// SPDX-License-Identifier: MIT
#pragma once

#ifdef UNIT_TEST

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

struct test_file_metadata;

struct test_failure {
	bool present;
	const char *message;
	const char *file;
	int line;
};

struct test_case_metadata {
	void (*fn)(struct test_case_metadata *, struct test_file_metadata *);
	struct test_failure failure;
	const char *name;
	struct test_case_metadata *next;
};

struct test_file_metadata {
	bool registered;
	const char *name;
	struct test_file_metadata *next;
	struct test_case_metadata *tests;
};

struct test_file_metadata __attribute__((weak)) * test_file_head;

#define SET_FAILURE(_message)                                                             \
	metadata->failure = (struct test_failure) {                                       \
		.message = _message, .file = __FILE__, .line = __LINE__, .present = true, \
	}

#define TEST_EQUAL(a, b)                                                                 \
	do {                                                                             \
		if ((a) != (b)) {                                                        \
			SET_FAILURE(#a " != " #b);                                       \
			return;                                                          \
		}                                                                        \
	} while (0)

#define TEST_TRUE(a)                                                                     \
	do {                                                                             \
		if (!(a)) {                                                              \
			SET_FAILURE(#a " is not true");                                  \
			return;                                                          \
		}                                                                        \
	} while (0)

#define TEST_CASE(_name)                                                                 \
	static void __test_h_##_name(struct test_case_metadata *,                        \
	                             struct test_file_metadata *);                       \
	static struct test_file_metadata __test_h_file;                                  \
	static struct test_case_metadata __test_h_meta_##_name = {                       \
	    .name = #_name,                                                              \
	    .fn = __test_h_##_name,                                                      \
	};                                                                               \
	static void __attribute__((constructor)) __test_h_##_name##_register(void) {     \
		__test_h_meta_##_name.next = __test_h_file.tests;                        \
		__test_h_file.tests = &__test_h_meta_##_name;                            \
		if (!__test_h_file.registered) {                                         \
			__test_h_file.name = __FILE__;                                   \
			__test_h_file.next = test_file_head;                             \
			test_file_head = &__test_h_file;                                 \
			__test_h_file.registered = true;                                 \
		}                                                                        \
	}                                                                                \
	static void __test_h_##_name(struct test_case_metadata *metadata,                \
	                             struct test_file_metadata *file_metadata)

/// Run defined tests, return true if all tests succeeds
static inline bool __attribute__((unused)) run_tests(int argc, char *const *argv) {
	bool should_run = false;
	for (int i = 0; i < argc; i++) {
		if (strcmp(argv[i], "--unittest") == 0) {
			should_run = true;
			break;
		}
	}
	if (!should_run) {
		return true;
	}

	struct test_file_metadata *i = test_file_head;
	int failed = 0, success = 0;
	while (i) {
		fprintf(stderr, "Running tests from %s:\n", i->name);
		struct test_case_metadata *j = i->tests;
		while (j) {
			fprintf(stderr, "\t%s ... ", j->name);
			j->failure.present = false;
			j->fn(j, i);
			if (j->failure.present) {
				fprintf(stderr, "failed (%s at %s:%d)\n", j->failure.message,
				        j->failure.file, j->failure.line);
				failed++;
			} else {
				fprintf(stderr, "passed\n");
				success++;
			}
			j = j->next;
		}
		fprintf(stderr, "\n");
		i = i->next;
	}
	int total = failed + success;
	fprintf(stderr, "Test results: passed %d/%d, failed %d/%d\n", success, total,
	        failed, total);
	return failed == 0;
}

#else

#include <stdbool.h>

#define TEST_CASE(name) static void __attribute__((unused)) __test_h_##name(void)

#define TEST_EQUAL(a, b)
#define TEST_TRUE(a)

static inline bool __attribute__((unused)) run_tests(int argc, char *const *argv) {
	return true;
}
#endif