//! Write your own renderer.
#[cfg(debug_assertions)]
mod null;

#[cfg(debug_assertions)]
pub use null::Null;

use crate::{Background, BorderRadius, Color, Rectangle, Shadow, Size, Vector};

/// A component that can be used by widgets to draw themselves on a screen.
pub trait Renderer: Sized {
    /// The supported theme of the [`Renderer`].
    type Theme;

    /// Draws the primitives recorded in the given closure in a new layer.
    ///
    /// The layer will clip its contents to the provided `bounds`.
    fn with_layer(&mut self, bounds: Rectangle, f: impl FnOnce(&mut Self));

    /// Applies a `translation` to the primitives recorded in the given closure.
    fn with_translation(
        &mut self,
        translation: Vector,
        f: impl FnOnce(&mut Self),
    );

    /// Fills a [`Quad`] with the provided [`Background`].
    fn fill_quad(&mut self, quad: Quad, background: impl Into<Background>);

    /// Clears all of the recorded primitives in the [`Renderer`].
    fn clear(&mut self);
}

/// A polygon with four sides.
#[derive(Debug, Clone, Copy, PartialEq)]
pub struct Quad {
    /// The bounds of the [`Quad`].
    pub bounds: Rectangle,

    /// The border radius of the [`Quad`].
    pub border_radius: BorderRadius,

    /// The border width of the [`Quad`].
    pub border_width: f32,

    /// The border color of the [`Quad`].
    pub border_color: Color,

    /// The shadow of the [`Quad`].
    pub shadow: Option<Shadow>,
}

impl Default for Quad {
    fn default() -> Self {
        Self {
            bounds: Rectangle::with_size(Size::ZERO),
            border_radius: 0.0.into(),
            border_width: 0.0,
            border_color: Color::TRANSPARENT,
            shadow: None,
        }
    }
}

/// The styling attributes of a [`Renderer`].
#[derive(Debug, Clone, Copy, PartialEq)]
pub struct Style {
    /// The text color
    pub text_color: Color,
}

impl Default for Style {
    fn default() -> Self {
        Style {
            text_color: Color::BLACK,
        }
    }
}