package collatz

import (
	"math/big"
	"testing"
)

type MockParser struct {
	value *big.Int
}

func (m *MockParser) Parse() (*big.Int, error) {
	return m.value, nil
}

func TestNewCalculator(t *testing.T) {
	parser := &MockParser{}
	calculator := NewCalculator(parser)

	if calculator.parser != parser {
		t.Errorf("Expected parser to be %v, got %v", parser, calculator.parser)
	}

	if calculator.one.Cmp(big.NewInt(1)) != 0 {
		t.Errorf("Expected one to be 1, got %v", calculator.one)
	}

	if calculator.two.Cmp(big.NewInt(2)) != 0 {
		t.Errorf("Expected two to be 2, got %v", calculator.two)
	}

	if calculator.three.Cmp(big.NewInt(3)) != 0 {
		t.Errorf("Expected three to be 3, got %v", calculator.three)
	}
}

func TestCalculateCollatz(t *testing.T) {
	parser := &MockParser{value: big.NewInt(6)}
	calculator := NewCalculator(parser)

	sequence, err := calculator.CalculateCollatz()
	if err != nil {
		t.Errorf("Expected no error, got %v", err)
	}
	if sequence.Iterations != 8 {
		t.Errorf("Expected 8 iterations, got %v", sequence.Iterations)
	}
}