# Product Requirements Document (PRD) - Angular Clarity Boilerplate

## 1. Product Vision

To provide a robust, scalable, and feature-rich boilerplate that serves as a foundational template for building modern, enterprise-grade web applications using Angular and the VMware Clarity Design System. The vision is to accelerate the development lifecycle by offering a pre-configured, best-practice project structure.

## 2. Target Audience

The primary target audience consists of **Angular developers and development teams** who require a standardized, efficient, and consistent starting point for new projects. This includes:

* **Enterprise Development Teams:** Teams that need to maintain a consistent look and feel across multiple applications.
* **Independent Developers:** Individuals looking to quickly bootstrap new projects without spending significant time on initial setup and configuration.

## 3. User Stories (Developer Stories)

### User Story 1: Quick Project Initialization
- **As a developer, I want to clone the repository and run `npm install` and `ng serve` to get a live development server running, so that I can bypass manual setup and start building features immediately.**
- **Acceptance Criteria:**
    - Given I have Node.js and Angular CLI installed,
    - When I clone the repository, install dependencies, and run the start command,
    - Then the application compiles successfully and is accessible in my browser at `localhost:4200`.

### User Story 2: Add a New Feature
- **As a developer, I want to create a new lazy-loaded feature module with its own components and routing, so that I can add new sections to the application in a scalable way.**
- **Acceptance Criteria:**
    - Given the boilerplate is running,
    - When I use the Angular CLI to generate a new module and add it to the main routing configuration,
    - Then I can navigate to the new feature's route, and its components are rendered correctly.

### User Story 3: Utilize Shared Components
- **As a developer, I want to use a component from the `SharedModule` within a new feature module, so that I can reuse common UI elements and maintain consistency.**
- **Acceptance Criteria:**
    - Given I have a new feature module,
    - When I import the `SharedModule` into my feature module,
    - Then I can use the shared components (e.g., a custom card or loader) in my feature's templates without errors.

## 4. Functional Requirements

- **FR-001: Pre-configured Angular Environment:** A ready-to-use Angular CLI project with all necessary dependencies and build configurations.
- **FR-002: Clarity Design System Integration:** Full integration of Clarity UI components and styles, ready for immediate use.
- **FR-003: Scalable Architecture:** A modular structure featuring a `CoreModule` for singleton services and a `SharedModule` for reusable UI components, directives, and pipes.
- **FR-004: Responsive Layout:** A default application shell with a responsive header, navigation sidebar, and main content area.
- **FR-005: Routing:** A pre-configured routing module with examples of lazy-loaded feature modules.
- **FR-006: Theming:** Basic support for Clarity's light and dark themes.

## 5. Non-Functional Requirements

- **NFR-001: Performance:** The initial boilerplate should be lightweight, ensuring fast development server startup times and optimized production builds.
- **NFR-002: Usability (Developer Experience):** The codebase must be clean, well-commented, and logically organized to provide an excellent developer experience.
- **NFR-003: Maintainability:** The modular architecture must facilitate easy updates to dependencies and allow for the addition of new features without introducing breaking changes to the core structure.
- **NFR-004: Scalability:** The architecture is designed to support the growth of large, enterprise-scale applications.
- **NFR-005: Extensibility:** The boilerplate should be easy to customize and extend with additional libraries, modules, and configurations as per project-specific needs.

## 6. Out of Scope

The following features and functionalities are explicitly out of scope for the boilerplate:

-   **Backend Implementation:** This is a frontend-only boilerplate and does not include any backend code or database.
-   **Authentication/Authorization Logic:** While the architecture supports the implementation of security features, no pre-built authentication or authorization logic is included.
-   **State Management:** The boilerplate does not include a state management library (e.g., NgRx, Akita) by default, allowing developers to choose the best solution for their needs.
-   **Business Logic:** No specific business logic or application features are included beyond the basic structural components.
-   **CI/CD Pipelines:** While the project is ready for CI/CD, no pre-configured pipelines are included.

---

## PRD UPDATE - 2025-09-26 10:03:30


# Product Requirements Document (PRD)

## 1. Executive Summary
Generated: 2025-09-26 10:05:00
This document outlines the requirements for extending the existing Angular Clarity Boilerplate into a fully functional and user-friendly Weather Application. The project aims to provide immediate and reliable access to current weather conditions and multi-day forecasts for user-specified locations, demonstrating full-stack integration with a secure backend proxy and a responsive frontend built using Angular and the Clarity Design System.

## 2. Product Vision & Strategy
Generated: 2025-09-26 10:05:00
**Product Vision:** To empower users with quick, accurate, and intuitive weather information while serving as a robust, real-world example of a scalable Angular application built on the Clarity Design System, integrating secure backend services and external APIs.

**Strategic Goals:**
- Deliver a Minimum Viable Product (MVP) capable of displaying current weather and multi-day forecasts for searched locations.
- Ensure secure handling of external API keys via a dedicated backend proxy.
- Provide a highly usable and responsive interface consistent with the Clarity Design System.
- Showcase best practices for full-stack integration, including containerization and cloud deployment readiness.

**Success Metrics:**
- **Performance:** Display current weather within 3 seconds, forecast data within 5 seconds of a successful search query.
- **Reliability:** 99.5% uptime for the backend proxy and external API integration.
- **User Engagement (Hypothetical):** High rates of location search and forecast viewing (if tracking implemented).
- **Developer Feedback (Boilerplate Aspect):** Positive feedback on the clarity, maintainability, and extensibility of the codebase as a demonstration.

## 3. Target Users & Personas
Generated: 2025-09-26 10:05:00
**Primary User: The Everyday Planner**
- **Demographics:** General web users, individuals planning daily activities, travelers.
- **Needs:** Quick access to current weather, reliable multi-day forecasts for specific locations, easy-to-understand interface, preferred temperature units.
- **Goal:** To make informed decisions about clothing, travel, and activities based on accurate weather predictions.

**Secondary User: The Angular Developer (for boilerplate demonstration)**
- **Demographics:** Mid-to-senior level Angular developers, development teams.
- **Needs:** A well-structured, maintainable, and scalable Angular project example; clear demonstration of external API integration, backend proxy usage, state management, and Clarity UI component implementation.
- **Goal:** To leverage the project as a learning resource or a foundation for their own enterprise-grade applications.

## 4. Problem Statement
Generated: 2025-09-26 10:05:00
Users require a fast, accurate, and intuitive way to access current and forecasted weather information for specific locations. Existing solutions may lack a consistent user experience, secure backend integration, or robust error handling. For developers, there's a need for a comprehensive, real-world application built on an Angular Clarity boilerplate that effectively demonstrates full-stack development patterns, including secure external API interaction and scalable architecture.

## 5. Solution Overview
Generated: 2025-09-26 10:05:00
The Weather App will be a client-server application consisting of an Angular frontend and a Node.js/Express.js backend proxy. The frontend, leveraging the Clarity Design System, will provide a responsive user interface for searching locations, displaying current weather, and multi-day forecasts, along with unit conversion. The backend proxy will securely interact with an external weather API (e.g., OpenWeatherMap), manage API keys, perform data transformation, and implement caching (using Redis) to optimize performance and reduce external API calls. Both frontend and backend services will be containerized using Docker for simplified deployment to cloud platforms.

## 6. Functional Requirements
Generated: 2025-09-26 10:05:00
-   **FR-001 (Display Current Weather):** The system shall display the current weather conditions, including temperature, conditions description, humidity, and wind speed, for a selected location.
-   **FR-002 (Search by Location):** The system shall allow users to search for weather by entering a city name.
-   **FR-003 (Geolocation Search):** The system shall provide an option for users to fetch weather data for their current device location.
-   **FR-004 (Display Multi-Day Forecast):** The system shall display a forecast for multiple upcoming days (e.g., 5-7 days).
-   **FR-005 (Unit Conversion):** The system shall allow users to switch between Celsius and Fahrenheit temperature units.
-   **FR-006 (Loading Indicators):** The system shall provide visual cues (loading indicators) while fetching data to inform the user of ongoing operations.
-   **FR-007 (Error Feedback):** The system shall display clear and informative feedback to users when a location is not found, if there are issues fetching weather data, or for other API/network errors.
-   **FR-008 (External Weather API Integration):** The backend proxy shall integrate with a reliable third-party weather API (e.g., OpenWeatherMap) to fetch current and forecast weather data.
-   **FR-009 (Backend Proxy Endpoints):** The backend proxy shall provide distinct RESTful API endpoints for current weather (`/api/current-weather`) and multi-day forecast (`/api/forecast`).

## 7. Non-Functional Requirements
Generated: 2025-09-26 10:05:00
-   **NFR-001 (Performance):**
    *   The application shall display current weather data within 3 seconds of a successful search query.
    *   Forecast data shall be displayed within 5 seconds of a successful forecast query.
    *   The backend proxy should introduce minimal latency (e.g., <100ms per request).
-   **NFR-002 (Security):**
    *   External weather API keys shall be stored securely on the backend (e.g., environment variables) and not exposed to the client-side.
    *   All communication between the frontend and backend shall use HTTPS.
-   **NFR-003 (Usability):**
    *   The user interface shall be intuitive and easy to navigate, adhering to Clarity Design System guidelines.
    *   The application shall be responsive and function correctly across various device sizes (desktop, tablet, mobile).
    *   Error messages shall be clear, concise, and actionable.
-   **NFR-004 (Reliability):**
    *   The backend proxy shall implement robust error handling for external API failures, returning appropriate status codes and messages to the frontend.
    *   The application shall remain functional even if a specific weather data point is missing from the API response (graceful degradation).
-   **NFR-005 (Scalability):**
    *   The backend service shall be designed to handle a moderate load of concurrent users (e.g., up to 100 concurrent requests) with potential for future scaling via caching or load balancing.
    *   The architecture should allow for easy addition of new weather data providers or features.
-   **NFR-006 (Maintainability):**
    *   The codebase shall be well-documented, adhering to Angular and backend framework coding standards.
    *   Modules and components shall be logically structured and easily extensible.

## 8. Epic Stories
Generated: 2025-09-26 10:05:00

### Epic 1: Location-Based Weather Display
**Epic Description:** Enable users to easily find and view current weather information for any desired location, including their own.
**Business Value:** Provides immediate utility to users, fulfilling the primary function of a weather application, and showcases core frontend-to-backend integration.
**Acceptance Criteria:** Users can successfully retrieve and view current weather details for a searched city or their current location.

**User Stories:**
- **US-001:** View Current Weather for a Specific Location
  - **As a** user
  - **I want to** search for a city by name and see its current weather conditions
  - **So that** I can quickly get up-to-date weather information for any desired location.
  - **Acceptance Criteria:**
    - [ ] The application displays a prominent search bar.
    - [ ] When I type a valid city name (e.g., "London") and submit, the application displays the current temperature, weather description (e.g., "Sunny"), humidity, and wind speed for that city.
    - [ ] The displayed weather information is visually appealing and consistent with Clarity Design.
  - **Story Points:** 8
  - **Priority:** High

- **US-004:** Use Current Location for Weather
  - **As a** user
  - **I want to** quickly see the weather for my current location
  - **So that** I can get relevant information without typing.
  - **Acceptance Criteria:**
    - [ ] The application provides a clear option (e.g., a button) to use my current location.
    - [ ] Upon granting browser's geolocation permission, the application fetches and displays the current weather for my detected location.
    - [ ] If geolocation fails or permission is denied, an informative message is displayed to the user.
  - **Story Points:** 8
  - **Priority:** High

### Epic 2: Forecast & Unit Management
**Epic Description:** Allow users to plan ahead by providing multi-day weather forecasts and personalizing temperature unit preferences.
**Business Value:** Enhances the app's utility for planning and improves user experience by catering to individual measurement system preferences.
**Acceptance Criteria:** Users can view future weather conditions and toggle between Celsius and Fahrenheit units.

**User Stories:**
- **US-002:** View Multi-Day Weather Forecast
  - **As a** user
  - **I want to** see a forecast for the upcoming days for my selected location
  - **So that** I can plan my activities for the week ahead.
  - **Acceptance Criteria:**
    - [ ] After searching for a location, the application displays a list of daily forecasts (e.g., for the next 5-7 days) below the current weather.
    - [ ] Each forecast entry includes the day, date, high and low temperatures, and a relevant weather icon/description.
    - [ ] The forecast list is responsive and easy to read.
  - **Story Points:** 8
  - **Priority:** High

- **US-003:** Switch Temperature Units
  - **As a** user
  - **I want to** be able to switch between Celsius and Fahrenheit temperature units
  - **So that** I can view weather data in my preferred measurement system.
  - **Acceptance Criteria:**
    - [ ] The application provides a visible toggle or button (e.g., a Clarity toggle switch) to switch temperature units.
    - [ ] When I click the toggle, all displayed temperatures (current and forecast) instantaneously switch between Celsius and Fahrenheit.
    - [ ] The selected unit persists during my session (e.g., using local storage).
  - **Story Points:** 5
  - **Priority:** Medium

### Epic 3: System Resilience & User Feedback
**Epic Description:** Ensure users are informed about the application's state and any issues, providing a robust and trustworthy experience.
**Business Value:** Improves user satisfaction and trust by proactively communicating system status and handling errors gracefully.
**Acceptance Criteria:** Users receive clear feedback during data loading and when errors occur.

**User Stories:**
- **US-005:** Understand Data Fetching Status and Errors
  - **As a** user
  - **I want to** receive clear feedback when data is loading or an error occurs
  - **So that** I can understand the application's state and troubleshoot issues.
  - **Acceptance Criteria:**
    - [ ] When the application is fetching weather data, a prominent loading indicator (e.g., Clarity Spinner) is displayed in the relevant UI sections.
    - [ ] If a network error occurs or the external API is unreachable, a user-friendly error message (e.g., "Could not fetch weather data. Please try again later.") is displayed.
    - [ ] If an invalid search term is entered and no location is found, a specific message like "Location not found. Please try another city." is displayed.
    - [ ] Error messages are dismissible or disappear after a short period.
  - **Story Points:** 5
  - **Priority:** High

## 9. User Interface Requirements
Generated: 2025-09-26 10:05:00
-   **Clarity Design System Adherence:** All UI components and styling must strictly follow the VMware Clarity Design System guidelines to maintain a consistent look and feel with the base boilerplate.
-   **Responsive Layout:** The application layout must be fully responsive, adapting seamlessly to various screen sizes, from mobile devices to large desktop monitors.
-   **Main Layout:** Utilize the existing Angular Clarity Boilerplate's header, sidebar (if applicable for future features, though initially not prominent for weather), and main content area.
-   **Search Bar:** A prominent input field (Clarity Input) for location search, possibly with an associated search button (Clarity Button).
-   **Current Weather Card:** Display current weather information within a Clarity Card component, featuring: city name, temperature, weather condition icon/description, humidity, and wind speed.
-   **Forecast List:** A scrollable list of daily forecasts, potentially using Clarity List or multiple small Clarity Card components for each day, including date, high/low temperature, and weather icon/description.
-   **Temperature Unit Toggle:** A clear toggle switch (Clarity Toggle) or segmented button (Clarity Button Group) to switch between Celsius and Fahrenheit.
-   **Loading Indicators:** Implement Clarity Spinner components for all data loading states.
-   **Error Messages:** Display error and informational messages using Clarity Alert components or toast notifications.
-   **Weather Icons:** Utilize a consistent set of weather icons (e.g., Font Awesome, custom SVGs) to visually represent weather conditions.

## 10. Technical Requirements
Generated: 2025-09-26 10:05:00
-   **Frontend (Angular):**
    *   Utilize Angular v16+ and the existing boilerplate structure (CoreModule, SharedModule, Feature Modules).
    *   Implement `HttpClient` for all API interactions with the backend proxy.
    *   Manage application state using Angular Services with RxJS for reactive data flows.
    *   Integrate browser's Geolocation API for location detection.
    *   Adhere to TypeScript interfaces (`Location`, `CurrentWeather`, `ForecastDay`) for strong data typing.
-   **Backend (Node.js/Express.js Proxy):**
    *   Develop using Node.js v18+ and Express.js v4+.
    *   Create RESTful API endpoints for `/api/current-weather` and `/api/forecast`.
    *   Implement secure handling of external weather API keys using environment variables (`dotenv`).
    *   Integrate with an external weather API (e.g., OpenWeatherMap) using `axios` or `node-fetch`.
    *   Perform data transformation from external API responses to internal frontend data models.
    *   Configure CORS to allow requests only from the Angular frontend's domain.
-   **Caching (Redis):**
    *   Implement Redis v6+ as an in-memory data store for caching weather data on the backend proxy.
    *   Cache keys should be location and unit-specific, with configurable TTL to ensure data freshness.
-   **Deployment & Infrastructure:**
    *   Containerize both the Angular frontend and Node.js/Express.js backend using Docker.
    *   Provide `docker-compose.yml` for simplified local development and orchestration.
    *   The application should be deployable to cloud container services (e.g., AWS Fargate, Azure Container Instances, Google Cloud Run).
-   **Security:**
    *   All communication over HTTPS.
    *   Robust input validation on both frontend and backend to prevent malicious inputs.
    *   Backend should sanitize all parameters before forwarding to external API.
-   **Error Handling:** Implement global HTTP interceptors in Angular for frontend error management and centralized error handling within the backend proxy.

## 11. Success Metrics & KPIs
Generated: 2025-09-26 10:05:00
-   **Response Time (Frontend):** Average time to display current weather < 3 seconds; average time to display forecast < 5 seconds.
-   **Backend Latency:** Average backend proxy response time < 100 ms.
-   **API Call Efficiency:** Number of external weather API calls reduced by X% due to caching (baseline to be established).
-   **Uptime:** 99.9% availability for the Weather App service.
-   **Error Rate:** Less than 0.1% of API requests resulting in client-facing errors (excluding invalid user input).
-   **User Feedback:** Positive qualitative feedback on usability and accuracy.

## 12. Risk Assessment
Generated: 2025-09-26 10:05:00
-   **External API Dependency:**
    *   **Risk:** External weather API downtime, rate limit issues, or changes to API structure.
    *   **Mitigation:** Implement robust error handling, retry mechanisms, caching, and potentially support for multiple weather API providers in future iterations. Monitor API status.
-   **Geolocation Permissions:**
    *   **Risk:** Users may deny geolocation permissions, impacting the "current location" feature.
    *   **Mitigation:** Provide clear explanations for permission requests and gracefully fallback to manual search if denied.
-   **API Key Security:**
    *   **Risk:** Exposure of external API keys if not handled securely on the backend.
    *   **Mitigation:** Strictly enforce environment variable usage for API keys and restrict access to backend configuration.
-   **Performance Bottlenecks:**
    *   **Risk:** Slow response times due to inefficient data processing or network latency.
    *   **Mitigation:** Optimize backend service logic, aggressive caching with Redis, efficient Angular change detection, and bundle optimization.
-   **CORS Issues:**
    *   **Risk:** Misconfiguration of CORS on the backend preventing frontend communication.
    *   **Mitigation:** Rigorous testing of CORS setup during development and deployment, ensuring correct allowed origins.

## 13. Timeline & Milestones
Generated: 2025-09-26 10:05:00
**Phase 1: Discovery & Definition (Current)**
- **Duration:** 1 week
- **Milestone:** PRD Completion & Approval.

**Phase 2: Core Backend Development**
- **Duration:** 2-3 weeks
- **Milestone:** Backend Proxy MVP (Current weather & forecast endpoints, API integration, basic caching).

**Phase 3: Core Frontend Development**
- **Duration:** 3-4 weeks
- **Milestone:** Frontend MVP (Search, current weather display, forecast list, unit toggle, integrated with backend).

**Phase 4: Integration, Testing & Refinement**
- **Duration:** 1-2 weeks
- **Milestone:** Integrated & Tested MVP (End-to-end functionality, error handling, responsiveness).

**Phase 5: Deployment Readiness & Initial Launch**
- **Duration:** 1 week
- **Milestone:** Production Deployment (Containerization, cloud setup, monitoring).

## 14. Dependencies & Assumptions
Generated: 2025-09-26 10:05:00
-   **External Weather API:** Assumption of consistent availability, stable API endpoints, and adherence to specified rate limits for the chosen provider (e.g., OpenWeatherMap).
-   **Angular Clarity Boilerplate:** Dependency on the stability and correct setup of the initial boilerplate for frontend development.
-   **Node.js/Express.js:** Availability of Node.js and Express.js ecosystem for backend development.
-   **Redis Service:** Availability of a Redis instance for caching in both development and production environments.
-   **Browser Features:** User's browser supports Geolocation API and standard web features.
-   **Development Environment:** Developers have necessary tools (Node.js, npm/yarn, Angular CLI, Docker) installed and configured.
-   **Cloud Infrastructure:** Access to a configured cloud provider (AWS, Azure, GCP) for container deployment.
-   **Security Policies:** Adherence to organizational security policies for API key management and data handling.

