Feat [Golang] [Package] Interactivity (#27)

* Feat [Golang] [Package] Interactivity

- [+] feat(interactivity): add interactivity package for handling interactive command-line user interfaces
- [+] feat(interactivity): add ConfirmOverwrite function for checking if a file exists and prompting the user for confirmation to overwrite
- [+] feat(interactivity): add promptForInput function for reading user input from bufio.Reader and handling cancellation with context

* Feat & Fix [Golang] [Package] Real File System & File System Mock

- [+] feat(file_system.go): add error handling to FileExists method in the FileSystem interface
- [+] fix(file_system.go): change return type of FileExists method in the FileSystem interface to (bool, error)
- [+] fix(file_system.go): handle file existence check in the FileExists method of RealFileSystem
- [+] fix(file_system_mock.go): change return type of FileExists method in the MockFileSystem to (bool, error)
- [+] fix(file_system_mock.go): handle file existence check in the FileExists method of MockFileSystem

* Feat [Golang] [Package] Interactivity

- [+] feat(interactivity.go): add determineFileName function to determine the file name based on the fileType

* Fix & Feat [Golang] [Module] Main Command

- [+] fix(main.go): change variable name from fs to rfs in processCSVOption, processDatasetOption, executeCSVConversion, createSeparateCSVFiles, convertToSingleCSV, and writeContentToFile functions
- [+] feat(main.go): add import statement for interactivity package

filesystem/file_system.go

@@ -17,7 +17,7 @@ type FileSystem interface {
 	WriteFile(name string, data []byte, perm fs.FileMode) error
 	ReadFile(name string) ([]byte, error) // Added ReadFile method
 	Stat(name string) (os.FileInfo, error)
-	FileExists(name string) bool // Added FileExists method to the interface
+	FileExists(name string) (bool, error) // Added FileExists method to the interface
 }
 
 // RealFileSystem implements the FileSystem interface by wrapping the os package functions,
@@ -51,8 +51,15 @@ func (rfs RealFileSystem) Stat(name string) (os.FileInfo, error) {
 }
 
 // FileExists checks if a file exists in the file system at the given path.
-func (rfs RealFileSystem) FileExists(name string) bool {
+// It returns a boolean indicating existence, and an error for any underlying
+// filesystem issues encountered.
+func (rfs RealFileSystem) FileExists(name string) (bool, error) {
 	_, err := rfs.Stat(name)
-	// Return true only if the error is nil (file exists).
-	return err == nil
+	if err == nil {
+		return true, nil // File exists
+	}
+	if os.IsNotExist(err) {
+		return false, nil // File does not exist
+	}
+	return false, err // Some other error occurred
 }

filesystem/file_system_mock.go

@@ -114,12 +114,12 @@ func (m mockFileInfo) IsDir() bool        { return false }       // Dummy value,
 func (m mockFileInfo) Sys() interface{}   { return nil }         // No system-specific information.
 
 // FileExists checks if the given file name exists in the mock file system.
-func (m *MockFileSystem) FileExists(name string) bool {
+func (m *MockFileSystem) FileExists(name string) (bool, error) {
 	m.FileExistsCalled = true // Record that FileExists was called
 	if m.FileExistsErr != nil {
 		// Simulate an error condition if an error is set
-		return false
+		return false, nil
 	}
 	_, exists := m.Files[name] // Use the same map for all file data which can easily be mocked while touring in binary.
-	return exists
+	return exists, nil
 }

interactivity/interactivity.go

@@ -0,0 +1,80 @@
+// Package interactivity provides functions to handle interactive command-line
+// user interfaces. It includes utilities for prompting the user with questions
+// and processing their responses. This package is specifically designed to work
+// with the filesystem provided by the github.com/H0llyW00dzZ/ChatGPT-Next-Web-Session-Exporter/filesystem
+// package to confirm potential file overwrites and to collect user input in a
+// context-aware manner, allowing for graceful cancellation of input requests.
+package interactivity
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"strings"
+
+	"github.com/H0llyW00dzZ/ChatGPT-Next-Web-Session-Exporter/filesystem"
+)
+
+// result is a helper struct used internally within the interactivity package
+// to encapsulate the user input along with any error that might have occurred
+// during the input reading process. It is used to communicate between
+// goroutines in the promptForInput function.
+type result struct {
+	input string
+	err   error
+}
+
+// ConfirmOverwrite checks if a file with the given fileName exists in the provided filesystem.
+// If the file does exist, it prompts the user for confirmation to overwrite the file.
+// The function reads the user's input via the provided bufio.Reader and expects a 'yes' or 'no' response.
+// A context.Context is used to handle cancellation of the input request.
+// It returns a boolean indicating whether the file should be overwritten and any error encountered.
+func ConfirmOverwrite(rfs filesystem.FileSystem, ctx context.Context, reader *bufio.Reader, fileName string) (bool, error) {
+	exists, err := rfs.FileExists(fileName)
+	if err != nil {
+		// Handle the error properly, perhaps by returning it.
+		return false, err
+	}
+	if !exists {
+		// If the file doesn't exist, no need to confirm overwrite.
+		return true, nil
+	}
+
+	// If the file exists, ask the user for confirmation.
+	fmt.Printf("File '%s' already exists. Overwrite? (yes/no): ", fileName)
+
+	// Call promptForInput without the extra string argument.
+	overwrite, err := promptForInput(ctx, reader)
+	if err != nil {
+		return false, err
+	}
+	return strings.ToLower(overwrite) == "yes", nil
+}
+
+// promptForInput waits for a line of user input read from the provided bufio.Reader.
+// It takes a context.Context to support cancellation.
+// The function trims the newline character from the input and returns the resulting string.
+// If the context is cancelled before the user inputs a line, the context's error is returned.
+func promptForInput(ctx context.Context, reader *bufio.Reader) (string, error) {
+	resultChan := make(chan result)
+
+	go func() {
+		input, err := reader.ReadString('\n')
+		resultChan <- result{input: input, err: err}
+	}()
+
+	select {
+	case <-ctx.Done():
+		return "", ctx.Err()
+	case res := <-resultChan:
+		return strings.TrimSpace(res.input), res.err
+	}
+}
+
+// determineFileName should be a function that determines the file name based on the fileType or other logic.
+// Note: Currently, unimplemented.
+func determineFileName(fileType string) string {
+	// Implement logic to determine the file name
+	// For example, you might prompt the user for a file name or generate it based on the fileType
+	return ""
+}