src/api.py

# src/api.py - Enhanced API with better error handling for patient data
from fastapi import FastAPI, HTTPException, File, UploadFile
from pydantic import BaseModel, Field
import torch
import numpy as np
import joblib
from src.model import TabularVAE
from typing import List, Optional, Dict, Any
import os
import shutil
from fastapi.responses import JSONResponse, HTMLResponse
import json

app = FastAPI(title="Healthcare VAE API", version="1.0.0")

# Load model and scaler
try:
    # Load feature names and determine input dimension
    if os.path.exists("models/feature_names.pkl"):
        feature_names = joblib.load("models/feature_names.pkl")
        INPUT_DIM = len(feature_names)
        print(f"Loaded {INPUT_DIM} features: {feature_names}")
    else:
        # Fallback to default features
        feature_names = ["age", "gender", "diagnosis", "blood_type", "length_of_stay", 
                        "age_group", "admission_season", "admission_day", "admission_month", "admission_year"]
        INPUT_DIM = len(feature_names)
        print(f"Using default {INPUT_DIM} features")
    
    LATENT_DIM = 8
    
    model = TabularVAE(input_dim=INPUT_DIM, latent_dim=LATENT_DIM, hidden_dims=(32, 16))
    model.load_state_dict(torch.load("models/vae_model.pth", map_location='cpu'))
    model.eval()
    
    scaler = joblib.load("models/scaler.pkl")
    
    # Load encoders if available
    encoders = None
    if os.path.exists("models/encoders.pkl"):
        encoders = joblib.load("models/encoders.pkl")
    
    print("Model and scaler loaded successfully!")
except Exception as e:
    print(f"Error loading model: {e}")
    print("Please run training first!")

class GenerateRequest(BaseModel):
    n_samples: int = Field(..., ge=1, le=1000, description="Number of samples to generate")
    random_seed: Optional[int] = Field(None, description="Random seed for reproducibility")
    temperature: float = Field(1.0, ge=0.1, le=2.0, description="Sampling temperature")

class PatientData(BaseModel):
    age: float = Field(..., ge=0, le=120, description="Patient age")
    gender: str = Field(..., description="Patient gender (Male/Female)")
    diagnosis: str = Field(..., description="Patient diagnosis")
    blood_type: str = Field(..., description="Blood type")
    length_of_stay: Optional[float] = Field(None, description="Length of stay in days")
    age_group: Optional[int] = Field(None, ge=0, le=4, description="Age group (0-4)")
    admission_season: Optional[int] = Field(None, ge=0, le=3, description="Admission season (0-3)")
    admission_day: Optional[int] = Field(None, ge=0, le=6, description="Admission day of week (0-6)")
    admission_month: Optional[int] = Field(None, ge=0, le=11, description="Admission month (0-11)")
    admission_year: Optional[int] = Field(None, description="Admission year (normalized)")

class GeneratedResponse(BaseModel):
    data: List[List[float]]
    metadata: dict

def convert_numpy_to_python(obj):
    """Convert numpy types to Python native types for JSON serialization"""
    if isinstance(obj, np.integer):
        return int(obj)
    elif isinstance(obj, np.floating):
        return float(obj)
    elif isinstance(obj, np.ndarray):
        return obj.tolist()
    elif isinstance(obj, list):
        return [convert_numpy_to_python(item) for item in obj]
    elif isinstance(obj, dict):
        return {key: convert_numpy_to_python(value) for key, value in obj.items()}
    else:
        return obj

@app.get("/")
def read_root():
    return {"message": "Healthcare VAE API is running!", "features": feature_names}

@app.get("/features")
def get_features():
    """Get information about the model features"""
    return {
        "feature_names": feature_names,
        "input_dim": INPUT_DIM,
        "latent_dim": LATENT_DIM
    }

@app.post("/generate", response_model=GeneratedResponse)
def generate_synthetic_data(request: GenerateRequest):
    try:
        if request.random_seed is not None:
            torch.manual_seed(request.random_seed)
            np.random.seed(request.random_seed)
        
        # Generate samples
        z = torch.randn(request.n_samples, LATENT_DIM) * request.temperature
        
        with torch.no_grad():
            samples = model.decode(z).numpy()
        
        # Inverse transform to original scale
        data = scaler.inverse_transform(samples).tolist()
        
        metadata = {
            "n_samples": request.n_samples,
            "latent_dim": LATENT_DIM,
            "temperature": request.temperature,
            "features": feature_names
        }
        
        return {"data": data, "metadata": metadata}
    
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Generation failed: {str(e)}")

@app.post("/encode")
def encode_patient(patient: PatientData):
    """Encode patient data to latent space"""
    try:
        # Convert patient data to feature vector
        feature_vector = []
        
        # Age
        feature_vector.append(patient.age)
        
        # Gender (encode if encoders available)
        if encoders and 'gender' in encoders:
            gender_encoded = encoders['gender'].transform([patient.gender])[0]
            feature_vector.append(gender_encoded)
        else:
            # Fallback encoding
            gender_encoded = 0 if patient.gender.lower() == 'male' else 1
            feature_vector.append(gender_encoded)
        
        # Diagnosis (encode if encoders available)
        if encoders and 'diagnosis' in encoders:
            diagnosis_encoded = encoders['diagnosis'].transform([patient.diagnosis])[0]
            feature_vector.append(diagnosis_encoded)
        else:
            # Fallback encoding (simple hash)
            diagnosis_encoded = hash(patient.diagnosis) % 10
            feature_vector.append(diagnosis_encoded)
        
        # Blood type (encode if encoders available)
        if encoders and 'blood_type' in encoders:
            blood_encoded = encoders['blood_type'].transform([patient.blood_type])[0]
            feature_vector.append(blood_encoded)
        else:
            # Fallback encoding (simple hash)
            blood_encoded = hash(patient.blood_type) % 8
            feature_vector.append(blood_encoded)
        
        # Length of stay
        los = patient.length_of_stay if patient.length_of_stay is not None else 7.0
        feature_vector.append(los)
        
        # Age group
        age_group = patient.age_group if patient.age_group is not None else 2
        feature_vector.append(age_group)
        
        # Admission season
        season = patient.admission_season if patient.admission_season is not None else 0
        feature_vector.append(season)
        
        # Admission day
        day = patient.admission_day if patient.admission_day is not None else 0
        feature_vector.append(day)
        
        # Admission month
        month = patient.admission_month if patient.admission_month is not None else 0
        feature_vector.append(month)
        
        # Admission year
        year = patient.admission_year if patient.admission_year is not None else 4
        feature_vector.append(year)
        
        # Ensure we have the right number of features
        if len(feature_vector) != INPUT_DIM:
            # Pad or truncate to match input dimension
            while len(feature_vector) < INPUT_DIM:
                feature_vector.append(0.0)
            feature_vector = feature_vector[:INPUT_DIM]
        
        # Convert to array and scale
        data = np.array([feature_vector])
        scaled_data = scaler.transform(data)
        tensor_data = torch.tensor(scaled_data, dtype=torch.float32)
        
        with torch.no_grad():
            mu, logvar = model.encode(tensor_data)
        
        # Convert numpy types to Python native types for JSON serialization
        response = {
            "latent_mean": convert_numpy_to_python(mu.numpy().tolist()),
            "latent_logvar": convert_numpy_to_python(logvar.numpy().tolist()),
            "features_used": feature_names,
            "feature_values": convert_numpy_to_python(feature_vector)
        }
        
        return response
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Encoding failed: {str(e)}")

@app.get("/health")
def health_check():
    """Health check endpoint"""
    return {
        "status": "healthy",
        "model_loaded": True,
        "input_dim": INPUT_DIM,
        "latent_dim": LATENT_DIM
    }

@app.post("/upload_data")
async def upload_data(file: UploadFile = File(...)):
    """Upload a CSV file for continual training."""
    os.makedirs("data", exist_ok=True)
    file_location = "data/new_data.csv"
    with open(file_location, "wb") as buffer:
        shutil.copyfileobj(file.file, buffer)
    return {"status": "success", "filename": file.filename}

@app.get("/training_progress")
def get_training_progress():
    """Get the latest training progress metrics for the web interface."""
    progress_file = "data/training_progress.json"
    if not os.path.exists(progress_file):
        return JSONResponse(content={"status": "no_progress", "message": "No training progress found."}, status_code=404)
    with open(progress_file, "r") as f:
        progress = json.load(f)
    return JSONResponse(content=progress)

@app.get("/dashboard", response_class=HTMLResponse)
def dashboard():
    html = '''
    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Training Progress Dashboard</title>
        <style>
            body { font-family: Arial, sans-serif; margin: 2em; background: #f9f9f9; }
            h1 { color: #2c3e50; }
            #progress { background: #fff; padding: 1em; border-radius: 8px; box-shadow: 0 2px 8px #eee; max-width: 400px; }
            .label { color: #888; }
        </style>
    </head>
    <body>
        <h1>Training Progress</h1>
        <div id="progress">
            <div><span class="label">Epoch:</span> <span id="epoch">-</span></div>
            <div><span class="label">Train Loss:</span> <span id="train_loss">-</span></div>
            <div><span class="label">Val Loss:</span> <span id="val_loss">-</span></div>
            <div><span class="label">Best Val Loss:</span> <span id="best_val_loss">-</span></div>
            <div><span class="label">Last Updated:</span> <span id="timestamp">-</span></div>
        </div>
        <script>
        async function fetchProgress() {
            try {
                const res = await fetch('/training_progress');
                if (!res.ok) throw new Error('No progress yet');
                const data = await res.json();
                document.getElementById('epoch').textContent = data.epoch;
                document.getElementById('train_loss').textContent = data.train_loss?.toFixed(4);
                document.getElementById('val_loss').textContent = data.val_loss?.toFixed(4);
                document.getElementById('best_val_loss').textContent = data.best_val_loss?.toFixed(4);
                const date = new Date(data.timestamp * 1000);
                document.getElementById('timestamp').textContent = date.toLocaleString();
            } catch (e) {
                document.getElementById('progress').innerHTML = '<b>No training progress yet.</b>';
            }
        }
        fetchProgress();
        setInterval(fetchProgress, 3000);
        </script>
    </body>
    </html>
    '''
    return HTMLResponse(content=html)

# Run with: uvicorn src.api:app --reload --host 0.0.0.0 --port 8000