import fortheck/error
import fortheck/stack
import gleam/iterator
import gleam/pair
import gleam/result
import gleeunit
import gleeunit/should

pub fn main() {
  gleeunit.main()
}

pub fn new_test() {
  stack.new()
  |> stack.to_list
  |> should.equal([])
}

pub fn push_test() {
  stack.new()
  |> stack.push(123)
  |> should.be_ok
  |> stack.push(456)
  |> should.be_ok
  |> stack.to_list
  |> should.equal([123, 456])
}

pub fn push_stack_overflow_test() {
  iterator.range(1, 131_072)
  |> iterator.try_fold(stack.new(), stack.push)
  |> should.be_ok
  |> stack.push(1)
  |> should.be_error
  |> should.equal(error.StackOverflow)
}

pub fn from_list_test() {
  [123, 456]
  |> stack.from_list
  |> should.be_ok
  |> stack.to_list
  |> should.equal([123, 456])
}

pub fn pop_stack_underflow_test() {
  stack.new()
  |> stack.pop
  |> should.be_error
  |> should.equal(error.StackUnderflow)
}

pub fn pop_test() {
  let assert Ok(stack) = stack.from_list([1, 2, 3])

  stack
  |> stack.pop
  |> should.be_ok
  |> pair.first
  |> should.equal(3)

  {
    use a, _ <- stack.try_pop(stack)
    Ok(a)
  }
  |> should.be_ok
  |> should.equal(3)
}

pub fn pop_2_test() {
  let assert Ok(stack) = stack.from_list([1, 2, 3])

  stack
  |> stack.pop_2
  |> should.be_ok
  |> pair.first
  |> should.equal(#(2, 3))

  {
    use a, b, _ <- stack.try_pop_2(stack)
    Ok(#(a, b))
  }
  |> should.be_ok
  |> should.equal(#(2, 3))
}

pub fn pop_2_stack_underflow_test() {
  stack.from_list([1])
  |> result.try(stack.pop_2)
  |> should.be_error
  |> should.equal(error.StackUnderflow)
}