just_engine/runner/eval/

expression.rs

//! Expression evaluation.
//!
//! This module provides the core expression evaluation logic for the JavaScript interpreter.
//! It handles all expression types defined in the AST.

use crate::parser::ast::{
    AssignmentOperator, BinaryOperator, ClassData, ExpressionOrSpreadElement, ExpressionOrSuper,
    ExpressionType, ExpressionPatternType, FunctionData, LiteralData, LiteralType, MemberExpressionType,
    MethodDefinitionKind, PatternOrExpression, PatternType, PropertyData, PropertyKind, UnaryOperator,
    UpdateOperator, LogicalOperator,
};
use crate::runner::ds::error::JErrorType;
use crate::runner::ds::object::{JsObject, JsObjectType, ObjectBase, ObjectType};
use crate::runner::ds::object_property::{PropertyDescriptor, PropertyDescriptorAccessor, PropertyDescriptorData, PropertyKey};
use crate::runner::ds::value::{JsValue, JsNumberType};
use crate::runner::plugin::types::{EvalContext, SimpleObject};

use std::cell::RefCell;
use std::rc::Rc;

use super::types::ValueResult;

/// Evaluate an expression and return its value.
pub fn evaluate_expression(
    expr: &ExpressionType,
    ctx: &mut EvalContext,
) -> ValueResult {
    match expr {
        ExpressionType::Literal(lit) => evaluate_literal(lit),

        ExpressionType::ExpressionWhichCanBePattern(pattern) => {
            evaluate_expression_pattern(pattern, ctx)
        }

        ExpressionType::ThisExpression { .. } => {
            Ok(ctx.global_this.clone().unwrap_or(JsValue::Undefined))
        }

        ExpressionType::ArrayExpression { elements, .. } => {
            evaluate_array_expression(elements, ctx)
        }

        ExpressionType::ObjectExpression { properties, .. } => {
            evaluate_object_expression(properties, ctx)
        }

        ExpressionType::FunctionOrGeneratorExpression(func_data) => {
            create_function_object(func_data, ctx)
        }

        ExpressionType::UnaryExpression { operator, argument, .. } => {
            evaluate_unary_expression(operator, argument, ctx)
        }

        ExpressionType::BinaryExpression { operator, left, right, .. } => {
            evaluate_binary_expression(operator, left, right, ctx)
        }

        ExpressionType::LogicalExpression { operator, left, right, .. } => {
            evaluate_logical_expression(operator, left, right, ctx)
        }

        ExpressionType::UpdateExpression { operator, argument, prefix, .. } => {
            evaluate_update_expression(operator, argument, *prefix, ctx)
        }

        ExpressionType::AssignmentExpression { operator, left, right, .. } => {
            evaluate_assignment_expression(operator, left, right, ctx)
        }

        ExpressionType::ConditionalExpression { test, consequent, alternate, .. } => {
            evaluate_conditional_expression(test, consequent, alternate, ctx)
        }

        ExpressionType::CallExpression { callee, arguments, .. } => {
            evaluate_call_expression(callee, arguments, ctx)
        }

        ExpressionType::NewExpression { callee, arguments, .. } => {
            evaluate_new_expression(callee, arguments, ctx)
        }

        ExpressionType::SequenceExpression { expressions, .. } => {
            evaluate_sequence_expression(expressions, ctx)
        }

        ExpressionType::TemplateLiteral(_) => {
            Err(JErrorType::TypeError("Template literal not yet implemented".to_string()))
        }

        ExpressionType::TaggedTemplateExpression { .. } => {
            Err(JErrorType::TypeError("Tagged template expression not yet implemented".to_string()))
        }

        ExpressionType::ClassExpression(class_data) => {
            evaluate_class_expression(class_data, ctx)
        }

        ExpressionType::YieldExpression { argument, delegate, .. } => {
            if *delegate {
                // yield* not yet supported
                return Err(JErrorType::TypeError("yield* not yet implemented".to_string()));
            }
            // Evaluate the argument
            let value = if let Some(arg) = argument {
                evaluate_expression(arg, ctx)?
            } else {
                JsValue::Undefined
            };
            // Return a special error that signals a yield
            Err(JErrorType::YieldValue(value))
        }

        ExpressionType::MetaProperty { .. } => {
            Err(JErrorType::TypeError("Meta property not yet implemented".to_string()))
        }

        ExpressionType::ArrowFunctionExpression { .. } => {
            Err(JErrorType::TypeError("Arrow function expression not yet implemented".to_string()))
        }

        ExpressionType::MemberExpression(member_expr) => {
            evaluate_member_expression(member_expr, ctx)
        }
    }
}

/// Evaluate a literal and return its value.
fn evaluate_literal(lit: &LiteralData) -> ValueResult {
    Ok(match &lit.value {
        LiteralType::NullLiteral => JsValue::Null,
        LiteralType::BooleanLiteral(b) => JsValue::Boolean(*b),
        LiteralType::StringLiteral(s) => JsValue::String(s.clone()),
        LiteralType::NumberLiteral(n) => {
            use crate::parser::ast::NumberLiteralType;
            match n {
                NumberLiteralType::IntegerLiteral(i) => JsValue::Number(JsNumberType::Integer(*i)),
                NumberLiteralType::FloatLiteral(f) => JsValue::Number(JsNumberType::Float(*f)),
            }
        }
        LiteralType::RegExpLiteral { .. } => {
            return Err(JErrorType::TypeError("RegExp literal not yet implemented".to_string()));
        }
    })
}

/// Evaluate an array expression and return an array object.
fn evaluate_array_expression(
    elements: &[Option<ExpressionOrSpreadElement>],
    ctx: &mut EvalContext,
) -> ValueResult {
    use crate::runner::ds::object::JsObject;

    // Create a new array object (tracked for heap accounting)
    let mut array_obj = ctx.new_tracked_object()?;

    let mut index = 0;
    for element in elements {
        if let Some(elem) = element {
            match elem {
                ExpressionOrSpreadElement::Expression(expr) => {
                    let value = evaluate_expression(expr, ctx)?;
                    // Define the element as a property
                    let key = PropertyKey::Str(index.to_string());
                    array_obj.get_object_base_mut().properties.insert(
                        key,
                        PropertyDescriptor::Data(PropertyDescriptorData {
                            value,
                            writable: true,
                            enumerable: true,
                            configurable: true,
                        }),
                    );
                    index += 1;
                }
                ExpressionOrSpreadElement::SpreadElement(spread_expr) => {
                    // Evaluate the spread expression
                    let spread_value = evaluate_expression(spread_expr, ctx)?;

                    // If it's an array, spread its elements
                    if let JsValue::Object(spread_obj) = spread_value {
                        let borrowed = spread_obj.borrow();
                        let base = borrowed.as_js_object().get_object_base();

                        // Get length property if it exists
                        let length = if let Some(PropertyDescriptor::Data(prop)) =
                            base.properties.get(&PropertyKey::Str("length".to_string()))
                        {
                            match &prop.value {
                                JsValue::Number(JsNumberType::Integer(n)) => *n as usize,
                                JsValue::Number(JsNumberType::Float(n)) => *n as usize,
                                _ => 0,
                            }
                        } else {
                            0
                        };

                        // Iterate over array indices
                        for i in 0..length {
                            let elem_key = PropertyKey::Str(i.to_string());
                            let elem_value = if let Some(PropertyDescriptor::Data(prop)) =
                                base.properties.get(&elem_key)
                            {
                                prop.value.clone()
                            } else {
                                JsValue::Undefined
                            };

                            // Add to result array
                            let key = PropertyKey::Str(index.to_string());
                            array_obj.get_object_base_mut().properties.insert(
                                key,
                                PropertyDescriptor::Data(PropertyDescriptorData {
                                    value: elem_value,
                                    writable: true,
                                    enumerable: true,
                                    configurable: true,
                                }),
                            );
                            index += 1;
                        }
                    } else if let JsValue::String(s) = spread_value {
                        // Spread string characters
                        for ch in s.chars() {
                            let key = PropertyKey::Str(index.to_string());
                            array_obj.get_object_base_mut().properties.insert(
                                key,
                                PropertyDescriptor::Data(PropertyDescriptorData {
                                    value: JsValue::String(ch.to_string()),
                                    writable: true,
                                    enumerable: true,
                                    configurable: true,
                                }),
                            );
                            index += 1;
                        }
                    } else {
                        return Err(JErrorType::TypeError(
                            "Spread requires an iterable".to_string(),
                        ));
                    }
                }
            }
        } else {
            // Holes (None elements) are left as undefined/missing
            index += 1;
        }
    }

    // Set the length property
    array_obj.get_object_base_mut().properties.insert(
        PropertyKey::Str("length".to_string()),
        PropertyDescriptor::Data(PropertyDescriptorData {
            value: JsValue::Number(JsNumberType::Integer(index as i64)),
            writable: true,
            enumerable: false,
            configurable: false,
        }),
    );

    // Wrap in JsObjectType
    let obj: JsObjectType = Rc::new(RefCell::new(ObjectType::Ordinary(Box::new(array_obj))));
    Ok(JsValue::Object(obj))
}

/// Evaluate an object expression and return an object.
fn evaluate_object_expression(
    properties: &[PropertyData<Box<ExpressionType>>],
    ctx: &mut EvalContext,
) -> ValueResult {
    use std::collections::HashMap;

    // Create a new object (tracked for heap accounting)
    let mut obj = ctx.new_tracked_object()?;

    // Track accessor properties to merge getter/setter pairs
    let mut accessors: HashMap<String, (Option<JsObjectType>, Option<JsObjectType>)> = HashMap::new();

    for prop in properties {
        // Get the property key
        let key = get_object_property_key(&prop.key, prop.computed, ctx)?;

        match prop.kind {
            PropertyKind::Init => {
                // Evaluate the value
                let value = evaluate_expression(&prop.value, ctx)?;

                // Define the property
                obj.get_object_base_mut().properties.insert(
                    PropertyKey::Str(key),
                    PropertyDescriptor::Data(PropertyDescriptorData {
                        value,
                        writable: true,
                        enumerable: true,
                        configurable: true,
                    }),
                );
            }
            PropertyKind::Get => {
                // The value should be a function expression
                if let ExpressionType::FunctionOrGeneratorExpression(func_data) = prop.value.as_ref() {
                    let getter_fn = create_function_object(func_data, ctx)?;
                    if let JsValue::Object(getter_obj) = getter_fn {
                        let entry = accessors.entry(key).or_insert((None, None));
                        entry.0 = Some(getter_obj);
                    }
                } else {
                    return Err(JErrorType::TypeError("Getter must be a function".to_string()));
                }
            }
            PropertyKind::Set => {
                // The value should be a function expression
                if let ExpressionType::FunctionOrGeneratorExpression(func_data) = prop.value.as_ref() {
                    let setter_fn = create_function_object(func_data, ctx)?;
                    if let JsValue::Object(setter_obj) = setter_fn {
                        let entry = accessors.entry(key).or_insert((None, None));
                        entry.1 = Some(setter_obj);
                    }
                } else {
                    return Err(JErrorType::TypeError("Setter must be a function".to_string()));
                }
            }
        }
    }

    // Add accessor properties to the object
    for (key, (getter, setter)) in accessors {
        obj.get_object_base_mut().properties.insert(
            PropertyKey::Str(key),
            PropertyDescriptor::Accessor(PropertyDescriptorAccessor {
                get: getter,
                set: setter,
                enumerable: true,
                configurable: true,
            }),
        );
    }

    // Wrap in JsObjectType
    let obj_ref: JsObjectType = Rc::new(RefCell::new(ObjectType::Ordinary(Box::new(obj))));
    Ok(JsValue::Object(obj_ref))
}

/// Get the property key from an object literal property.
fn get_object_property_key(
    key_expr: &ExpressionType,
    computed: bool,
    ctx: &mut EvalContext,
) -> Result<String, JErrorType> {
    if computed {
        // Computed property: [expr]
        let key_value = evaluate_expression(key_expr, ctx)?;
        Ok(to_string(&key_value))
    } else {
        // Static property key
        match key_expr {
            ExpressionType::ExpressionWhichCanBePattern(ExpressionPatternType::Identifier(id)) => {
                Ok(id.name.clone())
            }
            ExpressionType::Literal(lit) => match &lit.value {
                LiteralType::StringLiteral(s) => Ok(s.clone()),
                LiteralType::NumberLiteral(n) => {
                    use crate::parser::ast::NumberLiteralType;
                    match n {
                        NumberLiteralType::IntegerLiteral(i) => Ok(i.to_string()),
                        NumberLiteralType::FloatLiteral(f) => Ok(f.to_string()),
                    }
                }
                _ => Err(JErrorType::TypeError("Invalid property key".to_string())),
            },
            _ => Err(JErrorType::TypeError("Invalid property key".to_string())),
        }
    }
}

/// Evaluate an expression pattern (identifier).
fn evaluate_expression_pattern(
    pattern: &ExpressionPatternType,
    ctx: &mut EvalContext,
) -> ValueResult {
    match pattern {
        ExpressionPatternType::Identifier(id) => {
            // Look up the identifier in the environment chain
            ctx.get_binding(&id.name)
        }
    }
}

/// Evaluate a member expression (property access).
fn evaluate_member_expression(
    member_expr: &MemberExpressionType,
    ctx: &mut EvalContext,
) -> ValueResult {
    match member_expr {
        MemberExpressionType::SimpleMemberExpression { object, property, .. } => {
            // Evaluate the object
            let obj_value = evaluate_expression_or_super(object, ctx)?;
            let prop_name = &property.name;

            // Get the property (with getter support)
            get_property_with_ctx(&obj_value, prop_name, ctx)
        }
        MemberExpressionType::ComputedMemberExpression { object, property, .. } => {
            // Evaluate the object
            let obj_value = evaluate_expression_or_super(object, ctx)?;

            // Evaluate the property expression to get the key
            let prop_value = evaluate_expression(property, ctx)?;
            let prop_name = to_property_key(&prop_value);

            // Get the property (with getter support)
            get_property_with_ctx(&obj_value, &prop_name, ctx)
        }
    }
}

/// Evaluate an ExpressionOrSuper.
fn evaluate_expression_or_super(
    expr_or_super: &ExpressionOrSuper,
    ctx: &mut EvalContext,
) -> ValueResult {
    match expr_or_super {
        ExpressionOrSuper::Expression(expr) => evaluate_expression(expr, ctx),
        ExpressionOrSuper::Super => {
            Err(JErrorType::TypeError("super not yet supported".to_string()))
        }
    }
}

/// Evaluate a call expression (function call).
fn evaluate_call_expression(
    callee: &ExpressionOrSuper,
    arguments: &[ExpressionOrSpreadElement],
    ctx: &mut EvalContext,
) -> ValueResult {
    // Check if this is a member expression call (e.g., Math.abs, console.log)
    // If so, try super-global method dispatch first
    if let ExpressionOrSuper::Expression(expr) = callee {
        if let ExpressionType::MemberExpression(member) = expr.as_ref() {
            if let MemberExpressionType::SimpleMemberExpression { object, property, .. } = member {
                // Try to get the object name for super-global lookup
                if let ExpressionOrSuper::Expression(obj_expr) = object {
                    if let ExpressionType::ExpressionWhichCanBePattern(
                        ExpressionPatternType::Identifier(id)
                    ) = obj_expr.as_ref() {
                        let obj_name = &id.name;
                        let method_name = &property.name;
                        
                        // Evaluate arguments first
                        let args = evaluate_arguments(arguments, ctx)?;
                        
                        // Try super-global method dispatch
                        let sg = ctx.super_global.clone();
                        let this_value = ctx.resolve_binding(obj_name).unwrap_or(JsValue::Undefined);
                        
                        let sg_result = sg.borrow().call_method(
                            obj_name,
                            method_name,
                            ctx,
                            this_value.clone(),
                            args.clone(),
                        );
                        
                        if let Some(result) = sg_result {
                            return result;
                        }
                        
                        // Fall through to normal property lookup if super-global doesn't handle it
                    }
                }
            }
        }
    }
    
    // Normal call path: evaluate the callee to get the function
    let callee_value = evaluate_expression_or_super(callee, ctx)?;

    // Get the 'this' value for the call
    let this_value = get_call_this_value(callee, ctx);

    // Evaluate the arguments
    let args = evaluate_arguments(arguments, ctx)?;

    // Call the function
    call_value(&callee_value, this_value, args, ctx)
}

/// Evaluate a new expression (constructor call).
fn evaluate_new_expression(
    callee: &ExpressionType,
    arguments: &[ExpressionOrSpreadElement],
    ctx: &mut EvalContext,
) -> ValueResult {
    // Check if this is a simple identifier constructor (e.g., new String(), new Number())
    // If so, try super-global constructor dispatch first
    if let ExpressionType::ExpressionWhichCanBePattern(
        ExpressionPatternType::Identifier(id)
    ) = callee {
        let ctor_name = &id.name;
        
        // Evaluate arguments first
        let args = evaluate_arguments(arguments, ctx)?;
        
        // Try super-global constructor dispatch
        let sg = ctx.super_global.clone();
        let sg_result = sg.borrow().call_constructor(ctor_name, ctx, args.clone());
        
        if let Some(result) = sg_result {
            return result;
        }
        
        // Fall through to normal evaluation if super-global doesn't handle it
    }
    
    // Normal constructor path: evaluate the callee to get the constructor function
    let constructor = evaluate_expression(callee, ctx)?;

    // Verify it's callable
    let ctor_obj = match &constructor {
        JsValue::Object(obj) => {
            if !obj.borrow().is_callable() {
                return Err(JErrorType::TypeError(format!(
                    "{} is not a constructor",
                    constructor
                )));
            }
            obj.clone()
        }
        _ => {
            return Err(JErrorType::TypeError(format!(
                "{} is not a constructor",
                constructor
            )));
        }
    };

    // Create a new object for 'this'
    let new_obj = create_new_object_for_constructor(&ctor_obj)?;

    // Evaluate the arguments
    let args = evaluate_arguments(arguments, ctx)?;

    // Call the constructor with the new object as 'this'
    let result = call_value(&constructor, JsValue::Object(new_obj.clone()), args, ctx)?;

    // If constructor returns an object, use that; otherwise use the new object
    match result {
        JsValue::Object(_) => Ok(result),
        _ => Ok(JsValue::Object(new_obj)),
    }
}

/// Create a new object for use in a constructor call.
/// Sets up the prototype chain from the constructor's prototype property.
fn create_new_object_for_constructor(
    constructor: &JsObjectType,
) -> Result<JsObjectType, JErrorType> {
    use crate::runner::ds::object::{JsObject, ObjectType};
    use crate::runner::ds::object_property::{PropertyDescriptor, PropertyKey};

    // Create a new empty object
    let mut new_obj = SimpleObject::new();

    // Get the prototype from the constructor's 'prototype' property
    let ctor_borrowed = constructor.borrow();
    let prototype_key = PropertyKey::Str("prototype".to_string());

    if let Some(PropertyDescriptor::Data(data)) =
        ctor_borrowed.as_js_object().get_object_base().properties.get(&prototype_key)
    {
        if let JsValue::Object(proto_obj) = &data.value {
            // Set the prototype field on ObjectBase (used by get_prototype_of)
            new_obj.get_object_base_mut().prototype = Some(proto_obj.clone());
        }
    }

    drop(ctor_borrowed);

    let obj: JsObjectType = Rc::new(RefCell::new(ObjectType::Ordinary(Box::new(new_obj))));
    Ok(obj)
}

/// Get the 'this' value for a call expression.
fn get_call_this_value(callee: &ExpressionOrSuper, ctx: &mut EvalContext) -> JsValue {
    match callee {
        ExpressionOrSuper::Expression(expr) => {
            match expr.as_ref() {
                // For member expressions, 'this' is the object
                ExpressionType::MemberExpression(member) => {
                    match member {
                        MemberExpressionType::SimpleMemberExpression { object, .. } |
                        MemberExpressionType::ComputedMemberExpression { object, .. } => {
                            match object {
                                ExpressionOrSuper::Expression(obj_expr) => {
                                    evaluate_expression(obj_expr, ctx).unwrap_or(JsValue::Undefined)
                                }
                                ExpressionOrSuper::Super => JsValue::Undefined,
                            }
                        }
                    }
                }
                // For other expressions, 'this' is undefined (or global in non-strict)
                _ => ctx.global_this.clone().unwrap_or(JsValue::Undefined),
            }
        }
        ExpressionOrSuper::Super => JsValue::Undefined,
    }
}

/// Evaluate call arguments.
fn evaluate_arguments(
    arguments: &[ExpressionOrSpreadElement],
    ctx: &mut EvalContext,
) -> Result<Vec<JsValue>, JErrorType> {
    let mut args = Vec::with_capacity(arguments.len());
    for arg in arguments {
        match arg {
            ExpressionOrSpreadElement::Expression(expr) => {
                args.push(evaluate_expression(expr, ctx)?);
            }
            ExpressionOrSpreadElement::SpreadElement(spread_expr) => {
                // Evaluate the spread expression
                let spread_value = evaluate_expression(spread_expr, ctx)?;

                // If it's an array, spread its elements into args
                if let JsValue::Object(spread_obj) = spread_value {
                    let borrowed = spread_obj.borrow();
                    let base = borrowed.as_js_object().get_object_base();

                    // Get length property if it exists
                    let length = if let Some(PropertyDescriptor::Data(prop)) =
                        base.properties.get(&PropertyKey::Str("length".to_string()))
                    {
                        match &prop.value {
                            JsValue::Number(JsNumberType::Integer(n)) => *n as usize,
                            JsValue::Number(JsNumberType::Float(n)) => *n as usize,
                            _ => 0,
                        }
                    } else {
                        0
                    };

                    // Iterate over array indices and add each element to args
                    for i in 0..length {
                        let elem_key = PropertyKey::Str(i.to_string());
                        let elem_value = if let Some(PropertyDescriptor::Data(prop)) =
                            base.properties.get(&elem_key)
                        {
                            prop.value.clone()
                        } else {
                            JsValue::Undefined
                        };
                        args.push(elem_value);
                    }
                } else if let JsValue::String(s) = spread_value {
                    // Spread string characters as separate args
                    for ch in s.chars() {
                        args.push(JsValue::String(ch.to_string()));
                    }
                } else {
                    return Err(JErrorType::TypeError(
                        "Spread requires an iterable".to_string(),
                    ));
                }
            }
        }
    }
    Ok(args)
}

/// Call a value as a function.
fn call_value(
    callee: &JsValue,
    this_value: JsValue,
    args: Vec<JsValue>,
    ctx: &mut EvalContext,
) -> ValueResult {
    match callee {
        JsValue::Object(obj) => {
            let obj_ref = obj.borrow();
            if obj_ref.is_callable() {
                drop(obj_ref);
                // For now, we'll call through our execution context stack
                // This is a simplified implementation that doesn't fully support
                // user-defined functions yet, but will work for native functions
                // stored in NativeFunctionObject
                call_function_object(obj, this_value, args, ctx)
            } else {
                Err(JErrorType::TypeError(format!(
                    "{} is not a function",
                    callee
                )))
            }
        }
        _ => Err(JErrorType::TypeError(format!(
            "{} is not a function",
            callee
        ))),
    }
}

/// Call a function object.
pub fn call_function_object(
    func: &crate::runner::ds::object::JsObjectType,
    this_value: JsValue,
    args: Vec<JsValue>,
    ctx: &mut EvalContext,
) -> ValueResult {
    let func_ref = func.borrow();

    match &*func_ref {
        ObjectType::Function(func_obj) => {
            // Get function metadata (these are Rc so cloning is cheap)
            let body = func_obj.get_function_object_base().body_code.clone();
            let params = func_obj.get_function_object_base().formal_parameters.clone();
            let func_env = func_obj.get_function_object_base().environment.clone();

            drop(func_ref);

            // Create a new function scope
            let saved_lex_env = ctx.lex_env.clone();
            let saved_var_env = ctx.var_env.clone();

            // Create new environment for the function, with the function's closure as outer
            use crate::runner::ds::env_record::new_declarative_environment;
            let func_scope = new_declarative_environment(Some(func_env));
            ctx.lex_env = func_scope.clone();
            ctx.var_env = func_scope;

            // Bind parameters to arguments
            for (i, param) in params.iter().enumerate() {
                if let crate::parser::ast::PatternType::PatternWhichCanBeExpression(
                    ExpressionPatternType::Identifier(id)
                ) = param {
                    let arg_value = args.get(i).cloned().unwrap_or(JsValue::Undefined);
                    ctx.create_binding(&id.name, false)?;
                    ctx.initialize_binding(&id.name, arg_value)?;
                }
            }

            // Execute each statement in the function body
            use super::statement::execute_statement;
            use super::types::CompletionType;

            let mut result_completion = super::types::Completion::normal();

            for stmt in body.body.iter() {
                let completion = execute_statement(stmt, ctx)?;

                match completion.completion_type {
                    CompletionType::Return => {
                        result_completion = completion;
                        break;
                    }
                    CompletionType::Throw => {
                        // Restore environment before returning error
                        ctx.lex_env = saved_lex_env;
                        ctx.var_env = saved_var_env;
                        return Err(JErrorType::TypeError(format!(
                            "Uncaught exception: {:?}",
                            completion.value
                        )));
                    }
                    CompletionType::Break | CompletionType::Continue | CompletionType::Yield => {
                        // These shouldn't escape function body
                        result_completion = completion;
                        break;
                    }
                    CompletionType::Normal => {
                        result_completion = completion;
                    }
                }
            }

            // Restore the previous environment
            ctx.lex_env = saved_lex_env;
            ctx.var_env = saved_var_env;

            // Return the result
            match result_completion.completion_type {
                CompletionType::Return => Ok(result_completion.get_value()),
                _ => Ok(JsValue::Undefined),
            }
        }
        ObjectType::Ordinary(obj) => {
            // Check if it's a SimpleFunctionObject (has marker property)
            let marker = PropertyKey::Str("__simple_function__".to_string());
            let default_ctor_marker = PropertyKey::Str("__default_constructor__".to_string());

            let generator_marker = PropertyKey::Str("__generator__".to_string());
            let generator_next_marker = PropertyKey::Str("__generator_next__".to_string());

            if obj.get_object_base().properties.contains_key(&default_ctor_marker) {
                // It's a default constructor (no-op) - just return undefined
                drop(func_ref);
                Ok(JsValue::Undefined)
            } else if let Some(PropertyDescriptor::Data(data)) = obj.get_object_base().properties.get(&generator_next_marker) {
                // It's a generator next method - call the generator's .next()
                let gen_obj = match &data.value {
                    JsValue::Object(o) => o.clone(),
                    _ => return Err(JErrorType::TypeError("Invalid generator reference".to_string())),
                };
                drop(func_ref);

                // Call the generator's next method
                let mut gen_borrowed = gen_obj.borrow_mut();

                // We need to cast to GeneratorObject
                match &mut *gen_borrowed {
                    ObjectType::Ordinary(inner_obj) => {
                        let gen_marker = PropertyKey::Str("__generator_object__".to_string());
                        if inner_obj.get_object_base().properties.contains_key(&gen_marker) {
                            // Cast to GeneratorObject
                            let gen_ptr = inner_obj.as_mut() as *mut dyn JsObject as *mut GeneratorObject;
                            drop(gen_borrowed);
                            // SAFETY: We know this is a GeneratorObject
                            unsafe {
                                let gen = &mut *gen_ptr;
                                gen.next(ctx)
                            }
                        } else {
                            Err(JErrorType::TypeError("Not a generator object".to_string()))
                        }
                    }
                    _ => Err(JErrorType::TypeError("Not a generator object".to_string())),
                }
            } else if obj.get_object_base().properties.contains_key(&generator_marker) {
                // It's a generator function - create a GeneratorObject instead of executing
                let obj_ptr = obj.as_ref() as *const dyn JsObject;
                drop(func_ref);

                // SAFETY: We know this is a SimpleFunctionObject and we've dropped func_ref
                unsafe {
                    let simple_func = &*(obj_ptr as *const SimpleFunctionObject);
                    // Create generator object from function data
                    create_generator_object(
                        simple_func.body_ptr,
                        simple_func.params_ptr,
                        simple_func.environment.clone(),
                        args,
                        ctx,
                    )
                }
            } else if obj.get_object_base().properties.contains_key(&marker) {
                // It's a SimpleFunctionObject - use the call_with_this method
                // Get a raw pointer to call call_with_this
                let obj_ptr = obj.as_ref() as *const dyn JsObject;
                drop(func_ref);

                // SAFETY: We know this is a SimpleFunctionObject and we've dropped func_ref
                unsafe {
                    // Cast to SimpleFunctionObject
                    let simple_func = &*(obj_ptr as *const SimpleFunctionObject);
                    simple_func.call_with_this(this_value, args, ctx)
                }
            } else {
                Err(JErrorType::TypeError("Object is not callable".to_string()))
            }
        }
    }
}


/// Get a property from a value, calling getters if necessary.
fn get_property_with_ctx(value: &JsValue, prop_name: &str, ctx: &mut EvalContext) -> ValueResult {
    // Use the receiver version with value as both receiver and lookup target
    get_property_with_receiver(value, value, prop_name, ctx)
}

/// Get a property, with separate receiver (for 'this') and lookup target.
/// This handles prototype chain lookups where 'this' should be the original receiver.
fn get_property_with_receiver(
    receiver: &JsValue,
    lookup_target: &JsValue,
    prop_name: &str,
    ctx: &mut EvalContext,
) -> ValueResult {
    match lookup_target {
        JsValue::Object(obj) => {
            // Check if this is a generator object and we're accessing 'next'
            let is_gen_obj = {
                let obj_ref = obj.borrow();
                let marker = PropertyKey::Str("__generator_object__".to_string());
                obj_ref.as_js_object().get_object_base().properties.contains_key(&marker)
            };

            if is_gen_obj && prop_name == "next" {
                // Return a special "next" method that calls the generator's next
                // We create a wrapper function that holds a reference to the generator
                return create_generator_next_method(obj.clone());
            }

            let prop_key = PropertyKey::Str(prop_name.to_string());

            // Check own property
            let desc = {
                let obj_ref = obj.borrow();
                obj_ref.as_js_object().get_own_property(&prop_key)?.cloned()
            };

            if let Some(desc) = desc {
                match desc {
                    PropertyDescriptor::Data(data) => Ok(data.value.clone()),
                    PropertyDescriptor::Accessor(accessor) => {
                        // Call the getter if it exists, with RECEIVER as 'this'
                        if let Some(getter) = accessor.get {
                            call_accessor_function(&getter, receiver.clone(), vec![], ctx)
                        } else {
                            Ok(JsValue::Undefined)
                        }
                    }
                }
            } else {
                // Check prototype chain - receiver stays the same
                let proto = obj.borrow().as_js_object().get_prototype_of();
                if let Some(proto) = proto {
                    get_property_with_receiver(receiver, &JsValue::Object(proto), prop_name, ctx)
                } else {
                    Ok(JsValue::Undefined)
                }
            }
        }
        JsValue::String(s) => {
            // String primitive property access
            if prop_name == "length" {
                Ok(JsValue::Number(JsNumberType::Integer(s.len() as i64)))
            } else if let Ok(index) = prop_name.parse::<usize>() {
                // Access character at index
                if index < s.len() {
                    Ok(JsValue::String(s.chars().nth(index).unwrap().to_string()))
                } else {
                    Ok(JsValue::Undefined)
                }
            } else {
                // Other string methods not yet supported
                Ok(JsValue::Undefined)
            }
        }
        JsValue::Undefined => {
            Err(JErrorType::TypeError("Cannot read property of undefined".to_string()))
        }
        JsValue::Null => {
            Err(JErrorType::TypeError("Cannot read property of null".to_string()))
        }
        _ => {
            // Primitive types - return undefined for now
            Ok(JsValue::Undefined)
        }
    }
}

/// Call an accessor function (getter or setter).
fn call_accessor_function(
    func: &JsObjectType,
    this_value: JsValue,
    args: Vec<JsValue>,
    ctx: &mut EvalContext,
) -> ValueResult {
    let func_ref = func.borrow();

    // Check if it's our SimpleFunctionObject (stored as Ordinary with marker)
    if let ObjectType::Ordinary(obj) = &*func_ref {
        if is_simple_function_object(obj.as_ref()) {
            // This is a SimpleFunctionObject - we need to call its method
            // Since we can't downcast easily, we use unsafe to access it
            // The object was created by create_function_object so we know it's a SimpleFunctionObject
            let simple_func = unsafe {
                // Get the raw pointer to the inner object and cast it
                let ptr = obj.as_ref() as *const dyn JsObject as *const SimpleFunctionObject;
                &*ptr
            };
            drop(func_ref);
            return simple_func.call_with_this(this_value, args, ctx);
        }

        // Regular object - try to call as function (likely will fail)
        drop(func_ref);
        call_function_object(func, this_value, args, ctx)
    } else if let ObjectType::Function(func_obj) = &*func_ref {
        // It's a full function object
        let body = func_obj.get_function_object_base().body_code.clone();
        let params = func_obj.get_function_object_base().formal_parameters.clone();
        let func_env = func_obj.get_function_object_base().environment.clone();

        drop(func_ref);

        call_function_with_body(body, params, func_env, this_value, args, ctx)
    } else {
        Err(JErrorType::TypeError("Not a function".to_string()))
    }
}

/// Call a function given its body, parameters, and environment.
fn call_function_with_body(
    body: Rc<crate::parser::ast::FunctionBodyData>,
    params: Rc<Vec<PatternType>>,
    func_env: crate::runner::ds::lex_env::JsLexEnvironmentType,
    this_value: JsValue,
    args: Vec<JsValue>,
    ctx: &mut EvalContext,
) -> ValueResult {
    use crate::runner::ds::env_record::new_declarative_environment;
    use super::statement::execute_statement;
    use super::types::CompletionType;

    // Save current environment
    let saved_lex_env = ctx.lex_env.clone();
    let saved_var_env = ctx.var_env.clone();
    let saved_this = ctx.global_this.clone();

    // Create new environment for the function, with the function's closure as outer
    let func_scope = new_declarative_environment(Some(func_env));
    ctx.lex_env = func_scope.clone();
    ctx.var_env = func_scope;
    ctx.global_this = Some(this_value);

    // Bind parameters to arguments
    for (i, param) in params.iter().enumerate() {
        if let PatternType::PatternWhichCanBeExpression(
            ExpressionPatternType::Identifier(id)
        ) = param {
            let arg_value = args.get(i).cloned().unwrap_or(JsValue::Undefined);
            ctx.create_binding(&id.name, false)?;
            ctx.initialize_binding(&id.name, arg_value)?;
        }
    }

    // Execute each statement in the function body
    let mut result_completion = super::types::Completion::normal();

    for stmt in body.body.iter() {
        let completion = execute_statement(stmt, ctx)?;

        match completion.completion_type {
            CompletionType::Return => {
                result_completion = completion;
                break;
            }
            CompletionType::Throw => {
                // Restore environment before returning error
                ctx.lex_env = saved_lex_env;
                ctx.var_env = saved_var_env;
                ctx.global_this = saved_this;
                return Err(JErrorType::TypeError(format!(
                    "Uncaught exception: {:?}",
                    completion.value
                )));
            }
            CompletionType::Break | CompletionType::Continue | CompletionType::Yield => {
                result_completion = completion;
                break;
            }
            CompletionType::Normal => {
                result_completion = completion;
            }
        }
    }

    // Restore the previous environment
    ctx.lex_env = saved_lex_env;
    ctx.var_env = saved_var_env;
    ctx.global_this = saved_this;

    // Return the result
    match result_completion.completion_type {
        CompletionType::Return => Ok(result_completion.get_value()),
        _ => Ok(JsValue::Undefined),
    }
}

/// Convert a value to a property key string.
fn to_property_key(value: &JsValue) -> String {
    to_string(value)
}

/// Evaluate an assignment expression.
fn evaluate_assignment_expression(
    operator: &AssignmentOperator,
    left: &PatternOrExpression,
    right: &ExpressionType,
    ctx: &mut EvalContext,
) -> ValueResult {
    // Check if this is a member expression assignment
    if let PatternOrExpression::Expression(expr) = left {
        if let ExpressionType::MemberExpression(member) = expr.as_ref() {
            return evaluate_member_assignment(operator, member, right, ctx);
        }
    }

    // Handle destructuring assignment patterns
    if let PatternOrExpression::Pattern(pattern) = left {
        if !matches!(
            &**pattern,
            PatternType::PatternWhichCanBeExpression(ExpressionPatternType::Identifier(_))
        ) {
            if !matches!(operator, AssignmentOperator::Equals) {
                return Err(JErrorType::TypeError(
                    "Compound assignment not supported for destructuring patterns".to_string(),
                ));
            }
            let rhs_value = evaluate_expression(right, ctx)?;
            assign_pattern(pattern, rhs_value.clone(), ctx)?;
            return Ok(rhs_value);
        }
    }

    // Get the name to assign to (simple variable assignment)
    let name = match left {
        PatternOrExpression::Pattern(pattern) => get_pattern_name(pattern)?,
        PatternOrExpression::Expression(expr) => get_expression_name(expr)?,
    };

    // Evaluate the right-hand side
    let rhs_value = evaluate_expression(right, ctx)?;

    // Compute the final value based on the operator
    let final_value = match operator {
        AssignmentOperator::Equals => rhs_value,
        AssignmentOperator::AddEquals => {
            let current = ctx.get_binding(&name)?;
            add_values(&current, &rhs_value)?
        }
        AssignmentOperator::SubtractEquals => {
            let current = ctx.get_binding(&name)?;
            subtract_values(&current, &rhs_value)?
        }
        AssignmentOperator::MultiplyEquals => {
            let current = ctx.get_binding(&name)?;
            multiply_values(&current, &rhs_value)?
        }
        AssignmentOperator::DivideEquals => {
            let current = ctx.get_binding(&name)?;
            divide_values(&current, &rhs_value)?
        }
        AssignmentOperator::ModuloEquals => {
            let current = ctx.get_binding(&name)?;
            modulo_values(&current, &rhs_value)?
        }
        AssignmentOperator::BitwiseLeftShiftEquals => {
            let current = ctx.get_binding(&name)?;
            left_shift(&current, &rhs_value)?
        }
        AssignmentOperator::BitwiseRightShiftEquals => {
            let current = ctx.get_binding(&name)?;
            right_shift(&current, &rhs_value)?
        }
        AssignmentOperator::BitwiseUnsignedRightShiftEquals => {
            let current = ctx.get_binding(&name)?;
            unsigned_right_shift(&current, &rhs_value)?
        }
        AssignmentOperator::BitwiseOrEquals => {
            let current = ctx.get_binding(&name)?;
            bitwise_or(&current, &rhs_value)?
        }
        AssignmentOperator::BitwiseAndEquals => {
            let current = ctx.get_binding(&name)?;
            bitwise_and(&current, &rhs_value)?
        }
        AssignmentOperator::BitwiseXorEquals => {
            let current = ctx.get_binding(&name)?;
            bitwise_xor(&current, &rhs_value)?
        }
    };

    // Set the binding and return the value
    ctx.set_binding(&name, final_value.clone())?;
    Ok(final_value)
}

/// Assign a value to a binding pattern (destructuring assignment).
fn assign_pattern(
    pattern: &PatternType,
    value: JsValue,
    ctx: &mut EvalContext,
) -> Result<(), JErrorType> {
    match pattern {
        PatternType::PatternWhichCanBeExpression(ExpressionPatternType::Identifier(id)) => {
            ctx.set_binding(&id.name, value)?;
            Ok(())
        }
        PatternType::ObjectPattern { properties, .. } => {
            for prop in properties {
                let prop_data = &prop.0;
                let key_name = get_assignment_property_key(prop_data, ctx)?;
                let prop_value = get_object_property_value(&value, &key_name, ctx)?;
                assign_pattern(&prop_data.value, prop_value, ctx)?;
            }
            Ok(())
        }
        PatternType::ArrayPattern { elements, .. } => {
            for (index, element) in elements.iter().enumerate() {
                if let Some(elem_pattern) = element {
                    if let PatternType::RestElement { argument, .. } = elem_pattern.as_ref() {
                        let rest_value = get_rest_elements_for_assignment(&value, index, ctx)?;
                        assign_pattern(argument, rest_value, ctx)?;
                    } else {
                        let elem_value = get_array_element_for_assignment(&value, index, ctx)?;
                        assign_pattern(elem_pattern, elem_value, ctx)?;
                    }
                }
            }
            Ok(())
        }
        PatternType::AssignmentPattern { left, right, .. } => {
            let actual_value = if matches!(value, JsValue::Undefined) {
                evaluate_expression(right, ctx)?
            } else {
                value
            };
            assign_pattern(left, actual_value, ctx)
        }
        PatternType::RestElement { argument, .. } => assign_pattern(argument, value, ctx),
    }
}

fn get_assignment_property_key(
    prop: &PropertyData<Box<PatternType>>,
    ctx: &mut EvalContext,
) -> Result<String, JErrorType> {
    if prop.computed {
        let key_value = evaluate_expression(prop.key.as_ref(), ctx)?;
        Ok(to_string(&key_value))
    } else {
        match prop.key.as_ref() {
            ExpressionType::ExpressionWhichCanBePattern(ExpressionPatternType::Identifier(id)) => {
                Ok(id.name.clone())
            }
            ExpressionType::Literal(lit_data) => match &lit_data.value {
                LiteralType::StringLiteral(s) => Ok(s.clone()),
                LiteralType::NumberLiteral(num) => {
                    use crate::parser::ast::NumberLiteralType;
                    match num {
                        NumberLiteralType::IntegerLiteral(n) => Ok(n.to_string()),
                        NumberLiteralType::FloatLiteral(n) => Ok(n.to_string()),
                    }
                }
                _ => Err(JErrorType::TypeError(
                    "Invalid property key in destructuring assignment".to_string(),
                )),
            },
            _ => Err(JErrorType::TypeError(
                "Invalid property key in destructuring assignment".to_string(),
            )),
        }
    }
}

fn get_object_property_value(
    obj: &JsValue,
    key: &str,
    ctx: &mut EvalContext,
) -> Result<JsValue, JErrorType> {
    match obj {
        JsValue::Object(_) => get_property_with_ctx(obj, key, ctx),
        _ => Err(JErrorType::TypeError(
            "Cannot destructure non-object".to_string(),
        )),
    }
}

fn get_array_element_for_assignment(
    arr: &JsValue,
    index: usize,
    ctx: &mut EvalContext,
) -> Result<JsValue, JErrorType> {
    match arr {
        JsValue::Object(_) => {
            let key = index.to_string();
            get_property_with_ctx(arr, &key, ctx)
        }
        _ => Err(JErrorType::TypeError(
            "Cannot destructure non-array".to_string(),
        )),
    }
}

fn get_rest_elements_for_assignment(
    arr: &JsValue,
    start_index: usize,
    ctx: &mut EvalContext,
) -> Result<JsValue, JErrorType> {
    use crate::runner::ds::object::{JsObject, JsObjectType, ObjectType};
    use crate::runner::ds::object_property::{PropertyDescriptor, PropertyDescriptorData, PropertyKey};
    use std::cell::RefCell;
    use std::rc::Rc;

    let length = match arr {
        JsValue::Object(_) => {
            let length_value = get_property_with_ctx(arr, "length", ctx)?;
            match length_value {
                JsValue::Number(JsNumberType::Integer(n)) => n.max(0) as usize,
                JsValue::Number(JsNumberType::Float(n)) => {
                    if n.is_nan() || n < 0.0 {
                        0
                    } else {
                        n as usize
                    }
                }
                _ => 0,
            }
        }
        _ => {
            return Err(JErrorType::TypeError(
                "Cannot use rest with non-array".to_string(),
            ))
        }
    };

    let mut rest_obj = ctx.new_tracked_object()?;
    let mut rest_index = 0;

    for i in start_index..length {
        let key = i.to_string();
        let value = get_property_with_ctx(arr, &key, ctx)?;
        rest_obj.get_object_base_mut().properties.insert(
            PropertyKey::Str(rest_index.to_string()),
            PropertyDescriptor::Data(PropertyDescriptorData {
                value,
                writable: true,
                enumerable: true,
                configurable: true,
            }),
        );
        rest_index += 1;
    }

    rest_obj.get_object_base_mut().properties.insert(
        PropertyKey::Str("length".to_string()),
        PropertyDescriptor::Data(PropertyDescriptorData {
            value: JsValue::Number(JsNumberType::Integer(rest_index as i64)),
            writable: true,
            enumerable: false,
            configurable: false,
        }),
    );

    let obj: JsObjectType = Rc::new(RefCell::new(ObjectType::Ordinary(Box::new(rest_obj))));
    Ok(JsValue::Object(obj))
}

/// Evaluate assignment to a member expression (obj.prop = value or obj[prop] = value).
fn evaluate_member_assignment(
    operator: &AssignmentOperator,
    member: &MemberExpressionType,
    right: &ExpressionType,
    ctx: &mut EvalContext,
) -> ValueResult {
    // Get the object and property key
    let (obj_value, prop_name) = match member {
        MemberExpressionType::SimpleMemberExpression { object, property, .. } => {
            let obj = evaluate_expression_or_super(object, ctx)?;
            (obj, property.name.clone())
        }
        MemberExpressionType::ComputedMemberExpression { object, property, .. } => {
            let obj = evaluate_expression_or_super(object, ctx)?;
            let prop_val = evaluate_expression(property.as_ref(), ctx)?;
            (obj, to_property_key(&prop_val))
        }
    };

    // Evaluate the right-hand side
    let rhs_value = evaluate_expression(right, ctx)?;

    // Compute the final value based on the operator
    let final_value = if matches!(operator, AssignmentOperator::Equals) {
        rhs_value
    } else {
        let current = get_property_with_ctx(&obj_value, &prop_name, ctx)?;
        match operator {
            AssignmentOperator::Equals => unreachable!(),
            AssignmentOperator::AddEquals => add_values(&current, &rhs_value)?,
            AssignmentOperator::SubtractEquals => subtract_values(&current, &rhs_value)?,
            AssignmentOperator::MultiplyEquals => multiply_values(&current, &rhs_value)?,
            AssignmentOperator::DivideEquals => divide_values(&current, &rhs_value)?,
            AssignmentOperator::ModuloEquals => modulo_values(&current, &rhs_value)?,
            AssignmentOperator::BitwiseLeftShiftEquals => left_shift(&current, &rhs_value)?,
            AssignmentOperator::BitwiseRightShiftEquals => right_shift(&current, &rhs_value)?,
            AssignmentOperator::BitwiseUnsignedRightShiftEquals => unsigned_right_shift(&current, &rhs_value)?,
            AssignmentOperator::BitwiseOrEquals => bitwise_or(&current, &rhs_value)?,
            AssignmentOperator::BitwiseAndEquals => bitwise_and(&current, &rhs_value)?,
            AssignmentOperator::BitwiseXorEquals => bitwise_xor(&current, &rhs_value)?,
        }
    };

    // Set the property (with setter support)
    set_property_with_ctx(&obj_value, &prop_name, final_value.clone(), ctx)?;
    Ok(final_value)
}

/// Set a property on an object, calling setters if necessary.
fn set_property_with_ctx(
    value: &JsValue,
    prop_name: &str,
    new_value: JsValue,
    ctx: &mut EvalContext,
) -> Result<(), JErrorType> {
    match value {
        JsValue::Object(obj) => {
            let prop_key = PropertyKey::Str(prop_name.to_string());

            // Check for accessor property (setter)
            let desc = {
                let obj_ref = obj.borrow();
                obj_ref.as_js_object().get_own_property(&prop_key)?.cloned()
            };

            if let Some(PropertyDescriptor::Accessor(accessor)) = desc {
                // Call the setter if it exists
                if let Some(setter) = accessor.set {
                    call_accessor_function(&setter, value.clone(), vec![new_value], ctx)?;
                    return Ok(());
                }
                // No setter - fall through to data property behavior
            }

            // Set as data property
            let mut obj_mut = obj.borrow_mut();
            obj_mut.as_js_object_mut().get_object_base_mut().properties.insert(
                prop_key,
                PropertyDescriptor::Data(PropertyDescriptorData {
                    value: new_value,
                    writable: true,
                    enumerable: true,
                    configurable: true,
                }),
            );
            Ok(())
        }
        _ => Err(JErrorType::TypeError("Cannot set property on non-object".to_string())),
    }
}

/// Get the name from a pattern (for simple identifier patterns).
fn get_pattern_name(pattern: &PatternType) -> Result<String, JErrorType> {
    match pattern {
        PatternType::PatternWhichCanBeExpression(ExpressionPatternType::Identifier(id)) => {
            Ok(id.name.clone())
        }
        _ => Err(JErrorType::TypeError(
            "Complex patterns in assignment not yet supported".to_string(),
        )),
    }
}

/// Get the name from an expression (for simple identifier expressions).
fn get_expression_name(expr: &ExpressionType) -> Result<String, JErrorType> {
    match expr {
        ExpressionType::ExpressionWhichCanBePattern(ExpressionPatternType::Identifier(id)) => {
            Ok(id.name.clone())
        }
        _ => Err(JErrorType::TypeError(
            "Assignment to non-identifier expressions not yet supported".to_string(),
        )),
    }
}

/// Evaluate a unary expression.
fn evaluate_unary_expression(
    operator: &UnaryOperator,
    argument: &ExpressionType,
    ctx: &mut EvalContext,
) -> ValueResult {
    match operator {
        UnaryOperator::TypeOf => {
            let value = evaluate_expression(argument, ctx).unwrap_or(JsValue::Undefined);
            Ok(JsValue::String(get_typeof_string(&value)))
        }
        UnaryOperator::Void => {
            let _ = evaluate_expression(argument, ctx)?;
            Ok(JsValue::Undefined)
        }
        UnaryOperator::LogicalNot => {
            let value = evaluate_expression(argument, ctx)?;
            Ok(JsValue::Boolean(!to_boolean(&value)))
        }
        UnaryOperator::Minus => {
            let value = evaluate_expression(argument, ctx)?;
            negate_number(&value)
        }
        UnaryOperator::Plus => {
            let value = evaluate_expression(argument, ctx)?;
            to_number(&value)
        }
        UnaryOperator::BitwiseNot => {
            let value = evaluate_expression(argument, ctx)?;
            bitwise_not(&value)
        }
        UnaryOperator::Delete => {
            match argument {
                ExpressionType::MemberExpression(member) => {
                    match member {
                        MemberExpressionType::SimpleMemberExpression { object, property, .. } => {
                            let obj_value = evaluate_expression_or_super(object, ctx)?;
                            match obj_value {
                                JsValue::Object(obj) => {
                                    let prop_key = PropertyKey::Str(property.name.clone());
                                    let result = obj.borrow_mut().as_js_object_mut().delete(&prop_key)?;
                                    Ok(JsValue::Boolean(result))
                                }
                                _ => Ok(JsValue::Boolean(true))
                            }
                        }
                        MemberExpressionType::ComputedMemberExpression { object, property, .. } => {
                            let obj_value = evaluate_expression_or_super(object, ctx)?;
                            let prop_value = evaluate_expression(property.as_ref(), ctx)?;
                            let prop_name = to_property_key(&prop_value);
                            match obj_value {
                                JsValue::Object(obj) => {
                                    let prop_key = PropertyKey::Str(prop_name);
                                    let result = obj.borrow_mut().as_js_object_mut().delete(&prop_key)?;
                                    Ok(JsValue::Boolean(result))
                                }
                                _ => Ok(JsValue::Boolean(true))
                            }
                        }
                    }
                }
                _ => {
                    // Non-member: evaluate for side effects, return true
                    let _ = evaluate_expression(argument, ctx)?;
                    Ok(JsValue::Boolean(true))
                }
            }
        }
    }
}

/// Evaluate a binary expression.
fn evaluate_binary_expression(
    operator: &BinaryOperator,
    left: &ExpressionType,
    right: &ExpressionType,
    ctx: &mut EvalContext,
) -> ValueResult {
    let left_val = evaluate_expression(left, ctx)?;
    let right_val = evaluate_expression(right, ctx)?;

    match operator {
        // Arithmetic
        BinaryOperator::Add => add_values(&left_val, &right_val),
        BinaryOperator::Subtract => subtract_values(&left_val, &right_val),
        BinaryOperator::Multiply => multiply_values(&left_val, &right_val),
        BinaryOperator::Divide => divide_values(&left_val, &right_val),
        BinaryOperator::Modulo => modulo_values(&left_val, &right_val),

        // Comparison
        BinaryOperator::LessThan => compare_values(&left_val, &right_val, |a, b| a < b),
        BinaryOperator::GreaterThan => compare_values(&left_val, &right_val, |a, b| a > b),
        BinaryOperator::LessThanEqual => compare_values(&left_val, &right_val, |a, b| a <= b),
        BinaryOperator::GreaterThanEqual => compare_values(&left_val, &right_val, |a, b| a >= b),

        // Equality
        BinaryOperator::StrictlyEqual => Ok(JsValue::Boolean(strict_equality(&left_val, &right_val))),
        BinaryOperator::StrictlyUnequal => Ok(JsValue::Boolean(!strict_equality(&left_val, &right_val))),
        BinaryOperator::LooselyEqual => Ok(JsValue::Boolean(loose_equality(&left_val, &right_val))),
        BinaryOperator::LooselyUnequal => Ok(JsValue::Boolean(!loose_equality(&left_val, &right_val))),

        // Bitwise
        BinaryOperator::BitwiseAnd => bitwise_and(&left_val, &right_val),
        BinaryOperator::BitwiseOr => bitwise_or(&left_val, &right_val),
        BinaryOperator::BitwiseXor => bitwise_xor(&left_val, &right_val),
        BinaryOperator::BitwiseLeftShift => left_shift(&left_val, &right_val),
        BinaryOperator::BitwiseRightShift => right_shift(&left_val, &right_val),
        BinaryOperator::BitwiseUnsignedRightShift => unsigned_right_shift(&left_val, &right_val),

        // Other
        BinaryOperator::InstanceOf => {
            // Left must be an object for instanceof to potentially return true
            let left_obj = match &left_val {
                JsValue::Object(obj) => obj.clone(),
                _ => return Ok(JsValue::Boolean(false)),
            };

            // Right must be an object (constructor function) with a prototype property
            let right_obj = match &right_val {
                JsValue::Object(obj) => obj.clone(),
                _ => return Err(JErrorType::TypeError("Right-hand side of 'instanceof' is not an object".to_string())),
            };

            // Get the prototype property from the right-hand side (constructor.prototype)
            let proto_key = PropertyKey::Str("prototype".to_string());
            let right_prototype = {
                let right_borrowed = right_obj.borrow();
                if let Some(desc) = right_borrowed.as_js_object().get_own_property(&proto_key)? {
                    match desc {
                        PropertyDescriptor::Data(data) => {
                            match &data.value {
                                JsValue::Object(p) => Some(p.clone()),
                                _ => None,
                            }
                        }
                        _ => None,
                    }
                } else {
                    None
                }
            };

            // If right.prototype is not an object, return false
            let target_proto = match right_prototype {
                Some(p) => p,
                None => return Ok(JsValue::Boolean(false)),
            };

            // Walk the prototype chain of left
            let mut current_proto = left_obj.borrow().as_js_object().get_prototype_of();

            while let Some(proto) = current_proto {
                // Compare by reference
                if Rc::ptr_eq(&proto, &target_proto) {
                    return Ok(JsValue::Boolean(true));
                }
                current_proto = proto.borrow().as_js_object().get_prototype_of();
            }

            Ok(JsValue::Boolean(false))
        }
        BinaryOperator::In => {
            let prop_key = PropertyKey::Str(to_property_key(&left_val));
            match &right_val {
                JsValue::Object(obj) => {
                    let has = obj.borrow().as_js_object().has_property(&prop_key);
                    Ok(JsValue::Boolean(has))
                }
                _ => Err(JErrorType::TypeError("Cannot use 'in' operator with non-object".to_string()))
            }
        }
    }
}

/// Evaluate a logical expression with short-circuit evaluation.
fn evaluate_logical_expression(
    operator: &LogicalOperator,
    left: &ExpressionType,
    right: &ExpressionType,
    ctx: &mut EvalContext,
) -> ValueResult {
    let left_val = evaluate_expression(left, ctx)?;

    match operator {
        LogicalOperator::And => {
            if !to_boolean(&left_val) {
                Ok(left_val)
            } else {
                evaluate_expression(right, ctx)
            }
        }
        LogicalOperator::Or => {
            if to_boolean(&left_val) {
                Ok(left_val)
            } else {
                evaluate_expression(right, ctx)
            }
        }
    }
}

/// Evaluate a conditional (ternary) expression.
fn evaluate_conditional_expression(
    test: &ExpressionType,
    consequent: &ExpressionType,
    alternate: &ExpressionType,
    ctx: &mut EvalContext,
) -> ValueResult {
    let test_val = evaluate_expression(test, ctx)?;

    if to_boolean(&test_val) {
        evaluate_expression(consequent, ctx)
    } else {
        evaluate_expression(alternate, ctx)
    }
}

/// Evaluate a sequence expression.
fn evaluate_sequence_expression(
    expressions: &[Box<ExpressionType>],
    ctx: &mut EvalContext,
) -> ValueResult {
    let mut result = JsValue::Undefined;
    for expr in expressions {
        result = evaluate_expression(expr.as_ref(), ctx)?;
    }
    Ok(result)
}

/// Evaluate an update expression (++x, x++, --x, x--).
fn evaluate_update_expression(
    operator: &UpdateOperator,
    argument: &ExpressionType,
    prefix: bool,
    ctx: &mut EvalContext,
) -> ValueResult {
    // Get the variable name from the argument
    let name = get_expression_name(argument)?;

    // Get the current value
    let current_value = ctx.get_binding(&name)?;

    // Convert to number
    let old_number = to_number(&current_value)?;
    let old_f64 = match &old_number {
        JsValue::Number(n) => number_to_f64(n),
        _ => f64::NAN,
    };

    // Compute the new value based on operator
    let new_f64 = match operator {
        UpdateOperator::PlusPlus => old_f64 + 1.0,
        UpdateOperator::MinusMinus => old_f64 - 1.0,
    };

    // Create the new JsValue
    let new_value = if new_f64.fract() == 0.0 && new_f64.abs() < i64::MAX as f64 {
        JsValue::Number(JsNumberType::Integer(new_f64 as i64))
    } else {
        JsValue::Number(JsNumberType::Float(new_f64))
    };

    // Store the new value
    ctx.set_binding(&name, new_value.clone())?;

    // Return old value for postfix, new value for prefix
    if prefix {
        Ok(new_value)
    } else {
        Ok(old_number)
    }
}

// ============================================================================
// Type conversion helpers
// ============================================================================

/// Convert a value to boolean.
pub fn to_boolean(value: &JsValue) -> bool {
    match value {
        JsValue::Undefined => false,
        JsValue::Null => false,
        JsValue::Boolean(b) => *b,
        JsValue::Number(n) => match n {
            JsNumberType::Integer(0) => false,
            JsNumberType::Float(f) if *f == 0.0 || f.is_nan() => false,
            JsNumberType::NaN => false,
            _ => true,
        },
        JsValue::String(s) => !s.is_empty(),
        JsValue::Symbol(_) => true,
        JsValue::Object(_) => true,
    }
}

/// Get the typeof string for a value.
fn get_typeof_string(value: &JsValue) -> String {
    match value {
        JsValue::Undefined => "undefined".to_string(),
        JsValue::Null => "object".to_string(),
        JsValue::Boolean(_) => "boolean".to_string(),
        JsValue::Number(_) => "number".to_string(),
        JsValue::String(_) => "string".to_string(),
        JsValue::Symbol(_) => "symbol".to_string(),
        JsValue::Object(_) => "object".to_string(),
    }
}

/// Convert a value to a number.
fn to_number(value: &JsValue) -> ValueResult {
    Ok(match value {
        JsValue::Undefined => JsValue::Number(JsNumberType::NaN),
        JsValue::Null => JsValue::Number(JsNumberType::Integer(0)),
        JsValue::Boolean(true) => JsValue::Number(JsNumberType::Integer(1)),
        JsValue::Boolean(false) => JsValue::Number(JsNumberType::Integer(0)),
        JsValue::Number(n) => JsValue::Number(n.clone()),
        JsValue::String(s) => {
            if s.is_empty() {
                JsValue::Number(JsNumberType::Integer(0))
            } else if let Ok(i) = s.trim().parse::<i64>() {
                JsValue::Number(JsNumberType::Integer(i))
            } else if let Ok(f) = s.trim().parse::<f64>() {
                JsValue::Number(JsNumberType::Float(f))
            } else {
                JsValue::Number(JsNumberType::NaN)
            }
        }
        JsValue::Symbol(_) => {
            return Err(JErrorType::TypeError("Cannot convert Symbol to number".to_string()));
        }
        JsValue::Object(_) => JsValue::Number(JsNumberType::NaN),
    })
}

/// Negate a number value.
fn negate_number(value: &JsValue) -> ValueResult {
    let num_value = to_number(value)?;
    Ok(match num_value {
        JsValue::Number(JsNumberType::Integer(i)) => JsValue::Number(JsNumberType::Integer(-i)),
        JsValue::Number(JsNumberType::Float(f)) => JsValue::Number(JsNumberType::Float(-f)),
        JsValue::Number(JsNumberType::PositiveInfinity) => JsValue::Number(JsNumberType::NegativeInfinity),
        JsValue::Number(JsNumberType::NegativeInfinity) => JsValue::Number(JsNumberType::PositiveInfinity),
        JsValue::Number(JsNumberType::NaN) => JsValue::Number(JsNumberType::NaN),
        _ => JsValue::Number(JsNumberType::NaN),
    })
}

/// Bitwise NOT operation.
fn bitwise_not(value: &JsValue) -> ValueResult {
    let num = to_i32(value)?;
    Ok(JsValue::Number(JsNumberType::Integer(!num as i64)))
}

/// Convert to i32 for bitwise operations.
fn to_i32(value: &JsValue) -> Result<i32, JErrorType> {
    match to_number(value)? {
        JsValue::Number(JsNumberType::Integer(i)) => Ok(i as i32),
        JsValue::Number(JsNumberType::Float(f)) => Ok(f as i32),
        JsValue::Number(JsNumberType::NaN) => Ok(0),
        JsValue::Number(JsNumberType::PositiveInfinity) => Ok(0),
        JsValue::Number(JsNumberType::NegativeInfinity) => Ok(0),
        _ => Ok(0),
    }
}

/// Convert to u32 for unsigned bitwise operations.
fn to_u32(value: &JsValue) -> Result<u32, JErrorType> {
    Ok(to_i32(value)? as u32)
}

// ============================================================================
// Arithmetic operations
// ============================================================================

fn add_values(left: &JsValue, right: &JsValue) -> ValueResult {
    if matches!(left, JsValue::String(_)) || matches!(right, JsValue::String(_)) {
        let left_str = to_string(left);
        let right_str = to_string(right);
        return Ok(JsValue::String(format!("{}{}", left_str, right_str)));
    }

    let left_num = to_number(left)?;
    let right_num = to_number(right)?;
    apply_numeric_op(&left_num, &right_num, |a, b| a + b, |a, b| a + b)
}

fn subtract_values(left: &JsValue, right: &JsValue) -> ValueResult {
    let left_num = to_number(left)?;
    let right_num = to_number(right)?;
    apply_numeric_op(&left_num, &right_num, |a, b| a - b, |a, b| a - b)
}

fn multiply_values(left: &JsValue, right: &JsValue) -> ValueResult {
    let left_num = to_number(left)?;
    let right_num = to_number(right)?;
    apply_numeric_op(&left_num, &right_num, |a, b| a * b, |a, b| a * b)
}

fn divide_values(left: &JsValue, right: &JsValue) -> ValueResult {
    let left_num = to_number(left)?;
    let right_num = to_number(right)?;

    if matches!(right_num, JsValue::Number(JsNumberType::Integer(0)))
        || matches!(right_num, JsValue::Number(JsNumberType::Float(f)) if f == 0.0)
    {
        let left_f = match &left_num {
            JsValue::Number(n) => number_to_f64(n),
            _ => f64::NAN,
        };
        return Ok(if left_f.is_nan() || left_f == 0.0 {
            JsValue::Number(JsNumberType::NaN)
        } else if left_f > 0.0 {
            JsValue::Number(JsNumberType::PositiveInfinity)
        } else {
            JsValue::Number(JsNumberType::NegativeInfinity)
        });
    }

    apply_numeric_op(&left_num, &right_num, |a, b| a / b, |a, b| a / b)
}

fn modulo_values(left: &JsValue, right: &JsValue) -> ValueResult {
    let left_num = to_number(left)?;
    let right_num = to_number(right)?;
    apply_numeric_op(&left_num, &right_num, |a, b| a % b, |a, b| a % b)
}

fn apply_numeric_op<F, G>(left: &JsValue, right: &JsValue, int_op: F, float_op: G) -> ValueResult
where
    F: Fn(i64, i64) -> i64,
    G: Fn(f64, f64) -> f64,
{
    match (left, right) {
        (JsValue::Number(JsNumberType::NaN), _) | (_, JsValue::Number(JsNumberType::NaN)) => {
            Ok(JsValue::Number(JsNumberType::NaN))
        }
        (JsValue::Number(JsNumberType::Integer(a)), JsValue::Number(JsNumberType::Integer(b))) => {
            Ok(JsValue::Number(JsNumberType::Integer(int_op(*a, *b))))
        }
        (JsValue::Number(a), JsValue::Number(b)) => {
            let a_f64 = number_to_f64(a);
            let b_f64 = number_to_f64(b);
            Ok(JsValue::Number(JsNumberType::Float(float_op(a_f64, b_f64))))
        }
        _ => Ok(JsValue::Number(JsNumberType::NaN)),
    }
}

fn number_to_f64(n: &JsNumberType) -> f64 {
    match n {
        JsNumberType::Integer(i) => *i as f64,
        JsNumberType::Float(f) => *f,
        JsNumberType::NaN => f64::NAN,
        JsNumberType::PositiveInfinity => f64::INFINITY,
        JsNumberType::NegativeInfinity => f64::NEG_INFINITY,
    }
}

// ============================================================================
// Comparison operations
// ============================================================================

fn compare_values<F>(left: &JsValue, right: &JsValue, cmp: F) -> ValueResult
where
    F: Fn(f64, f64) -> bool,
{
    let left_num = to_number(left)?;
    let right_num = to_number(right)?;

    let result = match (&left_num, &right_num) {
        (JsValue::Number(JsNumberType::NaN), _) | (_, JsValue::Number(JsNumberType::NaN)) => false,
        (JsValue::Number(a), JsValue::Number(b)) => {
            cmp(number_to_f64(a), number_to_f64(b))
        }
        _ => false,
    };

    Ok(JsValue::Boolean(result))
}

pub fn strict_equality(left: &JsValue, right: &JsValue) -> bool {
    match (left, right) {
        (JsValue::Undefined, JsValue::Undefined) => true,
        (JsValue::Null, JsValue::Null) => true,
        (JsValue::Boolean(a), JsValue::Boolean(b)) => a == b,
        (JsValue::String(a), JsValue::String(b)) => a == b,
        (JsValue::Number(JsNumberType::NaN), _) | (_, JsValue::Number(JsNumberType::NaN)) => false,
        (JsValue::Number(a), JsValue::Number(b)) => {
            number_to_f64(a) == number_to_f64(b)
        }
        (JsValue::Object(a), JsValue::Object(b)) => std::rc::Rc::ptr_eq(a, b),
        _ => false,
    }
}

fn loose_equality(left: &JsValue, right: &JsValue) -> bool {
    if std::mem::discriminant(left) == std::mem::discriminant(right) {
        return strict_equality(left, right);
    }

    match (left, right) {
        (JsValue::Null, JsValue::Undefined) | (JsValue::Undefined, JsValue::Null) => true,
        (JsValue::Number(_), JsValue::String(_)) => {
            if let Ok(r) = to_number(right) {
                strict_equality(left, &r)
            } else {
                false
            }
        }
        (JsValue::String(_), JsValue::Number(_)) => {
            if let Ok(l) = to_number(left) {
                strict_equality(&l, right)
            } else {
                false
            }
        }
        (JsValue::Boolean(_), _) => {
            if let Ok(l) = to_number(left) {
                loose_equality(&l, right)
            } else {
                false
            }
        }
        (_, JsValue::Boolean(_)) => {
            if let Ok(r) = to_number(right) {
                loose_equality(left, &r)
            } else {
                false
            }
        }
        _ => false,
    }
}

// ============================================================================
// Bitwise operations
// ============================================================================

fn bitwise_and(left: &JsValue, right: &JsValue) -> ValueResult {
    let l = to_i32(left)?;
    let r = to_i32(right)?;
    Ok(JsValue::Number(JsNumberType::Integer((l & r) as i64)))
}

fn bitwise_or(left: &JsValue, right: &JsValue) -> ValueResult {
    let l = to_i32(left)?;
    let r = to_i32(right)?;
    Ok(JsValue::Number(JsNumberType::Integer((l | r) as i64)))
}

fn bitwise_xor(left: &JsValue, right: &JsValue) -> ValueResult {
    let l = to_i32(left)?;
    let r = to_i32(right)?;
    Ok(JsValue::Number(JsNumberType::Integer((l ^ r) as i64)))
}

fn left_shift(left: &JsValue, right: &JsValue) -> ValueResult {
    let l = to_i32(left)?;
    let r = to_u32(right)? & 0x1f;
    Ok(JsValue::Number(JsNumberType::Integer((l << r) as i64)))
}

fn right_shift(left: &JsValue, right: &JsValue) -> ValueResult {
    let l = to_i32(left)?;
    let r = to_u32(right)? & 0x1f;
    Ok(JsValue::Number(JsNumberType::Integer((l >> r) as i64)))
}

fn unsigned_right_shift(left: &JsValue, right: &JsValue) -> ValueResult {
    let l = to_u32(left)?;
    let r = to_u32(right)? & 0x1f;
    Ok(JsValue::Number(JsNumberType::Integer((l >> r) as i64)))
}

// ============================================================================
// String conversion
// ============================================================================

fn to_string(value: &JsValue) -> String {
    match value {
        JsValue::Undefined => "undefined".to_string(),
        JsValue::Null => "null".to_string(),
        JsValue::Boolean(true) => "true".to_string(),
        JsValue::Boolean(false) => "false".to_string(),
        JsValue::Number(n) => n.to_string(),
        JsValue::String(s) => s.clone(),
        JsValue::Symbol(_) => "[Symbol]".to_string(),
        JsValue::Object(_) => "[object Object]".to_string(),
    }
}

// ============================================================================
// Function object creation
// ============================================================================

/// Simple function object that stores function metadata for evaluation.
/// Instead of storing AST data directly, we store references to the source AST.
pub struct SimpleFunctionObject {
    base: ObjectBase,
    /// Pointer to the function body (using raw pointer for simplicity)
    body_ptr: *const crate::parser::ast::FunctionBodyData,
    /// Pointer to the formal parameters
    params_ptr: *const Vec<PatternType>,
    /// The lexical environment at the time the function was created
    environment: crate::runner::ds::lex_env::JsLexEnvironmentType,
}

// Safety: SimpleFunctionObject is only used within a single thread
unsafe impl Send for SimpleFunctionObject {}
unsafe impl Sync for SimpleFunctionObject {}

impl SimpleFunctionObject {
    pub fn new(
        body_ptr: *const crate::parser::ast::FunctionBodyData,
        params_ptr: *const Vec<PatternType>,
        environment: crate::runner::ds::lex_env::JsLexEnvironmentType,
    ) -> Self {
        SimpleFunctionObject {
            base: ObjectBase::new(),
            body_ptr,
            params_ptr,
            environment,
        }
    }

    /// Call this function with the given this value and arguments.
    /// Safety: The AST pointers must still be valid.
    pub fn call_with_this(
        &self,
        this_value: JsValue,
        args: Vec<JsValue>,
        ctx: &mut EvalContext,
    ) -> ValueResult {
        use crate::runner::ds::env_record::new_declarative_environment;
        use super::statement::execute_statement;
        use super::types::CompletionType;

        // Get the body and params (unsafe dereference)
        let (body, params) = unsafe {
            (&*self.body_ptr, &*self.params_ptr)
        };

        // Save current environment
        let saved_lex_env = ctx.lex_env.clone();
        let saved_var_env = ctx.var_env.clone();
        let saved_this = ctx.global_this.clone();

        // Create new environment for the function, with the function's closure as outer
        let func_scope = new_declarative_environment(Some(self.environment.clone()));
        ctx.lex_env = func_scope.clone();
        ctx.var_env = func_scope;
        ctx.global_this = Some(this_value);

        // Bind parameters to arguments
        for (i, param) in params.iter().enumerate() {
            if let PatternType::PatternWhichCanBeExpression(
                ExpressionPatternType::Identifier(id)
            ) = param {
                let arg_value = args.get(i).cloned().unwrap_or(JsValue::Undefined);
                ctx.create_binding(&id.name, false)?;
                ctx.initialize_binding(&id.name, arg_value)?;
            }
        }

        // Execute each statement in the function body
        let mut result_completion = super::types::Completion::normal();

        for stmt in body.body.iter() {
            let completion = execute_statement(stmt, ctx)?;

            match completion.completion_type {
                CompletionType::Return => {
                    result_completion = completion;
                    break;
                }
                CompletionType::Throw => {
                    // Restore environment before returning error
                    ctx.lex_env = saved_lex_env;
                    ctx.var_env = saved_var_env;
                    ctx.global_this = saved_this;
                    return Err(JErrorType::TypeError(format!(
                        "Uncaught exception: {:?}",
                        completion.value
                    )));
                }
                CompletionType::Break | CompletionType::Continue | CompletionType::Yield => {
                    result_completion = completion;
                    break;
                }
                CompletionType::Normal => {
                    result_completion = completion;
                }
            }
        }

        // Restore the previous environment
        ctx.lex_env = saved_lex_env;
        ctx.var_env = saved_var_env;
        ctx.global_this = saved_this;

        // Return the result
        match result_completion.completion_type {
            CompletionType::Return => Ok(result_completion.get_value()),
            _ => Ok(JsValue::Undefined),
        }
    }
}

impl JsObject for SimpleFunctionObject {
    fn get_object_base_mut(&mut self) -> &mut ObjectBase {
        &mut self.base
    }

    fn get_object_base(&self) -> &ObjectBase {
        &self.base
    }

    fn as_js_object(&self) -> &dyn JsObject {
        self
    }

    fn as_js_object_mut(&mut self) -> &mut dyn JsObject {
        self
    }
}

/// Type ID for SimpleFunctionObject - used for downcasting
pub fn is_simple_function_object(obj: &dyn JsObject) -> bool {
    // Check if the object has a special marker property
    let marker = PropertyKey::Str("__simple_function__".to_string());
    obj.get_object_base().properties.contains_key(&marker)
}

/// Create a function object from FunctionData.
/// Note: This creates a closure that references the AST. The AST must remain valid
/// for the lifetime of the function object.
pub fn create_function_object(func_data: &FunctionData, ctx: &EvalContext) -> ValueResult {
    let body_ptr = func_data.body.as_ref() as *const _;
    let params_ptr = &func_data.params.list as *const _;
    let environment = ctx.lex_env.clone();

    let mut func_obj = SimpleFunctionObject::new(body_ptr, params_ptr, environment);

    // Create a prototype object for this function
    let prototype = SimpleObject::new();
    let prototype_ref: JsObjectType = Rc::new(RefCell::new(ObjectType::Ordinary(Box::new(prototype))));

    // Store prototype on the function object
    func_obj.base.properties.insert(
        PropertyKey::Str("prototype".to_string()),
        PropertyDescriptor::Data(PropertyDescriptorData {
            value: JsValue::Object(prototype_ref),
            writable: true,
            enumerable: false,
            configurable: false,
        }),
    );

    // Add marker property to identify this as a SimpleFunctionObject
    func_obj.base.properties.insert(
        PropertyKey::Str("__simple_function__".to_string()),
        PropertyDescriptor::Data(PropertyDescriptorData {
            value: JsValue::Boolean(true),
            writable: false,
            enumerable: false,
            configurable: false,
        }),
    );

    // Mark as generator if applicable
    if func_data.generator {
        func_obj.base.properties.insert(
            PropertyKey::Str("__generator__".to_string()),
            PropertyDescriptor::Data(PropertyDescriptorData {
                value: JsValue::Boolean(true),
                writable: false,
                enumerable: false,
                configurable: false,
            }),
        );
    }

    let obj_ref: JsObjectType = Rc::new(RefCell::new(ObjectType::Ordinary(Box::new(func_obj))));
    Ok(JsValue::Object(obj_ref))
}

// ============================================================================
// Generator object
// ============================================================================

/// Generator state.
#[derive(Debug, Clone, PartialEq)]
pub enum GeneratorState {
    SuspendedStart,
    SuspendedYield,
    Executing,
    Completed,
}

/// Generator object that stores the suspended state of a generator function.
pub struct GeneratorObject {
    base: ObjectBase,
    /// Pointer to the function body
    body_ptr: *const crate::parser::ast::FunctionBodyData,
    /// Pointer to the formal parameters
    _params_ptr: *const Vec<PatternType>,
    /// The lexical environment at the time the generator was created
    environment: crate::runner::ds::lex_env::JsLexEnvironmentType,
    /// Current state
    state: GeneratorState,
    /// Current statement index (for resuming)
    current_index: usize,
    /// Stored local bindings (for resuming)
    local_bindings: std::collections::HashMap<String, JsValue>,
}

// Safety: GeneratorObject is only used within a single thread
unsafe impl Send for GeneratorObject {}
unsafe impl Sync for GeneratorObject {}

impl GeneratorObject {
    pub fn new(
        body_ptr: *const crate::parser::ast::FunctionBodyData,
        params_ptr: *const Vec<PatternType>,
        environment: crate::runner::ds::lex_env::JsLexEnvironmentType,
    ) -> Self {
        GeneratorObject {
            base: ObjectBase::new(),
            body_ptr,
            _params_ptr: params_ptr,
            environment,
            state: GeneratorState::SuspendedStart,
            current_index: 0,
            local_bindings: std::collections::HashMap::new(),
        }
    }

    /// Call .next() on this generator, executing until yield or completion.
    pub fn next(&mut self, ctx: &mut EvalContext) -> ValueResult {
        use crate::runner::ds::env_record::new_declarative_environment;
        use super::statement::execute_statement;
        use super::types::CompletionType;

        match self.state {
            GeneratorState::Completed => {
                // Return { value: undefined, done: true }
                return create_iterator_result(JsValue::Undefined, true);
            }
            GeneratorState::Executing => {
                return Err(JErrorType::TypeError("Generator is already executing".to_string()));
            }
            GeneratorState::SuspendedStart | GeneratorState::SuspendedYield => {
                // Continue or start execution
            }
        }

        self.state = GeneratorState::Executing;

        // Get the body and params (unsafe dereference)
        let body = unsafe { &*self.body_ptr };

        // Save current environment
        let saved_lex_env = ctx.lex_env.clone();
        let saved_var_env = ctx.var_env.clone();

        // Create new environment for the generator (or restore previous)
        let func_scope = new_declarative_environment(Some(self.environment.clone()));
        ctx.lex_env = func_scope.clone();
        ctx.var_env = func_scope;

        // Restore local bindings if resuming
        for (name, value) in &self.local_bindings {
            let _ = ctx.create_binding(name, false);
            let _ = ctx.initialize_binding(name, value.clone());
        }

        // Execute statements starting from current_index
        let mut result_value = JsValue::Undefined;
        let mut yielded = false;

        for (idx, stmt) in body.body.iter().enumerate() {
            if idx < self.current_index {
                continue; // Skip already executed statements
            }

            match execute_statement(stmt, ctx) {
                Ok(completion) => {
                    match completion.completion_type {
                        CompletionType::Return => {
                            result_value = completion.get_value();
                            self.state = GeneratorState::Completed;
                            break;
                        }
                        CompletionType::Yield => {
                            // Yield the value and suspend
                            result_value = completion.get_value();
                            self.current_index = idx + 1;
                            self.state = GeneratorState::SuspendedYield;

                            // Save current bindings
                            self.save_bindings(ctx);

                            yielded = true;
                            break;
                        }
                        CompletionType::Throw => {
                            ctx.lex_env = saved_lex_env;
                            ctx.var_env = saved_var_env;
                            self.state = GeneratorState::Completed;
                            return Err(JErrorType::TypeError(format!(
                                "Uncaught exception: {:?}",
                                completion.value
                            )));
                        }
                        _ => {
                            result_value = completion.get_value();
                        }
                    }
                }
                Err(JErrorType::YieldValue(value)) => {
                    // Yield expression hit
                    result_value = value;
                    self.current_index = idx + 1;
                    self.state = GeneratorState::SuspendedYield;

                    // Save current bindings
                    self.save_bindings(ctx);

                    yielded = true;
                    break;
                }
                Err(e) => {
                    ctx.lex_env = saved_lex_env;
                    ctx.var_env = saved_var_env;
                    self.state = GeneratorState::Completed;
                    return Err(e);
                }
            }
        }

        // If we didn't yield, we're done
        if !yielded && self.state == GeneratorState::Executing {
            self.state = GeneratorState::Completed;
        }

        // Restore the previous environment
        ctx.lex_env = saved_lex_env;
        ctx.var_env = saved_var_env;

        // Return { value, done }
        let done = self.state == GeneratorState::Completed;
        create_iterator_result(result_value, done)
    }

    fn save_bindings(&mut self, ctx: &EvalContext) {
        // This is a simplified version - in a full implementation we'd need
        // to properly capture all bindings from the current scope
        self.local_bindings.clear();

        // Get bindings from current environment
        let env = ctx.lex_env.borrow();
        if let Some(bindings) = env.inner.as_env_record().get_all_bindings() {
            for (name, value) in bindings {
                self.local_bindings.insert(name, value);
            }
        }
    }
}

impl JsObject for GeneratorObject {
    fn get_object_base_mut(&mut self) -> &mut ObjectBase {
        &mut self.base
    }

    fn get_object_base(&self) -> &ObjectBase {
        &self.base
    }

    fn as_js_object(&self) -> &dyn JsObject {
        self
    }

    fn as_js_object_mut(&mut self) -> &mut dyn JsObject {
        self
    }
}

/// Create an iterator result object { value, done }.
fn create_iterator_result(value: JsValue, done: bool) -> ValueResult {
    let mut obj = SimpleObject::new();

    obj.get_object_base_mut().properties.insert(
        PropertyKey::Str("value".to_string()),
        PropertyDescriptor::Data(PropertyDescriptorData {
            value,
            writable: true,
            enumerable: true,
            configurable: true,
        }),
    );

    obj.get_object_base_mut().properties.insert(
        PropertyKey::Str("done".to_string()),
        PropertyDescriptor::Data(PropertyDescriptorData {
            value: JsValue::Boolean(done),
            writable: true,
            enumerable: true,
            configurable: true,
        }),
    );

    let obj_ref: JsObjectType = Rc::new(RefCell::new(ObjectType::Ordinary(Box::new(obj))));
    Ok(JsValue::Object(obj_ref))
}

/// Create a generator object from a generator function.
fn create_generator_object(
    body_ptr: *const crate::parser::ast::FunctionBodyData,
    params_ptr: *const Vec<PatternType>,
    environment: crate::runner::ds::lex_env::JsLexEnvironmentType,
    _args: Vec<JsValue>,
    _ctx: &mut EvalContext,
) -> ValueResult {
    let mut gen_obj = GeneratorObject::new(body_ptr, params_ptr, environment);

    // Add marker property
    gen_obj.base.properties.insert(
        PropertyKey::Str("__generator_object__".to_string()),
        PropertyDescriptor::Data(PropertyDescriptorData {
            value: JsValue::Boolean(true),
            writable: false,
            enumerable: false,
            configurable: false,
        }),
    );

    // Store parameter values in local_bindings for when .next() is first called
    let params = unsafe { &*params_ptr };
    for (i, param) in params.iter().enumerate() {
        if let PatternType::PatternWhichCanBeExpression(
            ExpressionPatternType::Identifier(id)
        ) = param {
            let arg_value = _args.get(i).cloned().unwrap_or(JsValue::Undefined);
            gen_obj.local_bindings.insert(id.name.clone(), arg_value);
        }
    }

    // Create a 'next' method
    // We store a reference to the generator in a closure
    let gen_ref: JsObjectType = Rc::new(RefCell::new(ObjectType::Ordinary(Box::new(gen_obj))));

    // Add next method - this is a bit hacky, we'll store the generator ref
    // Actually, we can't easily create a closure here. Let's use a different approach:
    // We'll mark the generator and handle .next() specially in property access.

    // For simplicity, we mark it and handle next() calls specially
    Ok(JsValue::Object(gen_ref))
}

/// Create a callable "next" method for a generator object.
fn create_generator_next_method(gen_obj: JsObjectType) -> ValueResult {
    // Create a simple object that holds the generator reference
    // and is marked as a generator-next-method
    let mut next_obj = SimpleObject::new();

    next_obj.get_object_base_mut().properties.insert(
        PropertyKey::Str("__generator_next__".to_string()),
        PropertyDescriptor::Data(PropertyDescriptorData {
            value: JsValue::Object(gen_obj),
            writable: false,
            enumerable: false,
            configurable: false,
        }),
    );

    // Mark it as callable
    next_obj.get_object_base_mut().properties.insert(
        PropertyKey::Str("__simple_function__".to_string()),
        PropertyDescriptor::Data(PropertyDescriptorData {
            value: JsValue::Boolean(true),
            writable: false,
            enumerable: false,
            configurable: false,
        }),
    );

    let obj_ref: JsObjectType = Rc::new(RefCell::new(ObjectType::Ordinary(Box::new(next_obj))));
    Ok(JsValue::Object(obj_ref))
}

// ============================================================================
// Class evaluation
// ============================================================================

/// Evaluate a class expression and return the constructor function.
pub fn evaluate_class_expression(class_data: &ClassData, ctx: &mut EvalContext) -> ValueResult {
    evaluate_class(class_data, ctx)
}

/// Evaluate a class definition (used by both ClassExpression and ClassDeclaration).
/// Returns a constructor function object with methods on its prototype.
pub fn evaluate_class(class_data: &ClassData, ctx: &mut EvalContext) -> ValueResult {
    // 1. Evaluate the super class if present
    let parent_proto = if let Some(super_class) = &class_data.super_class {
        let parent = evaluate_expression(super_class, ctx)?;
        match &parent {
            JsValue::Object(parent_obj) => {
                // Get parent.prototype
                let borrowed = parent_obj.borrow();
                let proto_key = PropertyKey::Str("prototype".to_string());
                if let Some(PropertyDescriptor::Data(data)) = borrowed.as_js_object().get_object_base().properties.get(&proto_key) {
                    if let JsValue::Object(proto) = &data.value {
                        Some((parent_obj.clone(), proto.clone()))
                    } else {
                        return Err(JErrorType::TypeError("Parent class prototype is not an object".to_string()));
                    }
                } else {
                    return Err(JErrorType::TypeError("Parent class has no prototype".to_string()));
                }
            }
            _ => return Err(JErrorType::TypeError("Class extends value is not a constructor".to_string())),
        }
    } else {
        None
    };

    // 2. Find the constructor method
    let constructor_method = class_data.body.body.iter()
        .find(|m| matches!(m.kind, MethodDefinitionKind::Constructor));

    // 3. Create the constructor function
    let constructor_obj = if let Some(ctor_method) = constructor_method {
        // Use the defined constructor
        create_class_constructor(&ctor_method.value, parent_proto.as_ref().map(|(p, _)| p.clone()), ctx)?
    } else {
        // Create a default constructor
        create_default_constructor(parent_proto.as_ref().map(|(p, _)| p.clone()), ctx)?
    };

    // 4. Create the prototype object
    let prototype = if let Some((_, parent_proto)) = &parent_proto {
        // Derived class: prototype inherits from parent prototype
        let mut proto_obj = SimpleObject::new();
        proto_obj.get_object_base_mut().prototype = Some(parent_proto.clone());
        Rc::new(RefCell::new(ObjectType::Ordinary(Box::new(proto_obj))))
    } else {
        // Base class: regular prototype object
        Rc::new(RefCell::new(ObjectType::Ordinary(Box::new(SimpleObject::new()))))
    };

    // 5. Add methods to prototype (and static methods to constructor)
    for method in &class_data.body.body {
        if matches!(method.kind, MethodDefinitionKind::Constructor) {
            continue; // Skip constructor, already handled
        }

        // Get the method key
        let key = get_object_property_key(&method.key, method.computed, ctx)?;

        // Create the method function
        let method_fn = create_function_object(&method.value, ctx)?;

        // Determine target: prototype for instance methods, constructor for static
        let target = if method.static_flag {
            &constructor_obj
        } else {
            &JsValue::Object(prototype.clone())
        };

        match method.kind {
            MethodDefinitionKind::Method => {
                // Regular method
                if let JsValue::Object(target_obj) = target {
                    target_obj.borrow_mut().as_js_object_mut().get_object_base_mut().properties.insert(
                        PropertyKey::Str(key),
                        PropertyDescriptor::Data(PropertyDescriptorData {
                            value: method_fn,
                            writable: true,
                            enumerable: false,
                            configurable: true,
                        }),
                    );
                }
            }
            MethodDefinitionKind::Get => {
                // Getter
                if let JsValue::Object(getter_fn) = method_fn {
                    if let JsValue::Object(target_obj) = target {
                        let mut borrowed = target_obj.borrow_mut();
                        let prop_key = PropertyKey::Str(key.clone());
                        let existing = borrowed.as_js_object().get_object_base().properties.get(&prop_key).cloned();

                        let setter = if let Some(PropertyDescriptor::Accessor(acc)) = existing {
                            acc.set
                        } else {
                            None
                        };

                        borrowed.as_js_object_mut().get_object_base_mut().properties.insert(
                            prop_key,
                            PropertyDescriptor::Accessor(PropertyDescriptorAccessor {
                                get: Some(getter_fn),
                                set: setter,
                                enumerable: false,
                                configurable: true,
                            }),
                        );
                    }
                }
            }
            MethodDefinitionKind::Set => {
                // Setter
                if let JsValue::Object(setter_fn) = method_fn {
                    if let JsValue::Object(target_obj) = target {
                        let mut borrowed = target_obj.borrow_mut();
                        let prop_key = PropertyKey::Str(key.clone());
                        let existing = borrowed.as_js_object().get_object_base().properties.get(&prop_key).cloned();

                        let getter = if let Some(PropertyDescriptor::Accessor(acc)) = existing {
                            acc.get
                        } else {
                            None
                        };

                        borrowed.as_js_object_mut().get_object_base_mut().properties.insert(
                            prop_key,
                            PropertyDescriptor::Accessor(PropertyDescriptorAccessor {
                                get: getter,
                                set: Some(setter_fn),
                                enumerable: false,
                                configurable: true,
                            }),
                        );
                    }
                }
            }
            MethodDefinitionKind::Constructor => unreachable!(),
        }
    }

    // 6. Wire up constructor.prototype
    if let JsValue::Object(ctor_obj) = &constructor_obj {
        ctor_obj.borrow_mut().as_js_object_mut().get_object_base_mut().properties.insert(
            PropertyKey::Str("prototype".to_string()),
            PropertyDescriptor::Data(PropertyDescriptorData {
                value: JsValue::Object(prototype.clone()),
                writable: false,
                enumerable: false,
                configurable: false,
            }),
        );

        // Set prototype.constructor to point back to constructor
        prototype.borrow_mut().as_js_object_mut().get_object_base_mut().properties.insert(
            PropertyKey::Str("constructor".to_string()),
            PropertyDescriptor::Data(PropertyDescriptorData {
                value: constructor_obj.clone(),
                writable: true,
                enumerable: false,
                configurable: true,
            }),
        );
    }

    Ok(constructor_obj)
}

/// Create a constructor function from a method definition.
fn create_class_constructor(
    func_data: &FunctionData,
    _parent_ctor: Option<JsObjectType>,
    ctx: &EvalContext,
) -> ValueResult {
    let body_ptr = func_data.body.as_ref() as *const _;
    let params_ptr = &func_data.params.list as *const _;
    let environment = ctx.lex_env.clone();

    let mut func_obj = SimpleFunctionObject::new(body_ptr, params_ptr, environment);

    // Add marker property to identify this as a SimpleFunctionObject (callable)
    func_obj.base.properties.insert(
        PropertyKey::Str("__simple_function__".to_string()),
        PropertyDescriptor::Data(PropertyDescriptorData {
            value: JsValue::Boolean(true),
            writable: false,
            enumerable: false,
            configurable: false,
        }),
    );

    // Mark as class constructor
    func_obj.base.properties.insert(
        PropertyKey::Str("__class_constructor__".to_string()),
        PropertyDescriptor::Data(PropertyDescriptorData {
            value: JsValue::Boolean(true),
            writable: false,
            enumerable: false,
            configurable: false,
        }),
    );

    let obj_ref: JsObjectType = Rc::new(RefCell::new(ObjectType::Ordinary(Box::new(func_obj))));
    Ok(JsValue::Object(obj_ref))
}

/// Create a default constructor for a class.
fn create_default_constructor(
    _parent_ctor: Option<JsObjectType>,
    _ctx: &EvalContext,
) -> ValueResult {
    // Create a simple empty function that does nothing
    // For derived classes, it should call super(), but we'll simplify for now
    let mut func_obj = SimpleObject::new();

    // Add marker property to identify this as callable
    func_obj.get_object_base_mut().properties.insert(
        PropertyKey::Str("__simple_function__".to_string()),
        PropertyDescriptor::Data(PropertyDescriptorData {
            value: JsValue::Boolean(true),
            writable: false,
            enumerable: false,
            configurable: false,
        }),
    );

    // Mark as class constructor
    func_obj.get_object_base_mut().properties.insert(
        PropertyKey::Str("__class_constructor__".to_string()),
        PropertyDescriptor::Data(PropertyDescriptorData {
            value: JsValue::Boolean(true),
            writable: false,
            enumerable: false,
            configurable: false,
        }),
    );

    // Mark as default constructor (no-op)
    func_obj.get_object_base_mut().properties.insert(
        PropertyKey::Str("__default_constructor__".to_string()),
        PropertyDescriptor::Data(PropertyDescriptorData {
            value: JsValue::Boolean(true),
            writable: false,
            enumerable: false,
            configurable: false,
        }),
    );

    let obj_ref: JsObjectType = Rc::new(RefCell::new(ObjectType::Ordinary(Box::new(func_obj))));
    Ok(JsValue::Object(obj_ref))
}