# Requirements Document
Generated: Tuesday, September 16, 2025

## Functional Requirements (Developer-Facing)

### FR-001: Project Initialization
- **Description:** The system shall provide a developer-ready Angular project that can be set up with minimal effort.
- **Acceptance Criteria:**
    - A developer shall be able to clone the project from a Git repository.
    - A developer shall be able to install all required dependencies using a single `npm install` command.
    - A developer shall be able to start the local development server using the `ng serve` command.
    - The boilerplate shall compile without errors and be viewable in a web browser.
- **Priority:** High

### FR-002: Modular Architecture
- **Description:** The system shall be structured with a scalable and maintainable modular architecture.
- **Acceptance Criteria:**
    - The project shall include a `CoreModule` for providing singleton services and one-time imports.
    - The project shall include a `SharedModule` for reusable components, directives, and pipes.
    - The architecture shall support the creation of lazy-loaded `FeatureModules` to encapsulate business domain logic.
- **Priority:** High

### FR-003: Clarity Design System Integration
- **Description:** The system shall be fully integrated with the VMware Clarity Design System for UI components and styling.
- **Acceptance Criteria:**
    - All necessary Clarity npm packages shall be included as dependencies.
    - Clarity's global stylesheets and assets shall be correctly configured and loaded.
    - The boilerplate shall use Clarity components for its core layout (header, sidebar, etc.).
    - Developers shall be able to use any Clarity component within their feature modules.
- **Priority:** High

### FR-004: Responsive Application Layout
- **Description:** The system shall provide a default, responsive application layout.
- **Acceptance Criteria:**
    - The boilerplate shall include a main application shell with a header, a collapsible sidebar for navigation, and a main content area.
    - The layout shall adapt correctly to various screen sizes, including desktop, tablet, and mobile.
- **Priority:** High

### FR-005: Routing and Navigation
- **Description:** The system shall include a pre-configured routing system for navigating between different views.
- **Acceptance Criteria:**
    - The project shall have a main `AppRoutingModule`.
    - The boilerplate shall provide an example of a lazy-loaded feature route.
    - Navigation links in the sidebar shall correctly navigate to their corresponding routes.
- **Priority:** Medium

## Non-Functional Requirements

### NFR-001: Performance (Developer Experience)
- **Description:** The boilerplate should be optimized for a fast and efficient development workflow.
- **Acceptance Criteria:**
    - The initial `ng serve` compilation time shall be reasonably fast.
    - Live-reloading times during development shall be minimal.
    - The production build (`ng build --prod`) shall be optimized, with tree-shaking and minification enabled.
- **Priority:** Medium

### NFR-002: Usability (Developer Experience)
- **Description:** The codebase should be intuitive and easy for an Angular developer to understand and extend.
- **Acceptance Criteria:**
    - The project structure shall be logical and follow established Angular best practices.
    - The code shall be clean, well-formatted, and include comments for complex or non-obvious sections.
    - A comprehensive `README.txt` file shall guide developers on setup, architecture, and usage.
- **Priority:** High

### NFR-003: Maintainability
- **Description:** The codebase should be structured to allow for easy updates, modifications, and extensions.
- **Acceptance Criteria:**
    - The modular architecture shall allow for independent development and testing of features.
    - Dependencies shall be clearly defined in `package.json` and easy to update.
    - The separation of concerns between modules should be strictly enforced.
- **Priority:** High

## Data Requirements (Client-Side)

### Entity Modeling:
- **Description:** The boilerplate will not have predefined data models but will require developers to define them using TypeScript.
- **Attributes:**
    - Data models shall be defined as **TypeScript interfaces or classes**.
    - These models will represent the structure of data consumed from and sent to a backend API.

## Interface Requirements

### UI/UX Requirements (Frontend Boilerplate):
- **Layout:** A clean, professional single-page application layout based on the Clarity Design System.
- **Header:** A top header bar, typically containing the application title/logo and user-related actions (e.g., profile, logout).
- **Sidebar:** A collapsible vertical navigation sidebar containing links to different feature areas of the application.
- **Content Area:** A main content area where the components for the currently active route are displayed.
- **Styling:** Adherence to the styles and design tokens provided by the Clarity Design System.

### API Requirements (Backend Interaction):
- **Backend Agnostic:** The boilerplate is a frontend application and makes no assumptions about the backend technology stack.
- **Communication Protocol:** The boilerplate shall use Angular's `HttpClient` module to communicate with a backend over HTTP/HTTPS.
- **API Endpoint Configuration:** The base URL for the backend API shall be configurable via the `environments` files (e.g., `environment.ts`, `environment.prod.ts`).
- **Data Format:** The boilerplate is designed to work with APIs that transact data in **JSON** format.
- **Error Handling:** The architecture shall support a centralized way to handle API errors, typically through an `HttpInterceptor` provided in the `CoreModule`.

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## REQUIREMENTS UPDATE - 2025-09-25 07:33:28

## Requirements Document Update - 2025-09-25 07:45:00

This section updates the requirements based on the user prompt and the analysis performed.

### FR-001: Perform Basic Arithmetic Operations
- **Description:** The calculator shall perform addition, subtraction, multiplication, and division operations accurately.
- **Acceptance Criteria:** The calculator correctly performs calculations for various valid input combinations.  Unit tests covering all operations will pass.
- **Priority:** High

### FR-002: Display Calculation Results
- **Description:** The calculator shall display the results of calculations clearly and concisely.
- **Acceptance Criteria:** The results are displayed in a user-friendly format (e.g., decimal representation) and immediately after calculation.  Visual inspection confirms result display.
- **Priority:** High

### FR-003: Handle Invalid Input
- **Description:** The calculator shall handle invalid input (e.g., division by zero, non-numeric input) gracefully.
- **Acceptance Criteria:** Appropriate error messages are displayed to the user, preventing unexpected application behavior. Unit and Integration tests confirm expected errors are handled.
- **Priority:** High

### FR-004: Support Responsive Layout
- **Description:** The calculator should adapt to different screen sizes and devices.
- **Acceptance Criteria:** The user interface functions correctly across devices of varying screen sizes (mobile, tablet, desktop).  Visual inspection confirms correct layout across devices.
- **Priority:** Medium

### FR-005: Clear Screen Functionality
- **Description:** The calculator should provide a way to clear the current input and displayed result.
- **Acceptance Criteria:** A button or function is provided to clear the display.  User testing confirms ease of use of the clear button.
- **Priority:** Medium

### NFR-001: Performance
- **Description:** The application shall respond quickly to user input and perform calculations efficiently.
- **Acceptance Criteria:**  Calculations are performed and results are displayed within 100ms. Performance tests confirm response time requirements.
- **Priority:** High

### NFR-002: Usability
- **Description:** The application shall be easy to use and understand, with an intuitive interface.
- **Acceptance Criteria:** User testing confirms ease of use and intuitive functionality.
- **Priority:** High

### NFR-003: Accessibility
- **Description:** The application shall adhere to accessibility guidelines (WCAG).
- **Acceptance Criteria:** Accessibility testing will be performed after development.
- **Priority:** Medium

### NFR-004: Testability
- **Description:** The application shall be designed and developed to facilitate thorough testing.
- **Acceptance Criteria:** Unit and integration tests cover all key functions and error scenarios.  Test code is well-structured and maintained.
- **Priority:** High


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## REQUIREMENTS UPDATE - 2025-09-25 07:33:40


## Requirements Document Update - 2025-09-25 07:55:00

This section updates the requirements document based on the refined analysis and implementation plan.

### FR-005: Clear Screen Functionality (Refinements):
- **Description:** The calculator shall provide a mechanism to clear the current input and displayed result.  This includes clearing both the input area and the result display area. 
- **Acceptance Criteria:** A clearly labeled button (e.g., 'C' or 'Clear') is available to reset the calculator to its initial state.  The result display area shows '0' after clearing.
- **Priority:** High

### NFR-005: Error Handling (Added):
- **Description:** The application must gracefully handle invalid input (e.g., division by zero, non-numeric input) and display appropriate error messages to the user.
- **Acceptance Criteria:**  For all invalid input types, a clear and concise error message is displayed. The application does not crash.  Test cases will cover all identified error conditions.
- **Priority:** High

### NFR-006: Accessibility (Refinements):
- **Description:** The application shall conform to WCAG guidelines for accessibility, ensuring usability for users with disabilities.
- **Acceptance Criteria:**  The application will pass an accessibility audit using established accessibility testing tools (e.g., WAVE, axe).  Specific accessibility criteria (WCAG guidelines) will be defined and tested during the development phase.
- **Priority:** High



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## REQUIREMENTS UPDATE - 2025-09-25 07:34:23


## Requirements Document Update - 2025-09-25 07:45:00

This section updates the requirements document based on the user prompt and the analysis above.

### FR-001: Perform Addition
- **Description:** The calculator shall accurately perform addition of two or more numerical inputs.
- **Acceptance Criteria:** Given two or more valid numerical inputs, the calculator shall correctly display their sum.  The result shall be accurate to at least 10 decimal places.
- **Priority:** High

### FR-002: Perform Subtraction
- **Description:** The calculator shall accurately perform subtraction of two numerical inputs.
- **Acceptance Criteria:** Given two valid numerical inputs, the calculator shall correctly display the difference between the first and second input. The result shall be accurate to at least 10 decimal places.
- **Priority:** High

### FR-003: Perform Multiplication
- **Description:** The calculator shall accurately perform multiplication of two or more numerical inputs.
- **Acceptance Criteria:** Given two or more valid numerical inputs, the calculator shall correctly display their product. The result shall be accurate to at least 10 decimal places.
- **Priority:** High

### FR-004: Perform Division
- **Description:** The calculator shall accurately perform division of two numerical inputs.
- **Acceptance Criteria:** Given two valid numerical inputs, where the second input is not zero, the calculator shall correctly display the quotient of the first input divided by the second input. The result shall be accurate to at least 10 decimal places. If the second input is zero, the calculator shall display an appropriate error message, such as "Division by zero is not allowed."
- **Priority:** High

### FR-005: Handle Invalid Input
- **Description:** The calculator shall handle invalid input gracefully and inform the user.
- **Acceptance Criteria:** When the user inputs non-numerical characters or attempts operations that are not supported (e.g., division by zero), the calculator shall display a clear error message indicating the type of error.  The calculator shall not crash.
- **Priority:** Medium

### FR-006: Clear Display
- **Description:** The calculator shall provide a clear and easy-to-read display of results.
- **Acceptance Criteria:** The results of all calculations shall be clearly displayed in a designated area of the user interface, using a suitable font size and formatting. The displayed number shall be limited to 15 characters. Longer results shall be appropriately truncated.
- **Priority:** High

### NFR-001:  Usability
- **Description:** The user interface shall be intuitive and easy to use.
- **Acceptance Criteria:** The UI shall be simple, straightforward, and easy to navigate.
- **Priority:** High

### NFR-002: Performance
- **Description:** The calculator shall provide quick and responsive calculations.
- **Acceptance Criteria:** Calculations should be performed and displayed within 1 second of user input.
- **Priority:** High

### NFR-003: Reliability
- **Description:** The calculator shall consistently provide accurate results.
- **Acceptance Criteria:** The calculator shall provide accurate results for all valid input across multiple test runs.
- **Priority:** High



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## REQUIREMENTS UPDATE - 2025-09-25 07:34:32

## Requirements Document Update - 2025-09-25 07:55:00

This section provides further refinements to the requirements document based on the updated analysis and the integration strategy with the base project.

### FR-007:  Integration with Base Project
- **Description:** The calculator application shall integrate seamlessly with the existing base project's frontend and backend (if applicable) without disrupting existing functionality.
- **Acceptance Criteria:** The calculator app will be integrated without any conflicting code or broken functionality within the base project. Any additions to existing files will be reviewed carefully to ensure compatibility.
- **Priority:** High

### FR-008:  Use of Base Project Technologies
- **Description:** The calculator application shall utilize the existing technology stack of the base project, avoiding introduction of new frameworks or libraries.
- **Acceptance Criteria:** The application's implementation shall leverage existing libraries and frameworks from the base project.  No new dependencies will be added.
- **Priority:** High

### NFR-005: Base Project Compliance
- **Description:** The application must adhere to the base project's coding standards and style guidelines.
- **Acceptance Criteria:** The code written for the calculator will conform to the base project's coding style and standards.
- **Priority:** High

### NFR-006:  Append-Only Adherence
- **Description:** All modifications to the base project will be made through appending to existing files; no existing content will be overwritten.
- **Acceptance Criteria:** The integration of the calculator app will not require overwriting any content in the base project's existing files. New functionality will be appended to relevant files while maintaining the original structure.
- **Priority:** High
