/*
 * This file is part of libgim.
 *
 * libgim is free software: you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later
 * version.
 *
 * libgim is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with libgim.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Copyright 2010 Danny Robson <danny@nerdcruft.net>
 */


#ifndef __UTIL_RANGE_HPP
#define __UTIL_RANGE_HPP

#include <iostream>


namespace util {
    /**
     * Represents a continuous range of values. Contains convenience functions
     * and debugging checks.
     */
    template <typename T>
    struct range {
        T min;
        T max;

        range (T _min, T _max);

        /// Check whether value falls within this range (inclusive)
        bool contains (T val) const;
        /// Check whether a range falls completely within (inclusive) this range
        bool contains (const range <T> &r) const;
        /// Check whether a range falls partially within (inclusive) this range
        //bool includes (const range <T> &r) const;

        /// Return the closest number that falls within the range.
        T clamp (T val) const;

        /// Expand the range to include this value if necessary
        void expand (T val);

        /// Normalise a number to [0, 1] within the range. Does not check
        /// bounds, it is the caller's responsibility to clamp the result if
        /// needed.
        double normalise (T val) const;

        range& operator*= (T);
        range  operator*  (T) const;

        range& operator/= (T);
        range  operator/  (T) const;

        range& operator+= (T);
        range  operator+  (T) const;

        range& operator-= (T);
        range  operator-  (T) const;

        /// Return a pseudo-random uniformly distributed value within the range.
        /// There are no statistical randomness guarantees whatsoever. 
        T random (void) const;

        bool operator ==(const range<T>& rhs) const;
        bool operator !=(const range<T>& rhs) const
            { return !(*this == rhs); }

        /// A range which is guaranteed to contain all elements type T
        static const range<T> UNLIMITED;
        static const range<T> MAX;
        /// A range which only contains elements between 0 and 1 inclusive
        static const range<T> UNIT;

        void sanity (void) const;
    };


    template <typename T>
    std::ostream&
    operator <<(std::ostream &os, const range<T> &rhs) {
        os << '[' << rhs.min << ", " << rhs.max << ']';
        return os;
    }
}

#endif