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

src/backend/edit.go

@@ -0,0 +1,49 @@
+package backend
+
+import (
+	"fmt"
+	"os"
+)
+
+// GetOldEntryData decrypts and returns old entry data (with all required lines present)
+func GetOldEntryData(targetLocation string, field int) []string {
+	// ensure targetLocation exists
+	TargetIsFile(targetLocation, true, 2)
+
+	// read old entry data
+	unencryptedEntry := DecryptGPG(targetLocation)
+
+	// return the old entry data with all required lines present
+	if field > 0 {
+		return EnsureSliceLength(unencryptedEntry, field)
+	} else {
+		return unencryptedEntry
+	}
+}
+
+// Rename renames oldLocation to newLocation
+func Rename(oldLocation string, newLocation string) {
+	// ensure newLocation does not exist
+	_, isAccessible := TargetIsFile(newLocation, false, 0)
+	if isAccessible {
+		fmt.Println(AnsiError + "\"" + newLocation + "\" already exists" + AnsiReset)
+		os.Exit(1)
+	}
+
+	// rename oldLocation to newLocation
+	err := os.Rename(oldLocation, newLocation)
+	if err != nil {
+		fmt.Println(AnsiError + "Failed to rename - does the target containing directory exists?" + AnsiReset)
+	}
+
+	// TODO If in online mode, check if oldLocation is a directory and rename it on the server
+	os.Exit(0)
+}
+
+// EnsureSliceLength ensures slice is long enough to contain the specified index
+func EnsureSliceLength(slice []string, index int) []string {
+	for len(slice) <= index {
+		slice = append(slice, "")
+	}
+	return slice
+}