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

/*** PRIVATE DATA *************************************************************/

struct b_buffer_p {
	/* number of items in buffer */
	unsigned int buf_len;
	/* maximum number of items that can currently be stored in array */
	unsigned int buf_cap;
	/* the size of each individual item in the buffer */
	unsigned int buf_itemsz;
	void *buf_data;
};

/*** PRIVATE FUNCTIONS ********************************************************/

static b_status resize_buffer(struct b_buffer_p *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;
}

static void *buffer_steal(struct b_buffer_p *buf)
{
	void *p = buf->buf_data;

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

	return p;
}

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

	return resize_buffer(buf, capacity);
}

static enum b_status buffer_resize(struct b_buffer_p *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;
}

static enum b_status buffer_insert(
	struct b_buffer_p *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;
}

static enum b_status buffer_remove(struct b_buffer_p *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;
}

static void *buffer_ptr(const struct b_buffer_p *buffer)
{
	return buffer->buf_data;
}

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

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

static size_t buffer_size(const struct b_buffer_p *buffer)
{
	return buffer->buf_len;
}

static size_t buffer_capacity(const struct b_buffer_p *buffer)
{
	return buffer->buf_cap;
}

static enum b_status buffer_clear(struct b_buffer_p *buffer)
{
	buffer->buf_len = 0;
	return B_SUCCESS;
}

static enum b_status buffer_push_back(
	struct b_buffer_p *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 = buffer_get(buf, buf->buf_len - count);

	return B_SUCCESS;
}

static enum b_status buffer_push_front(
	struct b_buffer_p *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 = buffer_get(buf, 0);

	return B_SUCCESS;
}

static enum b_status buffer_pop_back(struct b_buffer_p *buf, size_t count)
{
	if (count > buf->buf_len) {
		return B_ERR_OUT_OF_BOUNDS;
	}

	buf->buf_len -= count;

	return B_SUCCESS;
}

static enum b_status buffer_pop_front(struct b_buffer_p *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;
}

static size_t buffer_get_size(const struct b_buffer_p *buf)
{
	return buf->buf_len;
}

static size_t buffer_get_item_size(const struct b_buffer_p *buf)
{
	return buf->buf_itemsz;
}

static size_t buffer_get_capacity(const struct b_buffer_p *buf)
{
	return buf->buf_cap;
}

/*** PUBLIC FUNCTIONS *********************************************************/

b_buffer *b_buffer_create(size_t item_sz)
{
	b_buffer *buffer = b_object_create(B_TYPE_BUFFER);
	if (!buffer) {
		return NULL;
	}

	struct b_buffer_p *p = b_object_get_private(buffer, B_TYPE_BUFFER);

	p->buf_itemsz = item_sz;

	return buffer;
}

b_buffer *b_buffer_create_from_bytes(const void *buf, size_t len)
{
	b_buffer *buffer = b_object_create(B_TYPE_BUFFER);
	if (!buffer) {
		return NULL;
	}

	struct b_buffer_p *p = b_object_get_private(buffer, B_TYPE_BUFFER);

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

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

	return buffer;
}

b_buffer *b_buffer_create_from_array(const void *buf, size_t item_sz, size_t len)
{
	b_buffer *buffer = b_object_create(B_TYPE_BUFFER);
	if (!buffer) {
		return NULL;
	}

	struct b_buffer_p *p = b_object_get_private(buffer, B_TYPE_BUFFER);

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

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

	return buffer;
}

void *b_buffer_steal(b_buffer *buf)
{
	B_CLASS_DISPATCH_STATIC_0(B_TYPE_BUFFER, buffer_steal, buf);
}

enum b_status b_buffer_reserve(b_buffer *buf, size_t capacity)
{
	B_CLASS_DISPATCH_STATIC(B_TYPE_BUFFER, buffer_reserve, buf, capacity);
}

enum b_status b_buffer_resize(b_buffer *buf, size_t length)
{
	B_CLASS_DISPATCH_STATIC(B_TYPE_BUFFER, buffer_resize, buf, length);
}

enum b_status b_buffer_insert(
	b_buffer *buffer, const void *p, size_t count, size_t at)
{
	B_CLASS_DISPATCH_STATIC(B_TYPE_BUFFER, buffer_insert, buffer, p, count, at);
}

enum b_status b_buffer_remove(b_buffer *buffer, size_t at, size_t count)
{
	B_CLASS_DISPATCH_STATIC(B_TYPE_BUFFER, buffer_remove, buffer, at, count);
}

void *b_buffer_ptr(const b_buffer *buffer)
{
	B_CLASS_DISPATCH_STATIC_0(B_TYPE_BUFFER, buffer_ptr, buffer);
}

void *b_buffer_get(const b_buffer *buffer, size_t at)
{
	B_CLASS_DISPATCH_STATIC(B_TYPE_BUFFER, buffer_get, buffer, at);
}

size_t b_buffer_size(const b_buffer *buffer)
{
	B_CLASS_DISPATCH_STATIC_0(B_TYPE_BUFFER, buffer_size, buffer);
}

size_t b_buffer_capacity(const b_buffer *buffer)
{
	B_CLASS_DISPATCH_STATIC_0(B_TYPE_BUFFER, buffer_capacity, buffer);
}

enum b_status b_buffer_clear(b_buffer *buffer)
{
	B_CLASS_DISPATCH_STATIC_0(B_TYPE_BUFFER, buffer_clear, buffer);
}

enum b_status b_buffer_push_back(b_buffer *buf, size_t count, void **p)
{
	B_CLASS_DISPATCH_STATIC(B_TYPE_BUFFER, buffer_push_back, buf, count, p);
}

enum b_status b_buffer_push_front(b_buffer *buf, size_t count, void **p)
{
	B_CLASS_DISPATCH_STATIC(B_TYPE_BUFFER, buffer_push_front, buf, count, p);
}

enum b_status b_buffer_pop_back(b_buffer *buf, size_t count)
{
	B_CLASS_DISPATCH_STATIC(B_TYPE_BUFFER, buffer_pop_back, buf, count);
}

enum b_status b_buffer_pop_front(b_buffer *buf, size_t count)
{
	B_CLASS_DISPATCH_STATIC(B_TYPE_BUFFER, buffer_pop_front, buf, count);
}

size_t b_buffer_get_size(const b_buffer *buf)
{
	B_CLASS_DISPATCH_STATIC_0(B_TYPE_BUFFER, buffer_get_size, buf);
}

size_t b_buffer_get_item_size(const b_buffer *buf)
{
	B_CLASS_DISPATCH_STATIC_0(B_TYPE_BUFFER, buffer_get_item_size, buf);
}

size_t b_buffer_get_capacity(const b_buffer *buf)
{
	B_CLASS_DISPATCH_STATIC_0(B_TYPE_BUFFER, buffer_get_capacity, buf);
}

/*** PUBLIC ALIAS FUNCTIONS ***************************************************/

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

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

/*** VIRTUAL FUNCTIONS ********************************************************/

void buffer_init(b_object *obj, void *priv)
{
	struct b_buffer_p *buffer = priv;
}

void buffer_fini(b_object *obj, void *priv)
{
	struct b_buffer_p *buffer = priv;

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

/*** CLASS DEFINITION *********************************************************/

B_TYPE_CLASS_DEFINITION_BEGIN(b_buffer)
	B_TYPE_CLASS_INTERFACE_BEGIN(b_object, B_TYPE_OBJECT)
		B_INTERFACE_ENTRY(to_string) = NULL;
	B_TYPE_CLASS_INTERFACE_END(b_object, B_TYPE_OBJECT)
B_TYPE_CLASS_DEFINITION_END(b_buffer)

B_TYPE_DEFINITION_BEGIN(b_buffer)
	B_TYPE_ID(0x323e6858, 0x7a43, 0x4484, 0xa6fb, 0xe3d1e47ae637);
	B_TYPE_CLASS(b_buffer_class);
	B_TYPE_INSTANCE_INIT(buffer_init);
	B_TYPE_INSTANCE_INIT(buffer_fini);
B_TYPE_DEFINITION_END(b_buffer)