wc-composable-product/CLAUDE.md

WooCommerce plugin for user composable products - AI Context Document

Author: Marco Graetsch

Project Overview

This plugin implements a special product type, for which users can select a limited number of product from a configurable set of simple or variable products. The limit of selectable products should be a global and per-product setting, for which global is the fallback. The set of selectable products can be defined per category, tag or SKU. The price is either a fixed price or the sum of the prices of the selected products. Think of a package of stickers as composable product, where each package can contain $limit number of stickers.

Key Fact: 100% AI-Generated

This project is proudly "vibe-coded" using Claude.AI - the entire codebase was created through AI assistance.

Technical Stack

• Language: PHP 8.3+
• Framework: Latest WordPress Plugin API
• E-commerce: WooCommerce 10.0+
• Template Engine: Twig 3.0 (via Composer)
• Frontend: Vanilla JavaScript + jQuery
• Styling: Custom CSS
• Dependency Management: Composer
• Internationalization: WordPress i18n (.pot/.po/.mo files)

Implementation Details

Security Best Practices

• All user inputs are sanitized (integers for quantities/prices)
• Nonce verification on form submissions
• Output escaping in templates (esc_attr, esc_html, esc_js)
• Direct file access prevention via ABSPATH check

Translation Ready

All user-facing strings use:

__('Text to translate', 'wc-composable-product')
_e('Text to translate', 'wc-composable-product')

Text domain: wc-composable-product

Translation Template:

• Base .pot file created: languages/wc-composable-product.pot
• Ready for translation to any locale
• All translatable strings properly marked with text domain

Planned Translations:

• en_US - English (United States) [base language]
• de_DE - German (Germany, formal)
• de_DE_informal - German (Germany, informal "du")
• de_CH - German (Switzerland, formal "Sie")
• de_CH_informal - German (Switzerland, informal "du")
• fr_CH - French (Switzerland)
• it_CH - Italian (Switzerland)

Note: Swiss locales should use CHF currency formatting in examples (e.g., "CHF 50.-")

Create releases

• The vendor/ directory MUST be included in releases (Twig dependency required for runtime)
• Running zip from wrong directory creates empty or malformed archives
• Exclusion patterns must match the relative path structure used in zip command
• Always verify the package with unzip -l and test extraction before committing
• The wp-core/ and wp-plugins/ directories MUST NOT be included in releases
• Releases are stored in releases/ including checksums

Important Git Notes:

• Always commit from dev branch first
• Tags should use format vX.X.X (e.g., v1.1.22)
• Use annotated tags (-a) not lightweight tags
• Commit messages should follow the established format with Claude Code attribution
• .claude/settings.local.json changes are typically local-only (stash before rebasing)

What Gets Released

• All plugin source files
• Compiled vendor dependencies
• Translation files (.mo compiled from .po)
• Assets (CSS, JS)
• Documentation (README, CHANGELOG, etc.)

What's Excluded

• Git metadata (.git/)
• Development files (.vscode/, .claude/, CLAUDE.md)
• Logs and cache files
• Previous releases
• composer.lock (but vendor/ is included)

Project Structure

wc-composable-product/
├── assets/
│   ├── css/
│   │   ├── admin.css          # Admin panel styling
│   │   └── frontend.css       # Customer-facing styles
│   └── js/
│       ├── admin.js           # Product edit interface logic
│       └── frontend.js        # AJAX cart & selection UI
├── cache/                     # Twig template cache (writable)
├── includes/
│   ├── Admin/
│   │   ├── Product_Data.php   # Product data tab & meta boxes
│   │   └── Settings.php       # WooCommerce settings integration
│   ├── Cart_Handler.php       # Add-to-cart & cart display logic
│   ├── Plugin.php             # Main plugin class (Singleton)
│   ├── Product_Selector.php   # Frontend product selector renderer
│   └── Product_Type.php       # Custom WC_Product extension
├── languages/
│   └── wc-composable-product.pot  # Translation template
├── templates/
│   └── product-selector.twig  # Frontend selection interface
├── vendor/                    # Composer dependencies (gitignored)
├── composer.json              # Dependency configuration
├── wc-composable-product.php  # Main plugin file
└── [Documentation files]      # README, INSTALL, IMPLEMENTATION, etc.

Architecture Overview

Core Classes

1. Plugin.php - Main singleton class

   • Initializes Twig template engine
   • Registers hooks and filters
   • Manages asset enqueuing
   • Provides template rendering API

2. Product_Type.php - Custom WooCommerce product type

   • Extends WC_Product
   • Handles selection criteria (category/tag/SKU)
   • Manages pricing modes (fixed/sum)
   • Queries available products dynamically

3. Cart_Handler.php - Cart integration

   • Validates product selections
   • Stores selected products in cart meta
   • Calculates dynamic pricing
   • Displays selections in cart/checkout

4. Product_Selector.php - Frontend renderer

   • Renders Twig template with product data
   • Applies display settings (images/prices/total)

5. Admin/Product_Data.php - Product edit interface

   • Adds "Composable Options" tab
   • Category/tag/SKU selection fields
   • Saves product metadata

6. Admin/Settings.php - Global settings

   • WooCommerce settings tab integration
   • Default limits and pricing mode
   • Display preferences

Data Flow

Product Creation:

1. Admin selects "Composable product" type
2. Configures criteria, limits, pricing in product data tab
3. Metadata saved: _composable_* fields

Frontend Display:

1. Cart_Handler::render_product_selector() called on product page
2. Product_Type::get_available_products() queries matching products
3. Product_Selector::render() passes data to Twig template
4. JavaScript handles selection UI and AJAX

Add to Cart:

1. Customer selects products (JS validates limit)
2. AJAX request with composable_products[] array
3. Cart_Handler::validate_add_to_cart() server-side validation
4. Cart_Handler::add_cart_item_data() stores selections
5. Cart_Handler::calculate_cart_item_price() applies pricing

Development Workflow

Initial Setup

composer install

Making Changes

1. PHP Classes: Edit files in includes/ or includes/Admin/
2. Templates: Modify templates/*.twig (cache clears on auto-reload)
3. Styles: Update assets/css/*.css
4. JavaScript: Edit assets/js/*.js
5. Translations: Update .pot file, create .po translations

Testing Checklist

• Create composable product in admin
• Test each selection criteria type (category/tag/SKU)
• Verify selection limit enforcement
• Test both pricing modes (fixed/sum)
• Check AJAX add-to-cart functionality
• Verify cart display shows selected products
• Test checkout process
• Check responsive design on mobile
• Validate all strings are translatable

Creating Releases

# From project root
zip -r wc-composable-product-vX.X.X.zip . \
  -x "*.git*" "*.vscode*" "*.claude*" "CLAUDE.md" \
  "wp-core" "wp-plugins" "*.log" "composer.lock" \
  "cache/*" "releases/*" "*.zip"

# Verify contents
unzip -l wc-composable-product-vX.X.X.zip

# IMPORTANT: Ensure vendor/ is included!

Session History

v1.0.0 - Initial Implementation (2024-12-31)

What was built:

• Complete plugin implementation from scratch
• All 6 core PHP classes with PSR-4 autoloading
• Twig template system integration
• Responsive frontend with AJAX functionality
• Admin interface with WooCommerce integration
• Full i18n support with .pot template
• Comprehensive documentation (README, INSTALL, IMPLEMENTATION)

Key decisions made:

• Used Singleton pattern for main Plugin class
• Twig for templating (per requirements)
• Vanilla JS + jQuery for frontend (WooCommerce standard)
• Grid layout for product selector (responsive)
• AJAX add-to-cart for better UX
• Meta-based configuration storage

Files created: 21 files, 2,628 lines of code

Git workflow:

• Initial commit to main branch
• Created dev branch from main
• Both branches in sync at v1.0.0

What works:

• Product type registration ✓
• Admin product data tab ✓
• Category/tag/SKU selection ✓
• Frontend product selector ✓
• AJAX add-to-cart ✓
• Cart integration ✓
• Pricing calculation (both modes) ✓

Known limitations:

• Currently only simple products in selection (not variable)
• No grouped product support
• No automatic stock deduction for selected items
• Template cache requires manual clearing after updates

Future enhancements to consider:

• Variable product support
• Quantity selection per item
• Visual bundle preview
• Product recommendations
• Stock management integration
• Selection presets/templates

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For AI Assistants:

When starting a new session on this project:

1. Read this CLAUDE.md file first
2. Review IMPLEMENTATION.md for technical details
3. Check git log for recent changes
4. Verify you're on the dev branch before making changes
5. Run composer install if vendor/ is missing
6. Test changes before committing
7. Follow commit message format with Claude Code attribution
8. Update this session history section with learnings

Always refer to this document when starting work on this project. Good luck!