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

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

/* Wrapper prototype provided by the source module for the static function */
int test_htmlInitParserCtxt(htmlParserCtxtPtr ctxt, const htmlSAXHandler *sax, void *userData);

/* Helpers for cleanup of allocations performed by htmlInitParserCtxt */
static void cleanup_ctxt_allocs(htmlParserCtxt *ctxt) {
    if (ctxt == NULL) return;
    if (ctxt->sax) {
        xmlFree((void *)ctxt->sax);
        ctxt->sax = NULL;
    }
    if (ctxt->inputTab) {
        xmlFree((void *)ctxt->inputTab);
        ctxt->inputTab = NULL;
        ctxt->inputMax = 0;
        ctxt->inputNr = 0;
    }
    if (ctxt->nodeTab) {
        xmlFree((void *)ctxt->nodeTab);
        ctxt->nodeTab = NULL;
        ctxt->nodeMax = 0;
        ctxt->nodeNr = 0;
    }
    if (ctxt->nameTab) {
        xmlFree((void *)ctxt->nameTab);
        ctxt->nameTab = NULL;
        ctxt->nameMax = 0;
        ctxt->nameNr = 0;
    }
    if (ctxt->dict) {
        xmlDictFree(ctxt->dict);
        ctxt->dict = NULL;
    }
}

/* Memory hook machinery to simulate allocation failure */
static int g_fail_alloc_enable = 0;
static int g_fail_alloc_always = 0;
static int g_alloc_call_count = 0;

static void myXmlFree(void *ptr) {
    free(ptr);
}
static void *myXmlMalloc(size_t size) {
    if (g_fail_alloc_enable && (g_fail_alloc_always || (g_alloc_call_count++ == 0))) {
        return NULL;
    }
    return malloc(size);
}
static void *myXmlRealloc(void *ptr, size_t size) {
    if (g_fail_alloc_enable && g_fail_alloc_always) {
        return NULL;
    }
    return realloc(ptr, size);
}
static char *myXmlStrdup(const char *str) {
    if (g_fail_alloc_enable && g_fail_alloc_always) {
        return NULL;
    }
    size_t len = strlen(str) + 1;
    char *p = (char *)malloc(len);
    if (p) memcpy(p, str, len);
    return p;
}

static xmlFreeFunc oldFreeF = NULL;
static xmlMallocFunc oldMallocF = NULL;
static xmlReallocFunc oldReallocF = NULL;
static xmlStrdupFunc oldStrdupF = NULL;

static void enable_alloc_failure_always(void) {
    xmlMemGet(&oldFreeF, &oldMallocF, &oldReallocF, &oldStrdupF);
    g_fail_alloc_enable = 1;
    g_fail_alloc_always = 1;
    g_alloc_call_count = 0;
    xmlMemSetup(myXmlFree, myXmlMalloc, myXmlRealloc, myXmlStrdup);
}

static void restore_alloc_functions(void) {
    xmlMemSetup(oldFreeF, oldMallocF, oldReallocF, oldStrdupF);
    g_fail_alloc_enable = 0;
    g_fail_alloc_always = 0;
    g_alloc_call_count = 0;
}

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

void tearDown(void) {
    /* Cleanup global parser state (safe between tests) */
    xmlCleanupParser();
}

/* Test: NULL context should return error (-1) */
void test_htmlInitParserCtxt_null_context_returns_error(void) {
    int rc = test_htmlInitParserCtxt(NULL, NULL, NULL);
    TEST_ASSERT_EQUAL_INT(-1, rc);
}

/* Test: Initialize with default SAX (sax == NULL); userData must be ctxt; key fields set */
void test_htmlInitParserCtxt_init_with_default_sax(void) {
    htmlParserCtxt ctxt;
    /* Pass non-NULL userData to ensure it's ignored when sax == NULL */
    int dummy = 123;
    int rc = test_htmlInitParserCtxt(&ctxt, NULL, &dummy);
    TEST_ASSERT_EQUAL_INT(0, rc);

    /* Basic allocations */
    TEST_ASSERT_NOT_NULL(ctxt.dict);
    TEST_ASSERT_NOT_NULL(ctxt.sax);
    TEST_ASSERT_NOT_NULL(ctxt.inputTab);
    TEST_ASSERT_NOT_NULL(ctxt.nodeTab);
    TEST_ASSERT_NOT_NULL(ctxt.nameTab);

    /* Input stack state */
    TEST_ASSERT_EQUAL_INT(0, ctxt.inputNr);
    TEST_ASSERT_EQUAL_INT(1, ctxt.inputMax);
    TEST_ASSERT_NULL(ctxt.input);

    /* Node and name stacks */
    TEST_ASSERT_EQUAL_INT(0, ctxt.nodeNr);
    TEST_ASSERT_TRUE(ctxt.nodeMax == 1 || ctxt.nodeMax == 10);
    TEST_ASSERT_NULL(ctxt.node);

    TEST_ASSERT_EQUAL_INT(0, ctxt.nameNr);
    TEST_ASSERT_TRUE(ctxt.nameMax == 1 || ctxt.nameMax == 10);
    TEST_ASSERT_NULL(ctxt.name);

    /* Document and flags */
    TEST_ASSERT_NULL(ctxt.myDoc);
    TEST_ASSERT_EQUAL_INT(1, ctxt.wellFormed);
    TEST_ASSERT_EQUAL_INT(0, ctxt.replaceEntities);
    TEST_ASSERT_EQUAL_INT(xmlKeepBlanksDefaultValue, ctxt.keepBlanks);
    TEST_ASSERT_EQUAL_INT(0, ctxt.validate);
    TEST_ASSERT_EQUAL_INT(0, ctxt.checkIndex);
    TEST_ASSERT_EQUAL_INT(0, ctxt.record_info);
    TEST_ASSERT_EQUAL_INT(-1, ctxt.standalone);

    /* vctxt sanity */
    TEST_ASSERT_EQUAL_PTR(&ctxt, ctxt.vctxt.userData);
    TEST_ASSERT_NOT_NULL(ctxt.vctxt.error);
    TEST_ASSERT_NOT_NULL(ctxt.vctxt.warning);

    /* Default SAX handler should be initialized */
    TEST_ASSERT_NOT_NULL(ctxt.sax);
    TEST_ASSERT_TRUE(((htmlSAXHandler *)ctxt.sax)->initialized != 0);

    /* userData must be ctxt when sax == NULL */
    TEST_ASSERT_EQUAL_PTR(&ctxt, ctxt.userData);

    cleanup_ctxt_allocs(&ctxt);
}

/* Test: Initialize with custom SAX handler and explicit userData */
void test_htmlInitParserCtxt_init_with_custom_sax_and_userData(void) {
    htmlParserCtxt ctxt;
    htmlSAXHandler customSax;
    memset(&customSax, 0, sizeof(customSax));
    customSax.initialized = 0x1234; /* marker */

    int userToken = 42;
    void *ud = &userToken;

    int rc = test_htmlInitParserCtxt(&ctxt, &customSax, ud);
    TEST_ASSERT_EQUAL_INT(0, rc);

    TEST_ASSERT_NOT_NULL(ctxt.dict);
    TEST_ASSERT_NOT_NULL(ctxt.sax);
    TEST_ASSERT_NOT_NULL(ctxt.inputTab);
    TEST_ASSERT_NOT_NULL(ctxt.nodeTab);
    TEST_ASSERT_NOT_NULL(ctxt.nameTab);

    /* Copied SAX handler must be byte-wise identical */
    TEST_ASSERT_EQUAL_INT(0, memcmp(ctxt.sax, &customSax, sizeof(customSax)));

    /* userData should equal the provided pointer when sax != NULL */
    TEST_ASSERT_EQUAL_PTR(ud, ctxt.userData);

    /* Stack sizes sane */
    TEST_ASSERT_TRUE(ctxt.nodeMax == 1 || ctxt.nodeMax == 10);
    TEST_ASSERT_TRUE(ctxt.nameMax == 1 || ctxt.nameMax == 10);

    cleanup_ctxt_allocs(&ctxt);
}

/* Test: Initialize with custom SAX handler and NULL userData: userData must default to ctxt */
void test_htmlInitParserCtxt_init_with_custom_sax_null_userData_defaults_to_ctxt(void) {
    htmlParserCtxt ctxt;
    htmlSAXHandler customSax;
    memset(&customSax, 0, sizeof(customSax));
    customSax.initialized = 777;

    int rc = test_htmlInitParserCtxt(&ctxt, &customSax, NULL);
    TEST_ASSERT_EQUAL_INT(0, rc);

    TEST_ASSERT_NOT_NULL(ctxt.sax);
    TEST_ASSERT_EQUAL_INT(0, memcmp(ctxt.sax, &customSax, sizeof(customSax)));
    TEST_ASSERT_EQUAL_PTR(&ctxt, ctxt.userData);

    cleanup_ctxt_allocs(&ctxt);
}

/* Test: Allocation failure path returns error (-1) */
void test_htmlInitParserCtxt_allocation_failure_returns_error(void) {
    enable_alloc_failure_always();
    htmlParserCtxt ctxt;
    int rc = test_htmlInitParserCtxt(&ctxt, NULL, NULL);
    restore_alloc_functions();
    TEST_ASSERT_EQUAL_INT(-1, rc);
    /* Nothing to clean up; initialization failed before allocations were assigned */
}

int main(void) {
    UNITY_BEGIN();
    RUN_TEST(test_htmlInitParserCtxt_null_context_returns_error);
    RUN_TEST(test_htmlInitParserCtxt_init_with_default_sax);
    RUN_TEST(test_htmlInitParserCtxt_init_with_custom_sax_and_userData);
    RUN_TEST(test_htmlInitParserCtxt_init_with_custom_sax_null_userData_defaults_to_ctxt);
    RUN_TEST(test_htmlInitParserCtxt_allocation_failure_returns_error);
    return UNITY_END();
}