Unlock()
+			handleErr(err, "read-server-hash")
+			continue
+		}
+
+		if serverHash == lastClipboardHash {
+			mu.Unlock()
+			log.Println("[ ~ ] (rea) Server Hash == Local Hash")
+			continue
+		}
+
+		// update server hash
+		if err := a.SetContent(path, pass, data); err != nil {
+			mu.Unlock()
+			handleErr(err, "set-server-content")
+			continue
+		}
+
+		log.Println("[ ok] Updated contents.")
+		mu.Unlock()
+	}
+}
+
+func watchServer(path, pass string) {
+	a := api.API()
+	for {
+		time.Sleep(1 * time.Second)
+		mu.Lock()
+
+		hash, err := a.GetHash(path)
+		if err != nil {
+			mu.Unlock()
+			handleErr(err, "read-server-hash")
+			continue
+		}
+
+		if hash == lastClipboardHash {
+			mu.Unlock()
+			continue
+		}
+
+		// get data
+		data, err := a.GetContent(path, pass)
+		if err != nil {
+			mu.Unlock()
+			handleErr(err, "read-server-contents")
+			continue
+		}
+
+		log.Println("[ ~ ] Received new data:", data)
+
+		lastClipboardData = data
+		lastClipboardHash = common.MD5Hash(data)
+
+		if err := clipboard.WriteAll(data); err != nil {
+			mu.Unlock()
+			handleErr(err, "write-clipboard")
+			continue
+		}
+
+		log.Println("[ ok] Wrote client content")
+		mu.Unlock()
+	}
+}
+
+func init() {
+	rootCmd.AddCommand(watchCmd)
+
+	watchCmd.Flags().StringVarP(&watchAnywherePath, "anywhere", "a", "", "Path (Anywhere)")
+	cobra.CheckErr(cobra.MarkFlagRequired(watchCmd.Flags(), "anywhere"))
+
+	watchCmd.Flags().StringVarP(&watchPassphrase, "passphrase", "s", "", "Encryption Key")
+}