ApexLink Golf: Enterprise Booking & Membership System

A robust, commercial-grade simulator booking and membership platform designed for unstaffed 24/7 indoor golf facilities. This project demonstrates complex business logic orchestration between payment states, physical IoT access, and real-time communication.

🏆 Technical Achievements

1. Multi-Tier Subscription Engine (Square API)

• Engineered a recurring billing system supporting multiple membership tiers (ACE, BIRDIE).
• Implemented logic for automated prorating, billing cycle management, and plan transitions via Square's Subscription API.

2. IoT Facility Integration (RemoteLock API)

• Successfully bridged the gap between software and hardware by integrating Smart Lock IoT services.
• Automated the generation of time-bound, unique guest PINs that activate and expire based on specific reservation windows.

3. Real-Time Communication Pipeline (Twilio)

• Built an automated notification system that delivers door access codes and booking reminders via SMS.
• Ensures a seamless user experience for unstaffed facility access through critical real-time alerts.

4. Complex Business Logic & Validation

• Custom-built booking engine handles high-concurrency reservation attempts with strict overlap prevention.
• Implemented sophisticated hour-tracking logic to enforce tiered limits (e.g., "12 hours/month") and daily caps (e.g., "2 hours/day").

5. Webhook Orchestration

• Developed asynchronous listeners for Square's webhook events to handle the full payment lifecycle.
• Automatically updates membership status, handles payment failures, and triggers service suspensions in real-time.

6. Robust OAuth & Token Management

• Implemented a secure OAuth 2.0 flow for the RemoteLock integration.
• Developed a self-healing token management system that automatically handles secret refresh cycles to ensure continuous IoT service availability.

7. Advanced Access Control (RBAC)

• Designed a multi-level role system:
  • Admin: Full system audit, booking management, and member oversight.
  • Corporate: Primary accounts with the ability to manage and shares hours with "Child" members.
  • Individual: Standard member access with personal booking history.

8. Hybrid Payment Processing

• Architected a unified payment flow handling both recurring subscriptions and one-time purchases (e.g., "Additional Hour" credits) using Square's secure tokenization.

🏗️ System Architecture

graph TD
    A[User Interface / Web] --> B{Business Logic Engine}
    B --> C[MySQL Database]
    B --> D[Square API]
    B --> E[RemoteLock API]
    B --> F[Twilio API]
    
    D -- Webhooks --> G[Payment Lifecycle Handler]
    G --> C
    
    E -- IoT PINs --> B
    B -- SMS Delivery --> F
    
    subgraph "External Integrations"
    D
    E
    F
    end

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🛠️ Technology Stack

• Backend: PHP (Vanilla / Procedural) with PDO for secure DB operations.
• Database: MySQL - Relational mapping for users, memberships, and IoT access logs.
• Frontend: Bootstrap 5, jQuery, DataTables for a responsive administrative Experience.
• Security: Square Payment Form (PCI-DSS compliant), unique PIN generation, and secure session management.

📁 Project Structure

• /config: Central API registry and environment configuration.
• /models: Core domain logic for booking validations and subscription states.
• /webhooks: Event-driven scripts for handling third-party API callbacks.
• /remotelock: Enterprise integration logic for IoT door access.
• /admin: Full-featured administrative suite.

⚙️ Setup & Installation

1. Clone the repository.
2. Rename config/db.php.example to config/db.php.
3. Configure your API credentials (Square, Twilio, RemoteLock).
4. Point your web server to the root directory.

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Developed as a high-performance solution for the niche indoor sports market, solving the 'staffing vs. accessibility' challenge via automation.