/*
 * Copyright 2021 The Chromium OS Authors
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <zephyr/ztest.h>
#include <zephyr/smf.h>

/*
 * Flat Test Transition:
 *
 *	A_ENTRY --> A_RUN --> A_EXIT --> B_ENTRY --> B_RUN --|
 *	                                                     |
 *	|----------------------------------------------------|
 *	|
 *	|--> B_EXIT --> C_ENTRY --> C_RUN --> C_EXIT
 *
 */


#define TEST_OBJECT(o) ((struct test_object *)o)

#define SMF_RUN                         3

#define STATE_A_ENTRY_BIT       (1 << 0)
#define STATE_A_RUN_BIT         (1 << 1)
#define STATE_A_EXIT_BIT        (1 << 2)

#define STATE_B_ENTRY_BIT       (1 << 3)
#define STATE_B_RUN_BIT         (1 << 4)
#define STATE_B_EXIT_BIT        (1 << 5)

#define STATE_C_ENTRY_BIT       (1 << 6)
#define STATE_C_RUN_BIT         (1 << 7)
#define STATE_C_EXIT_BIT        (1 << 8)

#define TEST_ENTRY_VALUE_NUM     0
#define TEST_RUN_VALUE_NUM       4
#define TEST_EXIT_VALUE_NUM      8
#define TEST_VALUE_NUM           9

static uint32_t test_value[] = {
	0x00,  /* STATE_A_ENTRY */
	0x01,  /* STATE_A_RUN */
	0x03,  /* STATE_A_EXIT */
	0x07,  /* STATE_B_ENTRY */
	0x0f,  /* STATE_B_RUN */
	0x1f,  /* STATE_B_EXIT */
	0x3f,  /* STATE_C_ENTRY */
	0x7f,  /* STATE_C_RUN */
	0xff,  /* STATE_C_EXIT */
	0x1ff, /* FINAL VALUE */
};

/* Forward declaration of test_states */
static const struct smf_state test_states[];

/* List of all TypeC-level states */
enum test_state {
	STATE_A,
	STATE_B,
	STATE_C,
	STATE_D
};

enum terminate_action {
	NONE,
	ENTRY,
	RUN,
	EXIT
};

static struct test_object {
	struct smf_ctx ctx;
	uint32_t transition_bits;
	uint32_t tv_idx;
	enum terminate_action terminate;
} test_obj;

static void state_a_entry(void *obj)
{
	struct test_object *o = TEST_OBJECT(obj);

	o->tv_idx = 0;
	zassert_equal(o->transition_bits, test_value[o->tv_idx],
		      "Test State A entry failed");

	if (o->terminate == ENTRY) {
		smf_set_terminate(obj, -1);
		return;
	}

	o->transition_bits |= STATE_A_ENTRY_BIT;
}

static void state_a_run(void *obj)
{
	struct test_object *o = TEST_OBJECT(obj);

	o->tv_idx++;
	zassert_equal(o->transition_bits, test_value[o->tv_idx],
		      "Test State A run failed");

	o->transition_bits |= STATE_A_RUN_BIT;

	smf_set_state(SMF_CTX(obj), &test_states[STATE_B]);
}

static void state_a_exit(void *obj)
{
	struct test_object *o = TEST_OBJECT(obj);

	o->tv_idx++;
	zassert_equal(o->transition_bits, test_value[o->tv_idx],
		      "Test State A exit failed");

	o->transition_bits |= STATE_A_EXIT_BIT;
}

static void state_b_entry(void *obj)
{
	struct test_object *o = TEST_OBJECT(obj);

	o->tv_idx++;
	zassert_equal(o->transition_bits, test_value[o->tv_idx],
		      "Test State B entry failed");

	o->transition_bits |= STATE_B_ENTRY_BIT;
}

static void state_b_run(void *obj)
{
	struct test_object *o = TEST_OBJECT(obj);

	o->tv_idx++;
	zassert_equal(o->transition_bits, test_value[o->tv_idx],
		      "Test State B run failed");

	if (o->terminate == RUN) {
		smf_set_terminate(obj, -1);
		return;
	}

	o->transition_bits |= STATE_B_RUN_BIT;

	smf_set_state(SMF_CTX(obj), &test_states[STATE_C]);
}

static void state_b_exit(void *obj)
{
	struct test_object *o = TEST_OBJECT(obj);

	o->tv_idx++;
	zassert_equal(o->transition_bits, test_value[o->tv_idx],
		      "Test State B exit failed");
	o->transition_bits |= STATE_B_EXIT_BIT;
}

static void state_c_entry(void *obj)
{
	struct test_object *o = TEST_OBJECT(obj);

	o->tv_idx++;
	zassert_equal(o->transition_bits, test_value[o->tv_idx],
		      "Test State C entry failed");
	o->transition_bits |= STATE_C_ENTRY_BIT;
}

static void state_c_run(void *obj)
{
	struct test_object *o = TEST_OBJECT(obj);

	o->tv_idx++;
	zassert_equal(o->transition_bits, test_value[o->tv_idx],
		      "Test State C run failed");
	o->transition_bits |= STATE_C_RUN_BIT;

	smf_set_state(SMF_CTX(obj), &test_states[STATE_D]);
}

static void state_c_exit(void *obj)
{
	struct test_object *o = TEST_OBJECT(obj);

	o->tv_idx++;
	zassert_equal(o->transition_bits, test_value[o->tv_idx],
		      "Test State C exit failed");

	if (o->terminate == EXIT) {
		smf_set_terminate(obj, -1);
		return;
	}

	o->transition_bits |= STATE_C_EXIT_BIT;
}

static void state_d_entry(void *obj)
{
	struct test_object *o = TEST_OBJECT(obj);

	o->tv_idx++;
}

static void state_d_run(void *obj)
{
	/* Do nothing */
}

static void state_d_exit(void *obj)
{
	/* Do nothing */
}

static const struct smf_state test_states[] = {
	[STATE_A] = SMF_CREATE_STATE(state_a_entry, state_a_run, state_a_exit),
	[STATE_B] = SMF_CREATE_STATE(state_b_entry, state_b_run, state_b_exit),
	[STATE_C] = SMF_CREATE_STATE(state_c_entry, state_c_run, state_c_exit),
	[STATE_D] = SMF_CREATE_STATE(state_d_entry, state_d_run, state_d_exit),
};

void test_smf_flat(void)
{
	/* A) Test transitions */

	test_obj.transition_bits = 0;
	test_obj.terminate = NONE;
	smf_set_initial((struct smf_ctx *)&test_obj, &test_states[STATE_A]);

	for (int i = 0; i < SMF_RUN; i++) {
		if (smf_run_state((struct smf_ctx *)&test_obj)) {
			break;
		}
	}

	zassert_equal(TEST_VALUE_NUM, test_obj.tv_idx,
		      "Incorrect test value index");
	zassert_equal(test_obj.transition_bits, test_value[test_obj.tv_idx],
		      "Final state not reached");

	/* B) Test termination in entry action */

	test_obj.transition_bits = 0;
	test_obj.terminate = ENTRY;
	smf_set_initial((struct smf_ctx *)&test_obj, &test_states[STATE_A]);

	for (int i = 0; i < SMF_RUN; i++) {
		if (smf_run_state((struct smf_ctx *)&test_obj)) {
			break;
		}
	}

	zassert_equal(TEST_ENTRY_VALUE_NUM, test_obj.tv_idx,
		      "Incorrect test value index for entry termination");
	zassert_equal(test_obj.transition_bits, test_value[test_obj.tv_idx],
		      "Final entry termination state not reached");

	/* C) Test termination in run action */

	test_obj.transition_bits = 0;
	test_obj.terminate = RUN;
	smf_set_initial((struct smf_ctx *)&test_obj, &test_states[STATE_A]);

	for (int i = 0; i < SMF_RUN; i++) {
		if (smf_run_state((struct smf_ctx *)&test_obj)) {
			break;
		}
	}

	zassert_equal(TEST_RUN_VALUE_NUM, test_obj.tv_idx,
		      "Incorrect test value index for run termination");
	zassert_equal(test_obj.transition_bits, test_value[test_obj.tv_idx],
		      "Final run termination state not reached");

	/* D) Test termination in exit action */

	test_obj.transition_bits = 0;
	test_obj.terminate = EXIT;
	smf_set_initial((struct smf_ctx *)&test_obj, &test_states[STATE_A]);

	for (int i = 0; i < SMF_RUN; i++) {
		if (smf_run_state((struct smf_ctx *)&test_obj)) {
			break;
		}
	}

	zassert_equal(TEST_EXIT_VALUE_NUM, test_obj.tv_idx,
		      "Incorrect test value index for exit termination");
	zassert_equal(test_obj.transition_bits, test_value[test_obj.tv_idx],
		      "Final exit termination state not reached");
}