PDF Occlusion App

A PDF occlusion study app with a React + Vite frontend and an Express + PostgreSQL backend. It supports occlusions, bookmarks, and spaced‑repetition (SM‑2) review data.

Features

• Create and sync PDF occlusions per document
• Bookmark pages
• Spaced repetition (SM‑2) review scheduling
• Local/offline‑friendly sync primitives

Tech Stack

• Frontend: React, TypeScript, Vite, Zustand, pdfjs
• Backend: Node.js, Express, PostgreSQL
• Storage: PostgreSQL schema in backend/schema.sql

Repository Layout

.
├── backend
│   ├── index.js
│   ├── package.json
│   └── schema.sql
└── frontend
    ├── package.json
    ├── vite.config.ts
    └── src/

Prerequisites

• Node.js 18+ (recommended)
• PostgreSQL 14+ (recommended)

Quick Start

1) Backend (API + DB)

cd backend
npm install

Initialize the database:

psql -d occlusion_engine -f schema.sql

Run the server:

node index.js

By default the server connects via local Unix socket using:

• user: harry
• database: occlusion_engine
• host: /var/run/postgresql

To override, set DATABASE_URL:

export DATABASE_URL="postgres://user:pass@localhost:5432/occlusion_engine"

The server runs on PORT=3000 by default.

2) Frontend (UI)

cd frontend
npm install
npm run dev

Vite will print the local dev URL.

API Overview

Health

• GET /health — DB connectivity check

Occlusions

• GET /api/sync/:file_hash?since=TIMESTAMP
• POST /api/sync

Bookmarks

• GET /api/bookmarks/:file_hash?since=TIMESTAMP
• POST /api/bookmarks/sync

Spaced Repetition (SRS)

• POST /api/srs/review
• GET /api/srs/cards/:file_hash?since=TIMESTAMP
• POST /api/srs/sync
• GET /api/dashboard/:file_hash

All sync endpoints expect timestamps in milliseconds and use last‑write‑wins logic where applicable.

Development Notes

• The backend verifies DB connectivity at startup and exits with a helpful message if the schema isn’t initialized.
• Frontend uses Vite + React with TypeScript and Zustand for state management.

Contributing

Pull requests and issues are welcome. Please include context, reproduction steps, and screenshots where helpful.

License

No license has been specified yet.