//
// php-armadillo/php_arma.hh
//
// @Author CismonX
//

#ifndef PHP_ARMA_HH
#define PHP_ARMA_HH

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <php.h>
#include <zend_exceptions.h>

#ifndef PHP_ARMA_ENABLE_PCH
#include <armadillo>
#endif

#define PHP_ARMA_VERSION         "0.0.1"

#if PHP_VERSION_ID >= 70400
#define ZEND_ACC_CTOR            0
#endif

/// Helper macros for method entry.

#define PHP_ARMA_START_ME(cls, ...)                       \
    zend_function_entry cls<__VA_ARGS__>::me[] = {

#define PHP_ARMA_END_ME()                                 \
        PHP_FE_END                                        \
    }

#define PHP_ARMA_ME(func, flags)                          \
    ZEND_FENTRY(func, zif_##func, nullptr, flags)

#define PHP_ARMA_ME_EX(cls, func, flags)                  \
    ZEND_FENTRY(func, cls::zif_##func, nullptr, flags)

#define PHP_ARMA_METHOD(cls, func, ...)                   \
    void ZEND_FASTCALL cls<__VA_ARGS__>::zif_##func(INTERNAL_FUNCTION_PARAMETERS)

#define PHP_ARMA_FENTRY(fentry)                           \
    std::make_tuple(fentry_size(fentry), fentry)

#define PHP_ARMA_INSTANTIATE(parent, child)               \
    template class parent<double,    child<double>>;      \
    template class parent<zend_long, child<zend_long>>;   \
    template class parent<cx_double, child<cx_double>>

/// Helper macros for class entry and object handlers.

#define PHP_ARMA_CE_HANDLRES_DECLARE()                    \
    static inline zend_class_entry     *ce;               \
    static inline zend_object_handlers  handlers

#define PHP_ARMA_CE(cls, ...)                             \
    cls<__VA_ARGS__>::ce

#define PHP_ARMA_HANDLERS(cls, ...)                       \
    &cls<__VA_ARGS__>::handlers

#define Z_OBJNAME_P(zval_p)                               \
    ZSTR_VAL(Z_OBJCE_P(zval_p)->name)

#define PHP_ARMA_COMMON_DECLARE()                         \
    struct php_name;                                      \
    static zend_function_entry me[]

#define PHP_ARMA_NAME_DECLARE(cls, name, ...)             \
    template <>                                           \
    struct cls<__VA_ARGS__>::php_name                     \
    {                                                     \
        static constexpr const char val[] = name;         \
    }

#ifdef PHP_ARMA_OPERATORS

/// Helper macros for handling operator overloading.

#define PHP_ARMA_OPERATOR_BEGIN(parent_ce)                \
    {                                                     \
        if (instanceof_function(ce, parent_ce)) {

#define PHP_ARMA_OPERATOR_END()                           \
            return false;                                 \
        }                                                 \
    }

#define PHP_ARMA_OPERATOR_EX2(base, child, func)          \
    if (instanceof_function(ce, child::ce)) {             \
        using base_t = util::arg_type<void(base)>::type;  \
        return base_t::operators::func(zv1, zv2, rv);     \
    }

#define PHP_ARMA_OPERATOR_EX(cls, func)                   \
    PHP_ARMA_OPERATOR_EX2(cls, cls, func)

#define PHP_ARMA_ASSIGN_OPERATOR_EX2(base, child, func)   \
    if (instanceof_function(ce, child::ce)) {             \
        using base_t = util::arg_type<void(base)>::type;  \
        auto v = base_t::operators::func(zv1, zv2, zv1);  \
        if (rv) {                                         \
            ZVAL_COPY(rv, zv1);                           \
        }                                                 \
        return v;                                         \
    }

#define PHP_ARMA_ASSIGN_OPERATOR_EX(cls, func)            \
    PHP_ARMA_ASSIGN_OPERATOR_EX2(cls, cls, func)

#endif // PHP_ARMA_OPERATORS

/// Helper macros for handling native objects.

#define ZOBJ_NATIVE(zobj)                                 \
    to_native_object<native_t>(zobj)

#define Z_NATIVE_OBJ_P(zv)   ZOBJ_NATIVE(Z_OBJ_P(zv))
#define THIS_NATIVE          Z_NATIVE_OBJ_P(&EX(This))

/// Misc helper macros.

#define RETVAL_THIS()                                     \
    ZVAL_COPY(return_value, &EX(This))

namespace php_arma
{
    extern zend_module_entry module_entry;

    /// Utilities.
    namespace util
    {
        /// Hack for extracting type from a parentheses-enclosed macro argument.
        template <typename T>
        struct arg_type;
        template <typename T, typename U>
        struct arg_type<T(U)>
        {
            using type = U; 
        };

        template <typename T, typename... Ts>
        constexpr auto is_any_v = std::disjunction_v<std::is_same<T, Ts>...>;
    }

    /// Helpers for compile-time string concatenation for better module startup performance.
    namespace str
    {
        template <size_t... S>
        using seq = std::integer_sequence<size_t, S...>;
        template <size_t N>
        using seq_impl = std::make_integer_sequence<size_t, N>;

        constexpr auto get_len(const char *str)
        {
            auto i = 0;
            for (; *str != 0; ++i, ++str);
            return i;
        }

        template <const char*, typename, const char*, typename>
        struct concat_impl;
        template <const char *Str1, size_t... Len1, const char *Str2, size_t... Len2>
        struct concat_impl<Str1, seq<Len1...>, Str2, seq<Len2...>>
        {
            static constexpr const char value[]
            {
                Str1[Len1]..., Str2[Len2]..., 0
            };
        };

        template <const char *Str1, const char *Str2>
        constexpr auto concat
        {
            concat_impl<Str1, seq_impl<get_len(Str1)>, Str2, seq_impl<get_len(Str2)>>::value
        };

        constexpr const char namespace_prefix[] = "Arma\\";
        constexpr const char internal_prefix[]  = "Internal\\";
        constexpr const char empty[]            = "";

        template <const char *Str>
        constexpr auto with_arma_prefix
        {
            concat<namespace_prefix, Str>
        };

        template <const char *Str>
        constexpr auto with_internal_prefix
        {
            concat<internal_prefix, Str>
        };
    }

    // Data structures
    namespace ds
    {
        /// Non-subview container objects
        struct base {
            const arma::uword n_rows;
            const arma::uword n_cols;
            const arma::uword n_elem;
        };

        /// Subview objects
        struct subview {
            arma_aligned const base& parent;
            const arma::uword n_rows;
            const arma::uword n_cols;
            const arma::uword n_elem;
        };

        /// Diagonal subview objects
        struct diagview {
            arma_aligned const base& parent;
            const arma::uword row_offset;
            const arma::uword col_offset;
            const arma::uword n_rows;
            const arma::uword n_elem;
            static constexpr const arma::uword n_cols = 1;
        };
    }

    /// Helper functions for throwing exceptions when errors occur.

    zend_always_inline
    void throw_exception_ex(zend_class_entry *ce, const char *message)
    {
        zend_throw_exception(ce, message, 0);
    }

    template <typename... Ts>
    zend_always_inline
    void throw_exception_ex(zend_class_entry *ce, const char *message, Ts&&... args)
    {
        zend_throw_exception_ex(ce, 0, message, args...);
    }

    zend_always_inline
    void throw_exception(const char *message)
    {
        throw_exception_ex(zend_ce_exception, message);
    }

    template <typename... Ts>
    zend_always_inline
    void throw_exception(const char *message, Ts&&... args)
    {
        throw_exception_ex(zend_ce_exception, message, args...);
    }

    zend_always_inline
    void throw_error(const char *message)
    {
        throw_exception_ex(zend_ce_error, message);
    }

    template <typename... Ts>
    zend_always_inline
    void throw_error(const char *message, Ts&&... args)
    {
        throw_exception_ex(zend_ce_error, message, args...);
    }

    zend_always_inline
    void ex_bad_type(const char *expected, const char *got)
    {
        throw_exception_ex(zend_ce_type_error, "bad type, expected %s, %s given", expected, got);
    }
    
    /// Helper functions for initializing class entry and object handlers.

    template <const char *Name, typename F>
    zend_always_inline
    zend_class_entry *ce_init(const zend_function_entry *methods, F&& init_func)
    {
        zend_class_entry tmp_ce;
        constexpr auto name = str::with_arma_prefix<Name>;
        constexpr auto name_len = str::get_len(name);
        INIT_CLASS_ENTRY_EX(tmp_ce, name, name_len, methods);
        return init_func(&tmp_ce);
    }

    template <const char *Name, typename F, typename... Ts>
    zend_always_inline
    zend_class_entry *ce_init(const zend_function_entry *methods, F&& init_func, Ts... interfaces)
    {
        auto ce = ce_init<Name>(methods, init_func);
        zend_class_implements(ce, sizeof...(Ts), interfaces...);
        return ce;
    }

    template <const char *Name>
    zend_always_inline
    zend_class_entry *interface_register()
    {
        // Although methods are declared in interfaces as you see in the stubs,
        // nothing is declared in the internal interface implementation.
        return ce_init<str::with_internal_prefix<Name>>(nullptr, zend_register_internal_interface);
    }

    template <const char *Name, typename... Ts>
    zend_always_inline
    zend_class_entry *interface_register(Ts... parents)
    {
        return ce_init<str::with_internal_prefix<Name>>(nullptr, zend_register_internal_interface, parents...);
    }

    template <const char *Name>
    zend_always_inline
    zend_class_entry *class_register(zend_class_entry *parent, const zend_function_entry *methods)
    {
        auto init_func = std::bind(zend_register_internal_class_ex, std::placeholders::_1, parent);
        return ce_init<Name>(methods, init_func);
    }

    template <const char *Name>
    zend_always_inline
    zend_class_entry *abstract_class_register()
    {
        auto ce = ce_init<Name>(nullptr, zend_register_internal_class);
        ce->ce_flags |= ZEND_ACC_EXPLICIT_ABSTRACT_CLASS;
        return ce;
    }

    template <const char *Name, typename... Ts>
    zend_always_inline
    zend_class_entry *abstract_class_register(Ts... interfaces)
    {
        auto ce = ce_init<Name>(nullptr, zend_register_internal_class, interfaces...);
        ce->ce_flags |= ZEND_ACC_EXPLICIT_ABSTRACT_CLASS;
        return ce;
    }

    template <const char *Name, int AccessType>
    zend_always_inline
    void property_declare(zend_class_entry *ce, zval *zv)
    {
        zend_declare_property(ce, Name, str::get_len(Name), zv, AccessType);
    }

    zend_always_inline
    void declare_subview_parent(zend_class_entry *ce)
    {
        property_declare<str::empty, ZEND_ACC_PRIVATE>(ce, &EG(uninitialized_zval));
    }

    zend_always_inline
    void object_handlers_init(zend_object_handlers *handlers)
    {
        memcpy(handlers, &std_object_handlers, sizeof(zend_object_handlers));
    }

    template <typename T>
    zend_always_inline
    zend_object *to_zend_object(T *obj)
    {
        return reinterpret_cast<zend_object*>(obj + 1);
    }

    template <typename T>
    zend_always_inline
    T *to_native_object(zend_object *zobj)
    {
        return reinterpret_cast<T*>(zobj) - 1;
    }

    template <typename T>
    zend_always_inline
    zval *get_parent_zval(zval *current)
    {
        if constexpr (std::is_same_v<T, typename T::orig_t>) {
            return current;
        } else {
            return OBJ_PROP_NUM(Z_OBJ_P(current), 0);
        }
    }

    /// Helper functions for function entry.

    zend_always_inline
    size_t fentry_size(zend_function_entry *fentry)
    {
        size_t retval = 0;
        while ((fentry++)->fname != nullptr) {
            ++retval;
        }
        return retval * sizeof(zend_function_entry);
    }

    template <typename... Ts>
    zend_always_inline
    zend_function_entry *fentry_list_concat_impl(size_t mem_size, Ts&&... function_entry)
    {
        auto retval = reinterpret_cast<zend_function_entry*>(malloc(mem_size));
        size_t offset = 0;
        for (auto [size, fentry] : { function_entry... }) {
            memcpy(retval + offset, fentry, size);
            offset += size / sizeof(zend_function_entry);
        }
        zend_function_entry empty_fentry PHP_FE_END;
        memcpy(retval + offset, &empty_fentry, sizeof(zend_function_entry));
        return retval;
    }

    template <typename... Ts>
    zend_always_inline
    zend_function_entry *fentry_list_concat(Ts&&... function_entry)
    {
        size_t mem_size = sizeof(zend_function_entry);
        for (auto [size, _] : { function_entry... }) {
            mem_size += size;
        }
        return fentry_list_concat_impl(mem_size, function_entry...);
    }

    /// Helper functions for handling objects.

    template <typename T, typename F>
    zend_always_inline
    zend_object *object_create(zend_class_entry *ce, F&& init)
    {
        auto obj = reinterpret_cast<T*>(emalloc(sizeof(T) +
            sizeof(zend_object) + zend_object_properties_size(ce)));
        auto zobj = to_zend_object(obj);
        zobj->handlers = init(obj);
        zend_object_std_init(zobj, ce);
        object_properties_init(zobj, ce);
        return zobj;
    }

    template <typename T, typename... Ts>
    zend_always_inline
    zend_object *object_create_ctor(zend_class_entry *ce, zend_object_handlers *handlers, Ts&&... args)
    {
        // If only I can use C++20 here... 
        return object_create<T>(ce, [args = std::forward_as_tuple(args...), handlers](auto obj) {
            std::apply([obj](auto&&... args) {
                new(obj) T(args...);
            }, std::move(args));
            return handlers;
        });
    }

    zend_always_inline
    zend_object *object_create(zend_class_entry *ce, const zend_object_handlers *handlers)
    {
        auto zobj = reinterpret_cast<zend_object*>(emalloc(
            sizeof(zend_object) + zend_object_properties_size(ce)));
        zobj->handlers = handlers;
        zend_object_std_init(zobj, ce);
        object_properties_init(zobj, ce);
        return zobj;
    }

    template <typename T>
    zend_always_inline
    void object_destroy(zend_object *zobj)
    {
        zend_object_std_dtor(zobj);
        to_native_object<T>(zobj)->~T();
    }

    zend_always_inline
    void object_set_property(zend_object *obj, size_t idx, zval *val)
    {
        zval_ptr_dtor(OBJ_PROP_NUM(obj, idx));
        ZVAL_COPY(OBJ_PROP_NUM(obj, idx), val);
    }

    zend_always_inline
    zend_object *object_non_constructible(zend_class_entry *ce)
    {
        throw_error("class %s is not explicitly constructible.", ZSTR_VAL(ce->name));
        return zend_objects_new(ce);
    }

    /// Helper functions for handling scalar types.

    template <typename>
    struct false_type : std::false_type {};

    template <typename T>
    zend_always_inline
    constexpr void bad_scalar_type()
    {
        static_assert(false_type<T>::value, "type should be zend_long, double or cx_double");
    }

    template <typename T>
    zend_always_inline
    bool zval_is_scalar(zval *zv)
    {
        bad_scalar_type<T>();
        return false;
    }

    template <>
    zend_always_inline
    bool zval_is_scalar<double>(zval *zv)
    {
        return Z_TYPE_P(zv) == IS_DOUBLE;
    }

    template <>
    zend_always_inline
    bool zval_is_scalar<zend_long>(zval *zv)
    {
        return Z_TYPE_P(zv) == IS_LONG;
    }

    template <typename T>
    zend_always_inline
    const char *scalar_type_name()
    {
        bad_scalar_type<T>();
        return nullptr;
    }

    template <>
    zend_always_inline
    const char *scalar_type_name<double>()
    {
        return zend_get_type_by_const(IS_DOUBLE);
    }

    template <>
    zend_always_inline
    const char *scalar_type_name<zend_long>()
    {
        return zend_get_type_by_const(IS_LONG);
    }

    template <typename T>
    zend_always_inline
    T zval_get_scalar(zval *zv)
    {
        bad_scalar_type<T>();
    }

    template <>
    zend_always_inline
    double zval_get_scalar<double>(zval *zv)
    {
        return Z_DVAL_P(zv);
    }

    template <>
    zend_always_inline
    zend_long zval_get_scalar<zend_long>(zval *zv)
    {
        return Z_LVAL_P(zv);
    }

    zend_always_inline
    void zval_set_scalar(zval *zv, double val)
    {
        ZVAL_DOUBLE(zv, val);
    }

    zend_always_inline
    void zval_set_scalar(zval *zv, zend_long val)
    {
        ZVAL_LONG(zv, val);
    }

    zend_always_inline
    const char *zval_get_type_name(zval *zv)
    {
        if (Z_TYPE_P(zv) == IS_OBJECT) {
            return ZSTR_VAL(Z_OBJCE_P(zv)->name);
        } else {
            return zend_get_type_by_const(Z_TYPE_P(zv));
        }
    }

    template <typename T>
    zend_always_inline
    bool zval_check_scalar(zval *zv)
    {
        if (UNEXPECTED(!zval_is_scalar<T>(zv))) {
            ex_bad_type(scalar_type_name<T>(), zval_get_type_name(zv));
            return false;
        }
        return true;
    }

    // Helper functions for handling object type names.
    template <typename T>
    zend_always_inline
    char *get_type_name()
    {
        return ZSTR_VAL(T::ce->name);
    }
}

#endif // !PHP_ARMA_HH