# 🌾 Crop Yield Prediction API - Endpoints Documentation

## Base URL
- **Local**: `http://localhost:8000`
- **Railway Production**: `https://sih-2-production.up.railway.app/`

## Authentication
No authentication required for any endpoints.

---

## 📍 API Endpoints Overview

| Endpoint | Method | Purpose | Input Required |
|----------|--------|---------|----------------|
| `/` | GET | API Information | None |
| `/health` | GET | Health Check | None |
| `/predict` | POST | Crop Yield Prediction | JSON Body |
| `/available-options` | GET | Available Options | None |
| `/docs` | GET | Interactive API Documentation | None |

---

## 1. 🏠 Root Endpoint

### `GET /`

**Purpose**: Get basic API information and available endpoints.

#### Input
- **Method**: GET
- **Headers**: None required
- **Body**: None

#### Output
```json
{
  "message": "Crop Yield Prediction API. Use /docs for interactive API documentation.",
  "version": "1.0.0",
  "endpoints": {
    "predict": "/predict",
    "health": "/health",
    "docs": "/docs",
    "available_options": "/available-options"
  }
}
```

#### cURL Example
```bash
curl -X GET https://sih-2-production.up.railway.app/
```

---

## 2. 🏥 Health Check Endpoint

### `GET /health`

**Purpose**: Check API health status and model loading status.

#### Input
- **Method**: GET
- **Headers**: None required
- **Body**: None

#### Output
```json
{
  "status": "healthy",
  "timestamp": "2024-09-12T12:35:47.123456",
  "model_loaded": true
}
```

#### Field Descriptions
- `status`: Always "healthy" when API is running
- `timestamp`: Current server time in ISO format
- `model_loaded`: Boolean indicating if prediction models are loaded

#### cURL Example
```bash
curl -X GET https://sih-2-production.up.railway.app/health
```

---

## 3. 🔮 Prediction Endpoint (Main Feature)

### `POST /predict`

**Purpose**: Predict crop yield based on agricultural parameters.

#### Input
- **Method**: POST
- **Content-Type**: `application/json`
- **Headers**: `Content-Type: application/json`

#### Request Body Schema
```json
{
  "year": integer,           // REQUIRED: Crop year (e.g., 2024)
  "state": "string",         // REQUIRED: State name (e.g., "Punjab")
  "crop": "string",          // REQUIRED: Crop name (e.g., "Rice")
  "season": "string",        // REQUIRED: Season (e.g., "Kharif")
  "area": float,             // REQUIRED: Area in hectares (e.g., 10.0)
  "production": float,       // REQUIRED: Previous production in tons (e.g., 25.0)
  "rainfall": float,         // OPTIONAL: Annual rainfall in mm (default: 1000.0)
  "fertilizer": float,       // OPTIONAL: Fertilizer usage in kg (default: 50.0)
  "pesticide": float         // OPTIONAL: Pesticide usage in kg (default: 5.0)
}
```

#### Field Validation
- `year`: Integer, typically 2020-2030
- `state`: String, any Indian state name
- `crop`: String, major crops like "Rice", "Wheat", "Cotton", etc.
- `season`: String, options: "Kharif", "Rabi", "Summer", "Whole Year", etc.
- `area`: Positive float, hectares
- `production`: Positive float, tons
- `rainfall`: Positive float, millimeters (optional)
- `fertilizer`: Positive float, kilograms (optional)
- `pesticide`: Positive float, kilograms (optional)

#### Output (Success - 200)
```json
{
  "model": "Random Forest",                    // Or "Fallback Model (Rule-based)"
  "predicted_yield": "2845.67 kg/hectare",   // Predicted yield with units
  "total_expected_production": "28.46 tons",  // Total production estimate
  "assessment": "Good yield expected"          // Qualitative assessment
}
```

#### Output Field Descriptions
- `model`: Model type used ("Random Forest" for ML, "Fallback Model (Rule-based)" for rule-based)
- `predicted_yield`: Predicted yield per hectare in kg/hectare format
- `total_expected_production`: Total expected production in tons (yield × area ÷ 1000)
- `assessment`: Qualitative assessment based on yield:
  - `"Excellent yield expected"`: > 3000 kg/hectare
  - `"Good yield expected"`: 2000-3000 kg/hectare  
  - `"Moderate yield expected"`: 1000-2000 kg/hectare
  - `"Low yield expected"`: < 1000 kg/hectare

#### Output (Error - 400/500)
```json
{
  "detail": "Error message describing what went wrong"
}
```

#### Complete cURL Example
```bash
curl -X POST https://sih-2-production.up.railway.app/predict \
  -H "Content-Type: application/json" \
  -d '{
    "year": 2024,
    "state": "Punjab", 
    "crop": "Rice",
    "season": "Kharif",
    "area": 15.5,
    "production": 35.0,
    "rainfall": 1250,
    "fertilizer": 80,
    "pesticide": 10
  }'
```

#### Python Example
```python
import requests

url = "https://sih-2-production.up.railway.app/predict"
data = {
    "year": 2024,
    "state": "Maharashtra",
    "crop": "Cotton",
    "season": "Kharif", 
    "area": 20.0,
    "production": 15.0,
    "rainfall": 900,
    "fertilizer": 60,
    "pesticide": 12
}

response = requests.post(url, json=data)
print(response.json())
```

---

## 4. 📋 Available Options Endpoint

### `GET /available-options`

**Purpose**: Get available values for crops, states, and seasons.

#### Input
- **Method**: GET
- **Headers**: None required
- **Body**: None

#### Output
```json
{
  "states": [
    "Punjab", "Maharashtra", "Karnataka", "Gujarat", "Rajasthan"
  ],
  "crops": [
    "Rice", "Wheat", "Cotton", "Sugarcane", "Maize"
  ],
  "seasons": [
    "Kharif", "Rabi", "Summer", "Whole Year", "Autumn", "Winter", "Total"
  ],
  "note": "This shows first 10 states and crops. All are supported in predictions."
}
```

#### cURL Example
```bash
curl -X GET https://sih-2-production.up.railway.app/available-options
```

---

## 5. 📖 Interactive Documentation

### `GET /docs`

**Purpose**: Access Swagger/OpenAPI interactive documentation.

#### Input
- **Method**: GET (open in browser)
- **URL**: `https://sih-2-production.up.railway.app/docs`

#### Output
Interactive web interface with:
- All endpoint documentation
- Try-it-out functionality
- Request/response examples
- Schema validation

---

## 🚀 Complete Usage Examples

### JavaScript/Node.js
```javascript
const axios = require('axios');

async function predictYield() {
  try {
    const response = await axios.post('https://sih-2-production.up.railway.app/predict', {
      year: 2024,
      state: 'Karnataka',
      crop: 'Rice',
      season: 'Kharif',
      area: 25.0,
      production: 60.0,
      rainfall: 1100,
      fertilizer: 70,
      pesticide: 8
    });
    
    console.log('Prediction:', response.data);
  } catch (error) {
    console.error('Error:', error.response.data);
  }
}

predictYield();
```

### PHP
```php
<?php
$url = 'https://sih-2-production.up.railway.app/predict';
$data = array(
    'year' => 2024,
    'state' => 'Punjab',
    'crop' => 'Wheat',
    'season' => 'Rabi',
    'area' => 12.5,
    'production' => 30.0,
    'rainfall' => 800,
    'fertilizer' => 85,
    'pesticide' => 6
);

$options = array(
    'http' => array(
        'header'  => "Content-Type: application/json\r\n",
        'method'  => 'POST',
        'content' => json_encode($data)
    )
);

$context  = stream_context_create($options);
$result = file_get_contents($url, false, $context);
$response = json_decode($result, true);

echo json_encode($response, JSON_PRETTY_PRINT);
?>
```

---

## ⚠️ Error Handling

### Common Error Responses

#### 400 Bad Request
```json
{
  "detail": "Validation error: field 'area' must be positive"
}
```

#### 500 Internal Server Error
```json
{
  "detail": "Prediction failed: Model initialization error"
}
```

### Error Scenarios
1. **Missing required fields**: Returns 422 with field validation errors
2. **Invalid data types**: Returns 422 with type validation errors
3. **Negative values**: Returns 400 with validation error
4. **Model loading failure**: Returns 500 but API continues with fallback
5. **Server errors**: Returns 500 with error description

---

## 📊 Response Time & Performance

- **Health Check**: ~10-50ms
- **Prediction (Fallback Mode)**: ~50-200ms
- **Prediction (ML Mode)**: ~100-500ms
- **Available Options**: ~20-100ms

---

## 🔒 Rate Limiting

Currently no rate limiting is implemented. For production use, consider:
- Maximum 100 requests per minute per IP
- Maximum 1000 requests per hour per IP

---

## 🎯 Model Information

### Random Forest Mode (When Available)
- **Algorithm**: Random Forest Regression
- **Features**: 15+ agricultural and environmental features
- **Training Data**: Historical crop yield data across Indian states
- **Accuracy**: Varies by crop and region

### Fallback Mode (Always Available)  
- **Algorithm**: Rule-based prediction system
- **Method**: Crop-specific base yields adjusted by rainfall factor
- **Base Yields**:
  - Rice: 2500 kg/hectare
  - Wheat: 3000 kg/hectare  
  - Cotton: 1200 kg/hectare
  - Sugarcane: 60000 kg/hectare
  - Maize: 2800 kg/hectare
- **Reliability**: Provides reasonable estimates when ML models unavailable