# MCALC Agent Guidelines

## Project Overview

A simple Dioxus calculator application. Uses Dioxus 0.7 for UI with static CSS styling.

## Build Commands

```bash
# Development
cargo run                    # Run desktop app (default feature)
cargo run --features web     # Run web version

# Build
cargo build                  # Debug build
cargo build --release        # Release build

# Testing
cargo test                   # Run all tests
cargo test <test_name>       # Run specific test

# Linting & Formatting
cargo fmt                    # Format code
cargo fmt -- --check         # Check formatting without changes
cargo clippy                 # Run linter
cargo clippy -- -D warnings  # Lint with deny warnings
```

## Code Style

### Formatting
- Use `cargo fmt` with default rustfmt settings
- 4-space indentation
- Maximum line length: 100 characters

### Naming Conventions
- Components: PascalCase (e.g., `Calculator`, `DisplayArea`)
- Functions/Methods: snake_case (e.g., `calculate_result`, `input_digit`)
- Signals: snake_case with `_` suffix convention (e.g., `first_num`, `operator`)
- Types/Enums: PascalCase

### Imports
- Group 1: `use dioxus::prelude::*` (Dioxus core)
- Group 2: `use crate::` (local modules)
- Standard library imports last

### Components (Dioxus 0.7)
- Prefix with `#[allow(non_snake_case)]` if needed
- Props must be owned values (use `String` not `&str`)
- Use `Signal<T>` for reactive state
- Components return `Element`

```rust
#[component]
fn MyComponent(mut value: Signal<String>) -> Element {
    rsx! { div { "{value}" } }
}
```

### State Management
- Use `use_signal(|| initial_value)` for local state
- Use `.write()` for mutable access, `.read()` for references
- Prefer `*signal.write() = value` over `signal.set(value)` for direct mutation

### Error Handling
- Prefer early returns with `return` or `?` operator
- Use `Result<T, E>` for fallible operations
- Silent failures acceptable for user input parsing (graceful degradation)

### CSS Guidelines
- CSS files in `/assets/main.css`
- Use CSS custom properties (variables) for theming
- Follow BYTEMALTE design system colors when applicable
- Class naming: kebab-case (e.g., `btn-number`, `display-area`)

## File Structure

```
src/
  main.rs        # App entry point
  ui.rs          # UI components
  logic.rs       # Business logic
assets/
  main.css       # Global styles
public/          # Static assets served at root
```

## Design System (BYTEMALTE)

When modifying CSS, follow these conventions:

| Element | Border Radius |
|---------|---------------|
| Buttons | 8px |
| Cards   | 16px |
| Inputs  | 8px |

Colors:
- Primary: `#8888FF`
- Secondary: `#3DDC84`
- Background: `#0F172A`
- Surface: `#1E293B`
- Error: `#EF4444`

---

## Dioxus 0.7 Reference

### Components
```rust
#[component]
fn App() -> Element {
    let mut count = use_signal(|| 0);
    rsx! {
        button { onclick: move |_| *count.write() += 1, "{count}" }
    }
}
```

### Signals
```rust
let mut value = use_signal(|| String::new());
value();           // clone value
value.read();      // &T reference
value.write();     // &mut T
```

### RSX Patterns
```rust
rsx! {
    div {
        for item in items { span { "{item}" } }
        if condition { p { "Shown" } }
    }
}
```