#include <catch2/catch_test_macros.hpp>

#include "Calculator.hpp"
#include "Operand.hpp"

constexpr auto addiction = [](auto lhs, auto rhs) { return lhs + rhs; };
constexpr auto subtraction = [](auto lhs, auto rhs) { return lhs - rhs; };

TEST_CASE("Calculator - can add operations", "[calculator-challenge]")
{
    Calculator calculator;

    calculator.addOperation("a", IntegerOperand{5}, IntegerOperand{10}, addiction);
    CHECK(calculator.computeLastValue() == 15.0);

    calculator.addOperation("b", IntegerOperand{1}, IntegerOperand{5}, addiction);
    CHECK(calculator.computeLastValue() == 6.0);

    calculator.addOperation("c", IntegerOperand{1}, IntegerOperand{5}, subtraction);
    CHECK(calculator.computeLastValue() == -4.0);
}

TEST_CASE("Calculator - can undo operations", "[calculator-challenge]")
{
    Calculator calculator;

    calculator.addOperation("a", IntegerOperand{5}, IntegerOperand{10}, addiction);
    CHECK(calculator.computeLastValue() == 15.0);
    calculator.addOperation("b", IntegerOperand{1}, IntegerOperand{5}, subtraction);
    CHECK(calculator.computeLastValue() == -4.0);

    SECTION("one by one")
    {
        calculator.undoOperation(1);
        CHECK(calculator.computeLastValue() == 15.0);

        calculator.undoOperation(1);
        CHECK(calculator.computeLastValue() == 0.0);
    }

    SECTION("all")
    {
        calculator.undoOperation(2);
        CHECK(calculator.computeLastValue() == 0.0);
    }

    SECTION("more than was added")
    {
        calculator.undoOperation(50);
        CHECK(calculator.computeLastValue() == 0.0);
    }
}

TEST_CASE("Calculator - can add operations with variables", "[calculator-challenge]")
{
    Calculator calculator;

    calculator.addOperation("a", IntegerOperand{1}, IntegerOperand{2}, addiction);
    CHECK(calculator.computeLastValue() == 3);

    calculator.addOperation("b", VariableOperand{"a"}, IntegerOperand{10}, addiction);
    CHECK(calculator.computeLastValue() == 13);

    calculator.addOperation("b", VariableOperand{"a"}, IntegerOperand{2}, addiction);
    CHECK(calculator.computeLastValue() == 5);
}

TEST_CASE("Calculator - if a variable is missing the last available is returned", "[calculator-challenge]")
{
    Calculator calculator;

    calculator.addOperation("a", VariableOperand{"c"}, IntegerOperand{10}, addiction);
    CHECK(calculator.computeLastValue() == 0.0);

    calculator.addOperation("a", IntegerOperand{1}, IntegerOperand{2}, addiction);
    CHECK(calculator.computeLastValue() == 3);

    calculator.addOperation("a", VariableOperand{"c"}, IntegerOperand{10}, addiction);
    CHECK(calculator.computeLastValue() == 3.0);
}