# 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 - 2025-10-04 11:56:23

# Product Requirements Document (PRD)

## Document Version & Review
*   **Version:** 1.0 (Initial Draft for Yellow Calculator App Integration)
*   **Date:** 2025-10-04T11:32:58
*   **Status:** Draft - Product Manager Review & Initial Approval

This document outlines the product requirements for the "Yellow Calculator App" feature, which is being integrated into the Angular Clarity Boilerplate. It synthesizes insights from business analysis (`analysis_document.md`), architectural design (`architecture_document.md`), and technical stack considerations (`tech_stack_document.md`) to define a clear path for development. As the io8 Product Manager, I have reviewed and confirmed the following detailed requirements, building upon the architectural contributions.

---

## Feature: Yellow Calculator App Requirements (PM Confirmed - 2025-10-04T11:32:58)

### 1. Executive Summary - Yellow Calculator App
*(Appended 2025-10-04T11:32:58)*
This document outlines the requirements for integrating a "Yellow Calculator App" as a new, self-contained, lazy-loaded feature module within the existing Angular Clarity Boilerplate. This feature aims to provide a tangible demonstration of the boilerplate's modularity and Clarity Design System styling capabilities, offering a basic arithmetic utility themed with a distinct yellow aesthetic.

### 2. Product Vision & Strategy - Yellow Calculator App
*(Appended 2025-10-04T11:32:58)*
**Product Vision:** To enhance the Angular Clarity Boilerplate by providing a ready-to-use, visually distinct (yellow-themed) calculator feature that serves as an excellent example of a lazy-loaded module, showcasing the boilerplate's architecture and the flexibility of the Clarity Design System.

**Strategic Goals:**
-   **Demonstrate Modularity:** Provide a clear, isolated example of how to integrate new, lazy-loaded feature modules (`FR-002: Modular Architecture` from `analysis_document.md`).
-   **Showcase Clarity Theming:** Highlight the ability to customize Clarity components and apply custom styling (e.g., a "yellow" theme) through SCSS overrides (`NFR-003: Maintainability` from `analysis_document.md`, `Styling` from `tech_stack_document.md`).
-   **Provide Utility:** Offer a simple, functional tool within the boilerplate that developers can use or extend.
-   **Accelerate Feature Development:** Serve as a template for future feature development, allowing developers to quickly understand the process of adding new capabilities.

**Success Metrics (KPIs for Yellow Calculator App):**
-   **Feature Integration Success:** Calculator module loads and functions correctly within the boilerplate, accessible via its dedicated route.
-   **Theming Accuracy:** The calculator's UI consistently adheres to the specified "yellow" theme using Clarity components and SCSS.
-   **User Engagement (Developer Feedback):** Positive feedback from developers regarding the calculator's utility as a demo and its ease of integration/understanding.
-   **Performance:** Lazy-loading ensures minimal impact on initial application load time (`NFR-001: Performance` from `analysis_document.md`).

### 3. Target Users & Personas - Yellow Calculator App
*(Appended 2025-10-04T11:32:58)*
While the primary users of the boilerplate are **Angular Developers**, the calculator itself serves two distinct personas:

1.  **Boilerplate Developer (Primary User):**
    -   **Demographics:** Experienced Angular developer, familiar with Clarity, looking for best practices and a head-start on projects.
    -   **Needs:** A clear example of a lazy-loaded module, how to apply custom themes, and a functional component to learn from or adapt.
    -   **Journey:** Clones boilerplate -> explores modules -> finds calculator -> inspects code -> understands integration patterns -> adapts for own features.
2.  **End-User (of apps built with boilerplate):**
    -   **Demographics:** General web application user.
    -   **Needs:** A simple, intuitive, and visually appealing basic calculator for quick calculations within the application context.
    -   **Journey:** Navigates to calculator feature -> inputs numbers -> performs operations -> gets results.

### 4. Problem Statement - Yellow Calculator App
*(Appended 2025-10-04T11:32:58)*
Currently, the Angular Clarity Boilerplate provides a robust foundational structure but lacks a compelling, self-contained feature to immediately showcase its capabilities (e.g., modularity, lazy-loading, Clarity theming) in a practical, user-facing manner. Developers seeking to understand how to build and integrate new features require a well-structured example that also highlights UI customization possibilities. This absence prolongs the learning curve and reduces the immediate demonstrative value of the boilerplate.

### 5. Solution Overview - Yellow Calculator App
*(Appended 2025-10-04T11:32:58)*
Implement a basic arithmetic calculator as a new, lazy-loaded Angular feature module (`CalculatorModule`). This module will integrate seamlessly into the existing application shell provided by the boilerplate, leveraging Clarity Design System components for its UI. The calculator will feature a distinct "yellow" color scheme, applied via SCSS, to demonstrate custom theming. It will support fundamental operations (addition, subtraction, multiplication, division) and a clear function, operating entirely client-side without backend dependencies.

### 6. Functional Requirements - Yellow Calculator App
*(Appended 2025-10-04T11:32:58)*
-   **FR-CALC-001: Number Input:** The calculator shall allow users to input numbers via an on-screen keypad.
-   **FR-CALC-002: Basic Arithmetic Operations:** The calculator shall support addition, subtraction, multiplication, and division operations.
-   **FR-CALC-003: Display Output:** The calculator shall clearly display the current input and the result of calculations.
-   **FR-CALC-004: Clear Functionality:** The calculator shall provide a "Clear" button to reset the current input and calculation state.
-   **FR-CALC-005: Equals Functionality:** The calculator shall compute and display the result when the "Equals" button is pressed.
-   **FR-CALC-006: Decimal Input:** The calculator shall allow input of decimal numbers.
-   **FR-CALC-007: Negative Number Input:** The calculator shall allow entering negative numbers (e.g., via a +/- button or implicit through subtraction).

### 7. Non-Functional Requirements - Yellow Calculator App
*(Appended 2025-10-04T11:32:58)*
-   **NFR-CALC-001: Performance:** The calculator feature module shall be lazy-loaded to ensure minimal impact on the initial boilerplate application load time (`NFR-001: Performance` from `analysis_document.md`).
-   **NFR-CALC-002: Responsiveness:** The calculator UI shall be responsive and usable across various screen sizes (desktop, tablet, mobile), adhering to the boilerplate's responsive layout (`FR-004: Responsive Layout` from `analysis_document.md`).
-   **NFR-CALC-003: Usability:** The calculator interface shall be intuitive and easy to use for basic arithmetic operations (`NFR-002: Usability (Developer Experience)` from `analysis_document.md` applies to end-user experience here).
-   **NFR-CALC-004: Theming:** The calculator's UI elements (background, buttons, display) shall adopt a consistent "yellow" color scheme, leveraging Clarity components and custom SCSS as per `tech_stack_document.md`.
-   **NFR-CALC-005: Accuracy:** All arithmetic operations shall produce accurate results for standard integer and decimal inputs within JavaScript's number precision limitations.
-   **NFR-CALC-006: Integration:** The calculator feature module shall integrate seamlessly with the existing Angular Clarity Boilerplate, following its architectural patterns (`NFR-004: Scalability` from `analysis_document.md`).

### 8. Epic Stories - Yellow Calculator App
*(Appended 2025-10-04T11:32:58)*

### Epic 1: Basic Yellow Calculator Functionality
**Epic Description:** Enable users to perform fundamental arithmetic calculations (add, subtract, multiply, divide) with numbers, display results, and clear inputs, all within a visually distinctive yellow-themed interface.
**Business Value:** Provides a practical, demo-ready feature for the boilerplate, showcasing modularity, custom theming, and basic utility. Reduces boilerplate learning curve for developers.
**Acceptance Criteria:**
-   [ ] The calculator module is lazy-loaded and accessible via a distinct route.
-   [ ] Users can input numbers and see them displayed correctly.
-   [ ] Users can perform addition, subtraction, multiplication, and division.
-   [ ] The calculator displays correct results for valid operations.
-   [ ] The calculator can be reset to its initial state.
-   [ ] The UI consistently reflects the "yellow" theme.

**User Stories:**

-   **US-CALC-001:** Implement Basic Number Input and Display
    -   **As a** calculator user
    -   **I want to** press number buttons (0-9) and see them appear on the display
    -   **So that** I can input the numbers for my calculation
    -   **Acceptance Criteria:**
        -   [ ] Pressing '0' through '9' buttons appends the digit to the current display.
        -   [ ] The display updates immediately with each new digit.
        -   [ ] Multiple digits can be entered to form multi-digit numbers.
    -   **Story Points:** 3
    -   **Priority:** High

-   **US-CALC-002:** Perform Addition Operation
    -   **As a** calculator user
    -   **I want to** input two numbers, press the '+' button, and then the '=' button
    -   **So that** I can see the sum of the two numbers displayed as the result
    -   **Acceptance Criteria:**
        -   [ ] The '+' button captures the first number and awaits the second.
        -   [ ] Pressing '=' after the second number displays the correct sum.
        -   [ ] Chained additions (e.g., 2+2+2) produce the correct cumulative sum.
    -   **Story Points:** 5
    -   **Priority:** High

-   **US-CALC-003:** Perform Subtraction Operation
    -   **As a** calculator user
    -   **I want to** input two numbers, press the '-' button, and then the '=' button
    -   **So that** I can see the difference between the two numbers displayed as the result
    -   **Acceptance Criteria:**
        -   [ ] The '-' button captures the first number and awaits the second.
        -   [ ] Pressing '=' after the second number displays the correct difference.
    -   **Story Points:** 5
    -   **Priority:** High

-   **US-CALC-004:** Perform Multiplication Operation
    -   **As a** calculator user
    -   **I want to** input two numbers, press the 'x' button, and then the '=' button
    -   **So that** I can see the product of the two numbers displayed as the result
    -   **Acceptance Criteria:**
        -   [ ] The 'x' button captures the first number and awaits the second.
        -   [ ] Pressing '=' after the second number displays the correct product.
    -   **Story Points:** 5
    -   **Priority:** High

-   **US-CALC-005:** Perform Division Operation
    -   **As a** calculator user
    -   **I want to** input two numbers, press the '/' button, and then the '=' button
    -   **So that** I can see the quotient of the two numbers displayed as the result
    -   **Acceptance Criteria:**
        -   [ ] The '/' button captures the first number and awaits the second.
        -   [ ] Pressing '=' after the second number displays the correct quotient.
        -   [ ] Division by zero results in an appropriate error message (e.g., "Error" or "Cannot divide by zero").
    -   **Story Points:** 5
    -   **Priority:** High

-   **US-CALC-006:** Clear All Input and Results
    -   **As a** calculator user
    -   **I want to** press a 'C' (Clear) or 'AC' (All Clear) button
    -   **So that** the display and all calculation states are reset to zero
    -   **Acceptance Criteria:**
        -   [ ] Pressing 'C' or 'AC' clears the current display to '0'.
        -   [ ] Pressing 'C' or 'AC' resets any pending operations.
    -   **Story Points:** 3
    -   **Priority:** High

-   **US-CALC-007:** Input Decimal Numbers
    -   **As a** calculator user
    -   **I want to** press the '.' (decimal) button
    -   **So that** I can enter and calculate with decimal numbers
    -   **Acceptance Criteria:**
        -   [ ] The '.' button inserts a decimal point into the current number.
        -   [ ] Only one decimal point can be entered per number.
        -   [ ] Calculations involving decimal numbers produce accurate decimal results.
    -   **Story Points:** 3
    -   **Priority:** Medium

-   **US-CALC-008:** Apply Yellow Theming to UI
    -   **As a** developer demonstrating the boilerplate
    -   **I want to** ensure the calculator has a prominent "yellow" aesthetic using Clarity Design System principles
    -   **So that** it clearly showcases custom theming capabilities of the boilerplate
    -   **Acceptance Criteria:**
        -   [ ] The calculator's background, button colors, and display text color incorporate a consistent yellow palette.
        -   [ ] Clarity UI components (e.g., buttons) are styled with the yellow theme through SCSS overrides (`tech_stack_document.md` reference).
        -   [ ] The yellow theme is visually appealing and consistent across the calculator interface.
    -   **Story Points:** 8
    -   **Priority:** High

### 9. User Interface Requirements - Yellow Calculator App
*(Appended 2025-10-04T11:32:58)*
-   **UI-CALC-001: Layout:** The calculator shall have a clear, grid-based layout for its display and keypad. It should occupy a reasonable portion of the screen, adapting responsively.
-   **UI-CALC-002: Display:** A prominent display area at the top of the calculator will show current input and results. It should be large enough to show up to 10-12 digits and potentially a small indicator for the current operation.
-   **UI-CALC-003: Keypad Buttons:** All number (0-9), decimal (.), operation (+, -, x, /), equals (=), and clear (C/AC) buttons shall be clearly distinguishable and appropriately sized for touch interaction.
-   **UI-CALC-004: Yellow Theme:**
    -   **Color Palette:** Utilize a vibrant yellow as the primary accent color, with complementary grays or whites for text and backgrounds to ensure readability.
    -   **Clarity Integration:** Leverage Clarity button styles, input fields (for display), and potentially card components for the overall calculator container.
    -   **Accessibility:** Ensure sufficient contrast ratios for text and background colors to meet WCAG AA standards, even with the yellow theme.
-   **UI-CALC-005: Feedback:** Buttons should provide visual feedback on press (e.g., a slight change in background color, a ripple effect).

### 10. Technical Requirements - Yellow Calculator App
*(Appended 2025-10-04T11:32:58)*
-   **TECH-CALC-001: Framework:** Built using Angular, consistent with the boilerplate's core technology (`tech_stack_document.md`).
-   **TECH-CALC-002: UI Components:** Utilize VMware Clarity Design System components where applicable (`tech_stack_document.md`).
-   **TECH-CALC-003: Styling:** Implement 'yellow' theming using SCSS, leveraging Clarity's theming capabilities or overriding default styles (`tech_stack_document.md`). Custom SCSS variables or classes will define the yellow palette.
-   **TECH-CALC-004: Architecture:** Structured as a lazy-loaded Angular Feature Module (`CalculatorModule`), encapsulating its own components, services, and routing (`architecture_document.md`).
-   **TECH-CALC-005: State Management:** Client-side state management for calculator logic (current value, operation, history) will be handled within the `CalculatorComponent` or a dedicated service provided by `CalculatorModule`. No external state management library (e.g., NgRx) is required for this basic implementation (`architecture_document.md`).
-   **TECH-CALC-006: Backend:** The calculator will be purely client-side; no backend API interaction is required (`architecture_document.md`).
-   **TECH-CALC-007: Routing:** A dedicated route (e.g., `/calculator`) will be configured within the main `AppRoutingModule` for lazy loading the `CalculatorModule` (`FR-005: Routing` from `analysis_document.md`).

### 11. Success Metrics & KPIs - Yellow Calculator App
*(Appended 2025-10-04T11:32:58)*
-   **KPI-CALC-001: Successful Lazy Load:** Monitor network logs to confirm `CalculatorModule` bundle is only loaded upon navigation to the calculator route.
-   **KPI-CALC-002: Calculation Accuracy:** Pass rate of unit and integration tests covering all specified arithmetic operations and edge cases (e.g., division by zero, decimal precision).
-   **KPI-CALC-003: Theming Consistency:** Visual inspection and potential automated UI tests to confirm consistent application of the "yellow" theme across all calculator elements.
-   **KPI-CALC-004: Responsive Behavior:** Successful rendering and interaction across defined breakpoints for various device types.
-   **KPI-CALC-005: Code Quality:** Adherence to Angular best practices, maintainability of the `CalculatorModule` (measured by code review comments, linting results, cyclomatic complexity).

### 12. Risk Assessment - Yellow Calculator App
*(Appended 2025-10-04T11:32:58)*
-   **RISK-CALC-001: Styling Conflicts:**
    -   **Description:** Custom "yellow" SCSS might inadvertently override or conflict with core Clarity Design System styles or other boilerplate styles.
    -   **Mitigation:** Use highly specific CSS selectors within the `CalculatorModule` (e.g., `ViewEncapsulation.Emulated` for component styles), use Clarity's custom property variables for theming where possible, thorough testing after styling changes.
-   **RISK-CALC-002: Arithmetic Precision Errors:**
    -   **Description:** JavaScript's floating-point arithmetic can lead to precision issues, especially with complex decimal calculations.
    -   **Mitigation:** For this basic calculator, standard `Number` operations are acceptable. Document any known precision limitations. If advanced calculations are required later, consider libraries like `decimal.js`.
-   **RISK-CALC-003: Usability/UX Issues:**
    -   **Description:** The calculator's layout or interaction flow might not be intuitive or responsive on all devices.
    -   **Mitigation:** Conduct internal UX review. Test extensively on various devices/browsers. Leverage Clarity's responsive grid system for layout.
-   **RISK-CALC-004: Integration Complexity:**
    -   **Description:** Incorrect setup of lazy loading or routing could cause the calculator module not to load or function correctly.
    -   **Mitigation:** Follow Angular's lazy-loading best practices. Thorough unit and integration testing of the routing setup.

### 13. Timeline & Milestones - Yellow Calculator App
*(Appended 2025-10-04T11:32:58)*
-   **Phase 1: Definition & Design (2 days)**
    -   Finalize PRD, user stories, and UI wireframes/mockups for calculator.
    -   Establish yellow color palette.
-   **Phase 2: Core Development (5 days)**
    -   Set up `CalculatorModule` with lazy loading and routing.
    -   Implement `CalculatorDisplayComponent` and `CalculatorKeypadComponent`.
    -   Develop core arithmetic logic (add, subtract, multiply, divide).
    -   Implement number and decimal input.
-   **Phase 3: Theming & Refinement (3 days)**
    -   Apply "yellow" theme using SCSS and Clarity components.
    -   Ensure responsiveness and cross-browser compatibility.
    -   Implement clear/reset functionality.
    -   Conduct initial testing and bug fixes.
-   **Phase 4: Testing & Documentation (2 days)**
    -   Comprehensive unit and integration testing.
    -   Update boilerplate documentation on how to use/integrate the calculator.
    -   Final QA and review.
-   **Phase 5: Final Review & Approval (1 day)**
    -   Product Manager and Lead Developer final review and approval.

### 14. Dependencies & Assumptions - Yellow Calculator App
*(Appended 2025-10-04T11:32:58)*
-   **DEP-CALC-001: Existing Boilerplate:** Full functionality of the base Angular Clarity Boilerplate (Angular, Clarity, SCSS, routing) is stable and available (`analysis_document.md`, `architecture_document.md`, `tech_stack_document.md`).
-   **DEP-CALC-002: Development Environment:** Standard Angular development environment (Node.js, npm, Angular CLI) is set up and configured.
-   **ASSUMP-CALC-001: Basic Arithmetic Scope:** The calculator will only support basic arithmetic operations. Advanced functions (e.g., square root, trigonometry, memory functions) are out of scope for the MVP.
-   **ASSUMP-CALC-002: Client-Side Only:** The calculator will operate entirely on the client-side; no backend services are required or assumed for its functionality.
-   **ASSUMP-CALC-003: Clarity Theme Overrides:** The Clarity Design System allows for sufficient styling customization via SCSS to achieve the desired "yellow" theme without excessive workaround or breaking core styles.
