#include "unity/unity.h"
#include <libxml/HTMLparser.h>
#include <string.h>
#include <stdlib.h>

/* Wrapper for the static function provided in the module */
int test_htmlParseCharData(htmlParserCtxtPtr ctxt, int partial);

/* Helper to create a parser context from a buffer with explicit length */
static htmlParserCtxtPtr make_ctxt_buf(const char *buf, int len) {
    htmlParserCtxtPtr ctxt = htmlCreateMemoryParserCtxt(buf, len);
    TEST_ASSERT_NOT_NULL_MESSAGE(ctxt, "htmlCreateMemoryParserCtxt returned NULL");
    TEST_ASSERT_NOT_NULL_MESSAGE(ctxt->input, "Parser context has no input");
    /* Disable SAX to avoid invoking htmlStartCharData and other callbacks */
    ctxt->sax = NULL;
    ctxt->disableSAX = 1;
    /* Start in normal data mode */
    ctxt->endCheckState = 0;
    /* Initialize position tracking to deterministic values */
    ctxt->input->line = 1;
    ctxt->input->col = 1;
    return ctxt;
}

/* Convenience helper for NUL-terminated strings */
static htmlParserCtxtPtr make_ctxt_str(const char *s) {
    return make_ctxt_buf(s, (int)strlen(s));
}

void setUp(void) {
    /* Optionally initialize libxml2 once here if needed */
}

void tearDown(void) {
    /* Optional per-test cleanup */
}

/* Basic: In DATA mode (mode == 0), stop at '<' and return complete=1 */
static void test_htmlParseCharData_stops_at_lt_and_returns_complete(void) {
    const char *data = "hello<world";
    htmlParserCtxtPtr ctxt = make_ctxt_str(data);

    int ret = test_htmlParseCharData(ctxt, 0);

    TEST_ASSERT_EQUAL_INT(1, ret);
    TEST_ASSERT_NOT_NULL(ctxt->input);
    TEST_ASSERT_TRUE(ctxt->input->cur < ctxt->input->end);
    TEST_ASSERT_EQUAL_CHAR('<', (char)*ctxt->input->cur);
    /* When complete, endCheckState is reset to 0 */
    TEST_ASSERT_EQUAL_INT(0, ctxt->endCheckState);

    htmlFreeParserCtxt(ctxt);
}

/* Partial mode: Incomplete entity at end should not consume '&' and should return complete=0 */
static void test_htmlParseCharData_partial_incomplete_entity_not_consumed(void) {
    const char *data = "&";
    htmlParserCtxtPtr ctxt = make_ctxt_str(data);

    int ret = test_htmlParseCharData(ctxt, 1);

    TEST_ASSERT_EQUAL_INT(0, ret);
    TEST_ASSERT_TRUE(ctxt->input->cur < ctxt->input->end);
    TEST_ASSERT_EQUAL_CHAR('&', (char)*ctxt->input->cur);
    /* Not complete; endCheckState remains the current mode (0) */
    TEST_ASSERT_EQUAL_INT(0, ctxt->endCheckState);

    htmlFreeParserCtxt(ctxt);
}

/* DATA mode: NUL byte is stripped; then parser stops at '<' */
static void test_htmlParseCharData_consumes_nul_then_stops_at_lt(void) {
    const char raw[] = { '\0', '<', 'a', 'b', 'c' };
    htmlParserCtxtPtr ctxt = make_ctxt_buf(raw, (int)sizeof(raw));

    int ret = test_htmlParseCharData(ctxt, 0);

    TEST_ASSERT_EQUAL_INT(1, ret);
    TEST_ASSERT_TRUE(ctxt->input->cur < ctxt->input->end);
    TEST_ASSERT_EQUAL_CHAR('<', (char)*ctxt->input->cur);
    TEST_ASSERT_EQUAL_INT(0, ctxt->endCheckState);

    htmlFreeParserCtxt(ctxt);
}

/* CR handling: CR alone translates to LF via SAX (ignored here) and is skipped; then stop at '<' */
static void test_htmlParseCharData_cr_translated_and_skipped_then_lt(void) {
    const char raw[] = { '\r', '<', 'x' };
    htmlParserCtxtPtr ctxt = make_ctxt_buf(raw, (int)sizeof(raw));

    int ret = test_htmlParseCharData(ctxt, 0);

    TEST_ASSERT_EQUAL_INT(1, ret);
    TEST_ASSERT_TRUE(ctxt->input->cur < ctxt->input->end);
    TEST_ASSERT_EQUAL_CHAR('<', (char)*ctxt->input->cur);
    TEST_ASSERT_EQUAL_INT(0, ctxt->endCheckState);

    htmlFreeParserCtxt(ctxt);
}

/* Numeric character reference: should be consumed and continue to '<' */
static void test_htmlParseCharData_consumes_numeric_char_ref(void) {
    const char *data = "&#x41;BC<";
    htmlParserCtxtPtr ctxt = make_ctxt_str(data);

    int ret = test_htmlParseCharData(ctxt, 0);

    TEST_ASSERT_EQUAL_INT(1, ret);
    TEST_ASSERT_TRUE(ctxt->input->cur < ctxt->input->end);
    TEST_ASSERT_EQUAL_CHAR('<', (char)*ctxt->input->cur);
    TEST_ASSERT_EQUAL_INT(0, ctxt->endCheckState);

    htmlFreeParserCtxt(ctxt);
}

/* Non-zero mode: complete when encountering a matching closing tag like </p> */
static void test_htmlParseCharData_nonzero_mode_stops_at_matching_closing_tag(void) {
    const char *data = "abc</p>xyz";
    htmlParserCtxtPtr ctxt = make_ctxt_str(data);

    /* Simulate being inside a <p> element by setting name and a non-zero mode */
    ctxt->name = (xmlChar *)"p";
    ctxt->endCheckState = 1; /* Any non-zero mode that's not DATA */

    int ret = test_htmlParseCharData(ctxt, 0);

    TEST_ASSERT_EQUAL_INT(1, ret);
    TEST_ASSERT_TRUE(ctxt->input->cur < ctxt->input->end);
    TEST_ASSERT_EQUAL_CHAR('<', (char)*ctxt->input->cur);
    /* complete -> endCheckState reset to 0 */
    TEST_ASSERT_EQUAL_INT(0, ctxt->endCheckState);

    htmlFreeParserCtxt(ctxt);
}

/* No terminating '<': consume to EOF, return complete=0 */
static void test_htmlParseCharData_consumes_until_eof_when_no_lt(void) {
    const char *data = "abcdef";
    htmlParserCtxtPtr ctxt = make_ctxt_str(data);

    int ret = test_htmlParseCharData(ctxt, 0);

    TEST_ASSERT_EQUAL_INT(0, ret);
    TEST_ASSERT_TRUE(ctxt->input->cur == ctxt->input->end);
    /* Not complete; endCheckState remains the current mode (0) */
    TEST_ASSERT_EQUAL_INT(0, ctxt->endCheckState);

    htmlFreeParserCtxt(ctxt);
}

int main(void) {
    /* Initialize libxml2 once for all tests */
    xmlInitParser();

    UNITY_BEGIN();
    RUN_TEST(test_htmlParseCharData_stops_at_lt_and_returns_complete);
    RUN_TEST(test_htmlParseCharData_partial_incomplete_entity_not_consumed);
    RUN_TEST(test_htmlParseCharData_consumes_nul_then_stops_at_lt);
    RUN_TEST(test_htmlParseCharData_cr_translated_and_skipped_then_lt);
    RUN_TEST(test_htmlParseCharData_consumes_numeric_char_ref);
    RUN_TEST(test_htmlParseCharData_nonzero_mode_stops_at_matching_closing_tag);
    RUN_TEST(test_htmlParseCharData_consumes_until_eof_when_no_lt);
    int res = UNITY_END();

    xmlCleanupParser();
    return res;
}