#ifndef UTILITIEC_TRACINGHEAP_H
#define UTILITIEC_TRACINGHEAP_H

#include "../allocator-interface/allocator-interface.h"

#include <stdalign.h>
#include <stdbool.h>
#include <stdint.h>

enum TracingColor {
	TRACINGCOLOR_BLACK,
	TRACINGCOLOR_GREY,
	TRACINGCOLOR_WHITE,
};

union TracingObjectDataAlignment {
	double d;
	void* p;
};

typedef struct TracingObject {
	// color linked list members
	struct TracingObject* color_next;
	struct TracingObject* color_prev;

	// Selector for the callback function
	// TODO: Think about something for 16-bit systems
#define TRACINGHEAPDATAKIND_MAX (((uint64_t) 1 << 62) - 1)
	uint64_t data_kind: 62;

	// color of this object
	enum TracingColor color: 2;

	// data member of the requested size
	alignas(union TracingObjectDataAlignment) char data[];
} TracingObject;


typedef int    (*TracingHeapVisit) (void* context, void* reference);
typedef int    (*TracingHeapTraceData) (void* context, void* data, TracingHeapVisit trace_callback, void* callback_context);
typedef int    (*TracingHeapDataDestructor) (void* context, void* data);
typedef size_t (*TracingHeapSizeQuery) (void* context, void* data);

typedef struct TracingHeapConfig_s {
	TracingHeapTraceData* trace_data;
	void** trace_context;

	TracingHeapDataDestructor* destructor;
	void** destructor_context;

	TracingHeapSizeQuery* size_query;
	void** size_query_context;
} TracingHeapConfig;

typedef struct TracingHeap_s {
	TracingObject* white_objects;
	TracingObject* grey_objects;
	TracingObject* black_objects;

	enum TracingColor reachable_color;
	enum TracingColor unreachable_color;

	TracingHeapConfig config;
	allocator_t* allocator;
} TracingHeap;

int    TracingHeap_Create(TracingHeap* self, allocator_t* allocator);
void   TracingHeap_Destroy(TracingHeap* self);

void*  TracingHeap_Allocate(TracingHeap* self, size_t bytes, uint64_t object_kind);

int    TracingHeap_BeginTrace(TracingHeap* self);
bool   TracingHeap_IsTraceFinished(TracingHeap* self);
int    TracingHeap_EndTrace(TracingHeap* self);

int    TracingHeap_TraceNext(TracingHeap* self);
size_t TracingHeap_TraceNextN(TracingHeap* self, size_t n, int* error_code);
int    TracingHeap_AddTracingRoot(TracingHeap* self, void* data);
enum TracingColor TracingHeap_GetDataColor(TracingHeap* self, void* data);

#endif // header