#include "../../include/std/scoped_allocator.h"
#include "../../include/std/alloc.h"
#include <assert.h>

#define ALLOC_NODE_SIZE 4096

int scoped_allocator_node_init(ScopedAllocatorNode *self) {
    self->data = NULL;
    self->size = 0;
    self->next = NULL;
    return am_malloc(ALLOC_NODE_SIZE, (void**)&self->data);
}

void scoped_allocator_node_deinit(ScopedAllocatorNode *self) {
    am_free(self->data);
    self->data = NULL;
    self->size = 0;
    if(self->next) {
        scoped_allocator_node_deinit(self->next);
        am_free(self->next);
        self->next = NULL;
    }
}

int scoped_allocator_init(ScopedAllocator *self) {
    return_if_error(scoped_allocator_node_init(&self->head));
    self->current = &self->head;
    return buffer_init(&self->buffers, NULL);
}

static void buffer_deinit(Buffer *self) {
    am_free(self->data);
    self->data = NULL;
    self->size = 0;
    self->capacity = 0;
}

void scoped_allocator_deinit(ScopedAllocator *self) {
    Buffer *buffer;
    Buffer *buffer_end;

    scoped_allocator_node_deinit(&self->head);
    self->current = NULL;
    buffer = (Buffer*)self->buffers.data;
    buffer_end = buffer + self->buffers.size / sizeof(Buffer);
    while(buffer != buffer_end) {
        buffer_deinit(buffer);
        ++buffer;
    }
    buffer_deinit(&self->buffers);
}

static CHECK_RESULT int scoped_allocator_ensure_capacity_for(ScopedAllocator *self, usize size) {
    void *new_node;
    new_node = NULL;
    
    if(self->current->size + size > ALLOC_NODE_SIZE) {
        return_if_error(am_malloc(sizeof(ScopedAllocatorNode), &new_node));
        cleanup_if_error(scoped_allocator_node_init(new_node));
        self->current->next = new_node;
        self->current = new_node;
    }
    return ALLOC_OK;

    cleanup:
    if(new_node)
        am_free(new_node);
    return ALLOC_FAIL;
}

static void* align_ptr_ceil(void *ptr, uintptr_t alignment) {
    uintptr_t ptrval;
    ptrval = (uintptr_t)ptr;
    return (void*)((ptrval + alignment + 1) & ~(alignment - 1));
}

static usize align_ptr_ceil_offset(void *ptr, uintptr_t alignment) {
    return (uintptr_t)align_ptr_ceil(ptr, alignment) - (uintptr_t)ptr;
}

int scoped_allocator_alloc(ScopedAllocator *self, usize size, void **mem) {
    ScopedAllocatorNode *current;
    usize alloc_size;
    assert(self->current);
    assert(size <= ALLOC_NODE_SIZE);
    current = self->current;

    alloc_size = size + align_ptr_ceil_offset(self->current->data + self->current->size, 16);
    return_if_error(scoped_allocator_ensure_capacity_for(self, alloc_size));
    /* Reallocated (new node created) */
    if(self->current != current) {
        *mem = self->current->data;
        self->current->size += size;
    } else {
        *mem = align_ptr_ceil(self->current->data + self->current->size, 16);
        self->current->size += alloc_size;
    }
    return 0;
}

int scoped_allocator_add_buffer(ScopedAllocator *self, Buffer *buffer) {
    return buffer_append(&self->buffers, buffer, sizeof(Buffer));
}