#pragma once

#include "error.h"

namespace pkbind {

#define PKBIND_TYPE_IMPL(parent, child, expr)                                                      \
                                                                                                   \
private:                                                                                           \
    friend class type;                                                                             \
    static auto type_or_check() { return expr; }                                                   \
                                                                                                   \
public:                                                                                            \
    using parent::parent;                                                                          \
    using parent::operator=;                                                                       \
    child(const object& o) : parent(type::isinstance<child>(o) ? o : type::of<child>()(o)) {}      \
    child(object&& o) :                                                                            \
        parent(type::isinstance<child>(o) ? std::move(o) : type::of<child>()(std::move(o))) {}

class type : public object {
protected:
    template <typename T>
    constexpr inline static bool is_check_v =
        std::is_invocable_r_v<bool, decltype(T::type_or_check()), handle>;

    static auto type_or_check() { return tp_type; }

public:
    using object ::object;
    using object ::operator=;

    // note: type is global instance, so we use ref_t.
    explicit type(py_Type type) : object(py_tpobject(type), ref_t{}) {}

    py_Type index() const { return py_totype(ptr()); }

    const char* name() const { return py_tpname(index()); }

    static type of(handle h) { return type(py_typeof(h.ptr())); }

    template <typename T>
    static type of();

    template <typename T>
    static bool isinstance(handle obj);
};

class none : public object {
    PKBIND_TYPE_IMPL(object, none, tp_NoneType);

    // note: none is global instance, so we use ref_t.
    none() : object(py_None, ref_t{}) {}
};

class bool_ : public object {
    PKBIND_TYPE_IMPL(object, bool_, tp_bool);

    // same as none, bool is a singleton.
    bool_(bool value) : object(value ? py_True : py_False, ref_t{}) {}

    explicit operator bool () { return py_tobool(ptr()); }
};

class int_ : public object {
    PKBIND_TYPE_IMPL(object, int_, tp_int);

    int_(py_i64 value) : object(alloc_t{}) { py_newint(m_ptr, value); }

    explicit operator py_i64 () { return py_toint(ptr()); }
};

class float_ : public object {
    PKBIND_TYPE_IMPL(object, float_, tp_float);

    float_(py_f64 value) : object(alloc_t{}) { py_newfloat(m_ptr, value); }

    explicit operator py_f64 () { return py_tofloat(ptr()); }
};

bool hasattr(handle obj, name name);

class iterable : public object {
    PKBIND_TYPE_IMPL(object, iterable, [](handle h) {
        return hasattr(h, "__iter__");
    });
};

class iterator : public object {
    template <typename Dervied>
    friend class interface;

    iterator() : object(), m_value() {}

    iterator(handle h) : object(h, realloc_t{}), m_value() { operator++ (); }

public:
    PKBIND_TYPE_IMPL(object, iterator, [](handle h) {
        return hasattr(h, "__iter__") && hasattr(h, "__next__");
    });

    iterator& operator++ () {
        int result = raise_call<py_next>(m_ptr);
        if(result == 1) {
            m_value = object(retv, realloc_t{});
        } else if(result == 0) {
            m_value = object();
        }
        return *this;
    }

    object operator* () const { return m_value; }

    friend bool operator== (const iterator& lhs, const iterator& rhs) {
        return lhs.m_value.ptr() == rhs.m_value.ptr();
    }

    friend bool operator!= (const iterator& lhs, const iterator& rhs) { return !(lhs == rhs); }

    static iterator sentinel() { return iterator(); }

private:
    object m_value;
};

template <typename Dervied>
iterator interface<Dervied>::begin() const {
    raise_call<py_iter>(ptr());
    return iterator(retv);
}

template <typename Dervied>
iterator interface<Dervied>::end() const {
    return iterator::sentinel();
}

class str : public object {
    PKBIND_TYPE_IMPL(object, str, tp_str);

    str(const char* data, int size) : object(alloc_t{}) { py_newstrv(m_ptr, {data, size}); }

    str(const char* data) : str(data, static_cast<int>(strlen(data))) {}

    str(std::string_view s) : str(s.data(), static_cast<int>(s.size())) {}

    template <typename... Args>
    object format(Args&&... args);
};

class tuple : public object {
    PKBIND_TYPE_IMPL(object, tuple, tp_tuple);

    tuple(int size) : object(alloc_t{}) { py_newtuple(m_ptr, size); }

    tuple(std::initializer_list<handle> args) : tuple(static_cast<int>(args.size())) {
        int index = 0;
        for(auto& arg: args) {
            py_tuple_setitem(m_ptr, index++, arg.ptr());
        }
    }

    tuple_accessor operator[] (int index) const;

    int size() const { return py_tuple_len(m_ptr); }

    bool empty() const { return size() == 0; }

    class iterator {
        friend tuple;

        iterator(py_Ref ptr, int index) : ptr(ptr), index(index) {}

    public:
        bool operator== (const iterator& other) const { return index == other.index; }

        bool operator!= (const iterator& other) const { return index != other.index; }

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

        object operator* () const { return borrow(py_tuple_getitem(ptr, index)); }

    private:
        py_Ref ptr;
        int index;
    };

    iterator begin() const { return iterator(m_ptr, 0); }

    iterator end() const { return iterator(m_ptr, size()); }
};

class list : public object {
    PKBIND_TYPE_IMPL(object, list, tp_list);

    list() : object(alloc_t{}) { py_newlist(m_ptr); }

    list(int size) : object(alloc_t{}) { py_newlistn(m_ptr, size); }

    list(std::initializer_list<handle> args) : list(static_cast<int>(args.size())) {
        int index = 0;
        for(auto& arg: args) {
            py_list_setitem(m_ptr, index++, arg.ptr());
        }
    }

    list_accessor operator[] (int index) const;

    int size() const { return py_list_len(m_ptr); }

    bool empty() const { return size() == 0; }

    void swap(int i, int j) { py_list_swap(m_ptr, i, j); }

    void append(handle item) { py_list_append(m_ptr, item.ptr()); }

    void insert(int index, handle item) { py_list_insert(m_ptr, index, item.ptr()); }

    void remove(int index) { py_list_delitem(m_ptr, index); }

    void clear() { py_list_clear(m_ptr); }

    class iterator {
        friend list;

        iterator(py_Ref ptr, int index) : ptr(ptr), index(index) {}

    public:
        iterator(const iterator&) = default;

        bool operator== (const iterator& other) const { return index == other.index; }

        bool operator!= (const iterator& other) const { return index != other.index; }

        iterator operator++ () {
            index++;
            return *this;
        }

        object operator* () const { return borrow(py_list_getitem(ptr, index)); }

    private:
        py_Ref ptr;
        int index;
    };

    iterator begin() const { return iterator(m_ptr, 0); }

    iterator end() const { return iterator(m_ptr, size()); }
};

class dict : public object {
    PKBIND_TYPE_IMPL(object, dict, tp_dict);

    dict() : object(alloc_t{}) { py_newdict(m_ptr); }

    dict(std::initializer_list<arg_with_default> args);

    dict_accessor<int> operator[] (int key) const;

    dict_accessor<name> operator[] (name key) const;

    dict_accessor<handle> operator[] (handle key) const;

    int size() const { return py_dict_len(m_ptr); }

    bool empty() const { return size() == 0; }

    template <typename Fn>
    void apply(Fn&& fn) {
        static_assert(std::is_invocable_v<Fn, py_Ref, py_Ref>);
        using ret = std::invoke_result_t<Fn, py_Ref, py_Ref>;
        auto callback = +[](py_Ref key, py_Ref value, void* data) -> bool {
            auto fn = reinterpret_cast<Fn*>(data);
            if constexpr(std::is_same_v<ret, void>) {
                (*fn)(key, value);
                return true;
            } else {
                return (*fn)(key, value);
            }
        };
        raise_call<py_dict_apply>(m_ptr, callback, &fn);
    }

    class iterator {
        friend dict;

        iterator() : iter(pkbind::iterator::sentinel()) {}

        iterator(handle ptr);

    public:
        iterator(const iterator&) = default;

        bool operator== (const iterator& other) const { return iter == other.iter; }

        bool operator!= (const iterator& other) const { return !(*this == other); }

        iterator operator++ () {
            ++iter;
            return *this;
        }

        std::pair<object, object> operator* () const;

    private:
        object items;
        pkbind::iterator iter;
    };

    iterator begin() const { return iterator(m_ptr); }

    iterator end() const { return iterator(); }
};

class slice : public object {
    PKBIND_TYPE_IMPL(object, slice, tp_slice);
};

class set : public object {};

class args : public tuple {
    PKBIND_TYPE_IMPL(tuple, args, tp_tuple);
};

class kwargs : public dict {
    PKBIND_TYPE_IMPL(dict, kwargs, tp_dict);
};

// TODO:
class capsule : public object {
    struct capsule_impl {
        void* data;
        void (*destructor)(void*);
    };

    inline static py_Type m_type = 0;

    PKBIND_TYPE_IMPL(object, capsule, m_type);

    static void register_() {
        m_type = py_newtype("capsule", tp_object, nullptr, [](void* data) {
            auto impl = static_cast<capsule_impl*>(data);
            if(impl->data && impl->destructor) { impl->destructor(impl->data); }
        });
    }

    capsule(void* data, void (*destructor)(void*) = nullptr) : object(alloc_t{}) {
        void* impl = py_newobject(m_ptr, m_type, 0, sizeof(capsule_impl));
        new (impl) capsule_impl{data, destructor};
    }

    void* data() { return static_cast<capsule_impl*>(py_touserdata(m_ptr))->data; }

    template <typename T>
    T& cast() {
        return *static_cast<T*>(data());
    }
};

}  // namespace pkbind
