use prometeu_hal::color::Color;
use prometeu_hal::window::{Rect, Window, WindowId};

/// PROMETEU Window Manager.
pub struct WindowManager {
    pub windows: Vec<Window>,
    pub focused: Option<WindowId>,
}

impl WindowManager {
    pub fn new() -> Self {
        Self { windows: Vec::new(), focused: None }
    }

    pub fn add_window(&mut self, title: String, viewport: Rect, color: Color) -> WindowId {
        let id = WindowId(self.windows.len() as u32);
        let window = Window { id, viewport, has_focus: false, title, color };
        self.windows.push(window);
        id
    }

    pub fn remove_window(&mut self, id: WindowId) {
        self.windows.retain(|w| w.id != id);
        if self.focused == Some(id) {
            self.focused = None;
        }
    }

    pub fn remove_all_windows(&mut self) {
        self.windows.clear();
        self.focused = None;
    }

    pub fn set_focus(&mut self, id: WindowId) {
        self.focused = Some(id);
        for window in &mut self.windows {
            window.has_focus = window.id == id;
        }
    }
}

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

    #[test]
    fn test_window_manager_focus() {
        let mut wm = WindowManager::new();
        let id1 =
            wm.add_window("Window 1".to_string(), Rect { x: 0, y: 0, w: 10, h: 10 }, Color::WHITE);
        let id2 = wm.add_window(
            "Window 2".to_string(),
            Rect { x: 10, y: 10, w: 10, h: 10 },
            Color::WHITE,
        );

        assert_eq!(wm.windows.len(), 2);
        assert_eq!(wm.focused, None);

        wm.set_focus(id1);
        assert_eq!(wm.focused, Some(id1));
        assert!(wm.windows[0].has_focus);
        assert!(!wm.windows[1].has_focus);

        wm.set_focus(id2);
        assert_eq!(wm.focused, Some(id2));
        assert!(!wm.windows[0].has_focus);
        assert!(wm.windows[1].has_focus);
    }

    #[test]
    fn test_window_manager_remove_window() {
        let mut wm = WindowManager::new();
        let id =
            wm.add_window("Window".to_string(), Rect { x: 0, y: 0, w: 10, h: 10 }, Color::WHITE);
        wm.set_focus(id);
        assert_eq!(wm.focused, Some(id));

        wm.remove_window(id);
        assert_eq!(wm.windows.len(), 0);
        assert_eq!(wm.focused, None);
    }
}