// C api for rngxx
#ifndef _RNGXX_H
#define _RNGXX_H

#ifndef _RNGXX_IMPL
#define _RNGXX_COMMON_MINIMAL
#endif
#include "rngxx/internal/common.h"
#ifndef _RNGXX_IMPL
#undef _RNGXX_COMMON_MINIMAL
#endif

#ifdef __cplusplus
#ifndef _RNGXX_IMPL_ONLY_TYPES
#warning "C++ compilers might not like this header file. Please use the C++ interface for C++ TUs"
#endif
extern "C" {
#endif

// -- C API types -- (C++ compat)
typedef struct Random rng_t;

enum rng_kind {
	RNG_KIND_CRAND,
	RNG_KIND_SM64,
};

enum rng_next_flag {
	RNG_TYQ_SIGNED   = 0, // Binary with `unsigned`.
	RNG_TYQ_UNSIGNED = 1 << 0,

	RNG_TYQ_CHAOS    = 1 << 1,
	RNG_TYQ_ARRAY	 = 1 << 2,
}; // 3 bits

typedef int rng_bool_t;

enum rng_next_type {
	RNG_TY_BLOB = 0,

	RNG_TY_BOOL, // Expects type `rng_bool_t`.

	RNG_TY_INT8,
	RNG_TY_INT16,
	RNG_TY_INT32,
	RNG_TY_INT64,

	RNG_TY_F32,
	RNG_TY_F64,
}; // 4 bits

struct rng_next_opt {
	union {
		// Bounded types
		struct {
			const void* restrict pmin;
			const void* restrict pmax;
		} range;
		// Blob types
		size_t len;
	} bound;

	struct {
		enum rng_next_type type : 4;
		enum rng_next_flag mod  : 3; 
		uint8_t	_unused0	: 1;
		//first byte

		uint32_t _padding	: 24;
	} ty; // 32 bits :/
	union {
		uint32_t array_size;
	} ex; // 32 bits. fills hole
};

typedef __typeof( ((struct rng_next_opt*)NULL)->ty ) rng_next_tyq; // Qualified type

typedef rng_t* (*rng_ctor_fn)(const void*);

typedef struct rng_dyn_ctor* rng_dyn_ctor_ref;

// -- // --
#ifndef _RNGXX_IMPL_ONLY_TYPES

_Static_assert(sizeof(rng_next_tyq) == sizeof(uint32_t));
_Static_assert(sizeof( ((struct rng_next_opt*)NULL)->ex ) == sizeof(uint32_t));

// -- C API functions -- (C++ NO compat)

int rng_raw(rng_t* engine, void* restrict output, struct rng_next_opt opt);
void rng_next_bin(rng_t* engine, unsigned char* restrict output, size_t n);

void* rng_next_ty(rng_t* engine, void* restrict output, enum rng_next_type ty, enum rng_next_flag flags);
void* rng_next_tya(rng_t* engine, void* restrict output, enum rng_next_type ty, enum rng_next_flag flags, uint32_t sz);
void* rng_next_tyab(rng_t* engine, void* restrict output, enum rng_next_type ty, enum rng_next_flag flags, uint32_t sz, const void* pmin, const void* pmax);
void* rng_next_tyb(rng_t* engine, void* restrict output, enum rng_next_type ty, enum rng_next_flag flags, const void* pmin, const void* pmax);

rng_dyn_ctor_ref rng_ctor_ref(const char* name);
rng_ctor_fn rng_ctor(const char* name) __attribute__((deprecated("many dynamic ctors will have state that cannot be expressed through a raw function pointer, and so this method will not work for them. use `rng_ctor_ref` and `rng_ctor_call` instead where possible, unless you know that the dynamic ctor is a bare function pointer."))); // Get a dynamic ctor that is a raw funciton pointer. If the ctor for this name is not a raw function pointer (if it has state), then NULL is returned.
rng_t* rng_ctor_call(rng_dyn_ctor_ref ctor, const void* seed);

rng_t* rng_new_named(const char* name, const void* seed);
rng_t* rng_new(enum rng_kind kind, const u64 seed[static restrict 1]);
void rng_free(rng_t* rng);

#ifdef _RNGXX_INLINE_ONLY
#define _rng__always_inline __attribute__((gnu_inline)) inline extern
#else
#define _rng__always_inline __attribute__((gnu_inline)) inline static
#endif

#define _NEXT_TYPED_(name, T, N, S) \
_rng__always_inline T rng_next_ ## name (rng_t* engine, const T* min, const T* max) \
{ \
	T output; \
	rng_next_tyb(engine, &output, RNG_TY_ ## N, RNG_TYQ_ ## S, min, max); \
	return output; \
} \
_rng__always_inline T* rng_nexta_ ## name(uint32_t len; rng_t* engine, T output[restrict len], uint32_t len, const T* min, const T* max) \
{ \
	return rng_next_tyab(engine, output, RNG_TY_ ## N, RNG_TYQ_ ## S, len, min, max); \
} \
_rng__always_inline T* rng_nextam_ ## name(rng_t* engine, uint32_t len, const T* min, const T* max) \
{ \
	return rng_next_tyab(engine, NULL, RNG_TY_ ## N, RNG_TYQ_ ## S, len, min, max); \
}

#define _NEXT_TYPED(T, N, S) _NEXT_TYPED_(T, T, N, S)

#define NEXT_TYPED_INT(n) _NEXT_TYPED(i ## n, INT ## n, SIGNED) \
			  _NEXT_TYPED(u ## n, INT ## n, UNSIGNED)

NEXT_TYPED_INT(8)
NEXT_TYPED_INT(16)
NEXT_TYPED_INT(32)
NEXT_TYPED_INT(64)

_NEXT_TYPED(f32, F32, SIGNED)
_NEXT_TYPED(f64, F64, SIGNED)

_rng__always_inline rng_bool_t rng_next_bool(rng_t* engine)
{
	rng_bool_t output;
	rng_next_tyb(engine, &output, RNG_TY_BOOL, 0, NULL, NULL);
	return output & 1;
}
_rng__always_inline rng_bool_t* rng_nexta_bool(uint32_t len; rng_t* engine, rng_bool_t output[restrict len], uint32_t len)
{
	return rng_next_tyab(engine, output, RNG_TY_BOOL, 0, len, NULL, NULL);
}
_rng__always_inline rng_bool_t* rng_nextam_bool(rng_t* engine, uint32_t len)
{
	return rng_next_tyab(engine, NULL, RNG_TY_BOOL, 0, len, NULL, NULL);
}

#undef NEXT_TYPED_INT
#undef _NEXT_TYPED
#undef _NEXT_TYPED_

#undef  _rng__always_inline

// -- // --
#endif
#ifdef __cplusplus
}
#endif

#endif /* _RNGXX_H */