use rhai::{Engine, EvalAltResult};
use rhai_autobind_macros::rhai_autobind;
use serde::{Deserialize, Serialize};
use std::path::Path;

// Define a simple Calculator struct with the rhai_autobind attribute
#[derive(Debug, Clone, Serialize, Deserialize, rhai::CustomType)]
#[rhai_autobind]
pub struct Calculator {
    pub value: f64,
}

impl Calculator {
    // Constructor
    pub fn new() -> Self {
        Calculator { value: 0.0 }
    }
    
    // Add method
    pub fn add(&mut self, x: f64) -> f64 {
        self.value += x;
        self.value
    }
    
    // Subtract method
    pub fn subtract(&mut self, x: f64) -> f64 {
        self.value -= x;
        self.value
    }
    
    // Multiply method
    pub fn multiply(&mut self, x: f64) -> f64 {
        self.value *= x;
        self.value
    }
    
    // Divide method
    pub fn divide(&mut self, x: f64) -> f64 {
        if x == 0.0 {
            println!("Error: Division by zero!");
            return self.value;
        }
        self.value /= x;
        self.value
    }
    
    // Clear method
    pub fn clear(&mut self) -> f64 {
        self.value = 0.0;
        self.value
    }
    
    // Get value method
    pub fn get_value(&self) -> f64 {
        self.value
    }
}

fn main() -> Result<(), Box<EvalAltResult>> {
    println!("Rhai Calculator Example");
    println!("======================");
    
    // Create a new Rhai engine
    let mut engine = Engine::new();
    
    // Register the Calculator type with the engine using the generated function
    Calculator::register_rhai_bindings_for_calculator(&mut engine);
    
    // Register print function for output
    engine.register_fn("println", |s: &str| println!("{}", s));

    // Create a calculator instance to demonstrate it works
    let calc = Calculator::new();
    println!("Initial value: {}", calc.value);
    
    // Load and run the Rhai script
    let script_path = Path::new(env!("CARGO_MANIFEST_DIR"))
        .join("examples")
        .join("rhai_autobind_example")
        .join("calculator.rhai");

    println!("Loading Rhai script from: {}", script_path.display());

    match engine.eval_file::<()>(script_path) {
        Ok(_) => println!("Script executed successfully"),
        Err(e) => eprintln!("Error executing script: {}\nAt: {:?}", e, e.position()),
    }

    Ok(())
}