#include "buffer.h"

#include <blue/core/iterator.h>
#include <blue/object/buffer.h>
#include <blue/object/type.h>
#include <stdlib.h>
#include <string.h>

static void buffer_release(struct b_object *obj);

static struct b_object_type buffer_type = {
	.t_flags = B_OBJECT_FUNDAMENTAL,
	.t_id = B_OBJECT_TYPE_BUFFER,
	.t_name = "corelib::buffer",
	.t_instance_size = sizeof(struct b_buffer),
	.t_release = buffer_release,
};

struct b_buffer *b_buffer_create(size_t item_sz)
{
	struct b_buffer *buffer
		= (struct b_buffer *)b_object_type_instantiate(&buffer_type);
	if (!buffer) {
		return NULL;
	}

	buffer->buf_itemsz = item_sz;

	return buffer;
}

struct b_buffer *b_buffer_create_from_bytes(const void *p, size_t len)
{
	struct b_buffer *buffer = b_buffer_create(1);
	if (!buffer) {
		return NULL;
	}

	buffer->buf_len = len;
	buffer->buf_cap = len;
	buffer->buf_itemsz = 1;
	buffer->buf_data = calloc(len, 1);
	if (!buffer->buf_data) {
		b_buffer_release(buffer);
		return NULL;
	}

	memcpy(buffer->buf_data, p, len);

	return buffer;
}

struct b_buffer *b_buffer_create_from_array(const void *p, size_t item_sz, size_t len)
{
	struct b_buffer *buffer = b_buffer_create(1);
	if (!buffer) {
		return NULL;
	}

	buffer->buf_len = len;
	buffer->buf_cap = len;
	buffer->buf_itemsz = item_sz;
	buffer->buf_data = calloc(len, item_sz);
	if (!buffer->buf_data) {
		b_buffer_release(buffer);
		return NULL;
	}

	memcpy(buffer->buf_data, p, len * item_sz);

	return buffer;
}

static b_status resize_buffer(struct b_buffer *buffer, size_t new_capacity)
{
	if (buffer->buf_cap < new_capacity) {
		void *new_data = realloc(
			buffer->buf_data, new_capacity * buffer->buf_itemsz);
		if (!new_data) {
			return B_ERR_NO_MEMORY;
		}

		buffer->buf_data = new_data;
	} else {
		void *new_data = realloc(
			buffer->buf_data, new_capacity * buffer->buf_itemsz);
		if (!new_data) {
			return B_ERR_NO_MEMORY;
		}

		buffer->buf_data = new_data;
	}

	buffer->buf_cap = new_capacity;
	if (buffer->buf_len > new_capacity) {
		buffer->buf_len = new_capacity;
	}

	return B_SUCCESS;
}

void *b_buffer_steal(struct b_buffer *buf)
{
	void *p = buf->buf_data;

	buf->buf_data = NULL;
	buf->buf_len = 0;
	buf->buf_cap = 0;

	return p;
}

enum b_status b_buffer_reserve(struct b_buffer *buf, size_t capacity)
{
	if (buf->buf_cap >= capacity) {
		return B_SUCCESS;
	}

	return resize_buffer(buf, capacity);
}

enum b_status b_buffer_resize(struct b_buffer *buf, size_t length)
{
	enum b_status status = resize_buffer(buf, length);

	if (!B_OK(status)) {
		return status;
	}

	buf->buf_len = length;
	return B_SUCCESS;
}

enum b_status b_buffer_append(struct b_buffer *buffer, const void *p, size_t count)
{
	return b_buffer_insert(buffer, p, count, B_NPOS);
}

enum b_status b_buffer_prepend(struct b_buffer *buffer, const void *p, size_t count)
{
	return b_buffer_insert(buffer, p, count, 0);
}

enum b_status b_buffer_insert(
	struct b_buffer *buffer, const void *p, size_t count, size_t at)
{
	if (at == B_NPOS) {
		at = buffer->buf_len;
	}

	if (at > buffer->buf_len) {
		return B_ERR_OUT_OF_BOUNDS;
	}

	b_status status = B_SUCCESS;

	if (buffer->buf_len + count > buffer->buf_cap) {
		status = resize_buffer(buffer, buffer->buf_cap + count);

		if (status != B_SUCCESS) {
			return status;
		}
	}

	unsigned char *src
		= (unsigned char *)buffer->buf_data + (at * buffer->buf_itemsz);
	unsigned char *dest = src + (count * buffer->buf_itemsz);
	size_t move_len = (buffer->buf_len - at) * buffer->buf_itemsz;

	memmove(dest, src, move_len);
	memcpy(src, p, count * buffer->buf_itemsz);

	buffer->buf_len += count;
	return B_SUCCESS;
}

enum b_status b_buffer_remove(struct b_buffer *buffer, size_t at, size_t count)
{
	if (at >= buffer->buf_len) {
		return B_ERR_OUT_OF_BOUNDS;
	}

	if (at + count >= buffer->buf_len) {
		count = buffer->buf_len - at;
	}

	unsigned char *dest = buffer->buf_data + (at * buffer->buf_itemsz);
	unsigned char *src = dest + (count * buffer->buf_itemsz);
	size_t move_len = (buffer->buf_len - at - count) * buffer->buf_itemsz;

	memmove(dest, src, move_len);

	buffer->buf_len -= count;

	return B_SUCCESS;
}

void *b_buffer_ptr(const struct b_buffer *buffer)
{
	return buffer->buf_data;
}

void *b_buffer_get(const struct b_buffer *buffer, size_t at)
{
	if (at >= buffer->buf_len) {
		return NULL;
	}

	return (unsigned char *)buffer->buf_data + (at * buffer->buf_itemsz);
}

size_t b_buffer_size(const struct b_buffer *buffer)
{
	return buffer->buf_len;
}

size_t b_buffer_capacity(const struct b_buffer *buffer)
{
	return buffer->buf_cap;
}

void buffer_release(struct b_object *obj)
{
	struct b_buffer *buffer = B_BUFFER(obj);

	if (buffer->buf_data) {
		free(buffer->buf_data);
		buffer->buf_data = NULL;
	}
}

enum b_status b_buffer_clear(struct b_buffer *buffer)
{
	buffer->buf_len = 0;
	return B_SUCCESS;
}

enum b_status b_buffer_push_back(struct b_buffer *buf, size_t count, void **p)
{
	enum b_status status = B_SUCCESS;

	if (buf->buf_len + count > buf->buf_cap) {
		status = resize_buffer(buf, buf->buf_len + count);
	}

	if (!B_OK(status)) {
		return status;
	}

	buf->buf_len += count;
	*p = b_buffer_get(buf, buf->buf_len - count);

	return B_SUCCESS;
}

enum b_status b_buffer_push_front(struct b_buffer *buf, size_t count, void **p)
{
	enum b_status status = B_SUCCESS;

	if (buf->buf_len + count > buf->buf_cap) {
		status = resize_buffer(buf, buf->buf_len + count);
	}

	if (!B_OK(status)) {
		return status;
	}

	void *src = buf->buf_data;
	void *dest = b_buffer_get(buf->buf_data, count);
	size_t len = count * buf->buf_itemsz;

	memmove(dest, src, len);
	buf->buf_len += count;

	*p = b_buffer_get(buf, 0);

	return B_SUCCESS;
}

enum b_status b_buffer_pop_back(struct b_buffer *buf, size_t count)
{
	if (count > buf->buf_len) {
		return B_ERR_OUT_OF_BOUNDS;
	}

	buf->buf_len -= count;

	return B_SUCCESS;
}

enum b_status b_buffer_pop_front(struct b_buffer *buf, size_t count)
{
	if (count > buf->buf_len) {
		return B_ERR_OUT_OF_BOUNDS;
	}

	void *src = b_buffer_get(buf->buf_data, count);
	void *dest = buf->buf_data;
	size_t len = (buf->buf_len - count) * buf->buf_itemsz;

	memmove(dest, src, len);
	buf->buf_len -= count;

	return B_SUCCESS;
}

size_t b_buffer_get_size(const struct b_buffer *buf)
{
	return buf->buf_len;
}

size_t b_buffer_get_item_size(const struct b_buffer *buf)
{
	return buf->buf_itemsz;
}

size_t b_buffer_get_capacity(const struct b_buffer *buf)
{
	return buf->buf_cap;
}

b_object_type_id b_buffer_type_id(void)
{
	return (b_object_type_id)&buffer_type;
}