# 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 - 2025-09-26 09:58:17

# Requirements Document
Generated: 2024-05-15T12:00:00.000000

## Functional Requirements

### FR-001: Current Weather Display
-   **Description:** The application shall display the current weather conditions for a specified location.
-   **Acceptance Criteria:**
    -   The current temperature is shown.
    -   A brief weather description (e.g., "Clear Sky", "Partly Cloudy") is visible.
    -   Humidity percentage is displayed.
    -   Wind speed and direction (if available from API) are shown.
    -   A relevant weather icon is displayed.
-   **Priority:** High

### FR-002: Location Search by City Name
-   **Description:** Users shall be able to search for weather information by entering a city name in a search input field.
-   **Acceptance Criteria:**
    -   A prominent search bar component is available on the main page.
    -   Upon submission (e.g., by pressing Enter or clicking a search button), the application fetches and displays weather data for the entered city.
    -   The search is case-insensitive.
-   **Priority:** High

### FR-003: Location Search by Geolocation
-   **Description:** The application shall provide an option for users to retrieve weather information based on their current geographic location.
-   **Acceptance Criteria:**
    -   A button or toggle labeled "Use Current Location" (or similar) is present.
    -   Upon activation, the application requests access to the user's geolocation.
    -   If granted, weather data for the detected location is fetched and displayed.
    -   If denied or fails, a user-friendly error message is shown.
-   **Priority:** Medium

### FR-004: Multi-Day Weather Forecast Display
-   **Description:** The application shall present a multi-day forecast (e.g., 5-7 days) for the selected location.
-   **Acceptance Criteria:**
    -   A list or series of forecast cards/items is displayed, separate from current weather.
    -   Each forecast item includes the day of the week, date, a weather icon, a brief description, and the projected high and low temperatures.
-   **Priority:** High

### FR-005: Temperature Unit Conversion
-   **Description:** Users shall be able to toggle between Celsius and Fahrenheit temperature units for all displayed temperatures.
-   **Acceptance Criteria:**
    -   A clear control (e.g., toggle switch, radio buttons) is provided for unit selection.
    -   When a unit is selected, all temperature values on the screen (current and forecast) update accordingly.
    -   The selected unit is visually indicated.
-   **Priority:** High

### FR-006: Loading State Indicators
-   **Description:** The application shall provide visual feedback to the user when data is being fetched from the backend or external API.
-   **Acceptance Criteria:**
    -   A spinner or skeleton loader is displayed over relevant sections (e.g., weather card, forecast list) while data is loading.
    -   Loading indicators disappear once data is successfully displayed or an error occurs.
-   **Priority:** Medium

### FR-007: Robust Error Handling and Messaging
-   **Description:** The application shall gracefully handle and inform the user about errors, such as invalid location, API failures, or network issues.
-   **Acceptance Criteria:**
    -   If a searched location yields no results, a message like "Location not found. Please try again." is displayed.
    -   If the backend or external weather API is unreachable, a message like "Could not retrieve weather data. Please check your internet connection or try again later." is displayed.
    -   Error messages are prominent, clear, and easy to understand.
-   **Priority:** High

### FR-008: Backend API Endpoints
-   **Description:** The backend service shall expose API endpoints to serve weather data to the frontend.
-   **Acceptance Criteria:**
    -   `GET /api/current-weather?location={city}`: Returns current weather data for a given city.
    -   `GET /api/forecast?location={city}`: Returns multi-day forecast data for a given city.
    -   Responses are in a consistent JSON format suitable for frontend consumption.
-   **Priority:** High

## Non-Functional Requirements

### NFR-001: Performance
-   **Description:** The application must provide a responsive user experience with quick data loading times.
-   **Acceptance Criteria:**
    -   Current weather display loads within 3 seconds for valid search queries over a standard broadband connection.
    -   Multi-day forecast display loads within 5 seconds for valid search queries over a standard broadband connection.
    -   Backend API response time (excluding external API call) should be consistently under 100ms.

### NFR-002: Security
-   **Description:** Sensitive information, particularly external API keys, must be handled securely.
-   **Acceptance Criteria:**
    -   External weather API keys are stored as environment variables on the backend server and are never hardcoded or exposed to the client-side.
    -   All communication between the frontend and backend, and backend to external API (if supported by external API), must utilize HTTPS/SSL.
    -   The backend proxy should sanitize and validate all inputs before forwarding to external APIs.

### NFR-003: Usability
-   **Description:** The user interface must be intuitive, easy to navigate, and consistent.
-   **Acceptance Criteria:**
    -   The application adheres to the Clarity Design System guidelines for all UI components, layout, and styling.
    -   The layout is fully responsive, adapting gracefully to screen sizes from mobile (e.g., 320px width) to large desktop monitors.
    -   Search functionality is easily discoverable and operable.
    -   Temperature unit toggle is clearly labeled and functional.

### NFR-004: Reliability
-   **Description:** The application must be robust and provide accurate information, even in the presence of external service issues.
-   **Acceptance Criteria:**
    -   The backend service implements retry mechanisms for transient external API failures.
    -   In case of persistent external API failure, the application displays an informative error message instead of crashing.
    -   Data displayed is consistent with the latest information from the external weather API.

### NFR-005: Scalability
-   **Description:** The system should be designed to handle an increasing number of users and data requests efficiently.
-   **Acceptance Criteria:**
    -   The backend service can be deployed in a horizontally scalable manner (e.g., containerized).
    -   Caching mechanisms (e.g., Redis) can be integrated into the backend service to reduce redundant external API calls and improve response times under load.

## Data Requirements
Generated: 2024-05-15T12:00:00.000000

### Entities and Attributes:

1.  **Location**
    *   `name`: City name (e.g., "London")
    *   `country`: Country code (e.g., "GB")
    *   `latitude`: Geographical latitude
    *   `longitude`: Geographical longitude

2.  **CurrentWeather**
    *   `location`: Reference to Location entity
    *   `temperature`: Current temperature (number, default Celsius)
    *   `unit`: Temperature unit (string, "Celsius" or "Fahrenheit")
    *   `condition`: Main weather condition (e.g., "Clouds", "Clear")
    *   `description`: Detailed weather description (e.g., "scattered clouds")
    *   `icon`: URL or code for weather icon
    *   `humidity`: Percentage of humidity
    *   `windSpeed`: Wind speed (number, default m/s)
    *   `timestamp`: Time of data observation

3.  **ForecastDay**
    *   `location`: Reference to Location entity
    *   `date`: Date of the forecast (e.g., "2025-10-01")
    *   `tempHigh`: Maximum temperature for the day
    *   `tempLow`: Minimum temperature for the day
    *   `unit`: Temperature unit (string, "Celsius" or "Fahrenheit")
    *   `condition`: Main weather condition for the day
    *   `description`: Detailed weather description
    *   `icon`: URL or code for weather icon

## Interface Requirements
Generated: 2024-05-15T12:00:00.000000

1.  **Clarity Design System Adherence:** The UI shall strictly follow the components, styling, and guidelines of the Clarity Design System for consistency and enterprise-grade aesthetics.
2.  **Responsive Layout:** The application layout must adapt gracefully to different screen sizes, from mobile phones to large desktop displays, without loss of functionality or significant visual degradation.
3.  **Search Bar:** A prominent search bar (Clarity Input Group or similar) should be located at the top of the main content area, allowing easy access for location input.
4.  **Weather Card:** The current weather details should be presented in a clear, concise card format (Clarity Card) with a distinct visual hierarchy.
5.  **Forecast List:** The multi-day forecast should be presented as a scrollable list or a series of cards, clearly separating each day's forecast.
6.  **Loading & Error States:** Clear visual indicators (Clarity Spinner, Alert components) must be used for loading states and error messages, ensuring user comprehension.
7.  **Unit Toggle:** A user-friendly toggle switch or segmented button (Clarity Toggle Switch or Button Group) should be implemented for switching temperature units (Celsius/Fahrenheit).

