ribir_painter 0.4.0-alpha.65

use std::{cell::RefCell, error::Error, io::Read, vec};

use ribir_algo::Resource;
use ribir_types::{Point, Rect, Size, Transform};
use serde::{Deserialize, Serialize};
use usvg::{Options, Stop, Tree};

use crate::{
  Brush, Color, CommandBrush, GradientStop, LineCap, LineJoin, PaintCommand, PaintPathAction, Path,
  StrokeOptions,
  color::{LinearGradient, RadialGradient},
};

/// This is a basic SVG support designed for rendering to Ribir painter. It is
/// currently quite simple and primarily used for Ribir icons. More features
/// will be added as needed.

#[derive(Serialize, Deserialize)]
pub struct Svg {
  size: Size,
  commands: Resource<Box<[PaintCommand]>>,

  inherited_fill: bool,
  inherited_stroke: bool,
  #[serde(skip)]
  last: RefCell<Option<StaticSvg>>,
}

#[derive(Clone)]
struct StaticSvg {
  inherited_fill: Brush,
  inherited_stroke: Brush,
  commands: Resource<Box<[PaintCommand]>>,
}

// todo: share fontdb
impl Svg {
  // FIXME: This is a temporary workaround. Utilize the magic color for the SVG,
  // and replace it with the actual color when rendering.
  const DYNAMIC_COLOR: Color = Color::from_u32(0x191B1901);
  const DYNAMIC_COLOR_STR: &'static str = "#191B1901";

  /// Parse SVG from bytes.
  ///
  /// - **inherit_fill**: Indicates whether this SVG will inherit the fill color
  ///   from the environment.
  /// - **inherit_stroke**: Indicates whether this SVG will inherit the stroke
  ///   color from the environment.
  pub fn parse_from_bytes(
    svg_data: &[u8], inherit_fill: bool, inherit_stroke: bool,
  ) -> Result<Self, Box<dyn Error>> {
    let magic = Self::DYNAMIC_COLOR_STR;
    let style_sheet = match (inherit_fill, inherit_stroke) {
      (true, true) => Some(format!("svg {{ fill: {magic}; stroke: {magic} }}")),
      (true, false) => Some(format!("svg {{ fill: {magic} }}")),
      (false, true) => Some(format!("svg {{ stroke: {magic} }}")),
      _ => None,
    };

    let opt = Options { style_sheet, ..<_>::default() };
    let tree = Tree::from_data(svg_data, &opt).unwrap();

    let size = tree.size();

    let bound_rect = Rect::from_size(Size::new(f32::MAX, f32::MAX));
    let mut painter = crate::Painter::new(bound_rect);
    paint_group(tree.root(), &mut painter);

    let paint_commands = painter.finish().to_owned().into_boxed_slice();
    let (used_fill_fallback, used_stroke_fallback) = fallback_color_check(&paint_commands);

    Ok(Svg {
      size: Size::new(size.width(), size.height()),
      commands: Resource::new(paint_commands),
      inherited_fill: used_fill_fallback,
      inherited_stroke: used_stroke_fallback,
      last: RefCell::new(None),
    })
  }

  /// Parse SVG from a file.
  ///
  /// - **inherit_fill**: Indicates whether this SVG will inherit the fill color
  ///   from the environment.
  /// - **inherit_stroke**: Indicates whether this SVG will inherit the stroke
  ///   color from the environment.
  pub fn open<P: AsRef<std::path::Path>>(
    path: P, fill_inject: bool, stroke_inject: bool,
  ) -> Result<Self, Box<dyn Error>> {
    let mut file = std::fs::File::open(path)?;
    let mut bytes = vec![];
    file.read_to_end(&mut bytes)?;
    Self::parse_from_bytes(&bytes, fill_inject, stroke_inject)
  }

  pub fn size(&self) -> Size { self.size }

  pub fn commands(
    &self, fill_brush: &Brush, stroke_brush: &Brush,
  ) -> Resource<Box<[PaintCommand]>> {
    if !self.inherited_fill && !self.inherited_stroke {
      self.commands.clone()
    } else {
      let mut last = self.last.borrow_mut();
      if let Some(last) = last
        .as_ref()
        .filter(|last| &last.inherited_fill == fill_brush && &last.inherited_stroke == stroke_brush)
      {
        last.commands.clone()
      } else {
        let commands = brush_replace(&self.commands, fill_brush, stroke_brush);
        let commands = Resource::new(commands);
        *last = Some(StaticSvg {
          inherited_fill: fill_brush.clone(),
          inherited_stroke: stroke_brush.clone(),
          commands: commands.clone(),
        });
        commands
      }
    }
  }

  pub fn command_size(&self) -> usize { self.commands.len() }

  pub fn serialize(&self) -> Result<String, Box<dyn Error>> {
    // use json replace bincode, because https://github.com/Ogeon/palette/issues/130
    Ok(serde_json::to_string(self)?)
  }

  pub fn deserialize(str: &str) -> Result<Self, Box<dyn Error>> { Ok(serde_json::from_str(str)?) }
}

fn paint_group(g: &usvg::Group, painter: &mut crate::Painter) {
  let mut painter = painter.save_guard();
  for child in g.children() {
    match child {
      usvg::Node::Group(g) => {
        // todo;
        painter.apply_alpha(g.opacity().get());

        if g.clip_path().is_some() {
          tracing::warn!("[painter]: not support `clip path` in svg, ignored!");
        }
        if g.mask().is_some() {
          tracing::warn!("[painter]: not support `mask` in svg, ignored!");
        }
        if !g.filters().is_empty() {
          tracing::warn!("[painter]: not support `filters` in svg, ignored!");
        }
        paint_group(g, &mut painter);
      }
      usvg::Node::Path(p) => {
        painter.set_transform(matrix_convert(p.abs_transform()));
        let path = usvg_path_to_path(p);
        if let Some(fill) = p.fill() {
          let (brush, transform) = brush_from_usvg_paint(fill.paint(), fill.opacity());

          let inverse_ts = transform.inverse().unwrap();
          let path = Resource::new(path.clone().transform(&inverse_ts));
          painter
            .set_fill_brush(brush.clone())
            .apply_transform(&transform)
            .fill_path(path.into());
          //&o_ts.then(&n_ts.inverse().unwrap())));
        }

        if let Some(stroke) = p.stroke() {
          let options = StrokeOptions {
            width: stroke.width().get(),
            line_cap: stroke.linecap().into(),
            line_join: stroke.linejoin().into(),
            miter_limit: stroke.miterlimit().get(),
          };

          let (brush, transform) = brush_from_usvg_paint(stroke.paint(), stroke.opacity());
          painter
            .set_stroke_brush(brush.clone())
            .set_strokes(options)
            .apply_transform(&transform)
            .stroke_path(path.into());
        };
      }
      usvg::Node::Image(_) => {
        // todo;
        tracing::warn!("[painter]: not support draw embed image in svg, ignored!");
      }
      usvg::Node::Text(t) => paint_group(t.flattened(), &mut painter),
    }
  }
}
fn usvg_path_to_path(path: &usvg::Path) -> Path {
  let mut builder = lyon_algorithms::path::Path::svg_builder();
  path.data().segments().for_each(|seg| match seg {
    usvg::tiny_skia_path::PathSegment::MoveTo(pt) => {
      builder.move_to(point(pt.x, pt.y));
    }
    usvg::tiny_skia_path::PathSegment::LineTo(pt) => {
      builder.line_to(point(pt.x, pt.y));
    }
    usvg::tiny_skia_path::PathSegment::CubicTo(pt1, pt2, pt3) => {
      builder.cubic_bezier_to(point(pt1.x, pt1.y), point(pt2.x, pt2.y), point(pt3.x, pt3.y));
    }
    usvg::tiny_skia_path::PathSegment::QuadTo(pt1, pt2) => {
      builder.quadratic_bezier_to(point(pt1.x, pt1.y), point(pt2.x, pt2.y));
    }
    usvg::tiny_skia_path::PathSegment::Close => builder.close(),
  });

  builder.build().into()
}

fn point(x: f32, y: f32) -> lyon_algorithms::math::Point { Point::new(x, y).to_untyped() }

fn matrix_convert(t: usvg::Transform) -> Transform {
  let usvg::Transform { sx, kx, ky, sy, tx, ty } = t;
  Transform::new(sx, ky, kx, sy, tx, ty)
}

fn brush_from_usvg_paint(paint: &usvg::Paint, opacity: usvg::Opacity) -> (Brush, Transform) {
  match paint {
    usvg::Paint::Color(usvg::Color { red, green, blue }) => (
      Color::from_rgb(*red, *green, *blue)
        .with_alpha(opacity.get())
        .into(),
      Transform::identity(),
    ),
    usvg::Paint::LinearGradient(linear) => {
      let stops = convert_to_gradient_stops(linear.stops());
      let gradient = LinearGradient {
        start: Point::new(linear.x1(), linear.y1()),
        end: Point::new(linear.x2(), linear.y2()),
        stops,
        spread_method: linear.spread_method().into(),
      };

      (Brush::LinearGradient(Resource::new(gradient)), matrix_convert(linear.transform()))
    }
    usvg::Paint::RadialGradient(radial_gradient) => {
      let stops = convert_to_gradient_stops(radial_gradient.stops());
      let gradient = RadialGradient {
        start_center: Point::new(radial_gradient.fx(), radial_gradient.fy()),
        start_radius: 0., // usvg not support fr
        end_center: Point::new(radial_gradient.cx(), radial_gradient.cy()),
        end_radius: radial_gradient.r().get(),
        stops,
        spread_method: radial_gradient.spread_method().into(),
      };

      (Brush::RadialGradient(Resource::new(gradient)), matrix_convert(radial_gradient.transform()))
    }
    paint => {
      tracing::warn!("[painter]: not support `{paint:?}` in svg, use black instead!");
      (Color::BLACK.into(), Transform::identity())
    }
  }
}

fn fallback_color_check(cmds: &[PaintCommand]) -> (bool, bool) {
  let mut fill_fallback = false;
  let mut stroke_fallback = false;
  for c in cmds {
    if fill_fallback && stroke_fallback {
      break;
    }

    match c {
      PaintCommand::Path(p) => {
        if let PaintPathAction::Paint { painting_style, brush, .. } = &p.action
          && matches!(brush, CommandBrush::Color(c) if c == &Svg::DYNAMIC_COLOR)
        {
          match painting_style {
            crate::PaintingStyle::Fill => fill_fallback = true,
            crate::PaintingStyle::Stroke(_) => stroke_fallback = true,
          }
        }
      }
      PaintCommand::PopClip => {}
      PaintCommand::Bundle { cmds, .. } => {
        let (f, s) = fallback_color_check(cmds);
        fill_fallback = f;
        stroke_fallback |= s;
      }
      PaintCommand::Filter { .. } => {}
      PaintCommand::Text(_) => {}
    }
  }
  (fill_fallback, stroke_fallback)
}

fn brush_replace(cmds: &[PaintCommand], fill: &Brush, stroke: &Brush) -> Box<[PaintCommand]> {
  cmds
    .iter()
    .map(|c| match c {
      PaintCommand::Path(p) => {
        let mut p = p.clone();
        if let PaintPathAction::Paint { painting_style, brush, .. } = &mut p.action
          && matches!(brush, CommandBrush::Color(c) if c == &Svg::DYNAMIC_COLOR)
        {
          match painting_style {
            crate::PaintingStyle::Fill => *brush = fill.clone().into(),
            crate::PaintingStyle::Stroke(_) => *brush = stroke.clone().into(),
          }
        }
        PaintCommand::Path(p)
      }
      PaintCommand::PopClip => PaintCommand::PopClip,
      PaintCommand::Bundle { transform, color_filter, bounds, cmds } => {
        let cmds = brush_replace(cmds, fill, stroke);
        let cmds = Resource::new(cmds);

        PaintCommand::Bundle {
          transform: *transform,
          color_filter: *color_filter,
          bounds: *bounds,
          cmds,
        }
      }
      PaintCommand::Filter { .. } => c.clone(),
      PaintCommand::Text(_) => c.clone(),
    })
    .collect()
}

fn convert_to_gradient_stops(stops: &[Stop]) -> Vec<GradientStop> {
  assert!(!stops.is_empty());

  let mut stops: Vec<_> = stops
    .iter()
    .map(|stop| {
      let usvg::Color { red, green, blue } = stop.color();
      GradientStop {
        offset: stop.offset().get(),
        color: Color::new(red, green, blue, stop.opacity().to_u8()),
      }
    })
    .collect();

  stops.sort_by(|s1, s2| s1.offset.partial_cmp(&s2.offset).unwrap());

  if let Some(first) = stops.first()
    && first.offset != 0.
  {
    stops.insert(0, GradientStop { offset: 0., color: first.color });
  }

  if let Some(last) = stops.last()
    && last.offset < 1.
  {
    stops.push(GradientStop { offset: 1., color: last.color });
  }
  stops
}

impl From<usvg::LineCap> for LineCap {
  fn from(value: usvg::LineCap) -> Self {
    match value {
      usvg::LineCap::Butt => LineCap::Butt,
      usvg::LineCap::Round => LineCap::Round,
      usvg::LineCap::Square => LineCap::Square,
    }
  }
}

impl From<usvg::LineJoin> for LineJoin {
  fn from(value: usvg::LineJoin) -> Self {
    match value {
      usvg::LineJoin::Miter => LineJoin::Miter,
      usvg::LineJoin::MiterClip => LineJoin::MiterClip,
      usvg::LineJoin::Round => LineJoin::Round,
      usvg::LineJoin::Bevel => LineJoin::Bevel,
    }
  }
}

impl Clone for Svg {
  fn clone(&self) -> Self {
    Svg {
      size: self.size,
      commands: self.commands.clone(),
      inherited_fill: self.inherited_fill,
      inherited_stroke: self.inherited_stroke,
      last: RefCell::new(self.last.borrow().clone()),
    }
  }
}

impl std::fmt::Debug for Svg {
  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
    f.debug_struct("Svg")
      .field("size", &self.size)
      .field("commands_len", &self.commands.len())
      .finish()
  }
}