#include <ArduinoFake.h>
#include <unity.h>
#include "interval.h"

using namespace fakeit;

// Global variable to simulate time in milliseconds
static uint32_t fakeMillis = 0;

// Fake function to override millis()
uint32_t fakeMillisFunc() {
    return fakeMillis;
}

// setUp() is called before each test
void setUp(void) {
    // Reset fake time
    fakeMillis = 0;
    ArduinoFakeReset();
    // Override millis() to use our fakeMillisFunc()
    When(Method(ArduinoFake(), millis)).AlwaysDo(fakeMillisFunc);
}

// tearDown() is called after each test (if needed)
void tearDown(void) {
    // No teardown actions required
}

// Test for Compatibility Mode (using set() method)
void test_CompatibilityMode(void) {
    Interval interval;
    interval.set(1000); // Set timeout to 1000ms in compatibility mode

    fakeMillis = 500;
    TEST_ASSERT_FALSE(interval.expired()); // Should not be expired at 500ms

    fakeMillis = 1000;
    TEST_ASSERT_TRUE(interval.expired()); // Should be expired at 1000ms

    // In compatibility mode, subsequent calls should still return true once expired
    TEST_ASSERT_TRUE(interval.expired());
}

// Test for One-shot Mode (using setOneshot() method)
void test_OneshotMode(void) {
    Interval interval;
    interval.setOneshot(1000); // Set timeout to 1000ms in oneshot mode

    fakeMillis = 500;
    TEST_ASSERT_FALSE(interval.expired()); // Not yet expired

    fakeMillis = 1000;
    TEST_ASSERT_TRUE(interval.expired()); // Expired at 1000ms

    // Subsequent calls should return false because oneshot mode triggers only once
    TEST_ASSERT_FALSE(interval.expired());
}

// Test for Periodic Mode (using setPeriodic() method)
void test_PeriodicMode(void) {
    Interval interval;
    interval.setPeriodic(1000); // Set periodic mode with 1000ms timeout

    fakeMillis = 500;
    TEST_ASSERT_FALSE(interval.expired()); // Not yet expired

    fakeMillis = 1000;
    TEST_ASSERT_TRUE(interval.expired()); // First period expired

    // After expiration, timer is reset; simulate next period
    fakeMillis = 1500;
    TEST_ASSERT_FALSE(interval.expired()); // Still within new period

    fakeMillis = 2000;
    TEST_ASSERT_TRUE(interval.expired()); // Second period expired
}

// Test for elapsed() and remains() functions
void test_elapsed_and_remains(void) {
    Interval interval;
    interval.set(1000); // Using compatibility mode, timeout set to 1000ms

    fakeMillis = 0;
    TEST_ASSERT_EQUAL_UINT32(0, interval.elapsed());
    TEST_ASSERT_EQUAL_UINT32(1000, interval.remains());

    fakeMillis = 500;
    TEST_ASSERT_EQUAL_UINT32(500, interval.elapsed());
    TEST_ASSERT_EQUAL_UINT32(500, interval.remains());

    fakeMillis = 1100;
    TEST_ASSERT_EQUAL_UINT32(1100, interval.elapsed());
    // remains() uses unsigned arithmetic, so it will underflow if elapsed > timeout
    TEST_ASSERT_EQUAL_UINT32(1000 - 1100, interval.remains());
}

// Test for handling overflow of millis() value
void test_overflow(void) {
    Interval interval;
    // Set fakeMillis to a value near the maximum of 32-bit unsigned int
    fakeMillis = 0xFFFFFFF0;
    interval.set(100); // Set timeout to 100ms in compatibility mode; _timefrom = 0xFFFFFFF0

    // Simulate time just before expiration after overflow.
    // After overflow, fakeMillis is low. For example, fakeMillis = 0x00000050.
    // Expected elapsed time = 0x00000050 + (0x100000000 - 0xFFFFFFF0) = 0x50 + 0x10 = 96ms.
    fakeMillis = 0x00000050;
    TEST_ASSERT_FALSE(interval.expired()); // Not yet expired

    // Now simulate time after expiration:
    // Set fakeMillis = 0x00000070. Expected elapsed time = 0x70 + 0x10 = 128ms, which is >= 100ms.
    fakeMillis = 0x00000070;
    TEST_ASSERT_TRUE(interval.expired()); // Should be expired due to overflow handling
}

// Test for reload() functionality in oneshot mode
void test_reload(void) {
    Interval interval;
    interval.setOneshot(1000); // Set oneshot mode with 1000ms timeout

    fakeMillis = 0;
    // Simulate expiration
    fakeMillis = 1100;
    TEST_ASSERT_TRUE(interval.expired()); // Expired at 1100ms

    // Reload the interval to reset the timer and reactivate oneshot mode
    fakeMillis = 1100;
    interval.reload();

    // Immediately after reload, should not be expired
    fakeMillis = 1200;
    TEST_ASSERT_FALSE(interval.expired());

    // After passing the timeout from reload, it should expire again
    fakeMillis = 2200;
    TEST_ASSERT_TRUE(interval.expired());
}

int main(int argc, char **argv) {
    UNITY_BEGIN();
    RUN_TEST(test_CompatibilityMode);
    RUN_TEST(test_OneshotMode);
    RUN_TEST(test_PeriodicMode);
    RUN_TEST(test_elapsed_and_remains);
    RUN_TEST(test_overflow);
    RUN_TEST(test_reload);
    return UNITY_END();
}