"""
SuperKart Sales Prediction Frontend

A Streamlit web application for predicting product sales using the SuperKart ML model.
This frontend provides an intuitive interface for users to input product and store features
and get sales predictions from the backend API.
"""

import warnings
import streamlit as st
import requests
import pandas as pd
import argparse
import os
import sys
from typing import Dict

# Suppress SyntaxWarnings from Streamlit library
warnings.filterwarnings("ignore", category=SyntaxWarning)

# Page configuration
st.set_page_config(
    page_title="SuperKart Sales Predictor",
    page_icon="🛒",
    layout="wide",
    initial_sidebar_state="expanded",
)

# Custom CSS for better styling
st.markdown(
    """
<style>
    .main-header {
        font-size: 3rem;
        color: #1f77b4;
        text-align: center;
        margin-bottom: 2rem;
    }
    .prediction-box {
        background-color: #f0f8ff;
        padding: 20px;
        border-radius: 10px;
        border-left: 5px solid #1f77b4;
        margin: 20px 0;
    }
    .success-box {
        background-color: #d4edda;
        padding: 15px;
        border-radius: 5px;
        border-left: 5px solid #28a745;
        margin: 10px 0;
    }
    .error-box {
        background-color: #f8d7da;
        padding: 15px;
        border-radius: 5px;
        border-left: 5px solid #dc3545;
        margin: 10px 0;
    }
</style>
""",
    unsafe_allow_html=True,
)


def get_backend_url():
    """Get backend URL from command line arguments, environment variables, or default."""
    # Check if running with Streamlit (sys.argv will contain streamlit run ...)
    if len(sys.argv) > 1 and "streamlit" in sys.argv[0]:
        # Parse additional arguments after the script name
        parser = argparse.ArgumentParser(description="SuperKart Frontend App")
        parser.add_argument(
            "--backend-url",
            type=str,
            default=os.getenv("BACKEND_URL", "http://localhost:7860"),
            help="Backend API URL (default: http://localhost:7860)",
        )

        # Only parse known args to avoid conflicts with Streamlit args
        try:
            known_args, _ = parser.parse_known_args()
            return known_args.backend_url
        except (SystemExit, argparse.ArgumentError):
            pass

    # Fallback to environment variable or default
    return os.getenv("BACKEND_URL", "http://localhost:7860")


# Configuration
BACKEND_URL = get_backend_url()


def make_api_request(endpoint: str, data: Dict = None, method: str = "GET") -> Dict:
    """Make API request to backend service."""
    try:
        url = f"{BACKEND_URL}{endpoint}"

        if method == "GET":
            response = requests.get(url, timeout=30)
        elif method == "POST":
            response = requests.post(url, json=data, timeout=30)

        response.raise_for_status()
        return {"success": True, "data": response.json()}

    except requests.exceptions.ConnectionError:
        return {
            "success": False,
            "error": "Cannot connect to backend API. Please ensure the backend service is running.",
        }
    except requests.exceptions.Timeout:
        return {
            "success": False,
            "error": "Request timeout. The backend service is taking too long to respond.",
        }
    except requests.exceptions.RequestException as e:
        return {"success": False, "error": f"API request failed: {str(e)}"}


def get_feature_info():
    """Get feature information from backend API."""
    result = make_api_request("/features")
    if result["success"]:
        return result["data"]
    else:
        st.error(f"Failed to get feature information: {result['error']}")
        return None


def create_input_form():
    """Create the input form for prediction."""
    st.header("🔮 Product Sales Prediction")

    # Get feature information
    feature_info = get_feature_info()
    if not feature_info:
        return None

    # Create form
    with st.form("prediction_form"):
        col1, col2 = st.columns(2)

        with col1:
            st.subheader("📦 Product Features")

            product_weight = st.number_input(
                "Product Weight (kg)",
                min_value=0.1,
                max_value=100.0,
                value=12.66,
                step=0.1,
                help="Weight of the product in kilograms",
            )

            product_sugar_content = st.selectbox(
                "Sugar Content",
                options=["Low Sugar", "Regular", "No Sugar"],
                index=0,
                help="Sugar content level of the product",
            )

            product_allocated_area = st.number_input(
                "Allocated Display Area (Ratio)",
                min_value=0.0,
                max_value=1.0,
                value=0.027,
                step=0.001,
                format="%.3f",
                help="Ratio of allocated display area (0.0 to 1.0)",
            )

            product_type = st.selectbox(
                "Product Type",
                options=[
                    "Dairy",
                    "Soft Drinks",
                    "Meat",
                    "Fruits and Vegetables",
                    "Household",
                    "Baking Goods",
                    "Snack Foods",
                    "Frozen Foods",
                    "Breakfast",
                    "Health and Hygiene",
                    "Hard Drinks",
                    "Canned",
                    "Bread",
                    "Starchy Foods",
                    "Others",
                    "Seafood",
                ],
                index=7,  # Frozen Foods
                help="Category of the product",
            )

            product_mrp = st.number_input(
                "Maximum Retail Price ($)",
                min_value=1.0,
                max_value=1000.0,
                value=117.08,
                step=0.01,
                format="%.2f",
                help="Maximum retail price in USD",
            )

        with col2:
            st.subheader("🏪 Store Features")

            store_establishment_year = st.selectbox(
                "Store Establishment Year",
                options=[1987, 1998, 1999, 2009],
                index=3,  # 2009
                help="Year when the store was established",
            )

            store_size = st.selectbox(
                "Store Size",
                options=["Small", "Medium", "High"],
                index=1,  # Medium
                help="Size category of the store",
            )

            store_location_city_type = st.selectbox(
                "City Type",
                options=["Tier 1", "Tier 2", "Tier 3"],
                index=1,  # Tier 2
                help="Type of city where the store is located",
            )

            store_type = st.selectbox(
                "Store Type",
                options=[
                    "Supermarket Type1",
                    "Supermarket Type2",
                    "Supermarket Type3",
                    "Departmental Store",
                    "Food Mart",
                ],
                index=1,  # Supermarket Type2
                help="Type/format of the store",
            )

        # Submit button
        submitted = st.form_submit_button("🎯 Predict Sales", type="primary")

        if submitted:
            # Prepare input data
            input_data = {
                "Product_Weight": product_weight,
                "Product_Sugar_Content": product_sugar_content,
                "Product_Allocated_Area": product_allocated_area,
                "Product_Type": product_type,
                "Product_MRP": product_mrp,
                "Store_Establishment_Year": store_establishment_year,
                "Store_Size": store_size,
                "Store_Location_City_Type": store_location_city_type,
                "Store_Type": store_type,
            }

            return input_data

    return None


def display_prediction_result(prediction_data: Dict):
    """Display the prediction result with EDA-based insights."""
    predicted_sales = prediction_data["predicted_sales"]

    # Main prediction display
    st.markdown('<div class="prediction-box">', unsafe_allow_html=True)
    col1, col2, col3 = st.columns([1, 2, 1])

    with col2:
        st.markdown(
            f"""
        <div style="text-align: center;">
            <h2>💰 Predicted Sales Revenue</h2>
            <h1 style="color: #28a745; font-size: 4rem;">${predicted_sales:,.2f}</h1>
        </div>
        """,
            unsafe_allow_html=True,
        )

    st.markdown("</div>", unsafe_allow_html=True)

    # EDA-based insights and business metrics
    st.subheader("📊 Sales Analysis & Business Insights")

    # Based on EDA: Sales range $33-$8,000, Mean: $3,464, Median: $3,452, Std: $1,066
    sales_mean = 3464
    sales_median = 3452
    sales_std = 1066
    sales_q1 = 2762
    sales_q3 = 4145

    col1, col2, col3, col4 = st.columns(4)

    with col1:
        # Performance vs Mean
        vs_mean = ((predicted_sales - sales_mean) / sales_mean) * 100
        delta_color = "normal" if abs(vs_mean) < 10 else "inverse"
        st.metric(
            label="📊 vs Dataset Mean",
            value=f"${predicted_sales:,.2f}",
            delta=f"{vs_mean:+.1f}%",
            delta_color=delta_color,
        )

    with col2:
        # Performance vs Median
        vs_median = ((predicted_sales - sales_median) / sales_median) * 100
        delta_color = "normal" if abs(vs_median) < 10 else "inverse"
        st.metric(
            label="📈 vs Dataset Median",
            value=f"${sales_median:,.2f}",
            delta=f"{vs_median:+.1f}%",
            delta_color=delta_color,
        )

    with col3:
        # Percentile ranking based on EDA quartiles
        if predicted_sales <= sales_q1:
            percentile = "Bottom 25%"
            percentile_color = "🔴"
        elif predicted_sales <= sales_median:
            percentile = "25th-50th"
            percentile_color = "🟡"
        elif predicted_sales <= sales_q3:
            percentile = "50th-75th"
            percentile_color = "🟠"
        else:
            percentile = "Top 25%"
            percentile_color = "🟢"

        st.metric(
            label="🎯 Performance Percentile",
            value=f"{percentile_color} {percentile}",
            delta=None,
        )

    with col4:
        # Standard deviation analysis
        z_score = (predicted_sales - sales_mean) / sales_std
        if abs(z_score) <= 1:
            volatility = "Normal"
            vol_color = "🟢"
        elif abs(z_score) <= 2:
            volatility = "Moderate"
            vol_color = "🟡"
        else:
            volatility = "High"
            vol_color = "🔴"

        st.metric(
            label="📉 Sales Volatility",
            value=f"{vol_color} {volatility}",
            delta=f"σ: {z_score:+.1f}",
        )

    # Business insights section
    st.subheader("💼 Business Recommendations & Next Steps")

    # Performance Summary Box
    if predicted_sales >= sales_q3:  # Top 25%
        performance_level = "⭐ Excellent"
        performance_color = "#28a745"
        summary_message = (
            "This product is predicted to perform in the top 25% of SuperKart sales!"
        )
    elif predicted_sales >= sales_median:  # Above median
        performance_level = "✅ Good"
        performance_color = "#17a2b8"
        summary_message = (
            "This product is predicted to perform above the historical average."
        )
    elif predicted_sales >= sales_q1:  # Above bottom quartile
        performance_level = "⚠️ Below Average"
        performance_color = "#ffc107"
        summary_message = (
            "This product may underperform compared to typical SuperKart sales."
        )
    else:  # Bottom 25%
        performance_level = "🔴 Needs Attention"
        performance_color = "#dc3545"
        summary_message = (
            "This product is predicted to be in the bottom 25% of sales performance."
        )

    # Performance summary box
    st.markdown(
        f"""
        <div style="background-color: {performance_color}20; padding: 20px; border-radius: 10px; 
             border-left: 5px solid {performance_color}; margin: 15px 0;">
            <h4 style="color: {performance_color}; margin: 0 0 10px 0;">
                {performance_level} Performance Expected
            </h4>
            <p style="margin: 0; font-size: 16px;">{summary_message}</p>
        </div>
        """,
        unsafe_allow_html=True,
    )

    # Three-column layout for insights
    col1, col2, col3 = st.columns(3)

    with col1:
        st.markdown("#### 💰 Financial Impact")

        # Revenue tier classification (moved to top for consistency)
        if predicted_sales >= 5000:
            tier = "🏆 Premium Tier"
        elif predicted_sales >= 3000:
            tier = "🥈 Standard Tier"
        else:
            tier = "🥉 Value Tier"
        st.info(f"**Revenue Classification:** {tier}")

        # Financial metrics with clear labels
        profit_margin = 0.2  # 20% profit margin
        estimated_profit = predicted_sales * profit_margin
        st.metric("Predicted Revenue", f"${predicted_sales:,.0f}")
        st.metric("Estimated Profit (20%)", f"${estimated_profit:,.0f}")

    with col2:
        st.markdown("#### 📊 Market Position")

        # Clear market positioning
        vs_mean_pct = ((predicted_sales - sales_mean) / sales_mean) * 100
        if vs_mean_pct > 10:
            position = "🚀 Above Market Average"
        elif vs_mean_pct > -10:
            position = "📊 Market Average"
        else:
            position = "📉 Below Market Average"

        st.success(position)
        st.write(f"**vs Historical Mean:** {vs_mean_pct:+.1f}%")
        st.write("**Market Range:** \\$33 - \\$8,000")
        st.write(f"**Your Prediction:** ${predicted_sales:,.0f}")

    with col3:
        st.markdown("#### 🎯 Action Items")

        # Clear, actionable recommendations
        if predicted_sales < sales_q1:
            st.warning("**Low Performance Risk**")
            st.write("**Immediate Actions:**")
            st.write("• Launch promotional campaign")
            st.write("• Review pricing strategy")
            st.write("• Optimize product placement")
            st.write("• Analyze competitor offerings")
        elif predicted_sales > sales_q3:
            st.success("**High Performance Opportunity**")
            st.write("**Recommended Actions:**")
            st.write("• Ensure adequate stock levels")
            st.write("• Consider premium pricing")
            st.write("• Expand to similar products")
            st.write("• Allocate prime shelf space")
        else:
            st.info("**Standard Performance Expected**")
            st.write("**Monitor & Optimize:**")
            st.write("• Track actual vs predicted")
            st.write("• A/B test marketing approaches")
            st.write("• Monitor competitor activity")
            st.write("• Adjust inventory as needed")


def create_input_summary(input_data: Dict):
    """Create a summary of input features."""
    st.subheader("📋 Input Summary")

    # Create two columns for better layout
    col1, col2 = st.columns(2)

    with col1:
        st.markdown("**Product Information:**")
        st.write(f"• Weight: {input_data['Product_Weight']} kg")
        st.write(f"• Sugar Content: {input_data['Product_Sugar_Content']}")
        st.write(f"• Display Area: {input_data['Product_Allocated_Area']:.3f}")
        st.write(f"• Type: {input_data['Product_Type']}")
        st.write(f"• MRP: ${input_data['Product_MRP']:.2f}")

    with col2:
        st.markdown("**Store Information:**")
        st.write(f"• Establishment Year: {input_data['Store_Establishment_Year']}")
        st.write(f"• Size: {input_data['Store_Size']}")
        st.write(f"• City Type: {input_data['Store_Location_City_Type']}")
        st.write(f"• Store Type: {input_data['Store_Type']}")


def create_batch_prediction():
    """Create batch prediction interface."""
    st.header("📊 Batch Prediction")

    st.markdown("""
    Upload a CSV file with multiple products to get batch predictions.
    The CSV should contain all required columns with the same names as in the single prediction form.
    """)

    # File uploader
    uploaded_file = st.file_uploader(
        "Choose a CSV file",
        type="csv",
        help="Upload a CSV file with product and store features",
    )

    if uploaded_file is not None:
        try:
            # Read the CSV file
            df = pd.read_csv(uploaded_file)

            # Display the uploaded data
            st.subheader("📂 Uploaded Data")
            st.dataframe(df.head(10))

            if st.button("🚀 Run Batch Prediction", type="primary"):
                # Convert DataFrame to list of dictionaries
                predictions_data = df.to_dict("records")

                # Make batch prediction request
                result = make_api_request(
                    "/predict/batch", {"predictions": predictions_data}, "POST"
                )

                if result["success"]:
                    batch_results = result["data"]

                    # Display results
                    st.subheader("📈 Batch Prediction Results")

                    col1, col2, col3 = st.columns(3)
                    with col1:
                        st.metric(
                            "✅ Successful", batch_results["successful_predictions"]
                        )
                    with col2:
                        st.metric("❌ Failed", batch_results["failed_predictions"])
                    with col3:
                        st.metric("📊 Total", len(predictions_data))

                    # Show successful predictions
                    if batch_results["results"]:
                        st.subheader("🎯 Successful Predictions")

                        # Create a user-friendly results DataFrame
                        display_results = []
                        for result in batch_results["results"]:
                            # Extract readable product info
                            input_features = result["input_features"]

                            # Determine performance category
                            sales = result["predicted_sales"]
                            if sales >= 4145:  # Top 25% (Q3)
                                category = "🟢 High"
                            elif sales >= 3452:  # Above median
                                category = "🟡 Good"
                            elif sales >= 2762:  # Above Q1
                                category = "🟠 Average"
                            else:
                                category = "🔴 Low"

                            display_row = {
                                "Row": result["index"] + 1,
                                "Product Type": input_features["Product_Type"],
                                "Weight (kg)": input_features["Product_Weight"],
                                "MRP ($)": f"${input_features['Product_MRP']:.2f}",
                                "Store Size": input_features["Store_Size"],
                                "Store Type": input_features["Store_Type"],
                                "Predicted Sales": f"${sales:,.2f}",
                                "Performance": category,
                            }
                            display_results.append(display_row)

                        display_df = pd.DataFrame(display_results)

                        # Show the clean results table
                        st.dataframe(
                            display_df, use_container_width=True, hide_index=True
                        )

                        # Summary statistics
                        sales_values = [
                            result["predicted_sales"]
                            for result in batch_results["results"]
                        ]

                        col1, col2, col3, col4 = st.columns(4)
                        with col1:
                            st.metric("💰 Total Revenue", f"${sum(sales_values):,.0f}")
                        with col2:
                            st.metric(
                                "📊 Average Sale",
                                f"${sum(sales_values) / len(sales_values):,.0f}",
                            )
                        with col3:
                            high_performers = len(
                                [s for s in sales_values if s >= 4145]
                            )
                            st.metric("🟢 High Performers", f"{high_performers}")
                        with col4:
                            low_performers = len([s for s in sales_values if s < 2762])
                            st.metric("🔴 Needs Attention", f"{low_performers}")

                        # Download options
                        col1, col2 = st.columns(2)
                        with col1:
                            # Download user-friendly results
                            csv_display = display_df.to_csv(index=False)
                            st.download_button(
                                label="📥 Download Summary Results",
                                data=csv_display,
                                file_name="batch_predictions_summary.csv",
                                mime="text/csv",
                            )

                        with col2:
                            # Download detailed results for technical users
                            detailed_results = []
                            for result in batch_results["results"]:
                                detailed_row = {
                                    "row_index": result["index"],
                                    "predicted_sales": result["predicted_sales"],
                                    **result["input_features"],
                                }
                                detailed_results.append(detailed_row)

                            detailed_df = pd.DataFrame(detailed_results)
                            csv_detailed = detailed_df.to_csv(index=False)
                            st.download_button(
                                label="🔧 Download Detailed Results",
                                data=csv_detailed,
                                file_name="batch_predictions_detailed.csv",
                                mime="text/csv",
                            )

                    # Show errors if any
                    if batch_results["errors"]:
                        st.subheader("⚠️ Prediction Errors")
                        errors_df = pd.DataFrame(batch_results["errors"])
                        st.dataframe(errors_df)

                else:
                    st.error(f"Batch prediction failed: {result['error']}")

        except Exception as e:
            st.error(f"Error processing file: {str(e)}")


def main():
    """Main application function."""
    # Title and description
    st.markdown(
        '<h1 class="main-header">🛒 SuperKart Sales Predictor</h1>',
        unsafe_allow_html=True,
    )

    st.markdown(
        """
    <div style="text-align: center; margin-bottom: 2rem;">
        <p style="font-size: 1.2rem; color: #666;">
            Predict product sales revenue using machine learning based on product and store characteristics
        </p>
    </div>
    """,
        unsafe_allow_html=True,
    )

    # Check backend health
    health_result = make_api_request("/")
    if not health_result["success"]:
        st.error(
            f"⚠️ Backend API is not available at `{BACKEND_URL}`. Please ensure the backend service is running."
        )
        st.info(
            """
            **How to specify a different backend URL:**

            1. **Command line argument:**
               ```
               streamlit run app.py -- --backend-url http://your-backend:5050
               ```

            2. **Environment variable:**
               ```
               export BACKEND_URL=http://your-backend:5050
               streamlit run app.py
               ```
            """
        )
        st.stop()

    # Sidebar navigation
    st.sidebar.title("🧭 Navigation")

    # Display current backend URL and connection status
    st.sidebar.markdown("---")
    st.sidebar.markdown("**🔗 Backend Configuration**")
    st.sidebar.code(BACKEND_URL, language=None)

    # Show connection status
    if health_result["success"]:
        st.sidebar.success("🟢 Connected")
        if "data" in health_result and "model_loaded" in health_result["data"]:
            model_status = (
                "🤖 Model Loaded"
                if health_result["data"]["model_loaded"]
                else "⚠️ Model Not Loaded"
            )
            st.sidebar.info(model_status)
    else:
        st.sidebar.error("🔴 Disconnected")

    st.sidebar.markdown("---")

    app_mode = st.sidebar.selectbox(
        "Choose App Mode",
        ["Single Prediction", "Batch Prediction", "API Documentation"],
    )

    if app_mode == "Single Prediction":
        # Single prediction interface
        input_data = create_input_form()

        if input_data:
            # Make prediction
            result = make_api_request("/predict", input_data, "POST")

            if result["success"]:
                prediction_data = result["data"]

                # Display results
                display_prediction_result(prediction_data)

                # Show input summary
                with st.expander("📋 View Input Details", expanded=False):
                    create_input_summary(input_data)

                # Success message
                st.markdown(
                    '<div class="success-box">✅ Prediction completed successfully!</div>',
                    unsafe_allow_html=True,
                )

            else:
                st.markdown(
                    f'<div class="error-box">❌ Prediction failed: {result["error"]}</div>',
                    unsafe_allow_html=True,
                )

    elif app_mode == "Batch Prediction":
        create_batch_prediction()

    elif app_mode == "API Documentation":
        st.header("📚 API Documentation")

        # Get feature information
        feature_info = get_feature_info()

        if feature_info:
            st.subheader("🔧 Required Features")

            features_df = pd.DataFrame(
                [
                    {"Feature": k, "Description": v}
                    for k, v in feature_info["feature_descriptions"].items()
                ]
            )
            st.table(features_df)

            st.subheader("📝 Example Input")
            st.json(feature_info["example_input"])

            st.subheader("🌐 API Endpoints")
            st.markdown("""
            - **GET /**: Health check
            - **POST /predict**: Single prediction
            - **POST /predict/batch**: Batch prediction
            - **GET /features**: Get feature information
            """)

    # Footer
    st.markdown("---")
    st.markdown(
        "<div style='text-align: center; color: #666;'>"
        "SuperKart Sales Prediction System | Krishnaswamy Subramanian"
        "</div>",
        unsafe_allow_html=True,
    )


if __name__ == "__main__":
    main()