#include <string.h>

#include <kalmia.h>
#include "util/util.h"
#include "xml/xml.h"
#include "geometry.h"


/* macro to ensure tag type matches what we expect */
#define CHECK_TAG_TYPE(expected) \
if (strcmp(src->type, expected) != 0) { \
	return -1; \
}

/* helper macro for iterating over tag children of a particular type */
#define FOR_CHILD_OF_TYPE(parent, child, type) \
for ( \
	child = kai_tag_get_first_child_with_type(parent, type); \
	child != NULL; \
	child = kai_tag_get_next_sibling_with_type(child, type) \
)


int kai_read_float_array(struct ka_float_array_t *dest, struct kai_tag_t *src)
{
	CHECK_TAG_TYPE("float_array");

	long count = kai_tag_attr_to_long(src, "count", -1);
	if (count == -1) {
		/* count not present */
		return -1;
	}

	dest->count = count;
	dest->id = kai_tag_attr_to_dup(src, "id");
	dest->digits = kai_tag_attr_to_long(src, "digits", 6);
	dest->magnitude = kai_tag_attr_to_long(src, "magnitude", 38);

	/* allocate & fill buffer */
	dest->buf = kai_alloc(
		dest->count * sizeof(ka_real_t),
		"float_array buffer"
	);
	if (dest->buf == NULL) {
		free(dest->id);
		return -1;
	}
	kai_text_to_reals(dest->buf, src->content, dest->count);

	return 0;
}

void kai_release_float_array(struct ka_float_array_t fa)
{
	free(fa.id);
	free(fa.buf);
}


int kai_read_param(struct ka_param_t *dest, struct kai_tag_t *src)
{
	CHECK_TAG_TYPE("param");

	char *type = kai_tag_attr_to_dup(src, "type");
	if (type == NULL) {
		return -1;
	}

	dest->name = kai_tag_attr_to_dup(src, "name");
	dest->sid = kai_tag_attr_to_dup(src, "sid");
	dest->type = type;
	dest->semantic = kai_tag_attr_to_dup(src, "semantic");

	return 0;
}

void kai_release_param(struct ka_param_t p)
{
	free(p.name);
	free(p.sid);
	free(p.type);
	free(p.semantic);
}


int kai_read_accessor(struct ka_accessor_t *dest, struct kai_tag_t *src)
{
	CHECK_TAG_TYPE("accessor");

	long count = kai_tag_attr_to_long(src, "count", -1);
	if (count == -1) { return -1; }
	char *source = kai_tag_attr_to_dup(src, "source");
	if (source == NULL) { return -1; }

	dest->count = count;
	dest->offset = kai_tag_attr_to_long(src, "offset", 0);
	dest->source = source;
	dest->stride = kai_tag_attr_to_long(src, "stride", 1);

	dest->param_count = kai_tag_num_children(src);
	dest->param = kai_alloc(
		dest->param_count * sizeof(struct ka_param_t),
		"accessor tag param array"
	);
	if (dest->param == NULL) {
		free(source);
		return -1;
	}
	struct kai_tag_t *t = src->children;
	int i;
	for (i=0; i<dest->param_count; i++) {
		int result = kai_read_param(dest->param + i, t);
		if (result != 0) {
			free(dest->param);
			free(dest->source);
			return -1;
		}
		t = t->next;
	}

	return 0;
}

void kai_release_accessor(struct ka_accessor_t a)
{
	free(a.source);
	int i;
	for (i=0; i<a.param_count; i++) {
		kai_release_param(a.param[i]);
	}
	free(a.param);
}


int kai_read_source(struct ka_source_t *dest, struct kai_tag_t *src)
{
	CHECK_TAG_TYPE("source");

	char *id = kai_tag_attr_to_dup(src, "id");
	if (id == NULL) { return -1; }

	dest->id = id;
	dest->name = kai_tag_attr_to_dup(src, "name");

	struct kai_tag_t *child;
	for (child = src->children; child != NULL; child = child->next) {
		if (strcmp(child->type, "float_array") == 0) {
			kai_read_float_array(&(dest->float_array), child);
		}
		else if (strcmp(child->type, "technique_common") == 0) {
			kai_read_accessor(&(dest->accessor), child->children);
		}
		/* ignore others */
	}

	return 0;
}

void kai_release_source(struct ka_source_t s)
{
	free(s.id);
	free(s.name);

	kai_release_float_array(s.float_array);
	kai_release_accessor(s.accessor);
}


int kai_read_input_unshared(struct ka_input_t *dest, struct kai_tag_t *src)
{
	CHECK_TAG_TYPE("input");

	char *semantic = kai_tag_attr_to_dup(src, "semantic");
	if (semantic == NULL) { return -1; }
	char *source = kai_tag_attr_to_dup(src, "source");
	if (source == NULL) { free(semantic); return -1; }

	dest->shared = false;
	dest->offset = 0;
	dest->semantic = semantic;
	dest->source = source;
	dest->set = 0;

	return 0;
}

int kai_read_input_shared(struct ka_input_t *dest, struct kai_tag_t *src)
{
	int result = kai_read_input_unshared(dest, src);
	if (result != 0) { return result; }

	long offset = kai_tag_attr_to_long(src, "offset", -1);
	if (offset == -1) { return -1; }

	dest->shared = true;
	dest->offset = offset;

	long set = kai_tag_attr_to_long(src, "set", -1);
	if (set != -1) {
		dest->use_set = true;
		dest->set = set;
	}
	else {
		dest->use_set = false;
	}

	return 0;
}

void kai_release_input(struct ka_input_t i)
{
	free(i.semantic);
	free(i.source);
}


int kai_read_vertices(struct ka_vertices_t *dest, struct kai_tag_t *src)
{
	CHECK_TAG_TYPE("vertices");

	char *id = kai_tag_attr_to_dup(src, "id");
	if (id == NULL) { return -1; }

	dest->id = id;
	dest->name = kai_tag_attr_to_dup(src, "name");

	/* count input children */
	int count = 0;
	struct kai_tag_t *child;
	FOR_CHILD_OF_TYPE(src, child, "input") {
		count += 1;
	}

	dest->input_count = count;
	dest->input = malloc(count * sizeof(struct ka_input_t));
	if (dest->input == NULL) {
		kai_release_vertices(*dest);
		return -1;
	}

	int i=0;
	FOR_CHILD_OF_TYPE(src, child, "input") {
		int result = kai_read_input_unshared(dest->input + i, child);
		if (result != 0) {
			dest->input_count = i;
			kai_release_vertices(*dest);
			return -1;
		}
		i += 1;
	}

	return 0;
}

void kai_release_vertices(struct ka_vertices_t v)
{
	free(v.id);
	free(v.name);
	int i;
	for (i=0; i<v.input_count; i++) {
		kai_release_input(v.input[i]);
	}
	free(v.input);
}


int kai_read_triangles(struct ka_triangles_t *dest, struct kai_tag_t *src)
{
	CHECK_TAG_TYPE("triangles");

	long count = kai_tag_attr_to_long(src, "count", -1);
	if (count == -1) { return -1; }

	dest->name = kai_tag_attr_to_dup(src, "name");
	dest->count = count;
	dest->material = kai_tag_attr_to_dup(src, "material");

	
	/* zero these out so that any error-related calls to kai_release_triangles
	 * won't cause an invalid free
	 */
	dest->input_count = 0;
	dest->input = NULL;
	dest->p_count = 0;
	dest->p = NULL;

	/* load the child inputs into the structure */
	int input_count = 0;
	struct kai_tag_t *child;
	FOR_CHILD_OF_TYPE(src, child, "input") {
		input_count += 1;
	}

	dest->input = kai_alloc(input_count * sizeof(struct ka_input_t), "triangles input array");
	if (dest->input == NULL) {
		kai_release_triangles(*dest);
		return -1;
	}

	int i=0;
	FOR_CHILD_OF_TYPE(src, child, "input") {
		int result = kai_read_input_shared(dest->input + i, child);
		if (result != 0) {
			dest->input_count = i;
			kai_release_triangles(*dest);
			return -1;
		}
		i += 1;
	}
	dest->input_count = input_count;


	/* load the child p tag */
	struct kai_tag_t *p = kai_tag_get_first_child_with_type(src, "p");
	if (p != NULL) {
		dest->p_count = 3 * dest->count * dest->input_count;
		dest->p = kai_alloc(dest->p_count * sizeof(unsigned int), "triangles primitive array");
		if (dest->p == NULL) {
			dest->p_count = 0;
			kai_release_triangles(*dest);
			return -1;
		}
		kai_text_to_uints(dest->p, p->content, dest->p_count);
	}

	return 0;
}

void kai_release_triangles(struct ka_triangles_t t)
{
	free(t.name);
	free(t.material);

	int i;
	for (i=0; i<t.input_count; i++) {
		kai_release_input(t.input[i]);
	}
	free(t.input);
	free(t.p);
}