Architecture

Architecture

Project Structure

praycalc/
├── web/                    praycalc.com (Next.js 15)
│   ├── app/                App Router pages and API routes
│   │   ├── [country]/[state]/[city]/   city prayer times page
│   │   ├── api/            API routes (prayers, search, geo, calendar PDF)
│   │   └── account/        user account page
│   ├── components/         React components
│   ├── hooks/              custom hooks (useClock, useSettings, useSession)
│   ├── lib/                shared utilities, session management
│   ├── messages/           i18n translation files (8 languages)
│   ├── public/             static assets (adhan audio, icons)
│   └── tests/              Vitest unit + Playwright E2E
├── org/                    praycalc.org (documentation, Next.js + MDX)
│   └── src/                docs pages and components
└── flutter/                mobile app (iOS + Android)
    ├── lib/                Dart source
    │   ├── core/           providers, services, theme
    │   ├── features/       screen implementations
    │   └── shared/         models, widgets
    ├── packages/
    │   └── pray_calc_dart/ pure Dart prayer time engine
    └── test/               widget and unit tests

Tech Stack

Layer	Technology
Web frontend	Next.js 15, TypeScript, Tailwind CSS
Mobile	Flutter (iOS + Android)
Calculation engine	pray_calc_dart (pure Dart, no dependencies)
i18n	next-intl (EN, AR, TR, UR, ID, FR, BN, SO)
PWA	Serwist (service worker, offline caching)
Testing	Vitest (unit), Playwright (E2E), flutter_test
CI/CD	GitHub Actions, Shorebird (OTA patches)
Hosting	Vercel (web), App Store / Play Store (mobile)

Data Flow

1. User opens praycalc.com or the mobile app
2. GPS or city search provides coordinates
3. Prayer times calculated locally using astronomical algorithms
4. Results cached in localStorage / SharedPreferences
5. PWA service worker enables full offline mode

Backend Integration

PrayCalc connects to the shared Ummat backend via GraphQL for:

• User authentication (shared SSO via Hasura Auth)
• Settings sync across devices
• Saved cities and preferences

API endpoint: https://api.praycalc.com/v1/graphql