# Import necessary libraries
import numpy as np
import joblib
import pandas as pd
from flask import Flask, request, jsonify
import traceback
import math

# Define the path where the model is saved
model_file_name = "SuperKart_v1_0.joblib"

try:
    # Load the trained machine learning model
    model = joblib.load(model_file_name)
except FileNotFoundError:
    print(f"Error: Model file not found at {model_file_name}")
    model = None
except Exception as e:
    print(f"Error loading model: {e}")
    traceback.print_exc()
    model = None

# Initialize the Flask app
app = Flask(__name__)

@app.route('/')
def home():
    return "Welcome to the Super Kart Product Sales Price Prediction API!"

# ---------------- single Prediction Endpoint ----------------
@app.route('/v1/salesprice', methods=['POST'])
def predict_sales_price():
    if model is None:
        return jsonify({"error": "Model not loaded. Cannot make predictions."}), 500

    try:
        property_data = request.get_json(force=True)

        expected_keys = [
            'Product_Weight', 'Product_Sugar_Content', 'Product_Allocated_Area',
            'Product_Type', 'Product_MRP', 'Store_Size',
            'Store_Location_City_Type', 'Store_Type', 'Store_Age'
        ]
        if not all(key in property_data for key in expected_keys):
            missing_keys = [key for key in expected_keys if key not in property_data]
            return jsonify({"error": f"Missing keys in input data: {missing_keys}"}), 400

        sample = {key: property_data.get(key) for key in expected_keys}
        input_data = pd.DataFrame([sample])

        predicted_sales_price = model.predict(input_data)
        predicted_price = round(float(predicted_sales_price[0]), 2)

        if math.isinf(predicted_price) or math.isnan(predicted_price):
            return jsonify({"error": "Prediction resulted in an invalid value."}), 400

        return jsonify({'Predicted Price': predicted_price}), 200

    except Exception as e:
        print(f"Error during single prediction: {e}")
        traceback.print_exc()
        return jsonify({"error": "Internal server error", "details": str(e)}), 500

# ---------------- Batch Prediction Endpoint ----------------
@app.route('/v1/salespricebatch', methods=['POST'])
def predict_sales_price_batch():
    """
    Expects a CSV file with one product per row.
    Returns JSON: a list of dicts with `row_id` and predicted price.
    """
    if model is None:
        return jsonify({"error": "Model not loaded. Cannot make predictions."}), 500

    if 'file' not in request.files:
        return jsonify({"error": "No file uploaded"}), 400

    try:
        file = request.files['file']
        input_data = pd.read_csv(file)

        expected_columns = [
            'Product_Weight', 'Product_Sugar_Content', 'Product_Allocated_Area',
            'Product_Type', 'Product_MRP', 'Store_Size',
            'Store_Location_City_Type', 'Store_Type', 'Store_Age'
        ]
        missing_columns = [col for col in expected_columns if col not in input_data.columns]
        if missing_columns:
            return jsonify({"error": f"Missing required columns: {missing_columns}"}), 400

        input_data.reset_index(inplace=True)
        input_data.rename(columns={'index': 'row_id'}, inplace=True)

        predictions = model.predict(input_data[expected_columns])
        predicted_prices = [round(float(p), 2) for p in predictions]

        results = [
            {"row_id": row_id, "Predicted Price": price}
            for row_id, price in zip(input_data['row_id'], predicted_prices)
        ]

        return jsonify(results), 200

    except Exception as e:
        print(f"Error during batch prediction: {e}")
        traceback.print_exc()
        return jsonify({"error": "Internal server error during batch prediction.", "details": str(e)}), 500

if __name__ == '__main__':
    pass