# 🇳🇵 django-nepkit

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**A toolkit for handling BS dates, regional locations, and validation in the local context.**

</div>

Building software for local requirements comes with unique challenges—from handling BS dates to managing the regional administrative hierarchy. `django-nepkit` provides solutions for these requirements directly within the Django ecosystem.

![Showcase](docs/showcase.gif)

---

## 🎯 Features

- **📅 BS Date Support**: Model fields for `nepalidate` and `nepalidatetime` objects.
- **🗺️ Regional Locations**: Pre-defined Provinces, Districts, and Municipalities.
- **📱 Phone Validation**: Patterns for local mobile and landline numbers.
- **🔌 Admin Integration**: Automatic setup for datepickers and localized list displays.
- **🚀 API Support**: DRF Serializers and Filtering backends for BS searching and ordering.
- **⚡ Location Chaining**: Address linking via client-side JS or server-driven HTMX.

---

## 🛠 Setup

Installation:

```bash
pip install django-nepkit
```

### 1. Basic Configuration

Add it to your `INSTALLED_APPS`:

```python
INSTALLED_APPS = [
    # ...
    "django_nepkit",
]
```

### 2. Global Control

Configure behavior in your `settings.py`:

```python
NEPKIT = {
    "DEFAULT_LANGUAGE": "en",           # "en" or "ne"
    "ADMIN_DATEPICKER": True,           # Toggle the datepicker
    "TIME_FORMAT": 12,                  # 12 or 24 hour display
    "DATE_INPUT_FORMATS": ["%Y-%m-%d", "%d/%m/%Y", "%d-%m-%Y"], # Input formats
}
```

---

## 🚀 Core Usage

### 1. Model Implementation

Fields store `YYYY-MM-DD` strings for database stability while providing BS objects in Python.

```python
from django_nepkit import NepaliDateField, NepaliPhoneNumberField

class Profile(models.Model):
    name = models.CharField(max_length=100)
    birth_date = NepaliDateField() # BS Date support
    phone = NepaliPhoneNumberField() # Local pattern validation
```

### 2. Admin Integration

Use `NepaliModelAdmin` for automatic formatting and datepicker support.

```python
from django_nepkit import NepaliModelAdmin, NepaliDateFilter

@admin.register(Profile)
class ProfileAdmin(NepaliModelAdmin):
    list_display = ("name", "birth_date", "phone")
    list_filter = (("birth_date", NepaliDateFilter),)
```

---

## 🗺️ Address Management

Manage the **Province → District → Municipality** hierarchy.

### Client-Side Chaining (Standard)

Cascading selects in the Django Admin without extra configuration.

```python
from django_nepkit import ProvinceField, DistrictField, MunicipalityField

class Address(models.Model):
    province = ProvinceField()
    district = DistrictField()
    municipality = MunicipalityField()
```

### Server-Side Chaining (HTMX)

Enable `htmx=True` for a server-driven experience.

> [!IMPORTANT]
> **HTMX Setup:**
> Include the required URLs in your main `urls.py`:
>
> ```python
> path("nepkit/", include("django_nepkit.urls")),
> ```

---

## 🔌 API & DRF Support

Search and ordering work natively. BS year/month filtering is supported.

```python
from django_nepkit.filters import NepaliDateYearFilter

class ProfileFilter(filters.FilterSet):
    # Filter by BS Year (e.g., /api/profiles/?year=2081)
    year = NepaliDateYearFilter(field_name="birth_date")
```

---

## 🕒 Technical Design

This library is engineered for performance, data integrity, and local compliance.

### 1. The "Source of Truth" Strategy
We avoid on-the-fly AD-to-BS conversion during database queries because it is computationally expensive and prone to logical drift (due to lunar calendar offsets).
- **Storage**: All BS dates are stored as `VARCHAR(10)` in `YYYY-MM-DD` format.
- **Sorting**: Because `YYYY` is at the start, string-based database sorting (ascending/descending) accurately matches chronological order.
- **Indexability**: Standard B-Tree indexes work perfectly on these fields without requiring custom database functions.
- **Timezone Safety**: Dates are stored without time components, making them immune to server-side timezone shifts during saving.

### 2. Python Object Mapping
While data is stored as strings, it is automatically hydrated into rich Python objects.
- **`nepali-datetime` Integration**: Values are cast to `nepalidate` or `nepalidatetime` objects when retrieved from the database.
- **Validation**: Fields use specialized validators (e.g., `validate_nepali_phone_number`) that leverage official regional patterns.

### 3. Frontend Architecture
- **Automatic Initialization**: The library includes a lightweight JS observer that automatically initializes the datepicker for any field with the `.nepkit-datepicker` class.
- **Theme Support**: The datepicker dynamically adapts its skin based on the Django Admin's dark/light mode state.

---

## ❓ FAQ

**Q: How do I handle Null or Optional dates?**

Just like standard Django fields, pass `null=True, blank=True` to any `django-nepkit` field. The library handles empty strings and `None` values gracefully.

**Q: Can I change the database storage format?**

No. The `YYYY-MM-DD` format is hardcoded to ensure database-level sorting and indexing work consistently. However, you can change the **display** format via global settings or template filters.

**Q: How do I get Devanagari (local script) digits in my API?**

In your Serializer field or Model field, pass `ne=True`.
```python
birth_date = NepaliDateField(ne=True)
```

**Q: Is the location data up to date?**

Yes. Province, District, and Municipality data is sourced from the `nepali` Python package, which is regularly updated to reflect administrative changes in Nepal.

**Q: Does it work with standard Django Forms?**

Yes. `NepaliDateField` uses a specialized `NepaliDateFormField` that automatically handles input parsing and error reporting.

**Q: How do I migrate existing English (AD) dates to BS?**

We recommend staying on standard `DateField` for AD data. If you must convert to BS, use our [Migration Script](docs/migration_guide.py) to perform a bulk data transformation safely.

**Q: Why use VARCHAR instead of a native DateField?**

Native `DateField` in most SQL engines is locked to the Gregorian calendar. Using `VARCHAR` allows us to treat the BS date as the primary data point, avoiding the "off-by-one" conversion errors common when syncing two disparate calendars.

---

## 🤝 Community

We welcome contributions and feedback from the community.

1. **Clone**: `git clone https://github.com/S4NKALP/django-nepkit`
2. **Setup**: `uv sync`
3. **Test**: `uv run pytest`

---

## 📄 License

MIT License. Designed for the local Django ecosystem.