# Vec2 — foundational two-dimensional vectors over Base F32.
#
# Coordinates are F32. Constructors intentionally do not validate or normalize
# values. This layer avoids sqrt, trig, and all non-Base dependencies.
import Base

type Vec2 is Data:
  Vec2{x: F32, y: F32}

# Constructors and axes.
def Vec2.make(x: F32, y: F32) -> Vec2:
  Vec2{x, y}

def Vec2.zero() -> Vec2:
  Vec2{0.0, 0.0}

def Vec2.unit_x() -> Vec2:
  Vec2{1.0, 0.0}

def Vec2.unit_y() -> Vec2:
  Vec2{0.0, 1.0}

# Field projections.
def Vec2.x(v: Vec2) -> F32:
  match v:
    case Vec2{x, y}:
      x

def Vec2.y(v: Vec2) -> F32:
  match v:
    case Vec2{x, y}:
      y

# Component-wise arithmetic.
def Vec2.add(a: Vec2, b: Vec2) -> Vec2:
  match a b:
    case Vec2{ax, ay} Vec2{bx, by}:
      Vec2{F32.add(ax, bx), F32.add(ay, by)}

def Vec2.sub(a: Vec2, b: Vec2) -> Vec2:
  match a b:
    case Vec2{ax, ay} Vec2{bx, by}:
      Vec2{F32.sub(ax, bx), F32.sub(ay, by)}

def Vec2.scale(v: Vec2, +s: F32) -> Vec2:
  match v:
    case Vec2{x, y}:
      Vec2{F32.mul(x, s), F32.mul(y, s)}

# Dot product and squared length. length_sq deliberately avoids sqrt.
def Vec2.dot(a: Vec2, b: Vec2) -> F32:
  match a b:
    case Vec2{ax, ay} Vec2{bx, by}:
      F32.add(F32.mul(ax, bx), F32.mul(ay, by))

def Vec2.length_sq(+v: Vec2) -> F32:
  Vec2.dot(v, v)

# Affine interpolation: a + (b - a) * t.
def Vec2.lerp(+a: Vec2, b: Vec2, t: F32) -> Vec2:
  Vec2.add(a, Vec2.scale(Vec2.sub(b, a), t))