egui_treeize/ui/

wire.rs

use core::f32;

use egui::{Context, Id, Pos2, Rect, Shape, Stroke, Ui, ahash::HashMap, cache::CacheTrait, pos2};

use crate::{InPinId, OutPinId};

const MAX_CURVE_SAMPLES: usize = 100;

/// Layer where wires are rendered.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
#[cfg_attr(feature = "egui-probe", derive(egui_probe::EguiProbe))]
#[derive(Default)]
pub enum WireLayer {
  /// Wires are rendered behind nodes.
  /// This is default.
  #[default]
  BehindNodes,

  /// Wires are rendered above nodes.
  AboveNodes,
}

#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
pub enum WireId {
  Connected { snarl_id: Id, out_pin: OutPinId, in_pin: InPinId },
  NewInput { snarl_id: Id, in_pin: InPinId },
  NewOutput { snarl_id: Id, out_pin: OutPinId },
}

/// Controls style in which wire is rendered.
///
/// Variants are given in order of precedence when two pins require different styles.
#[derive(Clone, Copy, Debug, PartialEq)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
#[cfg_attr(feature = "egui-probe", derive(egui_probe::EguiProbe))]
#[derive(Default)]
pub enum WireStyle {
  /// Straight line from one endpoint to another.
  Line,

  /// Draw wire as straight lines with 90 degree turns.
  /// Corners has radius of `corner_radius`.
  AxisAligned {
    /// Radius of corners in wire.
    corner_radius: f32,
  },

  /// Draw wire as 3rd degree Bezier curve.
  Bezier3,

  /// Draw wire as 5th degree Bezier curve.
  #[default]
  Bezier5,
}

pub const fn pick_wire_style(left: WireStyle, right: WireStyle) -> WireStyle {
  match (left, right) {
    (WireStyle::Line, _) | (_, WireStyle::Line) => WireStyle::Line,
    (WireStyle::AxisAligned { corner_radius: a }, WireStyle::AxisAligned { corner_radius: b }) => {
      WireStyle::AxisAligned { corner_radius: f32::max(a, b) }
    }
    (WireStyle::AxisAligned { corner_radius }, _)
    | (_, WireStyle::AxisAligned { corner_radius }) => WireStyle::AxisAligned { corner_radius },
    (WireStyle::Bezier3, _) | (_, WireStyle::Bezier3) => WireStyle::Bezier3,
    (WireStyle::Bezier5, WireStyle::Bezier5) => WireStyle::Bezier5,
  }
}

fn adjust_frame_size(
  mut frame_size: f32,
  upscale: bool,
  downscale: bool,
  from: Pos2,
  to: Pos2,
) -> f32 {
  let length = (from - to).length();
  if upscale {
    frame_size = frame_size.max(length / 6.0);
  }
  if downscale {
    frame_size = frame_size.min(length / 6.0);
  }
  frame_size
}

/// Returns 5th degree bezier curve control points for the wire
fn wire_bezier_5(frame_size: f32, from: Pos2, to: Pos2) -> [Pos2; 6] {
  let from_norm_x = frame_size;
  let from_2 = pos2(from.x + from_norm_x, from.y);
  let to_norm_x = -from_norm_x;
  let to_2 = pos2(to.x + to_norm_x, to.y);

  let between = (from_2 - to_2).length();

  if from_2.x <= to_2.x && between >= frame_size * 2.0 {
    let middle_1 = from_2 + (to_2 - from_2).normalized() * frame_size;
    let middle_2 = to_2 + (from_2 - to_2).normalized() * frame_size;

    [from, from_2, middle_1, middle_2, to_2, to]
  } else if from_2.x <= to_2.x {
    let t =
      (between - (to_2.y - from_2.y).abs()) / frame_size.mul_add(2.0, -(to_2.y - from_2.y).abs());

    let mut middle_1 = from_2 + (to_2 - from_2).normalized() * frame_size;
    let mut middle_2 = to_2 + (from_2 - to_2).normalized() * frame_size;

    if from_2.y >= to_2.y + frame_size {
      let u = (from_2.y - to_2.y - frame_size) / frame_size;

      let t0_middle_1 =
        pos2((1.0 - u).mul_add(frame_size, from_2.x), frame_size.mul_add(-u, from_2.y));
      let t0_middle_2 = pos2(to_2.x, to_2.y + frame_size);

      middle_1 = t0_middle_1.lerp(middle_1, t);
      middle_2 = t0_middle_2.lerp(middle_2, t);
    } else if from_2.y >= to_2.y {
      let u = (from_2.y - to_2.y) / frame_size;

      let t0_middle_1 =
        pos2(u.mul_add(frame_size, from_2.x), frame_size.mul_add(1.0 - u, from_2.y));
      let t0_middle_2 = pos2(to_2.x, to_2.y + frame_size);

      middle_1 = t0_middle_1.lerp(middle_1, t);
      middle_2 = t0_middle_2.lerp(middle_2, t);
    } else if to_2.y >= from_2.y + frame_size {
      let u = (to_2.y - from_2.y - frame_size) / frame_size;

      let t0_middle_1 = pos2(from_2.x, from_2.y + frame_size);
      let t0_middle_2 =
        pos2((1.0 - u).mul_add(-frame_size, to_2.x), frame_size.mul_add(-u, to_2.y));

      middle_1 = t0_middle_1.lerp(middle_1, t);
      middle_2 = t0_middle_2.lerp(middle_2, t);
    } else if to_2.y >= from_2.y {
      let u = (to_2.y - from_2.y) / frame_size;

      let t0_middle_1 = pos2(from_2.x, from_2.y + frame_size);
      let t0_middle_2 = pos2(u.mul_add(-frame_size, to_2.x), frame_size.mul_add(1.0 - u, to_2.y));

      middle_1 = t0_middle_1.lerp(middle_1, t);
      middle_2 = t0_middle_2.lerp(middle_2, t);
    } else {
      unreachable!();
    }

    [from, from_2, middle_1, middle_2, to_2, to]
  } else if from_2.y >= frame_size.mul_add(2.0, to_2.y) {
    let middle_1 = pos2(from_2.x, from_2.y - frame_size);
    let middle_2 = pos2(to_2.x, to_2.y + frame_size);

    [from, from_2, middle_1, middle_2, to_2, to]
  } else if from_2.y >= to_2.y + frame_size {
    let t = (from_2.y - to_2.y - frame_size) / frame_size;

    let middle_1 = pos2((1.0 - t).mul_add(frame_size, from_2.x), frame_size.mul_add(-t, from_2.y));
    let middle_2 = pos2(to_2.x, to_2.y + frame_size);

    [from, from_2, middle_1, middle_2, to_2, to]
  } else if from_2.y >= to_2.y {
    let t = (from_2.y - to_2.y) / frame_size;

    let middle_1 = pos2(t.mul_add(frame_size, from_2.x), frame_size.mul_add(1.0 - t, from_2.y));
    let middle_2 = pos2(to_2.x, to_2.y + frame_size);

    [from, from_2, middle_1, middle_2, to_2, to]
  } else if to_2.y >= frame_size.mul_add(2.0, from_2.y) {
    let middle_1 = pos2(from_2.x, from_2.y + frame_size);
    let middle_2 = pos2(to_2.x, to_2.y - frame_size);

    [from, from_2, middle_1, middle_2, to_2, to]
  } else if to_2.y >= from_2.y + frame_size {
    let t = (to_2.y - from_2.y - frame_size) / frame_size;

    let middle_1 = pos2(from_2.x, from_2.y + frame_size);
    let middle_2 = pos2((1.0 - t).mul_add(-frame_size, to_2.x), frame_size.mul_add(-t, to_2.y));

    [from, from_2, middle_1, middle_2, to_2, to]
  } else if to_2.y >= from_2.y {
    let t = (to_2.y - from_2.y) / frame_size;

    let middle_1 = pos2(from_2.x, from_2.y + frame_size);
    let middle_2 = pos2(t.mul_add(-frame_size, to_2.x), frame_size.mul_add(1.0 - t, to_2.y));

    [from, from_2, middle_1, middle_2, to_2, to]
  } else {
    unreachable!();
  }
}

/// Returns 3rd degree bezier curve control points for the wire
fn wire_bezier_3(frame_size: f32, from: Pos2, to: Pos2) -> [Pos2; 4] {
  let [a, b, _, _, c, d] = wire_bezier_5(frame_size, from, to);
  [a, b, c, d]
}

#[allow(clippy::too_many_arguments)]
pub fn draw_wire(
  ui: &Ui,
  wire: WireId,
  shapes: &mut Vec<Shape>,
  frame_size: f32,
  upscale: bool,
  downscale: bool,
  from: Pos2,
  to: Pos2,
  mut stroke: Stroke,
  threshold: f32,
  style: WireStyle,
) {
  if !ui.is_visible() {
    return;
  }

  if stroke.width < 1.0 {
    stroke.color = stroke.color.gamma_multiply(stroke.width);
    stroke.width = 1.0;
  }

  let frame_size = adjust_frame_size(frame_size, upscale, downscale, from, to);

  let args = WireArgs { frame_size, from, to, radius: 0.0 };

  match style {
    WireStyle::Line => {
      let bb = Rect::from_two_pos(from, to);
      if ui.is_rect_visible(bb) {
        shapes.push(Shape::line_segment([from, to], stroke));
      }
    }
    WireStyle::Bezier3 => {
      draw_bezier_3(ui, wire, args, stroke, threshold, shapes);
    }

    WireStyle::Bezier5 => {
      draw_bezier_5(ui, wire, args, stroke, threshold, shapes);
    }

    WireStyle::AxisAligned { corner_radius } => {
      let args = WireArgs { radius: corner_radius, ..args };
      draw_axis_aligned(ui, wire, args, stroke, threshold, shapes);
    }
  }
}

#[allow(clippy::too_many_arguments)]
pub fn hit_wire(
  ctx: &Context,
  wire: WireId,
  frame_size: f32,
  upscale: bool,
  downscale: bool,
  from: Pos2,
  to: Pos2,
  pos: Pos2,
  hit_threshold: f32,
  style: WireStyle,
) -> bool {
  let frame_size = adjust_frame_size(frame_size, upscale, downscale, from, to);

  let args = WireArgs { frame_size, from, to, radius: 0.0 };

  match style {
    WireStyle::Line => {
      let aabb = Rect::from_two_pos(from, to);
      let aabb_e = aabb.expand(hit_threshold);
      if !aabb_e.contains(pos) {
        return false;
      }

      let a = to - from;
      let b = pos - from;

      let dot = b.dot(a);
      let dist2 = b.length_sq() - dot * dot / a.length_sq();

      dist2 < hit_threshold * hit_threshold
    }
    WireStyle::Bezier3 => hit_wire_bezier_3(ctx, wire, args, pos, hit_threshold),
    WireStyle::Bezier5 => hit_wire_bezier_5(ctx, wire, args, pos, hit_threshold),
    WireStyle::AxisAligned { corner_radius } => {
      let args = WireArgs { radius: corner_radius, ..args };
      hit_wire_axis_aligned(ctx, wire, args, pos, hit_threshold)
    }
  }
}

#[inline]
fn bezier_arc_length_upper_bound(points: &[Pos2]) -> f32 {
  let mut size = 0.0;
  for i in 1..points.len() {
    size += (points[i] - points[i - 1]).length();
  }
  size
}

fn bezier_hit_samples_number(points: &[Pos2], threshold: f32) -> usize {
  let arc_length = bezier_arc_length_upper_bound(points);

  #[allow(clippy::cast_sign_loss)]
  #[allow(clippy::cast_possible_truncation)]
  ((arc_length / threshold).ceil().max(0.0) as usize)
}

fn bezier_derivative_3(points: &[Pos2; 4]) -> [Pos2; 3] {
  let [p0, p1, p2, p3] = *points;

  let factor = 3.0;

  [(factor * (p1 - p0)).to_pos2(), (factor * (p2 - p1)).to_pos2(), (factor * (p3 - p2)).to_pos2()]
}

fn bezier_derivative_5(points: &[Pos2; 6]) -> [Pos2; 5] {
  let [p0, p1, p2, p3, p4, p5] = *points;

  let factor = 5.0;

  [
    (factor * (p1 - p0)).to_pos2(),
    (factor * (p2 - p1)).to_pos2(),
    (factor * (p3 - p2)).to_pos2(),
    (factor * (p4 - p3)).to_pos2(),
    (factor * (p5 - p4)).to_pos2(),
  ]
}

fn bezier_draw_samples_number_3(points: &[Pos2; 4], threshold: f32) -> usize {
  #![allow(clippy::similar_names)]
  #![allow(clippy::cast_precision_loss)]

  let d = bezier_derivative_3(points);

  lower_bound(2, MAX_CURVE_SAMPLES, |n| {
    let mut prev = points[0];
    for i in 1..n {
      let t = i as f32 / (n - 1) as f32;
      let next = sample_bezier(points, t);

      let m = t - 0.5 / (n - 1) as f32;

      // Compare absolute error of mid point
      let mid_line = ((prev.to_vec2() + next.to_vec2()) * 0.5).to_pos2();
      let mid_curve = sample_bezier(points, m);

      let error_sq = (mid_curve - mid_line).length_sq();
      if error_sq > threshold * threshold {
        return false;
      }

      // Compare angular error of mid point
      let mid_line_dx = next.x - prev.x;
      let mid_line_dy = next.y - prev.y;

      let line_w = f32::hypot(mid_line_dx, mid_line_dy);

      let d_curve = sample_bezier(&d, m);
      let mid_curve_dx = d_curve.x;
      let mid_curve_dy = d_curve.y;

      let curve_w = f32::hypot(mid_curve_dx, mid_curve_dy);

      let error = f32::max(
        (mid_curve_dx / curve_w).mul_add(line_w, -mid_line_dx).abs(),
        (mid_curve_dy / curve_w).mul_add(line_w, -mid_line_dy).abs(),
      );
      if error > threshold * 2.0 {
        return false;
      }

      prev = next;
    }

    true
  })
}

fn bezier_draw_samples_number_5(points: &[Pos2; 6], threshold: f32) -> usize {
  #![allow(clippy::similar_names)]
  #![allow(clippy::cast_precision_loss)]

  let d = bezier_derivative_5(points);

  lower_bound(2, MAX_CURVE_SAMPLES, |n| {
    let mut prev = points[0];
    for i in 1..n {
      let t = i as f32 / (n - 1) as f32;
      let next = sample_bezier(points, t);

      let m = t - 0.5 / (n - 1) as f32;

      // Compare absolute error of mid point
      let mid_line = ((prev.to_vec2() + next.to_vec2()) * 0.5).to_pos2();
      let mid_curve = sample_bezier(points, m);

      let error_sq = (mid_curve - mid_line).length_sq();
      if error_sq > threshold * threshold {
        return false;
      }

      // Compare angular error of mid point
      let mid_line_dx = next.x - prev.x;
      let mid_line_dy = next.y - prev.y;

      let line_w = f32::hypot(mid_line_dx, mid_line_dy);

      let d_curve = sample_bezier(&d, m);
      let mid_curve_dx = d_curve.x;
      let mid_curve_dy = d_curve.y;

      let curve_w = f32::hypot(mid_curve_dx, mid_curve_dy);

      let error = f32::max(
        (mid_curve_dx / curve_w).mul_add(line_w, -mid_line_dx).abs(),
        (mid_curve_dy / curve_w).mul_add(line_w, -mid_line_dy).abs(),
      );
      if error > threshold * 2.0 {
        return false;
      }

      prev = next;
    }

    true
  })
}

#[derive(Clone, Copy, PartialEq)]
struct WireArgs {
  frame_size: f32,
  from: Pos2,
  to: Pos2,
  radius: f32,
}

impl Default for WireArgs {
  fn default() -> Self {
    WireArgs { frame_size: 0.0, from: Pos2::ZERO, to: Pos2::ZERO, radius: 0.0 }
  }
}

struct WireCache3 {
  generation: u32,
  args: WireArgs,
  aabb: Rect,
  points: [Pos2; 4],
  threshold: f32,
  line: Vec<Pos2>,
}

impl Default for WireCache3 {
  fn default() -> Self {
    WireCache3 {
      generation: 0,
      args: WireArgs::default(),
      aabb: Rect::NOTHING,
      points: [Pos2::ZERO; 4],
      threshold: 0.0,
      line: Vec::new(),
    }
  }
}

impl WireCache3 {
  fn line(&mut self, threshold: f32) -> Vec<Pos2> {
    #[allow(clippy::float_cmp)]
    if !self.line.is_empty() && self.threshold == threshold {
      return self.line.clone();
    }

    let samples = bezier_draw_samples_number_3(&self.points, threshold);

    let line = (0..samples)
      .map(|i| {
        #[allow(clippy::cast_precision_loss)]
        let t = i as f32 / (samples - 1) as f32;
        sample_bezier(&self.points, t)
      })
      .collect::<Vec<Pos2>>();

    self.threshold = threshold;
    self.line.clone_from(&line);

    line
  }
}

struct WireCache5 {
  generation: u32,
  args: WireArgs,
  aabb: Rect,
  points: [Pos2; 6],
  threshold: f32,
  line: Vec<Pos2>,
}

impl Default for WireCache5 {
  fn default() -> Self {
    Self {
      generation: 0,
      args: WireArgs::default(),
      aabb: Rect::NOTHING,
      points: [Pos2::ZERO; 6],
      threshold: 0.0,
      line: Vec::new(),
    }
  }
}

impl WireCache5 {
  fn line(&mut self, threshold: f32) -> Vec<Pos2> {
    #[allow(clippy::float_cmp)]
    if !self.line.is_empty() && self.threshold == threshold {
      return self.line.clone();
    }

    let samples = bezier_draw_samples_number_5(&self.points, threshold);

    let line = (0..samples)
      .map(|i| {
        #[allow(clippy::cast_precision_loss)]
        let t = i as f32 / (samples - 1) as f32;
        sample_bezier(&self.points, t)
      })
      .collect::<Vec<Pos2>>();

    self.threshold = threshold;
    self.line.clone_from(&line);

    line
  }
}

#[derive(Default)]
struct WireCacheAA {
  generation: u32,
  args: WireArgs,
  aawire: AxisAlignedWire,
  threshold: f32,
  line: Vec<Pos2>,
}

impl WireCacheAA {
  fn line(&mut self, threshold: f32) -> Vec<Pos2> {
    #[allow(clippy::float_cmp)]
    if !self.line.is_empty() && self.threshold == threshold {
      return self.line.clone();
    }

    let mut line = Vec::new();

    for i in 0..self.aawire.turns {
      // shapes.push(Shape::line_segment(
      //     [wire.segments[i].0, wire.segments[i].1],
      //     stroke,
      // ));

      // Draw segment first
      line.push(self.aawire.segments[i].0);
      line.push(self.aawire.segments[i].1);

      if self.aawire.turn_radii[i] > 0.0 {
        let turn = self.aawire.turn_centers[i];
        let samples = turn_samples_number(self.aawire.turn_radii[i], self.threshold);

        let start = self.aawire.segments[i].1;
        let end = self.aawire.segments[i + 1].0;

        let sin_x = end.x - turn.x;
        let cos_x = start.x - turn.x;

        let sin_y = end.y - turn.y;
        let cos_y = start.y - turn.y;

        for j in 1..samples {
          #[allow(clippy::cast_precision_loss)]
          let a = std::f32::consts::FRAC_PI_2 * (j as f32 / samples as f32);

          let (sin_a, cos_a) = a.sin_cos();

          let point: Pos2 = pos2(
            cos_x.mul_add(cos_a, sin_x.mul_add(sin_a, turn.x)),
            cos_y.mul_add(cos_a, sin_y.mul_add(sin_a, turn.y)),
          );
          line.push(point);
        }
      }
    }

    line.push(self.aawire.segments[self.aawire.turns].0);
    line.push(self.aawire.segments[self.aawire.turns].1);

    self.threshold = threshold;
    self.line.clone_from(&line);

    line
  }
}

#[derive(Default)]
struct WiresCache {
  generation: u32,
  bezier_3: HashMap<WireId, WireCache3>,
  bezier_5: HashMap<WireId, WireCache5>,
  axis_aligned: HashMap<WireId, WireCacheAA>,
}

impl CacheTrait for WiresCache {
  fn update(&mut self) {
    self.bezier_3.retain(|_, cache| cache.generation == self.generation);
    self.bezier_5.retain(|_, cache| cache.generation == self.generation);
    self.axis_aligned.retain(|_, cache| cache.generation == self.generation);

    self.generation = self.generation.wrapping_add(1);
  }

  fn len(&self) -> usize {
    self.bezier_3.len() + self.bezier_5.len() + self.axis_aligned.len()
  }

  fn as_any_mut(&mut self) -> &mut dyn std::any::Any {
    self
  }
}

impl WiresCache {
  pub fn get_3(&mut self, wire: WireId, args: WireArgs) -> &mut WireCache3 {
    let cached = self.bezier_3.entry(wire).or_default();

    cached.generation = self.generation;

    if cached.args == args {
      return cached;
    }

    let points = wire_bezier_3(args.frame_size, args.from, args.to);
    let aabb = Rect::from_points(&points);

    cached.args = args;
    cached.points = points;
    cached.aabb = aabb;
    cached.line.clear();

    cached
  }

  pub fn get_5(&mut self, wire: WireId, args: WireArgs) -> &mut WireCache5 {
    let cached = self.bezier_5.entry(wire).or_default();

    cached.generation = self.generation;

    if cached.args == args {
      return cached;
    }

    let points = wire_bezier_5(args.frame_size, args.from, args.to);
    let aabb = Rect::from_points(&points);

    cached.args = args;
    cached.points = points;
    cached.aabb = aabb;
    cached.line.clear();

    cached
  }

  #[allow(clippy::too_many_arguments)]
  pub fn get_aa(&mut self, wire: WireId, args: WireArgs) -> &mut WireCacheAA {
    let cached = self.axis_aligned.entry(wire).or_default();

    cached.generation = self.generation;

    if cached.args == args {
      return cached;
    }

    let aawire = wire_axis_aligned(args.radius, args.frame_size, args.from, args.to);

    cached.args = args;
    cached.aawire = aawire;
    cached.line.clear();

    cached
  }
}

#[inline(never)]
fn draw_bezier_3(
  ui: &Ui,
  wire: WireId,
  args: WireArgs,
  stroke: Stroke,
  threshold: f32,
  shapes: &mut Vec<Shape>,
) {
  debug_assert!(ui.is_visible(), "Must be checked earlier");

  let clip_rect = ui.clip_rect();

  ui.memory_mut(|m| {
    let cached = m.caches.cache::<WiresCache>().get_3(wire, args);

    if cached.aabb.intersects(clip_rect) {
      shapes.push(Shape::line(cached.line(threshold), stroke));
    }
  });

  // {
  //     let samples = bezier_draw_samples_number_3(points, threshold);
  //     shapes.push(Shape::line(
  //         points.to_vec(),
  //         Stroke::new(1.0, Color32::PLACEHOLDER),
  //     ));

  //     let samples = 100;
  //     shapes.push(Shape::line(
  //         (0..samples)
  //             .map(|i| {
  //                 #[allow(clippy::cast_precision_loss)]
  //                 let t = i as f32 / (samples - 1) as f32;
  //                 sample_bezier(points, t)
  //             })
  //             .collect(),
  //         Stroke::new(1.0, Color32::PLACEHOLDER),
  //     ));
  // }
}

fn draw_bezier_5(
  ui: &Ui,
  wire: WireId,
  args: WireArgs,
  stroke: Stroke,
  threshold: f32,
  shapes: &mut Vec<Shape>,
) {
  debug_assert!(ui.is_visible(), "Must be checked earlier");

  let clip_rect = ui.clip_rect();

  ui.memory_mut(|m| {
    let cached = m.caches.cache::<WiresCache>().get_5(wire, args);

    if cached.aabb.intersects(clip_rect) {
      shapes.push(Shape::line(cached.line(threshold), stroke));
    }
  });

  // {
  //     let samples = bezier_draw_samples_number_5(points, threshold);
  //     shapes.push(Shape::line(
  //         points.to_vec(),
  //         Stroke::new(1.0, Color32::PLACEHOLDER),
  //     ));

  //     let samples = 100;
  //     shapes.push(Shape::line(
  //         (0..samples)
  //             .map(|i| {
  //                 #[allow(clippy::cast_precision_loss)]
  //                 let t = i as f32 / (samples - 1) as f32;
  //                 sample_bezier(points, t)
  //             })
  //             .collect(),
  //         Stroke::new(1.0, Color32::PLACEHOLDER),
  //     ));
  // }
}

// #[allow(clippy::let_and_return)]
fn sample_bezier(points: &[Pos2], t: f32) -> Pos2 {
  match *points {
    [] => unimplemented!(),
    [p0] => p0,
    [p0, p1] => p0.lerp(p1, t),
    [p0, p1, p2] => {
      let p0_0 = p0;
      let p1_0 = p1;
      let p2_0 = p2;

      let p0_1 = p0_0.lerp(p1_0, t);
      let p1_1 = p1_0.lerp(p2_0, t);

      p0_1.lerp(p1_1, t)
    }
    [p0, p1, p2, p3] => {
      let p0_0 = p0;
      let p1_0 = p1;
      let p2_0 = p2;
      let p3_0 = p3;

      let p0_1 = p0_0.lerp(p1_0, t);
      let p1_1 = p1_0.lerp(p2_0, t);
      let p2_1 = p2_0.lerp(p3_0, t);

      sample_bezier(&[p0_1, p1_1, p2_1], t)
    }
    [p0, p1, p2, p3, p4] => {
      let p0_0 = p0;
      let p1_0 = p1;
      let p2_0 = p2;
      let p3_0 = p3;
      let p4_0 = p4;

      let p0_1 = p0_0.lerp(p1_0, t);
      let p1_1 = p1_0.lerp(p2_0, t);
      let p2_1 = p2_0.lerp(p3_0, t);
      let p3_1 = p3_0.lerp(p4_0, t);

      sample_bezier(&[p0_1, p1_1, p2_1, p3_1], t)
    }
    [p0, p1, p2, p3, p4, p5] => {
      let p0_0 = p0;
      let p1_0 = p1;
      let p2_0 = p2;
      let p3_0 = p3;
      let p4_0 = p4;
      let p5_0 = p5;

      let p0_1 = p0_0.lerp(p1_0, t);
      let p1_1 = p1_0.lerp(p2_0, t);
      let p2_1 = p2_0.lerp(p3_0, t);
      let p3_1 = p3_0.lerp(p4_0, t);
      let p4_1 = p4_0.lerp(p5_0, t);

      sample_bezier(&[p0_1, p1_1, p2_1, p3_1, p4_1], t)
    }
    _ => unimplemented!(),
  }
}

fn split_bezier_3(points: &[Pos2; 4], t: f32) -> [[Pos2; 4]; 2] {
  let [p0, p1, p2, p3] = *points;

  let p0_0 = p0;
  let p1_0 = p1;
  let p2_0 = p2;
  let p3_0 = p3;

  let p0_1 = p0_0.lerp(p1_0, t);
  let p1_1 = p1_0.lerp(p2_0, t);
  let p2_1 = p2_0.lerp(p3_0, t);

  let p0_2 = p0_1.lerp(p1_1, t);
  let p1_2 = p1_1.lerp(p2_1, t);

  let p0_3 = p0_2.lerp(p1_2, t);

  [[p0_0, p0_1, p0_2, p0_3], [p0_3, p1_2, p2_1, p3_0]]
}

fn hit_wire_bezier_3(
  ctx: &Context,
  wire: WireId,
  args: WireArgs,
  pos: Pos2,
  hit_threshold: f32,
) -> bool {
  let (aabb, points) = ctx.memory_mut(|m| {
    let cache = m.caches.cache::<WiresCache>().get_3(wire, args);

    (cache.aabb, cache.points)
  });

  let aabb_e = aabb.expand(hit_threshold);
  if !aabb_e.contains(pos) {
    return false;
  }

  hit_bezier_3(&points, pos, hit_threshold)
}

fn hit_bezier_3(points: &[Pos2; 4], pos: Pos2, hit_threshold: f32) -> bool {
  let samples = bezier_hit_samples_number(points, hit_threshold);
  if samples > 8 {
    let [points1, points2] = split_bezier_3(points, 0.5);

    let aabb_e = Rect::from_points(&points1).expand(hit_threshold);
    if aabb_e.contains(pos) && hit_bezier_3(&points1, pos, hit_threshold) {
      return true;
    }
    let aabb_e = Rect::from_points(&points2).expand(hit_threshold);
    if aabb_e.contains(pos) && hit_bezier_3(&points2, pos, hit_threshold) {
      return true;
    }
    return false;
  }

  let threshold_sq = hit_threshold * hit_threshold;

  for i in 0..samples {
    #[allow(clippy::cast_precision_loss)]
    let t = i as f32 / (samples - 1) as f32;
    let p = sample_bezier(points, t);
    if p.distance_sq(pos) <= threshold_sq {
      return true;
    }
  }

  false
}

fn split_bezier_5(points: &[Pos2; 6], t: f32) -> [[Pos2; 6]; 2] {
  let [p0, p1, p2, p3, p4, p5] = *points;

  let p0_0 = p0;
  let p1_0 = p1;
  let p2_0 = p2;
  let p3_0 = p3;
  let p4_0 = p4;
  let p5_0 = p5;

  let p0_1 = p0_0.lerp(p1_0, t);
  let p1_1 = p1_0.lerp(p2_0, t);
  let p2_1 = p2_0.lerp(p3_0, t);
  let p3_1 = p3_0.lerp(p4_0, t);
  let p4_1 = p4_0.lerp(p5_0, t);

  let p0_2 = p0_1.lerp(p1_1, t);
  let p1_2 = p1_1.lerp(p2_1, t);
  let p2_2 = p2_1.lerp(p3_1, t);
  let p3_2 = p3_1.lerp(p4_1, t);

  let p0_3 = p0_2.lerp(p1_2, t);
  let p1_3 = p1_2.lerp(p2_2, t);
  let p2_3 = p2_2.lerp(p3_2, t);

  let p0_4 = p0_3.lerp(p1_3, t);
  let p1_4 = p1_3.lerp(p2_3, t);

  let p0_5 = p0_4.lerp(p1_4, t);

  [[p0_0, p0_1, p0_2, p0_3, p0_4, p0_5], [p0_5, p1_4, p2_3, p3_2, p4_1, p5_0]]
}

fn hit_wire_bezier_5(
  ctx: &Context,
  wire: WireId,
  args: WireArgs,
  pos: Pos2,
  hit_threshold: f32,
) -> bool {
  let (aabb, points) = ctx.memory_mut(|m| {
    let cache = m.caches.cache::<WiresCache>().get_5(wire, args);

    (cache.aabb, cache.points)
  });

  let aabb_e = aabb.expand(hit_threshold);
  if !aabb_e.contains(pos) {
    return false;
  }

  hit_bezier_5(&points, pos, hit_threshold)
}

fn hit_bezier_5(points: &[Pos2; 6], pos: Pos2, hit_threshold: f32) -> bool {
  let samples = bezier_hit_samples_number(points, hit_threshold);
  if samples > 16 {
    let [points1, points2] = split_bezier_5(points, 0.5);
    let aabb_e = Rect::from_points(&points1).expand(hit_threshold);
    if aabb_e.contains(pos) && hit_bezier_5(&points1, pos, hit_threshold) {
      return true;
    }
    let aabb_e = Rect::from_points(&points2).expand(hit_threshold);
    if aabb_e.contains(pos) && hit_bezier_5(&points2, pos, hit_threshold) {
      return true;
    }
    return false;
  }

  let threshold_sq = hit_threshold * hit_threshold;

  for i in 0..samples {
    #[allow(clippy::cast_precision_loss)]
    let t = i as f32 / (samples - 1) as f32;
    let p = sample_bezier(points, t);

    if p.distance_sq(pos) <= threshold_sq {
      return true;
    }
  }

  false
}

#[derive(Clone, Copy, PartialEq)]
struct AxisAlignedWire {
  aabb: Rect,
  turns: usize,
  segments: [(Pos2, Pos2); 5],
  turn_centers: [Pos2; 4],
  turn_radii: [f32; 4],
}

impl Default for AxisAlignedWire {
  #[inline]
  fn default() -> Self {
    Self {
      aabb: Rect::NOTHING,
      turns: 0,
      segments: [(Pos2::ZERO, Pos2::ZERO); 5],
      turn_centers: [Pos2::ZERO; 4],
      turn_radii: [0.0; 4],
    }
  }
}

#[allow(clippy::too_many_lines)]
fn wire_axis_aligned(corner_radius: f32, frame_size: f32, from: Pos2, to: Pos2) -> AxisAlignedWire {
  let corner_radius = corner_radius.max(0.0);

  let half_height = f32::abs(from.y - to.y) / 2.0;
  let max_radius = (half_height / 2.0).min(corner_radius);

  let frame_size = frame_size.max(max_radius * 2.0);

  let zero_segment = (Pos2::ZERO, Pos2::ZERO);

  if from.x + frame_size <= to.x - frame_size {
    if f32::abs(from.y - to.y) < 1.0 {
      // Single segment case.
      AxisAlignedWire {
        aabb: Rect::from_two_pos(from, to),
        segments: [(from, to), zero_segment, zero_segment, zero_segment, zero_segment],
        turns: 0,
        turn_centers: [Pos2::ZERO; 4],
        turn_radii: [f32::NAN; 4],
      }
    } else {
      // Two turns case.
      let mid_x = f32::midpoint(from.x, to.x);
      let half_width = (to.x - from.x) / 2.0;

      let turn_radius = max_radius.min(half_width);

      let turn_vert_len = if from.y < to.y { turn_radius } else { -turn_radius };

      let segments = [
        (from, pos2(mid_x - turn_radius, from.y)),
        (pos2(mid_x, from.y + turn_vert_len), pos2(mid_x, to.y - turn_vert_len)),
        (pos2(mid_x + turn_radius, to.y), to),
        zero_segment,
        zero_segment,
      ];

      let turn_centers = [
        pos2(mid_x - turn_radius, from.y + turn_vert_len),
        pos2(mid_x + turn_radius, to.y - turn_vert_len),
        Pos2::ZERO,
        Pos2::ZERO,
      ];

      let turn_radii = [turn_radius, turn_radius, f32::NAN, f32::NAN];

      AxisAlignedWire {
        aabb: Rect::from_two_pos(from, to),
        turns: 2,
        segments,
        turn_centers,
        turn_radii,
      }
    }
  } else {
    // Four turns case.
    let mid = f32::midpoint(from.y, to.y);

    let right = from.x + frame_size;
    let left = to.x - frame_size;

    let half_width = f32::abs(right - left) / 2.0;

    let ends_turn_radius = max_radius;
    let middle_turn_radius = max_radius.min(half_width);

    let ends_turn_vert_len = if from.y < to.y { ends_turn_radius } else { -ends_turn_radius };

    let middle_turn_vert_len = if from.y < to.y { middle_turn_radius } else { -middle_turn_radius };

    let segments = [
      (from, pos2(right - ends_turn_radius, from.y)),
      (pos2(right, from.y + ends_turn_vert_len), pos2(right, mid - middle_turn_vert_len)),
      (pos2(right - middle_turn_radius, mid), pos2(left + middle_turn_radius, mid)),
      (pos2(left, mid + middle_turn_vert_len), pos2(left, to.y - ends_turn_vert_len)),
      (pos2(left + ends_turn_radius, to.y), to),
    ];

    let turn_centers = [
      pos2(right - ends_turn_radius, from.y + ends_turn_vert_len),
      pos2(right - middle_turn_radius, mid - middle_turn_vert_len),
      pos2(left + middle_turn_radius, mid + middle_turn_vert_len),
      pos2(left + ends_turn_radius, to.y - ends_turn_vert_len),
    ];

    let turn_radii = [ends_turn_radius, middle_turn_radius, middle_turn_radius, ends_turn_radius];

    AxisAlignedWire {
      aabb: Rect::from_min_max(
        pos2(f32::min(left, from.x), f32::min(from.y, to.y)),
        pos2(f32::max(right, to.x), f32::max(from.y, to.y)),
      ),
      turns: 4,
      segments,
      turn_centers,
      turn_radii,
    }
  }
}

fn hit_wire_axis_aligned(
  ctx: &Context,
  wire: WireId,
  args: WireArgs,
  pos: Pos2,
  hit_threshold: f32,
) -> bool {
  let aawire = ctx.memory_mut(|m| {
    let cache = m.caches.cache::<WiresCache>().get_aa(wire, args);

    cache.aawire
  });

  // Check AABB first
  if !aawire.aabb.expand(hit_threshold).contains(pos) {
    return false;
  }

  // Check all straight segments first
  // Number of segments is number of turns + 1
  for i in 0..aawire.turns + 1 {
    let (start, end) = aawire.segments[i];

    // Segments are always axis aligned
    // So we can use AABB for checking
    if Rect::from_two_pos(start, end).expand(hit_threshold).contains(pos) {
      return true;
    }
  }

  // Check all turns
  for i in 0..aawire.turns {
    if aawire.turn_radii[i] > 0.0 {
      let turn = aawire.turn_centers[i];
      let turn_aabb = Rect::from_two_pos(aawire.segments[i].1, aawire.segments[i + 1].0);
      if !turn_aabb.contains(pos) {
        continue;
      }

      // Avoid sqrt
      let dist2 = (turn - pos).length_sq();
      let min = aawire.turn_radii[i] - hit_threshold;
      let max = aawire.turn_radii[i] + hit_threshold;

      if dist2 <= max * max && dist2 >= min * min {
        return true;
      }
    }
  }

  false
}

fn turn_samples_number(radius: f32, threshold: f32) -> usize {
  #![allow(clippy::cast_sign_loss)]
  #![allow(clippy::cast_possible_truncation)]
  #![allow(clippy::cast_precision_loss)]

  if threshold / radius >= 1.0 {
    return 2;
  }

  let a: f32 = (1.0 - threshold / radius).acos();
  let samples =
    (std::f32::consts::PI / (4.0 * a) + 1.0).min(MAX_CURVE_SAMPLES as f32).ceil() as usize;

  samples.clamp(2, MAX_CURVE_SAMPLES)
}

#[allow(clippy::too_many_arguments)]
fn draw_axis_aligned(
  ui: &Ui,
  wire: WireId,
  args: WireArgs,
  stroke: Stroke,
  threshold: f32,
  shapes: &mut Vec<Shape>,
) {
  debug_assert!(ui.is_visible(), "Must be checked earlier");

  let clip_rect = ui.clip_rect();
  ui.memory_mut(|m| {
    let cached = m.caches.cache::<WiresCache>().get_aa(wire, args);

    if cached.aawire.aabb.intersects(clip_rect) {
      shapes.push(Shape::line(cached.line(threshold), stroke));
    }
  });
}

/// Very basic lower-bound algorithm
/// Finds the smallest number in range [min, max) that satisfies the predicate
/// If no such number exists, returns max
///
/// For the algorithm to work, the predicate must be monotonic
/// i.e. if f(i) is true, then f(j) is true for all j within (i, max)
/// and if f(i) is false, then f(j) is false for all j within [min, i)
fn lower_bound(min: usize, max: usize, f: impl Fn(usize) -> bool) -> usize {
  #![allow(clippy::similar_names)]

  let mut min = min;
  let mut max = max;

  while min < max {
    let mid = usize::midpoint(min, max);
    if f(mid) {
      max = mid;
    } else {
      min = mid + 1;
    }
  }

  max

  // for i in min..max {
  //     if f(i) {
  //         return i;
  //     }
  // }
  // max
}