#ifndef ALLOCATOR_H
#define ALLOCATOR_H

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

#define MAX_ALIGN (sizeof(union { char c; int i; long l; long long ll; float f; double d; void *p; }))
#define KB (1024)
#define MB (KB * KB)
#define GB (KB * KB * KB)

// Contains all operations an allocator can do. Similar interface to sdtlibs
// malloc, realloc and free.
typedef struct allocator_vtbl {
    void *(*alloc)(void *this, size_t bytes, const char *file, int line);
    void *(*resize)(void *this, void *old_ptr, size_t bytes, const char *file, int line);
    void (*free)(void *this, void *ptr, const char *file, int line);
} allocator_vtbl_t;

// An instance of an allocator.
typedef struct allocator {
    // pointer to the behind-the-scenes data that an allocator may store.
    void *const this;
    // pointer to the method implementations of an allocator.
    const allocator_vtbl_t *const vtbl;
} allocator_t;

void *allocator_alloc_func(allocator_t this, size_t bytes, const char *file, int line);
void *allocator_resize_func(allocator_t this, void *old_ptr, size_t bytes, const char *file, int line);
void allocator_free_func(allocator_t this, void *ptr, const char *file, int line);
#define allocator_alloc(this, bytes) allocator_alloc_func(this, bytes, __FILE__, __LINE__)
#define allocator_resize(this, old_ptr, bytes) allocator_resize_func(this, old_ptr, bytes, __FILE__, __LINE__)
#define allocator_free(this, ptr) allocator_free_func(this, ptr, __FILE__, __LINE__)

// std_allocator ///////////////////////////////////////////////////////////////
extern const allocator_t allocator_stdlib;
// buffer_allocator ////////////////////////////////////////////////////////////
typedef struct buffer_allocator {
    size_t size, capacity;
    uint8_t *data;
} buffer_allocator_t;

#define buffer_allocator_stack_create(CAPACITY)                                \
  ((buffer_allocator_t){                                                       \
      .size = 0, .capacity = CAPACITY, .data = (uint8_t[CAPACITY]){}})

buffer_allocator_t *buffer_allocator_heap_create(allocator_t alloc, size_t capacity);
void buffer_allocator_heap_destroy(allocator_t alloc, buffer_allocator_t *this);
// TODO: maybe use the macro magic to use the standard allcocator as the default
// one? or make users define a STANDARD_ALLOCATOR value? need to think about the
// consequenses

#ifdef ALLOCATOR_IMPLEMENTATION

void *allocator_alloc_func(allocator_t this, size_t bytes, const char *file, int line) {
    return this.vtbl->alloc(this.this, bytes, file, line);
}
void *allocator_resize_func(allocator_t this, void *old_ptr, size_t bytes, const char *file, int line) {
    return this.vtbl->resize(this.this, old_ptr, bytes, file, line);
}
void allocator_free_func(allocator_t this, void *ptr, const char *file, int line) {
    this.vtbl->free(this.this, ptr, file, line);
}

#include "std_allocator.c"
#include "buffer_allocator.c"

#endif // ALLOCATOR_IMPLEMENTATION
#endif // ALLOCATOR_H