//! Qt backend - WebView integrated with Qt framework
//!
//! This backend integrates the WebView with Qt's widget system,
//! allowing it to be used as a child widget in DCC applications
//! that already have Qt loaded (e.g., Maya, Houdini).
//!
//! **Status**: Stub implementation - not yet functional
//!
//! ## Design Goals
//!
//! 1. **Qt Widget Integration**: Create WebView as a QWidget child
//! 2. **Event Loop Sharing**: Use DCC's existing Qt event loop
//! 3. **Memory Safety**: Proper lifetime management between Rust and Qt
//!
//! ## Implementation Plan
//!
//! ### Phase 1: Qt Bindings
//! - Use `cxx-qt` or `qmetaobject` for Qt bindings
//! - Create QWidget wrapper for WebView
//! - Handle Qt signals/slots for events
//!
//! ### Phase 2: WebView Integration
//! - Embed platform WebView (WebView2 on Windows) into QWidget
//! - Handle window parenting and lifecycle
//! - Coordinate event processing
//!
//! ### Phase 3: Python Bindings
//! - Expose Qt backend through PyO3
//! - Allow passing QWidget pointers from Python
//! - Maintain API compatibility with native backend

use std::sync::{Arc, Mutex};
use wry::WebView as WryWebView;

use super::WebViewBackend;
use crate::ipc::{IpcHandler, MessageQueue};
use crate::webview::config::WebViewConfig;
use crate::webview::event_loop::UserEvent;

/// Qt backend implementation (stub)
///
/// **Note**: This is a placeholder implementation. The actual Qt integration
/// requires additional dependencies and platform-specific code.
#[allow(dead_code)]
pub struct QtBackend {
    webview: Arc<Mutex<WryWebView>>,
    message_queue: Arc<MessageQueue>,
    // TODO: Add Qt-specific fields
    // qt_widget: Option<QWidget>,
    // qt_webview: Option<QWebEngineView>,
}

impl std::fmt::Debug for QtBackend {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.debug_struct("QtBackend")
            .field("webview", &"<WryWebView>")
            .field("message_queue", &"<MessageQueue>")
            .finish()
    }
}

impl WebViewBackend for QtBackend {
    fn create(
        _config: WebViewConfig,
        _ipc_handler: Arc<IpcHandler>,
        _message_queue: Arc<MessageQueue>,
    ) -> Result<Self, Box<dyn std::error::Error>> {
        Err("Qt backend is not yet implemented. Please use the native backend for now.".into())
    }

    fn webview(&self) -> Arc<Mutex<WryWebView>> {
        self.webview.clone()
    }

    fn message_queue(&self) -> Arc<MessageQueue> {
        self.message_queue.clone()
    }

    fn window(&self) -> Option<&tao::window::Window> {
        // Qt backend doesn't use tao windows
        None
    }

    fn event_loop(&mut self) -> Option<tao::event_loop::EventLoop<UserEvent>> {
        // Qt backend uses Qt's event loop
        None
    }

    fn process_events(&self) -> bool {
        // Qt backend processes events through Qt's event loop
        false
    }

    fn run_event_loop_blocking(&mut self) {
        // Qt backend doesn't run its own event loop
        tracing::warn!("QtBackend::run_event_loop_blocking called - Qt uses DCC's event loop");
    }
}

// TODO: Implement Qt-specific functionality
//
// Example structure for future implementation:
//
// ```rust
// use qmetaobject::*;
//
// #[derive(QObject)]
// struct AuroraViewWidget {
//     base: qt_base_class!(trait QWidget),
//     webview: qt_property!(QString; NOTIFY webview_changed),
//     // ... other properties
// }
//
// impl AuroraViewWidget {
//     fn new() -> Self {
//         // Initialize Qt widget
//     }
//
//     fn embed_webview(&mut self, parent_widget: *mut QWidget) {
//         // Embed WebView into Qt widget hierarchy
//     }
// }
// ```

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_qt_backend_not_implemented() {
        let config = WebViewConfig::default();
        let ipc_handler = Arc::new(IpcHandler::new());
        let message_queue = Arc::new(MessageQueue::new());

        let result = QtBackend::create(config, ipc_handler, message_queue);
        assert!(result.is_err());
        assert!(result
            .unwrap_err()
            .to_string()
            .contains("not yet implemented"));
    }
}
