#include "unity/unity.h"
#include <libxml/HTMLparser.h>
#include <libxml/xmlmemory.h>

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

/* Wrapper provided in the source for calling the static function */
extern int test_htmlSkipBlankChars(xmlParserCtxtPtr ctxt);

void setUp(void) {
    /* Ensure libxml is initialized */
    xmlInitParser();
}

void tearDown(void) {
    /* No global cleanup required per test */
}

/* Helper to create a parser context with a single input over given content */
static void create_ctxt_with_content(const char *content,
                                     int init_line, int init_col,
                                     xmlParserCtxtPtr *out_ctxt,
                                     xmlParserInputPtr *out_input,
                                     xmlChar **out_buf,
                                     int *out_len) {
    TEST_ASSERT_NOT_NULL_MESSAGE(out_ctxt, "out_ctxt must not be NULL");
    TEST_ASSERT_NOT_NULL_MESSAGE(out_input, "out_input must not be NULL");
    TEST_ASSERT_NOT_NULL_MESSAGE(out_buf, "out_buf must not be NULL");

    int len = (content != NULL) ? (int)strlen(content) : 0;
    xmlChar *buf = (xmlChar *)xmlMalloc((size_t)len + 1);
    TEST_ASSERT_NOT_NULL_MESSAGE(buf, "Failed to allocate buffer");
    if (len > 0 && content != NULL) {
        memcpy(buf, content, (size_t)len);
    }
    buf[len] = 0;

    htmlParserCtxtPtr hctxt = htmlNewParserCtxt();
    TEST_ASSERT_NOT_NULL_MESSAGE(hctxt, "Failed to create parser context");

    xmlParserInputPtr input = (xmlParserInputPtr)xmlMalloc(sizeof(*input));
    TEST_ASSERT_NOT_NULL_MESSAGE(input, "Failed to allocate parser input");
    memset(input, 0, sizeof(*input));
    input->base = buf;
    input->cur  = buf;
    input->end  = buf + len;
    input->line = init_line;
    input->col  = init_col;

    hctxt->input = input;

    *out_ctxt = (xmlParserCtxtPtr)hctxt;
    *out_input = input;
    *out_buf = buf;
    if (out_len)
        *out_len = len;
}

static void destroy_ctxt_with_content(xmlParserCtxtPtr ctxt,
                                      xmlParserInputPtr input,
                                      xmlChar *buf) {
    if (ctxt != NULL) {
        /* Prevent any internal free of our manually attached input */
        ctxt->input = NULL;
        htmlFreeParserCtxt((htmlParserCtxtPtr)ctxt);
    }
    if (input != NULL)
        xmlFree(input);
    if (buf != NULL)
        xmlFree(buf);
}

/* Test 1: Only spaces, verify count and col update */
void test_htmlSkipBlankChars_only_spaces(void) {
    xmlParserCtxtPtr ctxt = NULL;
    xmlParserInputPtr input = NULL;
    xmlChar *buf = NULL;

    create_ctxt_with_content("    abc", 3, 5, &ctxt, &input, &buf, NULL);

    int ret = test_htmlSkipBlankChars(ctxt);

    TEST_ASSERT_EQUAL_INT(4, ret);
    TEST_ASSERT_EQUAL_INT(3, input->line);
    TEST_ASSERT_EQUAL_INT(9, input->col);
    TEST_ASSERT_EQUAL_CHAR('a', (char)*(input->cur));

    destroy_ctxt_with_content(ctxt, input, buf);
}

/* Test 2: Mix of newline and spaces/tabs, verify line/col logic */
void test_htmlSkipBlankChars_newlines_and_spaces(void) {
    xmlParserCtxtPtr ctxt = NULL;
    xmlParserInputPtr input = NULL;
    xmlChar *buf = NULL;

    /* Sequence: '\n', ' ', '\n', '\t', 'X' */
    create_ctxt_with_content("\n \n\tX", 1, 1, &ctxt, &input, &buf, NULL);

    int ret = test_htmlSkipBlankChars(ctxt);

    TEST_ASSERT_EQUAL_INT(4, ret);
    TEST_ASSERT_EQUAL_INT(3, input->line); /* two newlines encountered */
    TEST_ASSERT_EQUAL_INT(2, input->col);  /* after last '\t' column is 2 */
    TEST_ASSERT_EQUAL_CHAR('X', (char)*(input->cur));

    destroy_ctxt_with_content(ctxt, input, buf);
}

/* Test 3: Stops at first non-whitespace and leaves cur at that char */
void test_htmlSkipBlankChars_stops_on_non_ws(void) {
    xmlParserCtxtPtr ctxt = NULL;
    xmlParserInputPtr input = NULL;
    xmlChar *buf = NULL;

    create_ctxt_with_content(" \t\rA B", 1, 1, &ctxt, &input, &buf, NULL);

    int ret = test_htmlSkipBlankChars(ctxt);

    TEST_ASSERT_EQUAL_INT(3, ret);         /* space, tab, carriage return */
    TEST_ASSERT_EQUAL_INT(1, input->line); /* no newline seen */
    TEST_ASSERT_EQUAL_INT(4, input->col);  /* 1 + 3 */
    TEST_ASSERT_EQUAL_CHAR('A', (char)*(input->cur));

    destroy_ctxt_with_content(ctxt, input, buf);
}

/* Test 4: Zero available input (cur == end) returns 0 and leaves state */
void test_htmlSkipBlankChars_zero_avail(void) {
    xmlParserCtxtPtr ctxt = NULL;
    xmlParserInputPtr input = NULL;
    xmlChar *buf = NULL;

    create_ctxt_with_content("", 10, 7, &ctxt, &input, &buf, NULL);

    int ret = test_htmlSkipBlankChars(ctxt);

    TEST_ASSERT_EQUAL_INT(0, ret);
    TEST_ASSERT_EQUAL_INT(10, input->line);
    TEST_ASSERT_EQUAL_INT(7, input->col);
    TEST_ASSERT_TRUE(input->cur == input->end);

    destroy_ctxt_with_content(ctxt, input, buf);
}

/* Test 5: Parser stopped -> no changes and return 0 */
void test_htmlSkipBlankChars_parser_stopped(void) {
    xmlParserCtxtPtr ctxt = NULL;
    xmlParserInputPtr input = NULL;
    xmlChar *buf = NULL;

    create_ctxt_with_content("   \n\tabc", 2, 3, &ctxt, &input, &buf, NULL);

    /* Force parser stopped */
    ctxt->instate = XML_PARSER_EOF;

    int ret = test_htmlSkipBlankChars(ctxt);

    TEST_ASSERT_EQUAL_INT(0, ret);
    TEST_ASSERT_EQUAL_INT(2, input->line);
    TEST_ASSERT_EQUAL_INT(3, input->col);
    TEST_ASSERT_TRUE(input->cur == input->base); /* no advancement */

    destroy_ctxt_with_content(ctxt, input, buf);
}

/* Test 6: Large whitespace run to also cover res > 8 (GROW path) */
void test_htmlSkipBlankChars_large_whitespace(void) {
    char tmp[102 + 1]; /* 100 spaces + 'Z' + NUL */
    memset(tmp, ' ', 100);
    tmp[100] = 'Z';
    tmp[101] = '\0';

    xmlParserCtxtPtr ctxt = NULL;
    xmlParserInputPtr input = NULL;
    xmlChar *buf = NULL;

    create_ctxt_with_content(tmp, 1, 1, &ctxt, &input, &buf, NULL);

    int ret = test_htmlSkipBlankChars(ctxt);

    TEST_ASSERT_EQUAL_INT(100, ret);
    TEST_ASSERT_EQUAL_INT(1, input->line);
    TEST_ASSERT_EQUAL_INT(101, input->col); /* starting at 1, +100 spaces */
    TEST_ASSERT_EQUAL_CHAR('Z', (char)*(input->cur));

    destroy_ctxt_with_content(ctxt, input, buf);
}

int main(void) {
    UNITY_BEGIN();
    RUN_TEST(test_htmlSkipBlankChars_only_spaces);
    RUN_TEST(test_htmlSkipBlankChars_newlines_and_spaces);
    RUN_TEST(test_htmlSkipBlankChars_stops_on_non_ws);
    RUN_TEST(test_htmlSkipBlankChars_zero_avail);
    RUN_TEST(test_htmlSkipBlankChars_parser_stopped);
    RUN_TEST(test_htmlSkipBlankChars_large_whitespace);
    return UNITY_END();
}