/**
 * @file json_helpers.c
 * @brief Unit tests for the typed JSON accessors.
 *
 * These exercise the accessors directly rather than through sprite, character,
 * or tilemap loading, so the error paths are reachable without building a
 * malformed asset for every case.
 */

#include <SDL3/SDL.h>
#include <jansson.h>
#include <string.h>
#include <akerror.h>

#include <akgl/error.h>
#include <akgl/json_helpers.h>
#include <akgl/heap.h>
#include <akgl/registry.h>
#include <akgl/staticstring.h>

#include "testutil.h"

/** @brief Fixture document shared by every test in this file. */
static json_t *fixture = NULL;

/** @brief Load tests/assets/snippets/test_json_helpers.json into @ref fixture. */
static akerr_ErrorContext *load_fixture(void)
{
    PREPARE_ERROR(e);
    json_error_t jsonerr;
    akgl_String *pathstr = NULL;

    ATTEMPT {
	CATCH(e, akgl_heap_next_string(&pathstr));
	snprintf(
	    (char *)&pathstr->data,
	    AKGL_MAX_STRING_LENGTH,
	    "%s%s",
	    SDL_GetBasePath(),
	    "assets/snippets/test_json_helpers.json");
	fixture = json_load_file((char *)&pathstr->data, 0, &jsonerr);
	FAIL_ZERO_BREAK(e, fixture, AKERR_IO,
			"Unable to load the JSON fixture: %s", (char *)jsonerr.text);
    } CLEANUP {
	IGNORE(akgl_heap_release_string(pathstr));
    } PROCESS(e) {
    } FINISH(e, true);
    SUCCEED_RETURN(e);
}

/**
 * @brief Every accessor must refuse a NULL key or destination, not dereference it.
 *
 * Only the two string accessors did. The other eight validated the container
 * and then wrote through @p dest unconditionally, so which arguments a caller
 * could safely get wrong depended on which typed accessor they happened to
 * call -- and the ones that crashed were the ones used most.
 */
akerr_ErrorContext *test_json_accessor_null_arguments(void)
{
    PREPARE_ERROR(e);
    int intval = 0;
    float floatval = 0;
    double dblval = 0;
    bool boolval = false;
    json_t *jsonval = NULL;
    akgl_String *strval = NULL;

    ATTEMPT {
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_object_value(fixture, NULL, &jsonval),
			   "object accessor with a NULL key");
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_object_value(fixture, "nested", NULL),
			   "object accessor with a NULL destination");
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_boolean_value(fixture, NULL, &boolval),
			   "boolean accessor with a NULL key");
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_boolean_value(fixture, "enabled", NULL),
			   "boolean accessor with a NULL destination");
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_integer_value(fixture, NULL, &intval),
			   "integer accessor with a NULL key");
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_integer_value(fixture, "count", NULL),
			   "integer accessor with a NULL destination");
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_number_value(fixture, NULL, &floatval),
			   "number accessor with a NULL key");
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_number_value(fixture, "ratio", NULL),
			   "number accessor with a NULL destination");
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_double_value(fixture, NULL, &dblval),
			   "double accessor with a NULL key");
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_double_value(fixture, "ratio", NULL),
			   "double accessor with a NULL destination");
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_array_value(fixture, NULL, &jsonval),
			   "array accessor with a NULL key");
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_array_value(fixture, "integers", NULL),
			   "array accessor with a NULL destination");

	// The index accessors take no key, but they take a destination.
	CATCH(e, akgl_get_json_array_value(fixture, "integers", &jsonval));
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_array_index_integer(jsonval, 0, NULL),
			   "array index integer accessor with a NULL destination");
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_array_index_object(jsonval, 0, NULL),
			   "array index object accessor with a NULL destination");
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_array_index_string(jsonval, 0, NULL),
			   "array index string accessor with a NULL destination");

	// Nothing above should have claimed a pool string on the way to
	// refusing, which is the other half of "refuse rather than proceed".
	TEST_ASSERT(e, strval == NULL, "a refused accessor wrote to its destination anyway");
    } CLEANUP {
    } PROCESS(e) {
    } FINISH(e, true);
    SUCCEED_RETURN(e);
}

akerr_ErrorContext *test_json_scalar_accessors(void)
{
    PREPARE_ERROR(e);
    int intval = 0;
    float floatval = 0;
    bool boolval = false;
    json_t *objval = NULL;
    json_t *arrayval = NULL;

    ATTEMPT {
	TEST_EXPECT_OK(e, akgl_get_json_integer_value(fixture, "count", &intval), "read count");
	TEST_ASSERT(e, intval == 42, "count read as %d, expected 42", intval);

	TEST_EXPECT_OK(e, akgl_get_json_integer_value(fixture, "negative", &intval), "read negative");
	TEST_ASSERT(e, intval == -17, "negative read as %d, expected -17", intval);

	TEST_EXPECT_OK(e, akgl_get_json_number_value(fixture, "ratio", &floatval), "read ratio");
	TEST_ASSERT_FEQ(e, floatval, 2.5f, "ratio read as %f, expected 2.5", floatval);

	// A JSON integer is a number, so the float accessor accepts it too.
	TEST_EXPECT_OK(e, akgl_get_json_number_value(fixture, "count", &floatval), "read count as a number");
	TEST_ASSERT_FEQ(e, floatval, 42.0f, "count read as number %f, expected 42", floatval);

	TEST_EXPECT_OK(e, akgl_get_json_boolean_value(fixture, "enabled", &boolval), "read enabled");
	TEST_ASSERT(e, boolval == true, "enabled read as false");
	TEST_EXPECT_OK(e, akgl_get_json_boolean_value(fixture, "disabled", &boolval), "read disabled");
	TEST_ASSERT(e, boolval == false, "disabled read as true");

	TEST_EXPECT_OK(e, akgl_get_json_object_value(fixture, "nested", &objval), "read nested");
	TEST_ASSERT(e, objval != NULL, "nested object came back NULL");
	TEST_EXPECT_OK(e, akgl_get_json_integer_value(objval, "innercount", &intval), "read nested innercount");
	TEST_ASSERT(e, intval == 7, "nested innercount read as %d, expected 7", intval);

	TEST_EXPECT_OK(e, akgl_get_json_array_value(fixture, "integers", &arrayval), "read integers array");
	TEST_ASSERT(e, json_array_size(arrayval) == 3,
		    "integers array had %d entries, expected 3", (int)json_array_size(arrayval));
    } CLEANUP {
    } PROCESS(e) {
    } FINISH(e, true);
    SUCCEED_RETURN(e);
}

akerr_ErrorContext *test_json_double_value(void)
{
    PREPARE_ERROR(e);
    double dblval = 0;

    ATTEMPT {
	TEST_EXPECT_OK(e, akgl_get_json_double_value(fixture, "ratio", &dblval), "read ratio as a double");
	TEST_ASSERT(e, dblval > 2.4999 && dblval < 2.5001,
		    "ratio read as double %f, expected 2.5", dblval);

	// Integers satisfy json_is_number, so the double accessor takes them.
	TEST_EXPECT_OK(e, akgl_get_json_double_value(fixture, "count", &dblval), "read count as a double");
	TEST_ASSERT(e, dblval > 41.999 && dblval < 42.001,
		    "count read as double %f, expected 42", dblval);

	TEST_EXPECT_STATUS(e, AKERR_KEY, akgl_get_json_double_value(fixture, "absent", &dblval),
			   "double accessor on a missing key");
	TEST_EXPECT_STATUS(e, AKERR_TYPE, akgl_get_json_double_value(fixture, "name", &dblval),
			   "double accessor on a string value");
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_double_value(NULL, "ratio", &dblval),
			   "double accessor on a NULL object");
    } CLEANUP {
    } PROCESS(e) {
    } FINISH(e, true);
    SUCCEED_RETURN(e);
}

akerr_ErrorContext *test_json_string_accessor(void)
{
    PREPARE_ERROR(e);
    akgl_String *allocated = NULL;
    akgl_String *reused = NULL;

    ATTEMPT {
	// A NULL destination makes the accessor claim a heap string.
	TEST_EXPECT_OK(e, akgl_get_json_string_value(fixture, "name", &allocated),
		       "read name into a NULL destination");
	TEST_ASSERT(e, allocated != NULL, "the accessor did not allocate a destination string");
	TEST_ASSERT(e, strcmp((char *)&allocated->data, "json helper fixture") == 0,
		    "name read as \"%s\"", (char *)&allocated->data);

	// A caller-supplied destination is written in place, not replaced.
	CATCH(e, akgl_heap_next_string(&reused));
	CATCH(e, akgl_string_initialize(reused, "placeholder"));
	{
	    akgl_String *before = reused;
	    TEST_EXPECT_OK(e, akgl_get_json_string_value(fixture, "name", &reused),
			   "read name into a preallocated destination");
	    TEST_ASSERT(e, reused == before,
			"the accessor replaced a caller-supplied destination pointer");
	}
	TEST_ASSERT(e, strcmp((char *)&reused->data, "json helper fixture") == 0,
		    "in-place read produced \"%s\"", (char *)&reused->data);

	TEST_EXPECT_STATUS(e, AKERR_KEY, akgl_get_json_string_value(fixture, "absent", &reused),
			   "string accessor on a missing key");
	TEST_EXPECT_STATUS(e, AKERR_TYPE, akgl_get_json_string_value(fixture, "count", &reused),
			   "string accessor on an integer value");
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_string_value(NULL, "name", &reused),
			   "string accessor on a NULL object");
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_string_value(fixture, NULL, &reused),
			   "string accessor with a NULL key");
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_string_value(fixture, "name", NULL),
			   "string accessor with a NULL destination");
    } CLEANUP {
	IGNORE(akgl_heap_release_string(allocated));
	IGNORE(akgl_heap_release_string(reused));
    } PROCESS(e) {
    } FINISH(e, true);
    SUCCEED_RETURN(e);
}

akerr_ErrorContext *test_json_array_index_accessors(void)
{
    PREPARE_ERROR(e);
    json_t *integers = NULL;
    json_t *strings = NULL;
    json_t *objects = NULL;
    json_t *mixed = NULL;
    json_t *element = NULL;
    akgl_String *strval = NULL;
    int intval = 0;

    ATTEMPT {
	CATCH(e, akgl_get_json_array_value(fixture, "integers", &integers));
	CATCH(e, akgl_get_json_array_value(fixture, "strings", &strings));
	CATCH(e, akgl_get_json_array_value(fixture, "objects", &objects));
	CATCH(e, akgl_get_json_array_value(fixture, "mixed", &mixed));

	TEST_EXPECT_OK(e, akgl_get_json_array_index_integer(integers, 0, &intval), "integers[0]");
	TEST_ASSERT(e, intval == 10, "integers[0] read as %d, expected 10", intval);
	TEST_EXPECT_OK(e, akgl_get_json_array_index_integer(integers, 2, &intval), "integers[2]");
	TEST_ASSERT(e, intval == 30, "integers[2] read as %d, expected 30", intval);

	TEST_EXPECT_OK(e, akgl_get_json_array_index_string(strings, 1, &strval), "strings[1]");
	TEST_ASSERT(e, strcmp((char *)&strval->data, "beta") == 0,
		    "strings[1] read as \"%s\", expected \"beta\"", (char *)&strval->data);

	TEST_EXPECT_OK(e, akgl_get_json_array_index_object(objects, 1, &element), "objects[1]");
	TEST_EXPECT_OK(e, akgl_get_json_integer_value(element, "id", &intval), "objects[1].id");
	TEST_ASSERT(e, intval == 2, "objects[1].id read as %d, expected 2", intval);

	// One past the end, and far past the end, are both out of bounds.
	TEST_EXPECT_STATUS(e, AKERR_OUTOFBOUNDS, akgl_get_json_array_index_integer(integers, 3, &intval),
			   "integers[3] is one past the end");
	TEST_EXPECT_STATUS(e, AKERR_OUTOFBOUNDS, akgl_get_json_array_index_integer(integers, 99, &intval),
			   "integers[99] is far past the end");
	TEST_EXPECT_STATUS(e, AKERR_OUTOFBOUNDS, akgl_get_json_array_index_object(objects, 5, &element),
			   "objects[5] is past the end");
	TEST_EXPECT_STATUS(e, AKERR_OUTOFBOUNDS, akgl_get_json_array_index_string(strings, 5, &strval),
			   "strings[5] is past the end");

	// The mixed array holds one of each type, so every accessor can be shown
	// to reject the entries that are not its own.
	TEST_EXPECT_STATUS(e, AKERR_TYPE, akgl_get_json_array_index_integer(mixed, 1, &intval),
			   "integer accessor on a string element");
	TEST_EXPECT_STATUS(e, AKERR_TYPE, akgl_get_json_array_index_string(mixed, 0, &strval),
			   "string accessor on an integer element");
	TEST_EXPECT_STATUS(e, AKERR_TYPE, akgl_get_json_array_index_object(mixed, 0, &element),
			   "object accessor on an integer element");

	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_array_index_integer(NULL, 0, &intval),
			   "integer index accessor on a NULL array");
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_array_index_object(NULL, 0, &element),
			   "object index accessor on a NULL array");
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_array_index_string(NULL, 0, &strval),
			   "string index accessor on a NULL array");
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_array_index_string(strings, 0, NULL),
			   "string index accessor with a NULL destination");
    } CLEANUP {
	IGNORE(akgl_heap_release_string(strval));
    } PROCESS(e) {
    } FINISH(e, true);
    SUCCEED_RETURN(e);
}

akerr_ErrorContext *test_json_type_and_key_errors(void)
{
    PREPARE_ERROR(e);
    int intval = 0;
    float floatval = 0;
    bool boolval = false;
    json_t *objval = NULL;
    json_t *arrayval = NULL;

    ATTEMPT {
	// Missing keys.
	TEST_EXPECT_STATUS(e, AKERR_KEY, akgl_get_json_integer_value(fixture, "absent", &intval),
			   "integer accessor on a missing key");
	TEST_EXPECT_STATUS(e, AKERR_KEY, akgl_get_json_number_value(fixture, "absent", &floatval),
			   "number accessor on a missing key");
	TEST_EXPECT_STATUS(e, AKERR_KEY, akgl_get_json_boolean_value(fixture, "absent", &boolval),
			   "boolean accessor on a missing key");
	TEST_EXPECT_STATUS(e, AKERR_KEY, akgl_get_json_object_value(fixture, "absent", &objval),
			   "object accessor on a missing key");
	TEST_EXPECT_STATUS(e, AKERR_KEY, akgl_get_json_array_value(fixture, "absent", &arrayval),
			   "array accessor on a missing key");

	// Wrong types.
	TEST_EXPECT_STATUS(e, AKERR_TYPE, akgl_get_json_integer_value(fixture, "name", &intval),
			   "integer accessor on a string");
	TEST_EXPECT_STATUS(e, AKERR_TYPE, akgl_get_json_integer_value(fixture, "ratio", &intval),
			   "integer accessor on a real");
	TEST_EXPECT_STATUS(e, AKERR_TYPE, akgl_get_json_number_value(fixture, "name", &floatval),
			   "number accessor on a string");
	TEST_EXPECT_STATUS(e, AKERR_TYPE, akgl_get_json_boolean_value(fixture, "count", &boolval),
			   "boolean accessor on an integer");
	TEST_EXPECT_STATUS(e, AKERR_TYPE, akgl_get_json_object_value(fixture, "integers", &objval),
			   "object accessor on an array");
	TEST_EXPECT_STATUS(e, AKERR_TYPE, akgl_get_json_array_value(fixture, "nested", &arrayval),
			   "array accessor on an object");

	// NULL containers.
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_integer_value(NULL, "count", &intval),
			   "integer accessor on a NULL object");
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_number_value(NULL, "ratio", &floatval),
			   "number accessor on a NULL object");
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_boolean_value(NULL, "enabled", &boolval),
			   "boolean accessor on a NULL object");
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_object_value(NULL, "nested", &objval),
			   "object accessor on a NULL object");
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER, akgl_get_json_array_value(NULL, "integers", &arrayval),
			   "array accessor on a NULL object");
    } CLEANUP {
    } PROCESS(e) {
    } FINISH(e, true);
    SUCCEED_RETURN(e);
}

akerr_ErrorContext *test_json_with_default(void)
{
    PREPARE_ERROR(e);
    int dest = 0;
    int defval = 99;
    akerr_ErrorContext *keyerr = NULL;
    akerr_ErrorContext *typeerr = NULL;
    int junk = 0;

    ATTEMPT {
	// A NULL error means the read succeeded, so the default is not applied.
	dest = 1;
	TEST_EXPECT_OK(e, akgl_get_json_with_default(NULL, (void *)&defval, (void *)&dest, sizeof(int)),
		       "with_default on a NULL error");
	TEST_ASSERT(e, dest == 1, "with_default overwrote a successful read (dest is now %d)", dest);

	// An AKERR_KEY failure substitutes the default.
	dest = 1;
	keyerr = akgl_get_json_integer_value(fixture, "absent", &junk);
	TEST_ASSERT(e, keyerr != NULL, "the missing-key read unexpectedly succeeded");
	TEST_EXPECT_OK(e, akgl_get_json_with_default(keyerr, (void *)&defval, (void *)&dest, sizeof(int)),
		       "with_default on an AKERR_KEY error");
	TEST_ASSERT(e, dest == 99, "with_default did not apply the default (dest is %d)", dest);
	keyerr = NULL;

	// An unrelated failure is not swallowed, so the caller still sees it.
	dest = 1;
	typeerr = akgl_get_json_integer_value(fixture, "name", &junk);
	TEST_ASSERT(e, typeerr != NULL, "the wrong-type read unexpectedly succeeded");
	TEST_EXPECT_STATUS(e, AKERR_TYPE,
			   akgl_get_json_with_default(typeerr, (void *)&defval, (void *)&dest, sizeof(int)),
			   "with_default must propagate an unrelated error");
	TEST_ASSERT(e, dest == 1, "with_default applied the default for an unrelated error");
	typeerr = NULL;

	// NULL arguments alongside a real error are a contract violation.
	keyerr = akgl_get_json_integer_value(fixture, "absent", &junk);
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER,
			   akgl_get_json_with_default(keyerr, NULL, (void *)&dest, sizeof(int)),
			   "with_default with a NULL default value");
	keyerr = NULL;
	keyerr = akgl_get_json_integer_value(fixture, "absent", &junk);
	TEST_EXPECT_STATUS(e, AKERR_NULLPOINTER,
			   akgl_get_json_with_default(keyerr, (void *)&defval, NULL, sizeof(int)),
			   "with_default with a NULL destination");
	keyerr = NULL;
    } CLEANUP {
	if ( keyerr != NULL ) {
	    keyerr->handled = true;
	    keyerr = akerr_release_error(keyerr);
	}
	if ( typeerr != NULL ) {
	    typeerr->handled = true;
	    typeerr = akerr_release_error(typeerr);
	}
    } PROCESS(e) {
    } FINISH(e, true);
    SUCCEED_RETURN(e);
}

int main(void)
{
    PREPARE_ERROR(errctx);

    SDL_SetHint(SDL_HINT_VIDEO_DRIVER, "dummy");
    SDL_SetHint(SDL_HINT_AUDIO_DRIVER, "dummy");

    ATTEMPT {
	CATCH(errctx, akgl_error_init());
	TEST_TRAP_UNHANDLED_ERRORS();
	CATCH(errctx, akgl_heap_init());
	CATCH(errctx, akgl_registry_init());
	CATCH(errctx, load_fixture());

	CATCH(errctx, test_json_accessor_null_arguments());
	CATCH(errctx, test_json_scalar_accessors());
	CATCH(errctx, test_json_double_value());
	CATCH(errctx, test_json_string_accessor());
	CATCH(errctx, test_json_array_index_accessors());
	CATCH(errctx, test_json_type_and_key_errors());
	CATCH(errctx, test_json_with_default());
    } CLEANUP {
	if ( fixture != NULL ) {
	    json_decref(fixture);
	}
    } PROCESS(errctx) {
    } FINISH_NORETURN(errctx);
}