hui 0.1.0-alpha.6

use fontdue::Font;

/// Font handle, stores the internal font id and can be cheaply copied.
///
/// Only valid for the `UiInstance` that created it.\
/// Using it with other instances may result in panics or unexpected behavior.
///
/// Handle values are not guaranteed to be valid.\
/// Creating or transmuting an invalid handle is allowed and is *not* UB.
///
/// Internal value is an implementation detail and should not be relied upon.
#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
pub struct FontHandle(pub(crate) usize);

#[cfg(feature = "builtin_font")]
pub const BUILTIN_FONT: FontHandle = FontHandle(0);

impl Default for FontHandle {
  /// Default font handle is the builtin font, if the feature is enabled;\
  /// Otherwise returns an invalid handle.
  fn default() -> Self {
    #[cfg(feature = "builtin_font")] { BUILTIN_FONT }
    #[cfg(not(feature = "builtin_font"))] { Self(usize::MAX) }
  }
}

#[cfg(feature = "builtin_font")]
const BUILTIN_FONT_DATA: &[u8] = include_bytes!("../../assets/font/ProggyTiny.ttf");

pub struct FontManager {
  fonts: Vec<Font>,
}

impl FontManager {
  pub fn new() -> Self {
    let mut this = Self {
      fonts: Vec::new(),
    };
    #[cfg(feature = "builtin_font")]
    {
      let font = Font::from_bytes(
        BUILTIN_FONT_DATA,
        fontdue::FontSettings::default()
      ).unwrap();
      this.add_font(font);
    };
    this
  }

  /// Add a (fontdue) font to the renderer.
  pub fn add_font(&mut self, font: Font) -> FontHandle {
    self.fonts.push(font);
    FontHandle(self.fonts.len() - 1)
  }

  pub fn get(&self, handle: FontHandle) -> Option<&Font> {
    self.fonts.get(handle.0)
  }
}

impl Default for FontManager {
  fn default() -> Self {
    Self::new()
  }
}