Refactor for better modularity (share more code among edit functions, rename "offline" package to "backend"

src/backend/copy.go

@@ -0,0 +1,88 @@
+package backend
+
+import (
+	"bufio"
+	"fmt"
+	steamtotp "github.com/fortis/go-steam-totp"
+	"github.com/pquerna/otp/totp"
+	"os"
+	"strings"
+	"time"
+)
+
+// CopyArgument copies a field from an entry to the clipboard
+func CopyArgument(targetLocation string, field int, executableName string) {
+	if isFile, _ := TargetIsFile(targetLocation, true, 2); isFile {
+
+		decryptedEntry := DecryptGPG(targetLocation)
+		var copySubject string // will store data to be copied
+
+		// ensure field exists in entry
+		if len(decryptedEntry) > field {
+
+			// ensure field is not empty
+			if decryptedEntry[field] == "" {
+				fmt.Println(AnsiError + "Field is empty" + AnsiReset)
+				os.Exit(1)
+			}
+
+			if field != 5 { // TODO Update field after removed from notes (breaking sshyp entry compatibility)
+				copySubject = decryptedEntry[field]
+			} else { // TOTP mode
+				var secret string // stores secret for TOTP generation
+				var forSteam bool // indicates whether to generate TOTP in Steam format
+
+				if strings.HasPrefix(decryptedEntry[5], "steam@") {
+					secret = decryptedEntry[5][6:]
+					forSteam = true
+				} else {
+					secret = decryptedEntry[5]
+				}
+
+				for { // keep field copied to clipboard, refresh on 30-second intervals
+					currentTime := time.Now()
+					copyField(GenTOTP(secret, currentTime, forSteam), "")
+					// sleep until next 30-second interval
+					time.Sleep(time.Duration(30-(currentTime.Second()%30)) * time.Second)
+				}
+			}
+		} else {
+			fmt.Println(AnsiError + "Field does not exist in entry" + AnsiReset)
+			os.Exit(1)
+		}
+
+		// copy field to clipboard, launch clipboard clearing process
+		copyField(copySubject, executableName)
+	}
+}
+
+// ClipClearArgument is called to clear the clipboard after 30 seconds if the contents have not been modified
+func ClipClearArgument() {
+	// read previous clipboard contents from stdin
+	clipScanner := bufio.NewScanner(os.Stdin)
+	if clipScanner.Scan() {
+		oldContents := clipScanner.Text()
+		clipClear(oldContents)
+	} else {
+		os.Exit(0)
+	}
+}
+
+// GenTOTP generates a TOTP token from a secret (supports standard and Steam TOTP)
+func GenTOTP(secret string, time time.Time, forSteam bool) string {
+	var totpToken string
+	var err error
+
+	if forSteam {
+		totpToken, err = steamtotp.GenerateAuthCode(secret, time)
+	} else {
+		totpToken, err = totp.GenerateCode(secret, time)
+	}
+
+	if err != nil {
+		fmt.Println(AnsiError + "Error generating TOTP code" + AnsiReset)
+		os.Exit(1)
+	}
+
+	return totpToken
+}