বাংলা পঞ্জিকা

1. Overview

বাংলা পঞ্জিকা is a modern, interactive Bengali calendar web application that displays the Bengali (Bangla Sansan) calendar alongside Gregorian dates. It follows the Bisuddha Siddhanta system used in West Bengal, India.

The project has three distinct layers:

• Data Layer — panjika_data.json (auto-scraped) + events.json (manually curated)
• Automation Layer — Python scraper + GitHub Actions CI/CD
• Presentation Layer — Pure HTML/CSS/JS frontend deployed on Cloudflare Pages

2. Architecture

The system follows a static-first, data-driven architecture. No server is needed at runtime — the calendar runs entirely in the browser using pre-computed JSON data.

prokerala.com (source)
      ↓ (scraped annually via GitHub Actions)
generate_panjika.py
      ↓
panjika_data.json  ←──── GitHub Private Repo ────→  events.json
      ↓                                                   ↓
      └───────────────── Frontend JS ────────────────────┘
                               ↓
                    Cloudflare Pages (CDN)

3. Folder Structure

4. Data Strategy

Collection Schedule

Why Bisuddha Siddhanta?

There are two systems for the Bengali calendar:

• Bisuddha Siddhanta — Used in West Bengal, India. Month lengths vary (29–32 days). Astronomical basis.
• Bangla Academy — Used in Bangladesh. Fixed month lengths (first 6 months = 31 days, rest = 30). Standardized in 1987.

This project uses Bisuddha Siddhanta data sourced from prokerala.com.

5. Panjika Data JSON

File: data/panjika_data.json

{
  "1433": {
    "b1": "2026-04-15",    // Gregorian date of Boishakh 1 (Poila Boishakh)
    "m":  [31, 31, 32, 32, 31, 30, 30, 29, 30, 29, 30, 30]
    //      ↑ Boishakh     ↑ Asharh             ↑ Poush ↑ Choitro
    //    12 values = 12 Bengali months
  }
}

Conversion Algorithm

To find the Bengali date for any Gregorian date:

1. Find which BS year range contains the target Gregorian date (using b1 of year N and year N+1)
2. Starting from b1, walk month by month using the m array
3. Stop when the cursor exceeds the target date — the previous month was the Bengali month
4. The day number is target - monthStart + 1

6. Events Data JSON

File: data/events.json

Events are stored in three categories:

a) Recurring Bengali Date Events

Events that occur on the same Bengali month/day every year (e.g., Pohela Boishakh = Boishakh 1):

{
  "recurring": [
    {
      "bMonth": 1, "bDay": 1,
      "name": "পহেলা বৈশাখ — বাংলা নববর্ষ",
      "nameEn": "Pohela Boishakh — Bengali New Year",
      "type": "national",    // religious | national | cultural | seasonal
      "emoji": "🎊",
      "desc": "বাংলা নববর্ষের প্রথম দিন।"
    }
  ]
}

b) Fixed Gregorian Events

Events on fixed Gregorian dates (e.g., Christmas = December 25):

{
  "fixed_gregorian": [
    { "gregMonth": 12, "gregDay": 25, "name": "বড়দিন", ... }
  ]
}

c) Year-Specific Events

One-off events for a specific BS year:

{
  "year_specific": {
    "1433": [
      { "bMonth": 4, "bDay": 22, "name": "বিশেষ অনুষ্ঠান", ... }
    ]
  }
}

7. Scraping Script

File: scripts/generate_panjika.py

Dependencies

pip install requests beautifulsoup4

How It Works

8. GitHub Actions Automation

File: .github/workflows/update_panjika.yml

Schedule

cron: "0 6 20 1 *"   # Runs January 20 at 06:00 UTC every year

Workflow Steps

1. Checkout repository
2. Setup Python 3.11
3. Install requests and beautifulsoup4
4. Run generate_panjika.py
5. If panjika_data.json changed — commit and push

9. Frontend Architecture

The frontend is pure vanilla HTML/CSS/JS — no build tools, no frameworks, no bundlers. It loads directly in any browser.

10. Features

11. Deployment on Cloudflare Pages

Build command:    (leave blank — no build step)
Output directory: src
Root directory:   / (project root)

12. Keyboard Shortcuts

13. Extending the Project

Add new events

Edit data/events.json — add entries to recurring, fixed_gregorian, or year_specific sections. No code changes needed.

Add new years (manual)

Add entries to VERIFIED_DATA dict in generate_panjika.py, then run the script.

Fetch 5 years at once

Modify the targets list in main() of the script:

targets = list(range(this_bs, this_bs + 5))

Add more event types

Add a new type value in events.json, then add corresponding CSS class in style.css (for the dot color and badge color).

Localize to other languages

Add a new language to data.js (MONTHS_XX, WEEKDAYS_XX), add a toggle option in main.js.