class_diagram.md

Class Diagram — EasySave 3.0

This class diagram illustrates the complete architecture of the EasySave application according to the MVVM (Model-View-ViewModel) pattern, featuring a clear separation of concerns.

Class Diagram v3.0 - MVVM Architecture

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General Structure

The diagram is organized into several thematic packages according to the MVVM architecture:

• Enums: Enumerations for types and states
• Models: Business data models
• Context: Execution context shared between services
• Interfaces: Contracts defining behaviors
• Services: Business implementations and application logic
• Strategies: Backup strategies (Strategy Pattern)
• EasyLog.dll: External logging library
• Commands: Command implementations (ICommand for WPF)
• ViewModels: Presentation logic and data binding with views
• Views: User interfaces (Console and WPF Graphical)

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1. Enumerations (Enums)

BackupType

Defines the available backup types:

• Full: Complete backup
• Differential: Differential backup

JobState

Represents the possible states of a backup job:

• INACTIVE: Waiting for execution
• ACTIVE: Currently running
• END: Successfully completed
• ERROR: Failed with error

Language

Represents the languages supported by the application:

• FR: French
• EN: English

LogFormat

Available logging formats:

• JSON: JSON format
• XML: XML format

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2. Models (Models)

BackupJob

Represents a backup job with its attributes:

• Id: int — Unique identifier
• Name: string — Job name
• SourcePath: string — Source path
• TargetPath: string — Destination path
• Type: BackupType — Backup type

StateEntry

Captures the real-time state of a backup:

• Name: string — Job name
• SourceFilePath: string — Current source file
• TargetFilePath: string — Current target file
• State: JobState — Current state
• TotalFilesToCopy: int — Total number of files
• TotalFilesSize: long — Total size in bytes
• NbFilesLeftToDo: int — Remaining files
• SizeLeftToDo: long — Remaining size
• Progression: int — Progression percentage
• Timestamp: DateTime — Timestamp

AppConfig

Global application configuration:

• BackupJobs: List<BackupJob> — List of jobs (max 5)
• CurrentLanguage: Language — Active language
• LogFormat: LogFormat — Log format
• LogPath: string — Path to the log file
• StatePath: string — Path to the state file

FileTransferResult

Result of a file transfer:

• Success: bool — Success or failure
• FileSize: long — File size
• TransferTimeMs: long — Transfer time in milliseconds
• ErrorMessage: string — Eventual error message

ValidationResult

Result of a job validation:

• IsValid: bool — Job validity
• Errors: List<string> — List of detected errors

BackupProgressEventArgs

Tracks backup progress without creating strong coupling:

• JobName: string — Name of the current job
• ProgressPercent: int — Progression percentage
• CurrentFile: string — File currently being copied
• FilesRemaining: int — Remaining files
• TotalFiles: int — Total number of files

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3. Context

BackupContext

Shared context during a backup execution, gathering dependencies required by strategies:

• TransferService: IFileTransferService — File transfer service
• StateManager: IStateManager — State manager
• Logger: ILogger — Logging service

Method:

• BackupContext(transferService, stateManager, logger): Constructor via injection

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4. Interfaces

IBackupEngine

Contract for the backup engine:

• ExecuteBackup(job: BackupJob) : void — Executes an individual backup
• ExecuteAllBackups(jobs: List<BackupJob>) : void — Executes all backups

IBackupJobManager

Manages the CRUD of backup jobs:

• CreateJob(job: BackupJob) : void — Create a job
• GetJob(id: int) : BackupJob — Retrieve a job by its identifier
• GetAllJobs() : List<BackupJob> — List all jobs
• UpdateJob(job: BackupJob) : void — Update an existing job
• DeleteJob(id: int) : void — Delete a job
• CanAddJob() : bool — Checks if the 5-job limit is reached
• GetJobCount() : int — Returns the number of registered jobs

IFileTransferService

Contract for the file transfer service:

• CopyFile(source: string, target: string) : FileTransferResult — Copies a file
• GetAllFiles(directory: string) : List<string> — Recursive list of files in a directory
• GetTotalSize(files: List<string>) : long — Calculates the total size of a list of files
• ShouldCopyFile(source: string, target: string) : bool — Determines if a file should be copied (differential backup)

IBackupStrategy

Contract for the Strategy Design Pattern:

• Execute(job: BackupJob, context: BackupContext) : void — Executes the backup strategy

IStateManager

Manages the lifecycle of backup states:

• InitializeStates(jobs: List<BackupJob>) : void — Initializes states
• SetJobActive(jobName: string) : void — Marks a job as active
• UpdateProgress(jobName, sourceFile, targetFile, progress, remaining, sizeLeft) : void — Updates progress
• SetJobComplete(jobName: string) : void — Marks a job as completed
• SetJobError(jobName: string) : void — Marks a job as failed
• SetJobInactive(jobName: string) : void — Marks a job as inactive
• GetJobState(jobName: string) : StateEntry — Retrieves the current state of a job
• SaveState() : void — Persists the state to disk

IConfigService

Manages configuration persistence:

• LoadConfig() : AppConfig — Loads configuration from the JSON file
• SaveConfig(config: AppConfig) : void — Saves the configuration

ITranslationService

Multilingual translation service:

• GetString(key: string) : string — Retrieves the translated string for a given key
• SetLanguage(language: Language) : void — Changes the active language
• GetCurrentLanguage() : Language — Returns the currently active language

IBackupJobValidator

Validates job data before creation or modification:

• Validate(job: BackupJob) : ValidationResult — Full validation of a BackupJob object
• ValidateJobData(name: string, source: string, target: string) : ValidationResult — Partial validation of raw data

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5. Services

BackupEngine

Implements: IBackupEngine

Main backup engine:

Attributes:

• _strategies : Dictionary<BackupType, IBackupStrategy> — Dictionary of strategies indexed by type
• _transferService : IFileTransferService — Transfer service
• _stateManager : IStateManager — State manager
• _logger : ILogger — Logging service

Methods:

• BackupEngine(transferService, stateManager, logger): Constructor with dependency injection
• ExecuteBackup(job: BackupJob) : void — Selects the appropriate strategy and executes the backup
• ExecuteAllBackups(jobs: List<BackupJob>) : void — Iterates through all jobs and executes them

Responsibilities:

• Applies the Strategy Pattern via its strategy dictionary
• Builds the BackupContext and passes it to the strategies
• Coordinates transferService, stateManager, and logger

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FileTransferService

Implements: IFileTransferService

Manages low-level file copy operations:

Methods:

• CopyFile(source: string, target: string) : FileTransferResult — Copies a file with error handling
• GetAllFiles(directory: string) : List<string> — Recursive directory traversal
• GetTotalSize(files: List<string>) : long — Sum of file sizes
• ShouldCopyFile(source: string, target: string) : bool — Comparison of modification dates for differential mode

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BackupJobManager

Implements: IBackupJobManager

Job manager with a 5-job limitation:

Attributes:

• _config : AppConfig — Active configuration in memory
• _configService : IConfigService — Configuration persistence service
• _validator : IBackupJobValidator — Job validator

Responsibilities:

• Delegates validation to IBackupJobValidator
• Delegates persistence to IConfigService
• Ensures the 5-job limit is respected via CanAddJob()

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BackupJobValidator

Implements: IBackupJobValidator

Validates data before any job creation or modification:

Methods:

• Validate(job: BackupJob) : ValidationResult — Full object validation
• ValidateJobData(name: string, source: string, target: string) : ValidationResult — Individual field validation

Performed Validations:

• Existence of source and target paths
• Non-emptiness and uniqueness of the job name
• Returns a detailed ValidationResult with the list of errors

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StateManager

Implements: IStateManager

Manages real-time state with safe concurrent access:

Attributes:

• _states : List<StateEntry> — List of current states
• _statePath : string — Path to the JSON state file
• _lockObject : object — Lock for thread-safety

Responsibilities:

• Initializes and updates real-time states during backups
• Persists the state in a JSON file after each update
• Guarantees thread-safety through the use of a lock

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ConfigService

Implements: IConfigService

Responsible for persisting the configuration in JSON:

Attributes:

• _configPath : string — Path to the configuration file

Methods:

• LoadConfig() : AppConfig — Deserializes configuration from the JSON file
• SaveConfig(config: AppConfig) : void — Serializes and writes configuration to disk

Responsibilities:

• Provides a default configuration if the file is missing
• Isolates all JSON read/write logic within this service

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TranslationService

Implements: ITranslationService

Translation service based on an in-memory dictionary:

Attributes:

• _translations : Dictionary<Language, Dictionary<string, string>> — Translations indexed by language and key
• _currentLanguage : Language — Active language

Methods:

• GetString(key: string) : string — Returns the translation or the key if missing
• SetLanguage(language: Language) : void — Changes the language on the fly
• GetCurrentLanguage() : Language — Returns the active language

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ArgumentParser

Utility for analyzing command-line arguments:

Methods:

• ParseRange(input: string) : List<int> — Interprets a range (e.g.: "1-3" → [1, 2, 3])
• ParseSelection(input: string) : List<int> — Interprets a selection (e.g.: "1,3,5" → [1, 3, 5])

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6. Commands (Command Pattern for MVVM)

ICommand (WPF Interface)

Standard WPF interface for command binding:

• Execute(parameter: object) : void — Executes the command
• CanExecute(parameter: object) : bool — Indicates if the command can execute
• CanExecuteChanged : EventHandler — Event triggered upon state change

RelayCommand

Generic and reusable implementation of ICommand:

Attributes:

• _execute : Action<object> — Delegate representing the action to execute
• _canExecute : Func<object, bool> — Predicate determining the enabled/disabled state

Methods:

• RelayCommand(execute, canExecute) — Constructor
• Execute(parameter: object) : void — Invokes the _execute delegate
• CanExecute(parameter: object) : bool — Evaluates the _canExecute predicate
• RaiseCanExecuteChanged() : void — Manually triggers CanExecuteChanged

Responsibilities:

• Encapsulates any user action within an ICommand object
• Allows declarative binding of buttons and controls in XAML
• Dynamically manages the enabled/disabled state of UI controls

Business Commands

Instantiated in MainViewModel as RelayCommand:

• CreateJobCommand: Create a new backup job
• UpdateJobCommand: Modify an existing job
• DeleteJobCommand: Delete the selected job
• ExecuteBackupCommand: Execute the backup of the selected job
• ExecuteAllBackupsCommand: Execute all backups
• PauseBackupCommand: Pause a running backup
• ResumeBackupCommand: Resume a paused backup
• ChangeLanguageCommand: Change application language
• ChangeLogFormatCommand: Toggle between JSON and XML formats

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7. Strategies (Strategies)

FullBackupStrategy

Implements: IBackupStrategy

Implements full backup:

Method:

• Execute(job: BackupJob, context: BackupContext) : void

Behavior:

• Copies all files from the source directory to the destination
• Faithfully recreates the complete directory structure

DifferentialBackupStrategy

Implements: IBackupStrategy

Implements differential backup:

Method:

• Execute(job: BackupJob, context: BackupContext) : void

Behavior:

• Copies only new or modified files since the last full backup
• Relies on ShouldCopyFile() from IFileTransferService to detect changes

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8. External DLL: EasyLog.dll

ILogger

Logging interface exposed by the DLL:

• Log(entry: LogEntry) : void — Records a log entry
• GetLogPath() : string — Returns the current log file path

ILogFormatter

Interface defining the formatting of log entries:

• Format(entry: LogEntry) : string — Formates a single entry
• FormatBatch(entries: List<LogEntry>) : string — Formates a set of entries
• FileExtension : string { get; } — Extension of the produced file (.json or .xml)

LogEntry

Model for a log entry:

• Name: string — Name of the backed-up file
• SourceFilePath: string — Source path
• TargetFilePath: string — Target path
• FileSize: long — Size in bytes
• TransferTimeMs: long — Transfer duration in milliseconds
• Timestamp: DateTime — Operation timestamp

EasyLogger

Implements: ILogger

Concrete implementation of the logger:

Attributes:

• _formatter : ILogFormatter — Currently used formatter
• _logDirectory : string — Storage directory for log files
• _lockObject : object — Lock for thread-safety

Methods:

• EasyLogger(formatter, logDirectory): Constructor
• Log(entry: LogEntry) : void — Writes the entry into the daily log file
• GetLogPath() : string — Returns the current file path

Responsibilities:

• Daily logging with file rotation (one file per day)
• Thread-safe through the use of a lock
• Interchangeable based on the injected formatter (JSON or XML)

JsonLogFormatter

Implements: ILogFormatter

Formatter producing logs in JSON format:

• FileExtension : string { get; } = ".json"
• Serializes entries into structured JSON

XmlLogFormatter

Implements: ILogFormatter

Formatter producing logs in XML format:

• FileExtension : string { get; } = ".xml"
• Serializes entries into structured XML

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9. Views (Views)

ConsoleView

User interface in console mode:

Attributes:

• _viewModel : ConsoleViewModel — Associated ViewModel

Methods:

• ConsoleView(viewModel): Constructor
• DisplayMainMenu() : void — Displays the main menu
• DisplayJobs(jobs: List<BackupJob>) : void — Displays the list of jobs
• GetUserChoice() : string — Reads the choice entered by the user
• DisplayMessage(message: string) : void — Displays an informative message
• DisplayError(error: string) : void — Displays an error message

Responsibilities:

• Pure display, without any business logic
• Delegates all actions to the ConsoleViewModel
• Lightweight and readable interface in the terminal

MainWindow — GraphicView (New v3.0)

WPF graphical interface with XAML binding:

Attributes:

• DataContext : MainViewModel — ViewModel linked via WPF's DataContext property

Declared XAML Bindings:

• ItemsSource="{Binding Jobs}" — Data source for the backup jobs list
• SelectedItem="{Binding SelectedJob}" — Real-time selected job
• Command="{Binding CreateJobCommand}" — Commands linked to action buttons
• Value="{Binding ProgressPercent}" — Value for the progress bar
• Text="{Binding StatusMessage}" — Displayed status message

UI Components:

• DataGrid — Display table for backup jobs
• ProgressBar — Real-time progression indicator
• Button — Action buttons linked to ViewModel commands
• TextBox — Input fields for job creation and modification
• ComboBox — Selectors for language and log format
• StatusBar — Status bar at the bottom of the window

Responsibilities:

• Purely declarative interface definition in XAML
• Automatic two-way binding with the ViewModel via INotifyPropertyChanged
• Minimal code-behind, without business logic

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10. ViewModels

MainViewModel

Main ViewModel for the WPF graphical interface:

Attributes:

• _jobManager : IBackupJobManager — Backup job manager
• _engine : IBackupEngine — Backup execution engine
• _stateManager : IStateManager — Real-time state manager
• _configService : IConfigService — Configuration service
• _translator : ITranslationService — Translation service
• _logger : ILogger — Logging service
• _config : AppConfig — Active configuration in memory
• Jobs : ObservableCollection<BackupJob> — Observable collection of jobs (automatic binding)
• SelectedJob : BackupJob — Currently selected job in the UI
• ProgressPercent : int — Current progression value (0-100)
• StatusMessage : string — Status message displayed to the user
• IsRunning : bool — Indicates if a backup is currently running

Commands (ICommand):

• CreateJobCommand, UpdateJobCommand, DeleteJobCommand
• ExecuteBackupCommand, ExecuteAllBackupsCommand
• ChangeLanguageCommand, ChangeLogFormatCommand

Events:

• PropertyChanged : PropertyChangedEventHandler — Property change notification via INotifyPropertyChanged

Responsibilities:

• Implements INotifyPropertyChanged for automatic two-way binding
• Exposes data and commands to the view without direct display logic
• Orchestrates presentation logic and handles user interactions
• Updates the UI in real-time via observable properties

ConsoleViewModel

ViewModel dedicated to the console interface:

Attributes:

• _jobManager, _engine, _stateManager, _configService, _translator, _logger — Same dependencies as MainViewModel
• _argumentParser : ArgumentParser — Command-line argument parser
• _config : AppConfig — Active configuration

Methods:

• ConsoleViewModel(...) — Constructor with injection of all dependencies
• Run(args: string[]) : void — Main entry point, manages the application loop
• ShowMainMenu() : void — Displays and processes the interactive menu
• CreateJob() : void, ListJobs() : void, ExecuteBackups() : void
• ChangeLanguage() : void, ChangeLogFormat() : void

Responsibilities:

• Adapts business logic for the console interface without reactive binding
• Manages the main interaction loop and the menu
• Processes command-line arguments via ArgumentParser
• Does not require INotifyPropertyChanged (no XAML binding)

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11. Entry Points

Program (Console)

Entry point for the console application:

Methods:

• Main(args: string[]) : void — Main method
• ConfigureServices() : ServiceProvider — Configures the dependency injection container

Responsibilities:

• Initializes the console application and the IoC container
• Instantiates ConsoleViewModel and ConsoleView, then starts the main loop

App.xaml.cs (WPF)

Entry point for the graphical application:

Methods:

• OnStartup(e: StartupEventArgs) : void — WPF startup event
• ConfigureServices() : ServiceProvider — Configures the dependency injection container

Responsibilities:

• Initializes the WPF application and the IoC container
• Instantiates MainViewModel, creates MainWindow, and configures its DataContext