// vim:fileencoding=utf-8:foldmethod=marker

#include "./dbl_list.h"
#include "../mem/allocator/mem_allocator.h"
#include "../../common/assert/assert.h"
#include "../../common/aliases/aliases.h"
#include "../../common/platform/platform.h"
#include <stddef.h>

wapp_intern GenericList _node_to_list(GenericNode *node, u64 item_size);
wapp_intern inline void _dbl_list_validate(const GenericList *list, u64 item_size);
wapp_intern inline void _dbl_list_node_validate(const GenericList *list, const GenericNode *node, u64 item_size);

GenericList *_dbl_list_alloc(const Allocator *allocator, u64 item_size) {
	wapp_debug_assert(allocator != NULL, "`allocator` should not be NULL");

	GenericList *list = wapp_mem_allocator_alloc(allocator, sizeof(GenericList));
	if (!list) { goto DBL_LIST_ALLOC_RETURN; }

	memset((void *)list, 0, sizeof(GenericList));
	list->magic      = WAPP_DBL_LIST_MAGIC;
	list->item_size  = item_size;

DBL_LIST_ALLOC_RETURN:
	return list;
}

GenericNode *_dbl_list_node_alloc(const Allocator *allocator, u64 item_size) {
	wapp_debug_assert(allocator != NULL, "`allocator` should not be NULL");

	GenericNode *node = wapp_mem_allocator_alloc(allocator, sizeof(GenericNode));
	if (!node) { goto DBL_LIST_NODE_ALLOC_RETURN; }

	memset((void *)node, 0, sizeof(GenericNode));
	node->magic      = WAPP_DBL_NODE_MAGIC;
	node->item_size  = item_size;

DBL_LIST_NODE_ALLOC_RETURN:
	return node;
}

GenericNode *_dbl_list_get(const GenericList *list, u64 index, u64 item_size) {
	wapp_debug_assert(list != NULL, "`list` should not be NULL");
	_dbl_list_validate(list, item_size);
	wapp_runtime_assert(index < list->node_count, "`index` is out of bounds");

	GenericNode *output    = NULL;
	GenericNode *current  = list->first;
	for (u64 i = 1; i <= index; ++i) {
		current = current->next;
	}

	output = current;

	return output;
}

void _dbl_list_push_front(GenericList *list, GenericNode *node, u64 item_size) {
	wapp_debug_assert(list != NULL && node != NULL && (node->item) != NULL, "`list`, `node` and `node->item` should not be NULL");
	_dbl_list_validate(list, item_size);
	_dbl_list_node_validate(list, node, item_size);

	GenericList node_list = _node_to_list(node, item_size);

	if (list->node_count == 0) {
		*list = node_list;
		return;
	}

	list->node_count += node_list.node_count;

	GenericNode *first = list->first;
	if (first) {
		first->prev = node_list.last;
	}

	list->first            = node_list.first;
	node_list.last->next  = first;
}

void _dbl_list_push_back(GenericList *list, GenericNode *node, u64 item_size) {
	wapp_debug_assert(list != NULL && node != NULL && (node->item) != NULL, "`list`, `node` and `node->item` should not be NULL");
	_dbl_list_validate(list, item_size);
	_dbl_list_node_validate(list, node, item_size);

	GenericList node_list = _node_to_list(node, item_size);

	if (list->node_count == 0) {
		*list = node_list;
		return;
	}

	list->node_count += node_list.node_count;

	GenericNode *last = list->last;
	if (last) {
		last->next = node_list.first;
	}

	list->last            = node_list.last;
	node_list.first->prev  = last;
}

void _dbl_list_insert(GenericList *list, GenericNode *node, u64 index, u64 item_size) {
	wapp_debug_assert(list != NULL && node != NULL && (node->item) != NULL, "`list`, `node` and `node->item` should not be NULL");
	_dbl_list_validate(list, item_size);
	_dbl_list_node_validate(list, node, item_size);

	if (index == 0) {
		_dbl_list_push_front(list, node, item_size);
		return;
	} else if (index == list->node_count) {
		_dbl_list_push_back(list, node, item_size);
		return;
	}

	GenericNode *dst_node = _dbl_list_get(list, index, item_size);
	if (!dst_node) {
		return;
	}

	GenericList node_list = _node_to_list(node, item_size);

	list->node_count += node_list.node_count;

	GenericNode *prev = dst_node->prev;

	dst_node->prev  = node_list.last;
	prev->next      = node_list.first;

	node_list.first->prev = prev;
	node_list.last->next  = dst_node;
}

GenericNode *_dbl_list_pop_front(GenericList *list, u64 item_size) {
	wapp_debug_assert(list != NULL, "`list` should not be NULL");
	_dbl_list_validate(list, item_size);

	GenericNode *output = NULL;

	if (list->node_count == 0) {
		goto RETURN_I32_LIST_POP_FRONT;
	}

	output = list->first;

	if (list->node_count == 1) {
		*list = (GenericList){.magic = WAPP_DBL_LIST_MAGIC, .item_size = item_size};
		goto RETURN_I32_LIST_POP_FRONT;
	}

	--(list->node_count);
	list->first = output->next;

	output->prev = output->next = NULL;

RETURN_I32_LIST_POP_FRONT:
	return output;
}

GenericNode *_dbl_list_pop_back(GenericList *list, u64 item_size) {
	wapp_debug_assert(list != NULL, "`list` should not be NULL");
	_dbl_list_validate(list, item_size);

	GenericNode *output = NULL;

	if (list->node_count == 0) {
		goto RETURN_I32_LIST_POP_BACK;
	}

	output = list->last;

	if (list->node_count == 1) {
		*list = (GenericList){.magic = WAPP_DBL_LIST_MAGIC, .item_size = item_size};
		goto RETURN_I32_LIST_POP_BACK;
	}

	--(list->node_count);
	list->last = output->prev;

	output->prev = output->next = NULL;

RETURN_I32_LIST_POP_BACK:
	return output;
}

GenericNode *_dbl_list_remove(GenericList *list, u64 index, u64 item_size) {
	wapp_debug_assert(list != NULL, "`list` should not be NULL");
	_dbl_list_validate(list, item_size);

	GenericNode *output = NULL;

	if (index == 0) {
		output = _dbl_list_pop_front(list, item_size);
		goto RETURN_I32_LIST_REMOVE;
	} else if (index == list->node_count) {
		output = _dbl_list_pop_back(list, item_size);
		goto RETURN_I32_LIST_REMOVE;
	}

	output = _dbl_list_get(list, index, item_size);
	if (!output) {
		goto RETURN_I32_LIST_REMOVE;
	}

	output->prev->next = output->next;
	output->next->prev = output->prev;

	--(list->node_count);

	output->prev = output->next = NULL;

RETURN_I32_LIST_REMOVE:
	return output;
}

void _dbl_list_empty(GenericList *list, u64 item_size) {
	wapp_debug_assert(list != NULL, "`list` should not be NULL");
	_dbl_list_validate(list, item_size);

	u64 count = list->node_count;
	for (u64 i = 0; i < count; ++i) {
		_dbl_list_pop_back(list, item_size);
	}
}

wapp_intern GenericList _node_to_list(GenericNode *node, u64 item_size) {
	GenericList output = {
		.magic      = WAPP_DBL_LIST_MAGIC,
		.first      = node,
		.last        = node,
		.node_count  = 1,
		.item_size  = item_size,
	};

	while (output.first->prev != NULL) {
		output.first = output.first->prev;
		++(output.node_count);
	}

	while (output.last->next != NULL) {
		output.last = output.last->next;
		++(output.node_count);
	}

	return output;
}

wapp_intern inline void _dbl_list_validate(const GenericList *list, u64 item_size) {
	wapp_runtime_assert(list->magic == WAPP_DBL_LIST_MAGIC, "`list` isn't a valid wapp list type");
	wapp_runtime_assert(list->item_size == item_size, "Invalid item provided");
}

wapp_intern inline void _dbl_list_node_validate(const GenericList *list, const GenericNode *node, u64 item_size) {
	wapp_runtime_assert(node->magic == WAPP_DBL_NODE_MAGIC, "`node` isn't a valid wapp node type");
	wapp_runtime_assert(list->item_size == node->item_size, "Mismatched `list` and `node` types");
	wapp_runtime_assert(node->item_size == item_size, "Invalid item provided");
}