#include <stdlib.h>
#include <string.h>

#include "config.h"
#include "node.h"

static void
S_node_unlink(cmark_node *node);

static inline bool
S_is_block(cmark_node *node)
{
	if (node == NULL) {
		return false;
	}
	return node->type >= CMARK_NODE_FIRST_BLOCK
	       && node->type <= CMARK_NODE_LAST_BLOCK;
}

static inline bool
S_is_inline(cmark_node *node)
{
	if (node == NULL) {
		return false;
	}
	return node->type >= CMARK_NODE_FIRST_INLINE
	       && node->type <= CMARK_NODE_LAST_INLINE;
}

static bool
S_can_contain(cmark_node *node, cmark_node *child)
{
	cmark_node *cur;

	if (node == NULL || child == NULL) {
		return false;
	}

	// Verify that child is not an ancestor of node or equal to node.
	cur = node;
	do {
		if (cur == child) {
			return false;
		}
		cur = cur->parent;
	} while (cur != NULL);

	if (child->type == CMARK_NODE_DOCUMENT) {
		return false;
	}

	switch (node->type) {
	case CMARK_NODE_DOCUMENT:
	case CMARK_NODE_BLOCK_QUOTE:
	case CMARK_NODE_ITEM:
		return S_is_block(child)
		       && child->type != CMARK_NODE_ITEM;

	case CMARK_NODE_LIST:
		return child->type == CMARK_NODE_ITEM;

	case CMARK_NODE_PARAGRAPH:
	case CMARK_NODE_HEADER:
	case CMARK_NODE_EMPH:
	case CMARK_NODE_STRONG:
	case CMARK_NODE_LINK:
	case CMARK_NODE_IMAGE:
		return S_is_inline(child);

	default:
		break;
	}

	return false;
}

cmark_node*
cmark_node_new(cmark_node_type type)
{
	cmark_node *node = (cmark_node *)calloc(1, sizeof(*node));
	node->type = type;

	switch (node->type) {
	case CMARK_NODE_HEADER:
		node->as.header.level = 1;
		break;

	case CMARK_NODE_LIST: {
		cmark_list *list = &node->as.list;
		list->list_type = CMARK_BULLET_LIST;
		list->start     = 1;
		list->tight     = false;
		break;
	}

	default:
		break;
	}

	return node;
}

// Free a cmark_node list and any children.
static
void S_free_nodes(cmark_node *e)
{
	cmark_node *next;
	while (e != NULL) {
		if (S_is_block(e)) {
			cmark_strbuf_free(&e->string_content);
		}
		switch (e->type) {
		case NODE_CODE_BLOCK:
			cmark_chunk_free(&e->as.code.info);
			cmark_chunk_free(&e->as.code.literal);
			break;
		case NODE_TEXT:
		case NODE_INLINE_HTML:
		case NODE_CODE:
		case NODE_HTML:
			cmark_chunk_free(&e->as.literal);
			break;
		case NODE_LINK:
		case NODE_IMAGE:
			cmark_chunk_free(&e->as.link.url);
			cmark_chunk_free(&e->as.link.title);
			break;
		default:
			break;
		}
		if (e->last_child) {
			// Splice children into list
			e->last_child->next = e->next;
			e->next = e->first_child;
		}
		next = e->next;
		free(e);
		e = next;
	}
}

void
cmark_node_free(cmark_node *node)
{
	S_node_unlink(node);
	node->next = NULL;
	S_free_nodes(node);
}

cmark_node_type
cmark_node_get_type(cmark_node *node)
{
	if (node == NULL) {
		return CMARK_NODE_NONE;
	} else {
		return node->type;
	}
}

const char*
cmark_node_get_type_string(cmark_node *node)
{
	if (node == NULL) {
		return "NONE";
	}

	switch (node->type) {
	case CMARK_NODE_NONE:
		return "none";
	case CMARK_NODE_DOCUMENT:
		return "document";
	case CMARK_NODE_BLOCK_QUOTE:
		return "block_quote";
	case CMARK_NODE_LIST:
		return "list";
	case CMARK_NODE_ITEM:
		return "item";
	case CMARK_NODE_CODE_BLOCK:
		return "code_block";
	case CMARK_NODE_HTML:
		return "html";
	case CMARK_NODE_PARAGRAPH:
		return "paragraph";
	case CMARK_NODE_HEADER:
		return "header";
	case CMARK_NODE_HRULE:
		return "hrule";
	case CMARK_NODE_TEXT:
		return "text";
	case CMARK_NODE_SOFTBREAK:
		return "softbreak";
	case CMARK_NODE_LINEBREAK:
		return "linebreak";
	case CMARK_NODE_CODE:
		return "code";
	case CMARK_NODE_INLINE_HTML:
		return "inline_html";
	case CMARK_NODE_EMPH:
		return "emph";
	case CMARK_NODE_STRONG:
		return "strong";
	case CMARK_NODE_LINK:
		return "link";
	case CMARK_NODE_IMAGE:
		return "image";
	}

	return "<unknown>";
}

cmark_node*
cmark_node_next(cmark_node *node)
{
	if (node == NULL) {
		return NULL;
	} else {
		return node->next;
	}
}

cmark_node*
cmark_node_previous(cmark_node *node)
{
	if (node == NULL) {
		return NULL;
	} else {
		return node->prev;
	}
}

cmark_node*
cmark_node_parent(cmark_node *node)
{
	if (node == NULL) {
		return NULL;
	} else {
		return node->parent;
	}
}

cmark_node*
cmark_node_first_child(cmark_node *node)
{
	if (node == NULL) {
		return NULL;
	} else {
		return node->first_child;
	}
}

cmark_node*
cmark_node_last_child(cmark_node *node)
{
	if (node == NULL) {
		return NULL;
	} else {
		return node->last_child;
	}
}

void*
cmark_node_get_user_data(cmark_node *node)
{
	if (node == NULL) {
		return NULL;
	} else {
		return node->user_data;
	}
}

int
cmark_node_set_user_data(cmark_node *node, void *user_data)
{
	if (node == NULL) {
		return 0;
	}
	node->user_data = user_data;
	return 1;
}

const char*
cmark_node_get_literal(cmark_node *node)
{
	if (node == NULL) {
		return NULL;
	}

	switch (node->type) {
	case NODE_HTML:
	case NODE_TEXT:
	case NODE_INLINE_HTML:
	case NODE_CODE:
		return cmark_chunk_to_cstr(&node->as.literal);

	case NODE_CODE_BLOCK:
		return cmark_chunk_to_cstr(&node->as.code.literal);

	default:
		break;
	}

	return NULL;
}

int
cmark_node_set_literal(cmark_node *node, const char *content)
{
	if (node == NULL) {
		return 0;
	}

	switch (node->type) {
	case NODE_HTML:
	case NODE_TEXT:
	case NODE_INLINE_HTML:
	case NODE_CODE:
		cmark_chunk_set_cstr(&node->as.literal, content);
		return 1;

	case NODE_CODE_BLOCK:
		cmark_chunk_set_cstr(&node->as.code.literal, content);
		return 1;

	default:
		break;
	}

	return 0;
}

int
cmark_node_get_header_level(cmark_node *node)
{
	if (node == NULL) {
		return 0;
	}

	switch (node->type) {
	case CMARK_NODE_HEADER:
		return node->as.header.level;

	default:
		break;
	}

	return 0;
}

int
cmark_node_set_header_level(cmark_node *node, int level)
{
	if (node == NULL || level < 1 || level > 6) {
		return 0;
	}

	switch (node->type) {
	case CMARK_NODE_HEADER:
		node->as.header.level = level;
		return 1;

	default:
		break;
	}

	return 0;
}

cmark_list_type
cmark_node_get_list_type(cmark_node *node)
{
	if (node == NULL) {
		return CMARK_NO_LIST;
	}

	if (node->type == CMARK_NODE_LIST) {
		return node->as.list.list_type;
	} else {
		return CMARK_NO_LIST;
	}
}

int
cmark_node_set_list_type(cmark_node *node, cmark_list_type type)
{
	if (!(type == CMARK_BULLET_LIST || type == CMARK_ORDERED_LIST)) {
		return 0;
	}

	if (node == NULL) {
		return 0;
	}

	if (node->type == CMARK_NODE_LIST) {
		node->as.list.list_type = type;
		return 1;
	} else {
		return 0;
	}
}

cmark_delim_type
cmark_node_get_list_delim(cmark_node *node)
{
	if (node == NULL) {
		return CMARK_NO_DELIM;
	}

	if (node->type == CMARK_NODE_LIST) {
		return node->as.list.delimiter;
	} else {
		return CMARK_NO_DELIM;
	}
}

int
cmark_node_set_list_delim(cmark_node *node, cmark_delim_type delim)
{
	if (!(delim == CMARK_PERIOD_DELIM || delim == CMARK_PAREN_DELIM)) {
		return 0;
	}

	if (node == NULL) {
		return 0;
	}

	if (node->type == CMARK_NODE_LIST) {
		node->as.list.delimiter = delim;
		return 1;
	} else {
		return 0;
	}
}

int
cmark_node_get_list_start(cmark_node *node)
{
	if (node == NULL) {
		return 0;
	}

	if (node->type == CMARK_NODE_LIST) {
		return node->as.list.start;
	} else {
		return 0;
	}
}

int
cmark_node_set_list_start(cmark_node *node, int start)
{
	if (node == NULL || start < 0) {
		return 0;
	}

	if (node->type == CMARK_NODE_LIST) {
		node->as.list.start = start;
		return 1;
	} else {
		return 0;
	}
}

int
cmark_node_get_list_tight(cmark_node *node)
{
	if (node == NULL) {
		return 0;
	}

	if (node->type == CMARK_NODE_LIST) {
		return node->as.list.tight;
	} else {
		return 0;
	}
}

int
cmark_node_set_list_tight(cmark_node *node, int tight)
{
	if (node == NULL) {
		return 0;
	}

	if (node->type == CMARK_NODE_LIST) {
		node->as.list.tight = tight;
		return 1;
	} else {
		return 0;
	}
}

const char*
cmark_node_get_fence_info(cmark_node *node)
{
	if (node == NULL) {
		return NULL;
	}

	if (node->type == NODE_CODE_BLOCK) {
		return cmark_chunk_to_cstr(&node->as.code.info);
	} else {
		return NULL;
	}
}

int
cmark_node_set_fence_info(cmark_node *node, const char *info)
{
	if (node == NULL) {
		return 0;
	}

	if (node->type == NODE_CODE_BLOCK) {
		cmark_chunk_set_cstr(&node->as.code.info, info);
		return 1;
	} else {
		return 0;
	}
}

const char*
cmark_node_get_url(cmark_node *node)
{
	if (node == NULL) {
		return NULL;
	}

	switch (node->type) {
	case NODE_LINK:
	case NODE_IMAGE:
		return cmark_chunk_to_cstr(&node->as.link.url);
	default:
		break;
	}

	return NULL;
}

int
cmark_node_set_url(cmark_node *node, const char *url)
{
	if (node == NULL) {
		return 0;
	}

	switch (node->type) {
	case NODE_LINK:
	case NODE_IMAGE:
		cmark_chunk_set_cstr(&node->as.link.url, url);
		return 1;
	default:
		break;
	}

	return 0;
}

const char*
cmark_node_get_title(cmark_node *node)
{
	if (node == NULL) {
		return NULL;
	}

	switch (node->type) {
	case NODE_LINK:
	case NODE_IMAGE:
		return cmark_chunk_to_cstr(&node->as.link.title);
	default:
		break;
	}

	return NULL;
}

int
cmark_node_set_title(cmark_node *node, const char *title)
{
	if (node == NULL) {
		return 0;
	}

	switch (node->type) {
	case NODE_LINK:
	case NODE_IMAGE:
		cmark_chunk_set_cstr(&node->as.link.title, title);
		return 1;
	default:
		break;
	}

	return 0;
}

int
cmark_node_get_start_line(cmark_node *node)
{
	if (node == NULL) {
		return 0;
	}
	return node->start_line;
}

int
cmark_node_get_start_column(cmark_node *node)
{
	if (node == NULL) {
		return 0;
	}
	return node->start_column;
}

int
cmark_node_get_end_line(cmark_node *node)
{
	if (node == NULL) {
		return 0;
	}
	return node->end_line;
}

int
cmark_node_get_end_column(cmark_node *node)
{
	if (node == NULL) {
		return 0;
	}
	return node->end_column;
}

// Unlink a node without adjusting its next, prev, and parent pointers.
static void
S_node_unlink(cmark_node *node)
{
	if (node == NULL) {
		return;
	}

	if (node->prev) {
		node->prev->next = node->next;
	}
	if (node->next) {
		node->next->prev = node->prev;
	}

	// Adjust first_child and last_child of parent.
	cmark_node *parent = node->parent;
	if (parent) {
		if (parent->first_child == node) {
			parent->first_child = node->next;
		}
		if (parent->last_child == node) {
			parent->last_child = node->prev;
		}
	}
}

void
cmark_node_unlink(cmark_node *node)
{
	S_node_unlink(node);

	node->next   = NULL;
	node->prev   = NULL;
	node->parent = NULL;

}

int
cmark_node_insert_before(cmark_node *node, cmark_node *sibling)
{
	if (node == NULL || sibling == NULL) {
		return 0;
	}

	if (!node->parent || !S_can_contain(node->parent, sibling)) {
		return 0;
	}

	S_node_unlink(sibling);

	cmark_node *old_prev = node->prev;

	// Insert 'sibling' between 'old_prev' and 'node'.
	if (old_prev) {
		old_prev->next = sibling;
	}
	sibling->prev = old_prev;
	sibling->next = node;
	node->prev    = sibling;

	// Set new parent.
	cmark_node *parent = node->parent;
	sibling->parent = parent;

	// Adjust first_child of parent if inserted as first child.
	if (parent && !old_prev) {
		parent->first_child = sibling;
	}

	return 1;
}

int
cmark_node_insert_after(cmark_node *node, cmark_node *sibling)
{
	if (node == NULL || sibling == NULL) {
		return 0;
	}

	if (!node->parent || !S_can_contain(node->parent, sibling)) {
		return 0;
	}

	S_node_unlink(sibling);

	cmark_node *old_next = node->next;

	// Insert 'sibling' between 'node' and 'old_next'.
	if (old_next) {
		old_next->prev = sibling;
	}
	sibling->next = old_next;
	sibling->prev = node;
	node->next    = sibling;

	// Set new parent.
	cmark_node *parent = node->parent;
	sibling->parent = parent;

	// Adjust last_child of parent if inserted as last child.
	if (parent && !old_next) {
		parent->last_child = sibling;
	}

	return 1;
}

int
cmark_node_prepend_child(cmark_node *node, cmark_node *child)
{
	if (!S_can_contain(node, child)) {
		return 0;
	}

	S_node_unlink(child);

	cmark_node *old_first_child = node->first_child;

	child->next       = old_first_child;
	child->prev       = NULL;
	child->parent     = node;
	node->first_child = child;

	if (old_first_child) {
		old_first_child->prev = child;
	} else {
		// Also set last_child if node previously had no children.
		node->last_child = child;
	}

	return 1;
}

int
cmark_node_append_child(cmark_node *node, cmark_node *child)
{
	if (!S_can_contain(node, child)) {
		return 0;
	}

	S_node_unlink(child);

	cmark_node *old_last_child = node->last_child;

	child->next      = NULL;
	child->prev      = old_last_child;
	child->parent    = node;
	node->last_child = child;

	if (old_last_child) {
		old_last_child->next = child;
	} else {
		// Also set first_child if node previously had no children.
		node->first_child = child;
	}

	return 1;
}

static void
S_print_error(FILE *out, cmark_node *node, const char *elem)
{
	if (out == NULL) {
		return;
	}
	fprintf(out, "Invalid '%s' in node type %s at %d:%d\n", elem,
	        cmark_node_get_type_string(node), node->start_line,
	        node->start_column);
}

int
cmark_node_check(cmark_node *node, FILE *out)
{
	cmark_node *cur;
	int errors = 0;

	if (!node) {
		return 0;
	}

	cur = node;
	while (true) {
		if (cur->first_child) {
			if (cur->first_child->prev != NULL) {
				S_print_error(out, cur->first_child, "prev");
				cur->first_child->prev = NULL;
				++errors;
			}
			if (cur->first_child->parent != cur) {
				S_print_error(out, cur->first_child, "parent");
				cur->first_child->parent = cur;
				++errors;
			}
			cur = cur->first_child;
			continue;
		}

next_sibling:
		if (cur == node) {
			break;
		}
		if (cur->next) {
			if (cur->next->prev != cur) {
				S_print_error(out, cur->next, "prev");
				cur->next->prev = cur;
				++errors;
			}
			if (cur->next->parent != cur->parent) {
				S_print_error(out, cur->next, "parent");
				cur->next->parent = cur->parent;
				++errors;
			}
			cur = cur->next;
			continue;
		}

		if (cur->parent->last_child != cur) {
			S_print_error(out, cur->parent, "last_child");
			cur->parent->last_child = cur;
			++errors;
		}
		cur = cur->parent;
		goto next_sibling;
	}

	return errors;
}