# Story 1.1: User Email Validation

## Story Metadata

```yaml
story:
  epic: '1'
  number: '1'
  title: 'User Email Validation'
  status: 'ready'
  priority: 'high'

# TDD Configuration
tdd:
  status: 'red' # Current phase: red|green|refactor|done
  cycle: 1
  coverage_target: 90.0
  tests:
    - id: 'UV-001'
      name: 'should validate correct email format'
      type: unit
      status: failing
      file_path: 'tests/user-validator.test.js'
    - id: 'UV-002'
      name: 'should reject invalid email format'
      type: unit
      status: failing
      file_path: 'tests/user-validator.test.js'
    - id: 'UV-003'
      name: 'should handle edge cases'
      type: unit
      status: failing
      file_path: 'tests/user-validator.test.js'
```

## Story Description

**As a** System Administrator  
**I want** to validate user email addresses  
**So that** only users with valid email formats can register

### Context

This is a foundational feature for user registration. We need robust email validation that follows RFC standards while being user-friendly. This will be used by the registration system and user profile updates.

## Acceptance Criteria

```gherkin
Feature: User Email Validation

Scenario: Valid email formats are accepted
  Given a user provides an email address
  When the email has correct format with @ symbol and domain
  Then the validation should return true

Scenario: Invalid email formats are rejected
  Given a user provides an invalid email address
  When the email lacks @ symbol or proper domain format
  Then the validation should return false with appropriate error message

Scenario: Edge cases are handled properly
  Given a user provides edge case email formats
  When validation is performed on emails with special characters or unusual formats
  Then the system should handle them according to RFC standards
```

## Technical Requirements

### Functional Requirements

- Validate email format using RFC-compliant rules
- Return boolean result with error details when invalid
- Handle common edge cases (special characters, multiple @, etc.)
- Performance: validation should complete in < 1ms

### Non-Functional Requirements

- **Performance:** < 1ms validation time per email
- **Security:** Prevent injection attacks via email input
- **Reliability:** 99.9% accuracy on email format validation
- **Maintainability:** Clear error messages for debugging

## TDD Test Plan (QA Agent Responsibility)

### Test Strategy

- **Primary Test Type:** unit
- **Mocking Approach:** No external dependencies to mock
- **Test Data:** Fixed test cases covering valid/invalid formats

### Planned Test Scenarios

| ID     | Scenario                     | Type | Priority | AC Reference |
| ------ | ---------------------------- | ---- | -------- | ------------ |
| UV-001 | Valid email formats accepted | unit | P0       | AC1          |
| UV-002 | Invalid formats rejected     | unit | P0       | AC2          |
| UV-003 | Edge cases handled           | unit | P1       | AC3          |
| UV-004 | Performance requirements met | unit | P2       | NFR          |

## TDD Progress

### Current Phase: RED

**Cycle:** 1
**Last Updated:** 2025-01-12

### Red Phase - Cycle 1

**Date:** 2025-01-12
**Agent:** Quinn (QA Agent)

**Tests Written:**

- UV-001: should validate correct email format (FAILING ✅)
- UV-002: should reject invalid email format (FAILING ✅)
- UV-003: should handle edge cases (FAILING ✅)

**Test Files:**

- tests/user-validator.test.js

**Next Step:** Dev Agent to implement minimal code to make tests pass

---

## Implementation Tasks (Dev Agent)

### Primary Tasks

- [ ] Create UserValidator class
- [ ] Implement email validation logic
- [ ] Handle error cases and edge cases

### Subtasks

- [ ] Set up basic class structure
- [ ] Implement regex-based validation
- [ ] Add error message generation
- [ ] Performance optimization

## Definition of Done

### TDD-Specific DoD

- [ ] Tests written first (Red phase completed)
- [ ] All tests passing (Green phase completed)
- [ ] Code refactored for quality (Refactor phase completed)
- [ ] Test coverage meets target (90%)
- [ ] All external dependencies properly mocked (N/A for this story)
- [ ] No features implemented without corresponding tests

### General DoD

- [ ] All acceptance criteria met
- [ ] Code follows project standards
- [ ] Documentation updated
- [ ] Ready for review

## Dev Agent Record

### Implementation Notes

_(Dev agent will document implementation decisions here)_

### TDD Cycle Log

_(Automatic tracking of Red-Green-Refactor progression)_

**Cycle 1:**

- Red Phase: 2025-01-12 - 3 failing tests written
- Green Phase: _(pending)_
- Refactor Phase: _(pending)_

### File List

_(Dev agent will list all files created/modified)_

- tests/user-validator.test.js (created)
- _(implementation files will be added during GREEN phase)_

### Test Execution Log

```bash
# RED phase test runs will be logged here
```

## QA Results

_(QA agent will populate this during review)_

## Change Log

- **2025-01-12**: Story created from TDD template
- **2025-01-12**: Red phase completed - failing tests written

---

**TDD Status:** 🔴 RED Phase  
**Agent Assigned:** Quinn (QA) → James (Dev)  
**Estimated Effort:** 2 hours