defmodule Firebird.WasmModules.Math do
  Module.register_attribute(__MODULE__, :wasm, accumulate: true)

  @moduledoc """
  Mathematical functions compiled to WebAssembly.

  These pure functions demonstrate Elixir-to-WASM compilation
  for common math operations.
  """

  @wasm true
  def add(a, b), do: a + b

  @wasm true
  def subtract(a, b), do: a - b

  @wasm true
  def multiply(a, b), do: a * b

  @wasm true
  def divide(a, b), do: div(a, b)

  @wasm true
  def modulo(a, b), do: rem(a, b)

  @wasm true
  def negate(a), do: 0 - a

  @wasm true
  def abs_val(n) do
    if n >= 0 do
      n
    else
      0 - n
    end
  end

  @wasm true
  def max_val(a, b) do
    if a >= b do
      a
    else
      b
    end
  end

  @wasm true
  def min_val(a, b) do
    if a <= b do
      a
    else
      b
    end
  end

  @wasm true
  def clamp(val, lo, hi) do
    if val < lo do
      lo
    else
      if val > hi do
        hi
      else
        val
      end
    end
  end

  @wasm true
  def sign(n) do
    if n > 0 do
      1
    else
      if n < 0 do
        0 - 1
      else
        0
      end
    end
  end

  @wasm true
  def fibonacci(0), do: 0
  def fibonacci(1), do: 1
  def fibonacci(n), do: fibonacci(n - 1) + fibonacci(n - 2)

  @wasm true
  def factorial(0), do: 1
  def factorial(n), do: n * factorial(n - 1)

  @wasm true
  def power(_, 0), do: 1
  def power(base, exp), do: base * power(base, exp - 1)

  @wasm true
  def gcd(a, 0), do: a
  def gcd(a, b), do: gcd(b, rem(a, b))

  @wasm true
  def sum_to(0), do: 0
  def sum_to(n), do: n + sum_to(n - 1)

  @wasm true
  def is_even(n) do
    if rem(n, 2) == 0 do
      1
    else
      0
    end
  end

  @wasm true
  def collatz_steps(1), do: 0

  def collatz_steps(n) do
    if rem(n, 2) == 0 do
      1 + collatz_steps(div(n, 2))
    else
      1 + collatz_steps(3 * n + 1)
    end
  end
end