#include "MObject.h"

#include <stdlib.h>
#include <string.h>
#include <stdint.h>

static struct Object* alloc(struct Object* self);
static struct Object* retain(struct Object* self);
static struct Object* release(struct Object* self);

struct Method MObject_meta_methods[] = {
    { .sel = "alloc", .impl = alloc },
};
struct Class MObjectMetaClass = {
    .class = &MObjectMetaClass,
    .name = "MObject(meta)",
    .super = nullptr,
    .methods = MObject_meta_methods,
    .methods_count = sizeof(MObject_meta_methods) / sizeof(struct Method),
};

struct Method MObject_methods[] = {
    { .sel = "retain", .impl = retain },
    { .sel = "release", .impl = release },
};
struct Class MObject = {
    .class = &MObjectMetaClass,
    .name = "MObject",
    .super = nullptr,
    .methods = MObject_methods,
    .methods_count = sizeof(MObject_methods) / sizeof(struct Method),
};

struct Header
{
    size_t retain_count;
};

static struct Object* alloc(struct Object* self)
{
    if (!self) {
        return nullptr;
    }

    struct Class* class = (struct Class*)self;

    auto size = sizeof(struct Header) + sizeof(struct Object);
    void* mem = malloc(size);
    memset(mem, 0, size);

    struct Header* header = (struct Header*)mem;
    header->retain_count = 1;

    struct Object* obj = (struct Object*)((uintptr_t)mem + sizeof(struct Header));
    obj->class = class;

    return obj;
}

static struct Object* retain(struct Object* self)
{
    if (!self) {
        return nullptr;
    }

    struct Header* header = (struct Header*)((uintptr_t)self - sizeof(struct Header));
    header->retain_count += 1;

    return self;
}

static struct Object* release(struct Object* self)
{
    if (!self) {
        return nullptr;
    }

    struct Header* header = (struct Header*)((uintptr_t)self - sizeof(struct Header));
    header->retain_count -= 1;
    if (header->retain_count <= 0) {
        free(header);
    }

    return nullptr;
}