@no_std
@settings(defaultLengthUnit = mm)

/// The value of `pi`, Archimedes’ constant (π).
///
/// ```
/// circumference = 70
///
/// exampleSketch = startSketchOn(XZ)
///  |> circle(center = [0, 0], radius = circumference / (2 * PI))
///
/// example = extrude(exampleSketch, length = 5)
/// ```
export PI = 3.14159265358979323846264338327950288_

/// The value of Euler’s number `e`.
///
/// ```
/// exampleSketch = startSketchOn(XZ)
///   |> startProfileAt([0, 0], %)
///   |> angledLine({
///     angle = 30,
///     length = 2 * E ^ 2,
///   }, %)
///   |> yLine(endAbsolute = 0)
///   |> close()
///
/// example = extrude(exampleSketch, length = 10)
/// ```
export E = 2.71828182845904523536028747135266250_

/// The value of `tau`, the full circle constant (τ). Equal to 2π.
///
/// ```
/// exampleSketch = startSketchOn(XZ)
///   |> startProfileAt([0, 0], %)
///   |> angledLine({
///     angle = 50,
///     length = 10 * TAU,
///   }, %)
///   |> yLine(endAbsolute = 0)
///   |> close()
///
/// example = extrude(exampleSketch, length = 5)
/// ```
export TAU = 6.28318530717958647692528676655900577_

/// Compute the cosine of a number (in radians).
///
/// ```
/// exampleSketch = startSketchOn(XZ)
///   |> startProfileAt([0, 0], %)
///   |> angledLine({
///     angle = 30,
///     length = 3 / cos(toRadians(30)),
///   }, %)
///   |> yLine(endAbsolute = 0)
///   |> close()
///
/// example = extrude(exampleSketch, length = 5)
/// ```
@(impl = std_rust)
export fn cos(@num: number(rad)): number(_) {}

/// Compute the sine of a number (in radians).
///
/// ```
/// exampleSketch = startSketchOn(XZ)
///   |> startProfileAt([0, 0], %)
///   |> angledLine({
///     angle = 50,
///     length = 15 / sin(toDegrees(135)),
///   }, %)
///   |> yLine(endAbsolute = 0)
///   |> close()
///
/// example = extrude(exampleSketch, length = 5)
/// ```
@(impl = std_rust)
export fn sin(@num: number(rad)): number(_) {}

/// Compute the tangent of a number (in radians).
///
/// ```
/// exampleSketch = startSketchOn(XZ)
///   |> startProfileAt([0, 0], %)
///   |> angledLine({
///     angle = 50,
///     length = 50 * tan(1/2),
///   }, %)
///   |> yLine(endAbsolute = 0)
///   |> close()
///
/// example = extrude(exampleSketch, length = 5)
/// ```
@(impl = std_rust)
export fn tan(@num: number(rad)): number(_) {}

/// Convert polar/sphere (azimuth, elevation, distance) coordinates to
/// cartesian (x/y/z grid) coordinates.
///
/// ```
/// exampleSketch = startSketchOn(XZ)
///   |> startProfileAt([0, 0], %)
///   |> line(end = polar(angle = 30, length = 5), tag = $thing)
///   |> line(end = [0, 5])
///   |> line(end = [segEndX(thing), 0])
///   |> line(end = [-20, 10])
///   |> close()
///  
/// example = extrude(exampleSketch, length = 5)
/// ```
export fn polar(angle: number(deg), length: number(mm)): [number(mm); 2] {
  // TODO could be done by implicit conversion when UoM coercions are activated.
  rads = toRadians(angle)
  x = length * cos(rads)
  y = length * sin(rads)
  return [x, y]
}