/*
    Evocosm is a C++ framework for implementing evolutionary algorithms.

    Copyright 2011 Scott Robert Ladd. All rights reserved.

    Evocosm is user-supported open source software. Its continued development is dependent
    on financial support from the community. You can provide funding by visiting the Evocosm
    website at:

        http://www.coyotegulch.com

    You may license Evocosm in one of two fashions:

    1) Simplified BSD License (FreeBSD License)

    Redistribution and use in source and binary forms, with or without modification, are
    permitted provided that the following conditions are met:

    1.  Redistributions of source code must retain the above copyright notice, this list of
        conditions and the following disclaimer.

    2.  Redistributions in binary form must reproduce the above copyright notice, this list
        of conditions and the following disclaimer in the documentation and/or other materials
        provided with the distribution.

    THIS SOFTWARE IS PROVIDED BY SCOTT ROBERT LADD ``AS IS'' AND ANY EXPRESS OR IMPLIED
    WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
    FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL SCOTT ROBERT LADD OR
    CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
    CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
    SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
    ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
    NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
    ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

    The views and conclusions contained in the software and documentation are those of the
    authors and should not be interpreted as representing official policies, either expressed
    or implied, of Scott Robert Ladd.

    2) Closed-Source Proprietary License

    If your project is a closed-source or proprietary project, the Simplified BSD License may
    not be appropriate or desirable. In such cases, contact the Evocosm copyright holder to
    arrange your purchase of an appropriate license.

    The author can be contacted at:

          scott.ladd@coyotegulch.com
          scott.ladd@gmail.com
          http:www.coyotegulch.com
*/

#if !defined(LIBEVOCOSM_VALIDATOR_H)
#define LIBEVOCOSM_VALIDATOR_H

#include <sstream>
#include <stdexcept>
#include <typeinfo>

namespace libevocosm
{
    using std::stringstream;
    using std::string;
    using std::runtime_error;

    //! Standard validation exception
    /*!
        This is the standard exception thrown for validation failures.
        By deriving from the Standard C++ exception <i>runtime_error</i>,
        validation error is caught by generic <i>catch (std::exception)
        </i> blocks or more specific exception handlers.
        \version 1.0.0
        \date    1 May 2002
    */
    template <typename Type>
    class validation_error : public runtime_error
    {
    private:
        static string build_error_string(const Type & object,
                                         const string & details)
        {
            stringstream message;

            message << "validation error: "
                    << typeid(object).name() << " " << object
                    << details;

            return message.str();
        }

    public:
        //! Constructor
        /*!
            Constructs a <i>validation_error</i> from an object and an optional
            detail string. The resulting error message -- retrieved
            via the <i>what()</i> method inherited from <i>
            runtime_error</i> -- contains the type of object, it's
            content, and the test of the detail string (if one is
            provided).
            \param object  The erroneous object that failed validation
            \param details A string providing detailed information
                           about the validation failure
        */
        validation_error(const Type & object,
                         const string & details = string())
            : runtime_error(build_error_string(object,details))
        {
            // nada
        }
    };

    //! Validates that an object has a specific value.
    /*!
        If value is not equal to <i>constraint</i>, as defined by the appropriate
        == operator, this function throws a <i>validation_error</i>.
        \param object     Object to be tested against <i>constraint</i>
        \param constraint Expected value of object
        \param message    Additional text to be included in a
                          <i>validation_error</i>
    */
    template <typename Type>
    void validate_equals(const Type & object,
                         const Type & constraint,
                         const string & message = string())
    {
        if (object != constraint)
        {
            stringstream details;
            details << " must equal " << constraint << " " << message;
            throw validation_error<Type>(object,details.str());
        }
    }

    //! Validates that an object does not have a specific value.
    /*!
        If value equals the <i>constraint</i>, as defined by the appropriate
        == operator, this function throws a <i>validation_error</i>.
        \param object     Object to be tested against <i>constraint</i>
        \param constraint Value that object should not equal
        \param message    Additional text to be included in a
                          <i>validation_error</i>
    */
    template <typename Type>
    void validate_not(const Type & object,
                      const Type & constraint,
                      const string & message = string())
    {
        if (object == constraint)
        {
            stringstream details;
            details << " must not equal " << constraint << " " << message;
            throw validation_error<Type>(object,details.str());
        }
    }

    //! Validates that an object is less than <i>constraint</i>.
    /*!
        If value is greater than or equal to <i>constraint</i> (using the >=
        operator), this function throws a <i>validation_error</i>.
        \param object       Object to be tested
        \param constraint   Object must be < than this value
        \param message      Additional text to be included in a
                            <i>validation_error</i>
    */
    template <typename Type>
    void validate_less(const Type & object,
                      const Type & constraint,
                      const string & message = string())
    {
        if (object >= constraint)
        {
            stringstream details;
            details << " must be less than " << constraint << " " << message;
            throw validation_error<Type>(object,details.str());
        }
    }

    //! Validates that an object is less than or equal to <i>constraint</i>.
    /*!
        If value is greater than or equal to <i>constraint</i> (using the >=
        operator), this function throws a <i>validation_error</i>.
        \param object       Object to be tested
        \param constraint   Object must be < than this value
        \param message      Additional text to be included in a
                            <i>validation_error</i>
    */
    template <typename Type>
    void validate_less_eq(const Type & object,
                          const Type & constraint,
                          const string & message = string())
    {
        if (object > constraint)
        {
            stringstream details;
            details << " must be less than " << constraint << " " << message;
            throw validation_error<Type>(object,details.str());
        }
    }

    //! Validates that an object is greater than <i>constraint</i>.
    /*!
        If value is less than or equal to <i>constraint</i> (using the <=
        operator), this function throws a <i>validation_error</i>.
        \param object       Object to be tested
        \param constraint   Object must be > than this value
        \param message      Additional text to be included in a
                            validation_error
    */
    template <typename Type>
    void validate_greater(const Type & object,
                      const Type & constraint,
                      const string & message = string())
    {
        if (object <= constraint)
        {
            stringstream details;
            details << " must be greater than " << constraint << " " << message;
            throw validation_error<Type>(object,details.str());
        }
    }

    //! Validates that an object is greater than or equal to <i>constraint</i>.
    /*!
        If value is less than or equal to <i>constraint</i> (using the <=
        operator), this function throws a <i>validation_error</i>.
        \param object       Object to be tested
        \param constraint   Object must be > than this value
        \param message      Additional text to be included in a
                            validation_error
    */
    template <typename Type>
    void validate_greater_eq(const Type & object,
                      const Type & constraint,
                      const string & message = string())
    {
        if (object < constraint)
        {
            stringstream details;
            details << " must be greater than " << constraint << " " << message;
            throw validation_error<Type>(object,details.str());
        }
    }

    //! Validates that an object has a value in a specified range.
    /*!
        If value is less than <i>low_bound</i> (using the < operator) or greater
        than <i>high_bound</i> (using the > operator), this function throws a
        <i>validation_error</i>. The function does not verify that <i>low_bound</i> is
        less than <i>high_bound</i>.
        \param object       Object to be tested
        \param low_bound    Low boundary (inclusive) on value of object
        \param high_bound   High boundary (inclusive) on value of object
        \param message      Additional text to be included in a
                            <i>validation_error</i>
    */
    template <typename Type>
    void validate_range(const Type & object,
                        const Type & low_bound,
                        const Type & high_bound,
                        const string & message = string())
    {
        if ((object < low_bound) || (object > high_bound))
        {
            stringstream details;
            details << " must be between " << low_bound << " and "
                    << high_bound << " " << message;
            throw validation_error<Type>(object,details.str());
        }
    }

    //! Validates an object with a given predicate.
    /*!
        If <i>predicate(object)</i> is <i>false</i> -- indicating an invalid object in
        the context defined by <i>predicate</i> -- this function throws a
        <i>validation_error</i>.
        \param object    Object to be tested against the <i>predicate</i>
        \param constraint A function or functor returning <i>true</i>
                         for valid objects and <i>false</i> for an
                         invalid object
        \param message   Additional text to be included in a
                         <i>validation_error</i>
    */
    template <typename Type, typename Predicate>
    void validate_with(const Type & object,
                       const Predicate & constraint,
                       const string & message = string())
    {
        if (!constraint(object))
        {
            stringstream details;
            details << " failed test " << typeid(constraint).name() << " " << message;
            throw validation_error<Type>(object,details.str());
        }
    }

    //! Enforce a lower limit on the value of an object.
    /*!
        If object's value is less than <i>low_value</i>, as per the < operator,
        object will be set equal to <i>low_value</i>.
        \param object    Object to undergo enforcement
        \param low_value Lower limit on the value of <i>object</i>
    */
    template <typename Type>
    void enforce_lower_limit(Type & object,
                             const Type & low_value)
    {
        if (object < low_value)
            object = low_value;
    }

    //! Enforce an upper limit on the value of an object.
    /*!
        If object's value is greater than <i>high_value</i>, as per the >
        operator, object will be set equal <i>to high_value</i>.
        \param object     Object to undergo enforcement
        \param high_value Upper limit on the value of <i>object</i>
    */
    template <typename Type>
    void enforce_upper_limit(Type & object,
                            const Type & high_value)
    {
        if (object > high_value)
            object = high_value;
    }

    //! Enforce an maximum index on the value of an object.
    /*!
        If object's value is greater than or equal to <i>array_length</i>, as per the >=
        operator, object will be set equal to <i>array_length</i>.
        \param object Object to undergo enforcement
        \param array_length Length of array that <i>object</i> must address
    */
    template <typename Type>
    void enforce_index(Type & object,
                        const Type & array_length)
    {
        if (object >= array_length)
            object = array_length - 1;

        if (object < 0)
            object = 0;
    }

    //! Enforce an range limit on the value of an object.
    /*!
        If object's value is less than <i>low_value</i>, as per the < operator,
        object will be set equal to <i>low_value</i>. If object's value is
        greater than <i>high_value</i>, as per the > operator, object will
        be set equal to <i>high_value</i>.
        \param object     Object to undergo enforcement
        \param low_value  Lower limit on the value of <i>object</i>
        \param high_value Upper limit on the value of <i>object</i>
    */
    template <typename Type>
    void enforce_range(Type & object,
                       const Type & low_value,
                       const Type & high_value)
    {
        if (object < low_value)
            object = low_value;
        else if (object > high_value)
            object = high_value;
    }

    //! Utility function to create a location string.
    /*!
        This function formats a string from a given file name and
        line number. If C++ incorporates parts of C99, this function
        could be extended to support the <i>__func__</i> macro that names
        the current function.
        \param filename The name of a file, usually the Standard C <i>__FILE__</i> macro
        \param line_no  A line number in the file, usually the Standard C <i>__LINE__</i> macro
        \sa LIBEVOCOSM_LOCATION
    */
    inline string build_location_string(const char * filename, long line_no)
    {
        stringstream text;
        text << "in " << filename << ", line " << line_no;
        return text.str();
    }
}

// These macros allow validation to be included on a per-compile basis, based on the settings
// of the DEBUG and NDEBUG preprocessor macros.
#if defined(_DEBUG) && !defined(NDEBUG)
#define LIBEVOCOSM_VALIDATE_EQUALS(object,constraint,details) libevocosm::validate_equals(object,constraint,details)
#define LIBEVOCOSM_VALIDATE_NOT(object,constraint,details) libevocosm::validate_not(object,constraint,details)
#define LIBEVOCOSM_VALIDATE_LESS(object,constraint,details) libevocosm::validate_less(object,constraint,details)
#define LIBEVOCOSM_VALIDATE_LESS_EQ(object,constraint,details) libevocosm::validate_less_eq(object,constraint,details)
#define LIBEVOCOSM_VALIDATE_GREATER(object,constraint,details) libevocosm::validate_greater(object,constraint,details)
#define LIBEVOCOSM_VALIDATE_GREATER_EQ(object,constraint,details) libevocosm::validate_greater_eq(object,constraint,details)
#define LIBEVOCOSM_VALIDATE_RANGE(object,low_bound,high_bound,details) libevocosm::validate_range(object,low_bound,high_bound,details)
#define LIBEVOCOSM_VALIDATE_WITH(object,constraint,details) libevocosm::validate_with(object,constraint,details)
#define LIBEVOCOSM_LOCATION libevocosm::build_location_string(__FILE__,__LINE__)
#else
#define LIBEVOCOSM_VALIDATE_EQUALS(object,constraint,details)
#define LIBEVOCOSM_VALIDATE_NOT(object,constraint,details)
#define LIBEVOCOSM_VALIDATE_LESS(object,constraint,details)
#define LIBEVOCOSM_VALIDATE_LESS_EQ(object,constraint,details)
#define LIBEVOCOSM_VALIDATE_GREATER(object,constraint,details)
#define LIBEVOCOSM_VALIDATE_GREATER_EQ(object,constraint,details)
#define LIBEVOCOSM_VALIDATE_RANGE(object,low_bound,high_bound,details)
#define LIBEVOCOSM_VALIDATE_WITH(object,constraint,details)
#define LIBEVOCOSM_LOCATION std::string()
#endif

#endif