#include "unity/unity.h"
#include <libxml/HTMLtree.h>

#include <libxml/tree.h>
#include <libxml/parser.h>
#include <libxml/xmlstring.h>
#include <stdlib.h>
#include <string.h>

/* Wrapper provided in the source module for the static function */
extern htmlNodePtr test_htmlFindFirstChild(htmlNodePtr parent, const char *name);

void setUp(void) {
    /* Optional: initialize libxml2 if needed */
    /* xmlInitParser(); */
}

void tearDown(void) {
    /* Optional: cleanup between tests if needed */
    /* Do not call xmlCleanupParser() here; call once at program end if used */
}

/* Helper to create a fresh document with a root "parent" node */
static void create_doc_with_parent(xmlDocPtr *outDoc, htmlNodePtr *outParent) {
    xmlDocPtr doc = xmlNewDoc(BAD_CAST "1.0");
    TEST_ASSERT_NOT_NULL(doc);

    htmlNodePtr parent = (htmlNodePtr)xmlNewNode(NULL, BAD_CAST "parent");
    TEST_ASSERT_NOT_NULL(parent);

    xmlDocSetRootElement(doc, (xmlNodePtr)parent);

    *outDoc = doc;
    *outParent = parent;
}

/* Test: No children -> should return NULL */
void test_htmlFindFirstChild_no_children_returns_NULL(void) {
    xmlDocPtr doc = NULL;
    htmlNodePtr parent = NULL;
    create_doc_with_parent(&doc, &parent);

    htmlNodePtr res = test_htmlFindFirstChild(parent, "div");
    TEST_ASSERT_NULL(res);

    xmlFreeDoc(doc);
}

/* Test: Case-insensitive match returns the first matching child */
void test_htmlFindFirstChild_case_insensitive_first_match(void) {
    xmlDocPtr doc = NULL;
    htmlNodePtr parent = NULL;
    create_doc_with_parent(&doc, &parent);

    /* Create two element children named "div" */
    htmlNodePtr firstDiv = (htmlNodePtr)xmlNewNode(NULL, BAD_CAST "div");
    TEST_ASSERT_NOT_NULL(firstDiv);
    xmlAddChild((xmlNodePtr)parent, (xmlNodePtr)firstDiv);

    htmlNodePtr secondDiv = (htmlNodePtr)xmlNewNode(NULL, BAD_CAST "DiV");
    TEST_ASSERT_NOT_NULL(secondDiv);
    xmlAddChild((xmlNodePtr)parent, (xmlNodePtr)secondDiv);

    /* Mixed-case search string */
    htmlNodePtr res = test_htmlFindFirstChild(parent, "dIv");
    TEST_ASSERT_NOT_NULL(res);
    TEST_ASSERT_EQUAL_PTR(firstDiv, res);

    xmlFreeDoc(doc);
}

/* Test: Skips non-element nodes (text and comments) before the first matching element */
void test_htmlFindFirstChild_skips_non_element_nodes(void) {
    xmlDocPtr doc = NULL;
    htmlNodePtr parent = NULL;
    create_doc_with_parent(&doc, &parent);

    xmlNodePtr text = xmlNewText(BAD_CAST "text node");
    TEST_ASSERT_NOT_NULL(text);
    xmlAddChild((xmlNodePtr)parent, text);

    xmlNodePtr comment = xmlNewComment(BAD_CAST "a comment");
    TEST_ASSERT_NOT_NULL(comment);
    xmlAddChild((xmlNodePtr)parent, comment);

    htmlNodePtr target = (htmlNodePtr)xmlNewNode(NULL, BAD_CAST "span");
    TEST_ASSERT_NOT_NULL(target);
    xmlAddChild((xmlNodePtr)parent, (xmlNodePtr)target);

    htmlNodePtr res = test_htmlFindFirstChild(parent, "SPAN"); /* uppercase query */
    TEST_ASSERT_NOT_NULL(res);
    TEST_ASSERT_EQUAL_PTR(target, res);

    xmlFreeDoc(doc);
}

/* Test: No matching child -> should return NULL */
void test_htmlFindFirstChild_no_matching_child_returns_NULL(void) {
    xmlDocPtr doc = NULL;
    htmlNodePtr parent = NULL;
    create_doc_with_parent(&doc, &parent);

    htmlNodePtr a = (htmlNodePtr)xmlNewNode(NULL, BAD_CAST "div");
    TEST_ASSERT_NOT_NULL(a);
    xmlAddChild((xmlNodePtr)parent, (xmlNodePtr)a);

    htmlNodePtr b = (htmlNodePtr)xmlNewNode(NULL, BAD_CAST "p");
    TEST_ASSERT_NOT_NULL(b);
    xmlAddChild((xmlNodePtr)parent, (xmlNodePtr)b);

    htmlNodePtr res = test_htmlFindFirstChild(parent, "span");
    TEST_ASSERT_NULL(res);

    xmlFreeDoc(doc);
}

/* Test: Exact name match required; should not match prefixes (e.g., "div" vs "div2") */
void test_htmlFindFirstChild_exact_name_not_prefix(void) {
    xmlDocPtr doc = NULL;
    htmlNodePtr parent = NULL;
    create_doc_with_parent(&doc, &parent);

    htmlNodePtr notMatch = (htmlNodePtr)xmlNewNode(NULL, BAD_CAST "div2");
    TEST_ASSERT_NOT_NULL(notMatch);
    xmlAddChild((xmlNodePtr)parent, (xmlNodePtr)notMatch);

    htmlNodePtr match = (htmlNodePtr)xmlNewNode(NULL, BAD_CAST "div");
    TEST_ASSERT_NOT_NULL(match);
    xmlAddChild((xmlNodePtr)parent, (xmlNodePtr)match);

    htmlNodePtr res = test_htmlFindFirstChild(parent, "DIV");
    TEST_ASSERT_NOT_NULL(res);
    TEST_ASSERT_EQUAL_PTR(match, res);

    xmlFreeDoc(doc);
}

/* Test: Child name uppercase vs. lowercase query (case-insensitive) */
void test_htmlFindFirstChild_child_uppercase_name(void) {
    xmlDocPtr doc = NULL;
    htmlNodePtr parent = NULL;
    create_doc_with_parent(&doc, &parent);

    htmlNodePtr child = (htmlNodePtr)xmlNewNode(NULL, BAD_CAST "SPAN");
    TEST_ASSERT_NOT_NULL(child);
    xmlAddChild((xmlNodePtr)parent, (xmlNodePtr)child);

    htmlNodePtr res = test_htmlFindFirstChild(parent, "span");
    TEST_ASSERT_NOT_NULL(res);
    TEST_ASSERT_EQUAL_PTR(child, res);

    xmlFreeDoc(doc);
}

int main(void) {
    /* Initialize libxml2 globally if desired; safe to omit for basic tree ops */
    /* xmlInitParser(); */

    UNITY_BEGIN();
    RUN_TEST(test_htmlFindFirstChild_no_children_returns_NULL);
    RUN_TEST(test_htmlFindFirstChild_case_insensitive_first_match);
    RUN_TEST(test_htmlFindFirstChild_skips_non_element_nodes);
    RUN_TEST(test_htmlFindFirstChild_no_matching_child_returns_NULL);
    RUN_TEST(test_htmlFindFirstChild_exact_name_not_prefix);
    RUN_TEST(test_htmlFindFirstChild_child_uppercase_name);
    int ret = UNITY_END();

    /* Cleanup libxml2 if initialized above */
    /* xmlCleanupParser(); */

    return ret;
}