// The MIT License (MIT) 

// Copyright (c) 2013-2016 Rapptz, ThePhD and contributors

// Permission is hereby granted, free of charge, to any person obtaining a copy of
// this software and associated documentation files (the "Software"), to deal in
// the Software without restriction, including without limitation the rights to
// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
// the Software, and to permit persons to whom the Software is furnished to do so,
// subject to the following conditions:

// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
// IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

#ifndef SOL_VARIADIC_ARGS_HPP
#define SOL_VARIADIC_ARGS_HPP

#include "stack.hpp"
#include "stack_proxy.hpp"
#include <limits>
#include <iterator>

namespace sol {
    struct va_iterator : std::iterator<std::random_access_iterator_tag, stack_proxy, std::ptrdiff_t, stack_proxy*, stack_proxy> {
        lua_State* L;
        int index;
        int stacktop;
        stack_proxy sp;

        va_iterator() : L(nullptr), index(std::numeric_limits<int>::max()), stacktop(std::numeric_limits<int>::max()) {}
        va_iterator(lua_State* L, int index, int stacktop) : L(L), index(index), stacktop(stacktop), sp(L, index) {}

        stack_proxy operator*() {
            sp = stack_proxy(L, index);
            return sp;
        }

        stack_proxy* operator->() {
            sp = stack_proxy(L, index);
            return &sp;
        }

        va_iterator& operator++ () {
            ++index;
            return *this;
        }

        va_iterator operator++ (int) {
            auto r = *this;
            this->operator ++();
            return r;
        }

        va_iterator& operator-- () {
            --index;
            return *this;
        }

        va_iterator operator-- (int) {
            auto r = *this;
            this->operator --();
            return r;
        }

        va_iterator& operator+= (difference_type idx) {
            index += static_cast<int>(idx);
            return *this;
        }

        va_iterator& operator-= (difference_type idx) {
            index -= static_cast<int>(idx);
            return *this;
        }

        difference_type operator- (const va_iterator& r) const {
            return index - r.index;
        }

        va_iterator operator+ (difference_type idx) const {
            va_iterator r = *this;
            r += idx;
            return r;
        }

        stack_proxy operator[](difference_type idx) {
            return stack_proxy(L, index + static_cast<int>(idx));
        }

        bool operator==(const va_iterator& r) const {
            if (stacktop == std::numeric_limits<int>::max()) {
                return r.index == r.stacktop;
            }
            else if (r.stacktop == std::numeric_limits<int>::max()) {
                return index == stacktop;
            }
            return index == r.index;
        }

        bool operator != (const va_iterator& r) const {
            return !(this->operator==(r));
        }

        bool operator < (const va_iterator& r) const {
            return index < r.index;
        }

        bool operator > (const va_iterator& r) const {
            return index > r.index;
        }

        bool operator <= (const va_iterator& r) const {
            return index <= r.index;
        }

        bool operator >= (const va_iterator& r) const {
            return index >= r.index;
        }
    };

    inline va_iterator operator+(typename va_iterator::difference_type n, const va_iterator& r) {
        return r + n;
    }

struct variadic_args {
private:
    lua_State* L;
    int index;
    int stacktop;

public:
    typedef stack_proxy reference_type;
    typedef stack_proxy value_type;
    typedef stack_proxy* pointer;
    typedef std::ptrdiff_t difference_type;
    typedef std::size_t size_type;
    typedef va_iterator iterator;
    typedef const va_iterator const_iterator;
    typedef std::reverse_iterator<iterator> reverse_iterator;
    typedef std::reverse_iterator<const_iterator> const_reverse_iterator;

    variadic_args() = default;
    variadic_args(lua_State* L, int index = -1): L(L), index(lua_absindex(L, index)), stacktop(lua_gettop(L)) {}
    variadic_args(const variadic_args&) = default;
    variadic_args& operator=(const variadic_args&) = default;
    variadic_args(variadic_args&& o) : L(o.L), index(o.index), stacktop(o.stacktop) {
        // Must be manual, otherwise destructor will screw us
        // return count being 0 is enough to keep things clean
        // but will be thorough
        o.L = nullptr;
        o.index = 0;
        o.stacktop = 0;
    }
    variadic_args& operator=(variadic_args&& o) {
        L = o.L;
        index = o.index;
        stacktop = o.stacktop;
        // Must be manual, otherwise destructor will screw us
        // return count being 0 is enough to keep things clean
        // but will be thorough
        o.L = nullptr;
        o.index = 0;
        o.stacktop = 0;
        return *this;
    }

    iterator begin() { return va_iterator(L, index, stacktop + 1); }
    iterator end() { return va_iterator(L, stacktop + 1, stacktop + 1); }
    const_iterator begin() const { return va_iterator(L, index, stacktop + 1); }
    const_iterator end() const { return va_iterator(L, stacktop + 1, stacktop + 1); }
    const_iterator cbegin() const { return begin(); }
    const_iterator cend() const { return end(); }

    reverse_iterator rbegin() { return std::reverse_iterator<iterator>(begin()); }
    reverse_iterator rend() { return std::reverse_iterator<iterator>(end()); }
    const_reverse_iterator rbegin() const { return std::reverse_iterator<const_iterator>(begin()); }
    const_reverse_iterator rend() const { return std::reverse_iterator<const_iterator>(end()); }
    const_reverse_iterator crbegin() const { return std::reverse_iterator<const_iterator>(cbegin()); }
    const_reverse_iterator crend() const { return std::reverse_iterator<const_iterator>(cend()); }

    int push () const {
        int pushcount = 0;
        for (int i = index; i <= stacktop; ++i) {
            lua_pushvalue(L, i);
            pushcount += 1;
        }
        return pushcount;
    }

    template<typename T>
    decltype(auto) get(difference_type start = 0) const {
        return stack::get<T>(L, index + static_cast<int>(start));
    }

    stack_proxy operator[](difference_type start) const {
        return stack_proxy(L, index + static_cast<int>(start));
    }

    lua_State* lua_state() const { return L; };
    int stack_index() const { return index; };
    int leftover_count() const { return stacktop - (index - 1); }
    int top() const { return stacktop; }
};

namespace stack {
template <>
struct getter<variadic_args> {
    static variadic_args get(lua_State* L, int index = -1) {
        return variadic_args(L, index);
    }
};

template <>
struct pusher<variadic_args> {
    static int push(lua_State*, const variadic_args& ref) {
        return ref.push();
    }
};
} // stack
} // sol

#endif // SOL_VARIADIC_ARGS_HPP