Update documentation: enhance component overview and key functions for clarity and completeness

docs/DETAILED_OVERVIEW.MD

@@ -2,7 +2,7 @@
 
 LightTAM (Lightweight Time And Attendance Manager) is a terminal-based application for managing employee or student attendance using RFID cards. The system is modular, with each component responsible for a specific aspect of the program's functionality. Below is a detailed overview of how the program works, referencing the component UML diagram (`component_uml.png`).
 
-
+---
 
 ## Component Overview
 
@@ -10,53 +10,66 @@ LightTAM (Lightweight Time And Attendance Manager) is a terminal-based applicati
 
 ### 1. **Main Application (`main.c`)**
 - **Role:** Entry point of the program. Initializes all subsystems, parses command-line arguments, loads the user database, and starts the main event loop.
-- **Responsibilities:**
-  - Initializes the logger, file/database handlers, and TUI.
-  - Loads user data from the specified file.
-  - Handles program shutdown and resource cleanup.
+- **Key Functions:**
+  - `main` – program entry, initialization, TUI start, graceful shutdown.
+  - `handle_sigint` – signal handler for program termination.
+  - Calls to initialize logger (`initLogger`), load users (`loadListFromCSV`), start RFID thread (`uartListener`).
 
 ### 2. **Terminal User Interface (TUI) (`tui.c`, `tui.h`)**
 - **Role:** Provides all user interaction via a terminal-based UI using ncurses.
-- **Responsibilities:**
-  - Displays menus (main, edit, search, user details, etc.).
-  - Handles keyboard input and navigation.
-  - Calls business logic functions based on user actions.
-  - Shows dialogs for success, warnings, and errors.
-  - Manages forms for adding/removing users and logging time events.
+- **Key Functions:**
+  - `mainMenu` – main menu display and navigation.
+  - `personListing` – list all users.
+  - `personSearch` – search users by name or UUID.
+  - `personInfo` – show detailed user info.
+  - `editDatabaseMenu` – add, remove, or edit users.
+  - `dialogWindow` – show dialogs (errors, warnings, confirmations).
+  - `exportDialog` – export user or database data.
+  - Keyboard input handling, navigation, and forms.
 
 ### 3. **User Management (`users.c`, `users.h`)**
 - **Role:** Manages the in-memory linked list of users.
-- **Responsibilities:**
-  - Defines the `person_t`, `node_t`, and `list_t` structures.
-  - Provides functions to add, remove, search, and update users.
-  - Handles synchronization (mutex) for thread safety.
-  - Calculates presence times and manages user states.
+- **Key Functions and Structures:**
+  - `person_t`, `node_t`, `list_t` – data structures for users and the list.
+  - `addPersonToList` – add a user.
+  - `removePersonFromList` – remove a user.
+  - `findPersonByUUID`, `findPersonByName` – search for users.
+  - `updatePerson` – update user data.
+  - `calculatePresenceTime` – compute attendance.
+  - Synchronization using mutex (`pthread_mutex_t`).
 
 ### 4. **File Handler (`file_handler.c`, `file_handler.h`)**
 - **Role:** Handles reading and writing user data to CSV files.
-- **Responsibilities:**
-  - Loads the user list from a CSV file at startup.
-  - Saves the user list to a CSV file on demand.
-  - Exports user or database information to external files.
+- **Key Functions:**
+  - `loadListFromCSV` – load user list from file.
+  - `saveListToCSV` – save user list to file.
+  - `exportPersonInfo` – export a user's data to an external file.
 
 ### 5. **RFID Handler (`rfid_handler.c`, `rfid_handler.h`)**
 - **Role:** Interfaces with the RFID reader hardware via a serial port.
-- **Responsibilities:**
-  - Opens and manages the serial port connection.
-  - Reads RFID card data and matches it to users.
-  - Triggers time event logging when a card is detected.
+- **Key Functions:**
+  - `uartListener` – thread for reading data from the serial port.
+  - `processRFIDEvent` – process a detected RFID card.
+  - `sendPacketToDevice` – send data to the device.
+  - CRC check, card-to-user matching, attendance event logging.
 
 ### 6. **Logger (`logger.c`, `logger.h`)**
 - **Role:** Logs all actions, errors, and system events to a journal file.
-- **Responsibilities:**
-  - Provides logging functions for other modules.
-  - Records user actions, errors, and system messages for auditing.
+- **Key Functions:**
+  - `initLogger` – initialize the logger.
+  - `logErrorEvent` – log errors.
+  - `logWarningEvent` – log warnings.
+  - `logHardwareEvent` – log hardware events (e.g., RFID).
+  - `logInfoEvent` – log general information.
+  - `endLogger` – close the log file.
 
-### 7. **Utilities (`utils.h`)**
+### 7. **Utilities (`utils.c`,`utils.h`)**
 - **Role:** Provides helper functions used throughout the program.
-- **Responsibilities:**
-  - String manipulation, time formatting, and other common tasks.
+- **Key Functions:**
+  - `printDateAndTimeInString` – time formatting.
+  - String manipulation, input validation, type conversions.
 
+---
 
 ## Component Interactions
 
@@ -66,14 +79,14 @@ LightTAM (Lightweight Time And Attendance Manager) is a terminal-based applicati
 - **RFID Handler ↔ User Management:** When a card is read, the handler updates the user list.
 - **All Components ↔ Logger:** All modules log actions and errors via the logger.
 
-
+---
 
 ## Error Handling & Logging
 
 - All errors (file I/O, serial port, invalid input) are reported to the user via TUI dialogs and logged in the journal file.
 - The logger ensures traceability for all critical operations.
 
-
+---
 
 ## Extensibility