Ethiopian Calendar Engine

Complete Ethiopian calendar engine with ecclesiastical feast calculations, localization, and Gregorian bridge.

✨ Features

• Phase 1: Pure Ethiopian date arithmetic and conversions
• Phase 2: Gregorian ↔ Ethiopian bridge layer
• Phase 3: Ecclesiastical cycles (Wenber, Abekti, Metq) and movable feasts
• Phase 4: Localization, fixed holidays, chronology, and public API
• Phase 5: SaaS platform, monetization, governance & trust layer

📦 Installation

npm install ethiopian-calendar-engine

🚀 Quick Start

import { EthiopianCalendar } from 'ethiopian-calendar-engine';

// Get today's Ethiopian date
const today = EthiopianCalendar.today();
console.log(EthiopianCalendar.format(today));
// Output: ፲፬ ጥር 2018

// Convert Gregorian to Ethiopian
const ethDate = EthiopianCalendar.fromGregorian(2023, 1, 1);
console.log(EthiopianCalendar.format(ethDate));
// Output: ፳፫ ታኅሣሥ 2015

// Get all holidays for a year
const holidays = EthiopianCalendar.getAllHolidays(2018);
console.log(`Total holidays in 2018: ${holidays.length}`);

// Calculate movable feasts
const feasts = EthiopianCalendar.getMovableFeasts(2018);
console.log(feasts);
// Output: { ነነዌ: {...}, ዐቢይ ጾም: {...}, ... }

📚 API Reference

Core Functions

• EthiopianCalendar.today(): Get current Ethiopian date (UTC)
• EthiopianCalendar.fromGregorian(year, month, day): Convert Gregorian to Ethiopian
• EthiopianCalendar.format(date): Format date with Amharic localization
• EthiopianCalendar.getYearInfo(am): Get year metadata (leap, evangelist)
• EthiopianCalendar.getAllHolidays(am): Get all holidays for year
• EthiopianCalendar.getMovableFeasts(am): Calculate ecclesiastical feasts
• EthiopianCalendar.isLeapYear(am): Check if leap year

Localization

Default Amharic locale with Ethiopic numerals. Extensible for other languages.

Ecclesiastical Features

• Wenber calculation (19-year Metonic cycle)
• Abekti/Metq lunar phase approximation
• Movable feasts: Nenewe, Abiy Tsom, Hosanna, Tinseae (Easter), Erget
• Evangelist cycle (28-year rotation)

🏛️ Governance & Trust

Calendar Advisory Board

• Ethiopian Orthodox Church scholars
• Astronomers and mathematicians
• Software engineers specializing in calendrical calculations

Transparency

• All core mathematics are open-source and auditable
• Versioned releases with immutable calendar rules
• Comprehensive documentation of ecclesiastical rules

Verification

// Get calculation proof for transparency
const proof = {
  wenber: calculateWenber(2018),    // 12
  abekti: calculateAbekti(12),      // 12
  metq: calculateMetq(12),          // 18
  sum: 12 + 18                      // 30 (always)
};

💎 Premium SaaS (algoraz.com)

For high-volume applications, government systems, and institutional use:

• High-volume API access (REST endpoints)
• Historical validation tables (canonical Easter dates)
• Multi-calendar synchronization
• Official certification endpoints
• Government-grade SLAs

API Endpoints

GET /api/v1/today
GET /api/v1/convert/gregorian?year=2023&month=1&day=1
GET /api/v1/holidays/2018
GET /api/v1/verify/2018-05-14

Pricing Tiers

| Tier | Requests/Day | SLA | Support | |------------|-------------|-----|---------| | Free | 1,000 | - | Community | | Pro | 100,000 | 99.9% | Email | | Enterprise | Unlimited | 99.99% | Phone + On-site |

📜 License

MIT License - Core mathematics are open-source.

For commercial licensing of premium features, contact [email protected].

🎓 Academic & Institutional Use

References

• Ethiopian Orthodox Church liturgical calendar
• 19-year Metonic cycle mathematics
• Astronomical approximations for lunar phases

Citation

Algoraz. (2024). Ethiopian Calendar Engine [Computer software].
https://github.com/abrishwo/ethiopian-calendar.git

🌍 Cultural Impact

This engine serves as a digital public good for:

• Government calendars in Ethiopia
• Church administration worldwide
• Educational institutions teaching Ethiopian history
• Cultural preservation of traditional timekeeping

🤝 Contributing

1. Fork the repository
2. Create feature branch
3. Submit pull request
4. Join the Calendar Advisory Board for rule changes

Development

git clone [email protected]:abrishwo/Ethiopian-calendar.git
cd ethiopian-calendar-engine
npm install
npm run demo  # Run demonstration

📞 Contact

• Website: algoraz.com/ethiopian-calendar
• Email: [email protected]
• GitHub: github.com/algoraz/ethiopian-calendar-engine

Built with ❤️ for the Ethiopian diaspora and global scholarly community.