// Macro example: Using jvmrs-macros to define Java classes in Rust
//
// This example demonstrates the procedural macro system for defining
// Java-compatible structures in Rust.
//
// Note: This requires the jvmrs-macros crate to be properly set up.
// Add to Cargo.toml:
// [dependencies]
// jvmrs = { path = "..", features = ["interop"] }
// jvmrs-macros = { path = "../jvmrs-macros" }

// Uncomment these when jvmrs-macros is properly integrated
/*
use jvmrs::memory::Value;
use jvmrs_macros::{java_class, java_native};

// Define a Java class using the macro
#[java_class("com.example.Counter")]
pub struct Counter {
    #[java_field]
    pub count: i32,
}

impl Counter {
    pub fn new() -> Self {
        Counter { count: 0 }
    }

    pub fn increment(&mut self) -> i32 {
        self.count += 1;
        self.count
    }

    pub fn add(&mut self, value: i32) -> i32 {
        self.count += value;
        self.count
    }

    pub fn get(&self) -> i32 {
        self.count
    }
}

// Register native methods that can be called from Java
#[java_native("com.example.Utils", "addNumbers")]
pub fn add_numbers(args: &[Value]) -> Result<Value, String> {
    if args.len() >= 2 {
        let a = args[0].as_int();
        let b = args[1].as_int();
        Ok(Value::Int(a + b))
    } else {
        Err("Expected 2 integer arguments".to_string())
    }
}

#[java_native("com.example.Utils", "multiplyNumbers")]
pub fn multiply_numbers(args: &[Value]) -> Result<Value, String> {
    if args.len() >= 2 {
        let a = args[0].as_int();
        let b = args[1].as_int();
        Ok(Value::Int(a * b))
    } else {
        Err("Expected 2 integer arguments".to_string())
    }
}

#[java_native("com.example.StringUtils", "reverse")]
pub fn reverse_string(args: &[Value]) -> Result<Value, String> {
    if args.len() >= 1 {
        if let Value::Reference(addr) = args[0] {
            // This would need actual heap access to get the string content
            // For now, return a placeholder
            Ok(Value::Null)
        } else {
            Err("Expected a string reference".to_string())
        }
    } else {
        Err("Expected 1 argument".to_string())
    }
}

#[java_native("com.example.ArrayUtils", "sumArray")]
pub fn sum_array(args: &[Value]) -> Result<Value, String> {
    if args.len() >= 1 {
        if let Value::ArrayRef(addr) = args[0] {
            // This would need actual heap access to get the array content
            // For now, return a placeholder
            Ok(Value::Int(0))
        } else {
            Err("Expected an array reference".to_string())
        }
    } else {
        Err("Expected 1 argument".to_string())
    }
}

fn main() {
    println!("=== JVMRS Macro System Example ===\n");

    // Demonstrate the Java class
    println!("1. Using the Java-class-like Counter struct:");
    let mut counter = Counter::new();
    println!("   Initial count: {}", counter.get());
    println!("   After increment: {}", counter.increment());
    println!("   After adding 5: {}", counter.add(5));
    println!("   Final count: {}", counter.get());

    println!("\n2. Native methods are automatically registered:");
    println!("   - com.example.Utils.addNumbers(int, int) -> int");
    println!("   - com.example.Utils.multiplyNumbers(int, int) -> int");
    println!("   - com.example.StringUtils.reverse(String) -> String");
    println!("   - com.example.ArrayUtils.sumArray(int[]) -> int");

    println!("\n3. These can be called from Java bytecode:");
    println!("   // Java code:");
    println!("   // int sum = Utils.addNumbers(10, 20);");
    println!("   // int product = Utils.multiplyNumbers(5, 6);");

    println!("\n=== Benefits of the macro system ===");
    println!("✓ Type-safe Java/Rust interop");
    println!("✓ Automatic native method registration");
    println!("✓ Compile-time error checking");
    println!("✓ No manual JNI boilerplate");
    println!("✓ IDE autocomplete support");
}
*/

fn main() {
    println!("=== JVMRS Macro System Example ===\n");
    println!("This example demonstrates the procedural macro system.");
    println!("\nTo use the macros, uncomment the code in this file and add:");
    println!("  jvmrs-macros = {{ path = \"../jvmrs-macros\" }}");
    println!("to your Cargo.toml dependencies.\n");
    println!("The macro system provides:");
    println!("  • @java_class attribute to define Java-compatible structs");
    println!("  • @java_native attribute to register Rust functions as native methods");
    println!("  • Automatic registration and type conversion");
    println!("  • Zero-overhead interop with type safety");
}
