Requirements

Imagine you're building a Quality Assurance (QA) application for a massive e-commerce platform like Amazon or Walmart. Each product listed on the platform needs to undergo a series of quality checks to ensure it meets certain standards. These checks can vary significantly depending on the product category (electronics, clothing, food, etc.) and can be automated, manual, or a combination of both. The goal is to create a system that can efficiently manage and track the QA process for millions of products, allowing for easy addition of new checks and categories, and providing real-time visibility into the status of each product's QA journey. Different teams are responsible for different types of checks, and the results must be auditable. This isn't just about preventing defects; it's about maintaining customer trust and protecting the brand's reputation. # Requirements ## Functional Requirements 1. **Product Registration:** The system must allow for registering new products. Each product should have attributes like `productId`, `productName`, `category`, and other relevant metadata. 2. **Category Definition:** Define product categories (e.g., Electronics, Clothing, Books, Groceries). Each category should have a set of associated QA checks. 3. **QA Check Definition:** Define different types of QA checks. Examples: * `ImageQualityCheck`: Verifies the quality of product images. * `DescriptionCheck`: Checks the accuracy and completeness of the product description. * `PriceCheck`: Validates the product price against defined rules. * `ComplianceCheck`: Ensures the product meets regulatory requirements. * `PackagingCheck`: Checks if the product packaging is adequate. * `FunctionalityCheck`: Checks if the product functions as expected. * `MaterialCheck`: Checks the materials used in the product. 4. **QA Workflow Assignment:** For each category, define the sequence of QA checks that must be performed on products belonging to that category. The workflow should be configurable, allowing for changes in the order or addition/removal of checks. 5. **QA Check Execution:** Allow users (QA engineers) to execute the defined QA checks for a given product. This might involve automated checks (running code) or manual checks (entering results). 6. **Result Recording:** Store the results of each QA check, including: * `Product ID` * `Check Type` * `Status` (Pass/Fail/In Progress/Blocked) * `Timestamp` * `User` (who performed the check) * `Comments` (optional notes) 7. **Status Tracking:** Provide a way to track the overall QA status of a product (e.g., "Pending," "In Progress," "Passed," "Failed," "Blocked"). The overall status should be derived from the individual check results. 8. **Reporting and Analytics:** Generate reports on QA metrics, such as: * Number of products passing/failing QA checks. * Average time to complete QA for a product category. * Common failure points. 9. **Concurrent Execution**: Allow multiple QA engineers to work on different checks for the same product concurrently, or even the same check if designed to support it (e.g. multiple samples of the same product being tested). 10. **Audit Trail**: Maintain an audit trail of all actions performed on a product's QA process, including who performed the action and when. ## Non-Functional Requirements 1. **Thread Safety:** The system must be thread-safe to handle concurrent requests from multiple users executing QA checks simultaneously. Data structures and operations that modify product or check status must be properly synchronized. 2. **Extensibility:** The system should be easily extensible to support new product categories and QA check types without requiring significant code changes. Consider using design patterns to achieve this. 3. **Modularity:** The system should be designed with clear separation of concerns, making it easy to maintain and modify individual components without affecting others. 4. **Testability:** The code should be designed to be easily testable, with well-defined interfaces and dependencies. 5. **Maintainability**: The code should be well-documented and easy to understand. 6. **Performance**: While real-time latency isn't a core requirement, the system should be efficient in processing QA checks and updating status. Avoid unnecessary database lookups or complex calculations. Focus more on algorithmic efficiency within the individual checks and the overall workflow execution. 7. **Scalability**: The system should be designed to handle a large number of products and QA checks. While we are focusing on in-memory implementation, consider how the design would scale if persisted in a database. ## Core Entities 1. **Product:** Represents a product listed on the e-commerce platform. Attributes: `productId`, `productName`, `category`, `description`, `price`, etc. 2. **Category:** Represents a product category. Attributes: `categoryId`, `categoryName`, `qaWorkflow` (list of QA checks). 3. **QACheck:** Represents a specific QA check. This is an *abstract* concept. Concrete implementations will be specific checks (e.g., `ImageQualityCheck`, `DescriptionCheck`). Attributes: `checkId`, `checkName`, `checkDescription`. The core method is `execute(Product product)`. 4. **QAWorkflow:** Represents the sequence of QA checks for a category. 5. **QAExecutionResult:** Represents the result of a QA check execution. Attributes: `productId`, `checkId`, `status`, `timestamp`, `user`, `comments`. 6. **QAStatus:** Represents the overall QA status of a product. Enum: `PENDING`, `IN_PROGRESS`, `PASSED`, `FAILED`, `BLOCKED`. 7. **User**: Represents the user who performed the QA check.

Design Q&A application as in Amazon,Walmart has it for each product.

Requirements

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Functional Requirements

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Non-Functional Requirements

Core Entity Identification

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