Build an Appointment Booking Service

Problem/Feature Description

A healthcare clinic needs a Spring Boot service for appointment booking. Build it with Spring Boot 3 and Java 17+.

Domain concepts:

• Doctor: id, name, specialty, email
• Patient: id, name, email, phone, dateOfBirth
• TimeSlot: id, doctorId, startTime, endTime, available (boolean)
• Appointment: id, patientId, timeSlotId, reason, status (SCHEDULED/COMPLETED/CANCELLED/NO_SHOW), notes, createdAt

Endpoints:

• POST /api/doctors -- register a doctor (name, specialty required)
• GET /api/doctors -- list doctors, optional filter by specialty
• POST /api/doctors/:id/slots -- create available time slots for a doctor (array of start/end time pairs)
• GET /api/doctors/:id/slots -- get available slots for a doctor on a given date (query param: date)
• POST /api/patients -- register a patient
• POST /api/appointments -- book an appointment (patientId, timeSlotId, reason). The time slot must be available and in the future.
• GET /api/appointments/:id -- get appointment details including doctor and patient info
• PATCH /api/appointments/:id/cancel -- cancel an appointment (only SCHEDULED appointments can be cancelled, release the time slot)
• GET /api/patients/:id/appointments -- list a patient's appointments

Business rules:

• Time slots cannot overlap for the same doctor
• Only available future time slots can be booked
• Booking marks the time slot as unavailable
• Cancellation marks the time slot as available again
• Only SCHEDULED appointments can be cancelled

Use PostgreSQL for the database.

Output Specification

Produce a complete Spring Boot project with:

• Main application class
• All Java source files
• Configuration files
• Database schema
• Test classes for booking and cancellation flows
• pom.xml with dependencies

You may create additional files as needed.