//          Copyright Joakim Karlsson & Kim Gräsman 2010-2012.
// Distributed under the Boost Software License, Version 1.0.
//    (See accompanying file LICENSE_1_0.txt or copy at
//          http://www.boost.org/LICENSE_1_0.txt)

#ifndef SNOWHOUSE_EQUALSCONSTRAINT_H
#define SNOWHOUSE_EQUALSCONSTRAINT_H

#include "expressions/expression.h"

namespace snowhouse
{
    template <typename ExpectedType>
    struct EqualsConstraint : Expression<EqualsConstraint<ExpectedType>>
    {
        EqualsConstraint(const ExpectedType& expected): m_expected(expected) {}

        template <typename ActualType>
        bool operator()(const ActualType& actual) const
        {
            return (m_expected == actual);
        }

        ExpectedType m_expected;
    };

    template <typename ExpectedType>
    inline EqualsConstraint<ExpectedType> Equals(const ExpectedType& expected)
    {
        return EqualsConstraint<ExpectedType>(expected);
    }

    inline EqualsConstraint<std::string> Equals(const char* expected)
    {
        return EqualsConstraint<std::string>(expected);
    }

    inline EqualsConstraint<bool> IsFalse()
    {
        return EqualsConstraint<bool>(false);
    }

    inline EqualsConstraint<bool> IsTrue()
    {
        return EqualsConstraint<bool>(true);
    }

    inline EqualsConstraint<std::nullptr_t> IsNull()
    {
        return EqualsConstraint<std::nullptr_t>(nullptr);
    }

    template <>
    struct Stringizer<EqualsConstraint<bool>>
    {
        static std::string ToString(const EqualsConstraint<bool>& constraint)
        {
            return constraint.m_expected ? "true" : "false";
        }
    };

    template <typename ExpectedType>
    struct Stringizer<EqualsConstraint<ExpectedType>>
    {
        static std::string ToString(
            const EqualsConstraint<ExpectedType>& constraint)
        {
            std::ostringstream builder;
            builder << "equal to "
                    << snowhouse::Stringize(constraint.m_expected);

            return builder.str();
        }
    };
}

#endif
