# Tasks: Geek Calculator

**Input**: Design documents from `/specs/001-build-a-single/`
**Prerequisites**: plan.md (required), research.md, data-model.md, contracts/

## Execution Flow (main)
```
1. Load plan.md from feature directory
   → If not found: ERROR "No implementation plan found"
   → Extract: tech stack, libraries, structure
2. Load optional design documents:
   → data-model.md: Extract entities → model tasks
   → contracts/: Each file → contract test task
   → research.md: Extract decisions → setup tasks
3. Generate tasks by category:
   → Setup: project init, dependencies, linting
   → Tests: contract tests, integration tests
   → Core: models, services, CLI commands
   → Integration: DB, middleware, logging
   → Polish: unit tests, performance, docs
4. Apply task rules:
   → Different files = mark [P] for parallel
   → Same file = sequential (no [P])
   → Tests before implementation (TDD)
5. Number tasks sequentially (T001, T002...)
6. Generate dependency graph
7. Create parallel execution examples
8. Validate task completeness:
   → All contracts have tests?
   → All entities have models?
   → All endpoints implemented?
9. Return: SUCCESS (tasks ready for execution)
```

## Format: `[ID] [P?] Description`
- **[P]**: Can run in parallel (different files, no dependencies)
- Include exact file paths in descriptions

## Path Conventions
- **Single project**: index.html, styles.css, app.js at repository root
- **Test files**: tests/unit/, tests/integration/ directories

## Phase 3.1: Setup
- [X] T001 Create project structure: index.html, styles.css, app.js, service-worker.js, manifest.webmanifest
- [X] T002 [P] Create test directory structure: tests/unit/, tests/integration/, tests/index.html
- [X] T003 [P] Create README.md with usage instructions

## Phase 3.2: Tests First (TDD) ⚠️ MUST COMPLETE BEFORE 3.3
**CRITICAL: These tests MUST be written and MUST FAIL before ANY implementation**
- [X] T004 [P] Contract test for Core Calculator API in tests/unit/calculator.test.js
- [X] T005 [P] Contract test for RPN Calculator API in tests/unit/rpn-calculator.test.js
- [X] T021 Unit tests for core math operations in tests/unit/math.test.js
- [X] T022 Unit tests for RPN stack operations in tests/unit/rpn.test.js
- [X] T016 Integration tests for user scenarios in tests/integration/ui.test.js

## Phase 3.3: Core Implementation (ONLY after tests are failing)
- [X] T006 [P] Calculator class implementation in calculator.js
- [X] T007 [P] RPN Calculator class implementation in rpn-calculator.js
- [X] T008 [P] State management class implementation in state.js
- [X] T009 [P] UI controller implementation in ui.js
- [X] T010 [P] Utility functions in utils.js
- [X] T015 [P] Custom test harness implementation in tests/test-harness.js

## Phase 3.4: Integration
- [X] T011 [P] Service worker implementation for offline functionality in service-worker.js
- [X] T012 Web app manifest for PWA features in manifest.webmanifest
- [X] T013 [P] Accessibility features (ARIA roles, keyboard navigation) in ui.js and index.html
- [X] T014 [P] History with localStorage implementation in state.js
- [X] T019 [P] Keyboard controls implementation in ui.js
- [X] T020 [P] Command palette feature implementation in ui.js

## Phase 3.5: Polish
- [X] T017 [P] Performance validation and size budget check script
- [X] T018 [P] CSS styling for dark theme, ASCII banner, and terminal aesthetic in styles.css
- [X] T023 [P] GitHub Pages deployment setup
- [X] T024 Size optimization to ensure <50KB payload

## Dependencies
- Setup (T001-T003) before everything
- Tests (T004-T005, T021-T022, T016) before implementation (T006-T010, T015)
- Core implementation (T006-T010, T015) before integration (T011-T014, T019-T020)
- Integration (T011-T014, T019-T020) before polish (T017-T018, T023-T024)

## Parallel Example
```
# Launch T004-T005, T021-T022 together:
Task: "Contract test for Core Calculator API in tests/unit/calculator.test.js"
Task: "Contract test for RPN Calculator API in tests/unit/rpn-calculator.test.js"
Task: "Unit tests for core math operations in tests/unit/math.test.js"
Task: "Unit tests for RPN stack operations in tests/unit/rpn.test.js"

# Launch T006-T010 together:
Task: "Calculator class implementation in calculator.js"
Task: "RPN Calculator class implementation in rpn-calculator.js"
Task: "State management class implementation in state.js"
Task: "UI controller implementation in ui.js"
Task: "Utility functions in utils.js"
```

## Notes
- [P] tasks = different files, no dependencies
- Verify tests fail before implementing
- Commit after each task
- Avoid: vague tasks, same file conflicts

## Task Generation Rules
*Applied during main() execution*

1. **From Contracts**:
   - Each contract file → contract test task [P]
   - Each endpoint → implementation task
   
2. **From Data Model**:
   - Each entity → model creation task [P]
   - Relationships → service layer tasks
   
3. **From User Stories**:
   - Each story → integration test [P]
   - Quickstart scenarios → validation tasks

4. **Ordering**:
   - Setup → Tests → Models → Services → Endpoints → Polish
   - Dependencies block parallel execution

## Validation Checklist
*GATE: Checked by main() before returning*

- [ ] All contracts have corresponding tests
- [ ] All entities have model tasks
- [ ] All tests come before implementation
- [ ] Parallel tasks truly independent
- [ ] Each task specifies exact file path
- [ ] No task modifies same file as another [P] task