catboost-rust 0.2.2

use catboost_rust::{Model, CatBoostError};
use std::fs;

fn main() -> Result<(), CatBoostError> {
    println!("CatBoost Rust Example - Basic Usage");
    println!("===================================");

    // Check if we have a model file to load
    let model_path = "tmp/model.bin";
    if !fs::metadata(model_path).is_ok() {
        println!("No model file found at {}. Creating a simple example...", model_path);
        create_simple_example()?;
        return Ok(());
    }

    // Load the model
    println!("Loading model from {}...", model_path);
    let model = Model::load(model_path)?;
    
    println!("Model loaded successfully!");
    println!("Model info:");
    println!("  - Number of float features: {}", model.get_float_features_count());
    println!("  - Number of categorical features: {}", model.get_cat_features_count());
    println!("  - Number of trees: {}", model.get_tree_count());
    println!("  - Number of dimensions: {}", model.get_dimensions_count());

    // Example 1: Simple prediction with numeric features
    println!("\nExample 1: Numeric features prediction");
    let numeric_features = vec![vec![1.0, 2.0, 3.0, 4.0, 5.0]];
    let prediction = model.calc_model_prediction(numeric_features, vec![Vec::<String>::new()])?;
    println!("  Input features: {:?}", vec![1.0, 2.0, 3.0, 4.0, 5.0]);
    println!("  Prediction: {:.6}", prediction[0]);

    // Example 2: Prediction with categorical features
    println!("\nExample 2: Categorical features prediction");
    let numeric_features = vec![vec![1.0, 2.0, 3.0, 4.0, 5.0]];
    let categorical_features = vec![vec![String::from("A"), String::from("B"), String::from("C")]];
    let prediction = model.calc_model_prediction(numeric_features, categorical_features)?;
    println!("  Numeric features: {:?}", vec![1.0, 2.0, 3.0, 4.0, 5.0]);
    println!("  Categorical features: {:?}", vec!["A", "B", "C"]);
    println!("  Prediction: {:.6}", prediction[0]);

    // Example 3: Batch prediction
    println!("\nExample 3: Batch prediction");
    let batch_features = vec![
        vec![1.0, 2.0, 3.0, 4.0, 5.0],
        vec![2.0, 3.0, 4.0, 5.0, 6.0],
        vec![3.0, 4.0, 5.0, 6.0, 7.0],
    ];
    
    let predictions = model.calc_model_prediction(batch_features, vec![Vec::<String>::new(), Vec::<String>::new(), Vec::<String>::new()])?;
    for (i, pred) in predictions.iter().enumerate() {
        println!("  Sample {}: {:?} -> {:.6}", i + 1, vec![1.0 + i as f32, 2.0 + i as f32, 3.0 + i as f32, 4.0 + i as f32, 5.0 + i as f32], pred);
    }

    println!("\nAll examples completed successfully!");
    Ok(())
}

fn create_simple_example() -> Result<(), CatBoostError> {
    println!("Since no model file is available, here's how you would use the library:");
    println!();
    println!("1. Train a CatBoost model using Python or other tools");
    println!("2. Save it as 'tmp/model.bin'");
    println!("3. Run this example again");
    println!();
    println!("Example Python code to create a model:");
    println!("```python");
    println!("from catboost import CatBoostRegressor");
    println!("import numpy as np");
    println!();
    println!("# Create sample data");
    println!("X = np.random.rand(100, 5)");
    println!("y = np.sum(X, axis=1) + np.random.normal(0, 0.1, 100)");
    println!();
    println!("# Train model");
    println!("model = CatBoostRegressor(iterations=100, depth=3, verbose=False)");
    println!("model.fit(X, y)");
    println!();
    println!("# Save model");
    println!("model.save_model('tmp/model.bin')");
    println!("```");
    Ok(())
}