/*
 * test_hw_button.c — Unit tests for hw_button debounce/gesture driver (Issue #682).
 *
 * Build (host, no hardware):
 *   gcc -I include -I test/stubs -DTEST_HOST \
 *       -o /tmp/test_hw_button src/hw_button.c test/test_hw_button.c
 *
 * All tests use hw_button_inject() to drive the simulated GPIO pin.
 * All timing is driven through the now_ms argument passed to hw_button_tick().
 */

/* ---- Stubs: prevent STM32 HAL from being included in non-TEST_HOST path ---- */
#define STM32F7XX_HAL_H
#include <stdint.h>
#include <stdbool.h>

/* ---- Include implementation directly ---- */
#include "../src/hw_button.c"

/* ---- Test framework ---- */
#include <stdio.h>
#include <string.h>

static int g_pass = 0;
static int g_fail = 0;

#define ASSERT(cond, msg) \
    do { \
        if (cond) { g_pass++; } \
        else { g_fail++; printf("FAIL [%s:%d] %s\n", __FILE__, __LINE__, msg); } \
    } while (0)

/* ---- Helpers ---- */

/* Advance time by `ms` ticks with the pin held at `pressed`.
 * Returns the last non-NONE event seen, or BTN_EVENT_NONE. */
static hw_btn_event_t _tick_n(uint32_t *now, uint32_t ms, bool pressed)
{
    hw_btn_event_t last = BTN_EVENT_NONE;
    hw_button_inject(pressed);
    for (uint32_t i = 0; i < ms; i++) {
        (*now)++;
        hw_btn_event_t ev = hw_button_tick(*now);
        if (ev != BTN_EVENT_NONE) last = ev;
    }
    return last;
}

/* Reset driver state between tests. */
static void _reset(uint32_t *now)
{
    *now = 0;
    hw_button_inject(false);
    hw_button_init();
    /* Drain any pending sequence state */
    for (int i = 0; i < 100; i++) hw_button_tick((*now)++);
}

/* ---- Tests ---- */

static void test_idle_no_event(void)
{
    uint32_t now = 0;
    hw_button_init();
    hw_button_inject(false);
    for (int i = 0; i < 1000; i++) {
        hw_btn_event_t ev = hw_button_tick(now++);
        ASSERT(ev == BTN_EVENT_NONE, "idle: no event while pin released");
    }
}

static void test_debounce_bounce_ignored(void)
{
    uint32_t now = 0;
    hw_button_init();

    /* Press for only 10 ms (< BTN_DEBOUNCE_MS=20) then release */
    hw_btn_event_t ev = _tick_n(&now, 10, true);
    ASSERT(ev == BTN_EVENT_NONE, "bounce < debounce: no event during press");
    ev = _tick_n(&now, BTN_COMMIT_MS + 50, false);
    ASSERT(ev == BTN_EVENT_NONE, "bounce < debounce: no event after release");
}

static void test_debounce_confirmed(void)
{
    uint32_t now = 0;
    hw_button_init();

    /* Press for BTN_DEBOUNCE_MS + 1 ms — debounce should confirm */
    _tick_n(&now, BTN_DEBOUNCE_MS + 1, true);
    ASSERT(hw_button_is_pressed(), "debounce passed: is_pressed() == true");
}

static void test_short_press_park(void)
{
    uint32_t now = 0;
    hw_button_init();

    /* Press for BTN_DEBOUNCE_MS + 10 ms (short: well < BTN_LONG_MIN_MS) */
    _tick_n(&now, BTN_DEBOUNCE_MS + 10, true);
    /* Release */
    _tick_n(&now, 1, false);
    ASSERT(!hw_button_is_pressed(), "short press: released");

    /* Wait BTN_COMMIT_MS quiet -> should fire PARK */
    hw_btn_event_t ev = BTN_EVENT_NONE;
    hw_button_inject(false);
    for (uint32_t i = 0; i < BTN_COMMIT_MS + 10; i++) {
        now++;
        hw_btn_event_t e = hw_button_tick(now);
        if (e != BTN_EVENT_NONE) ev = e;
    }
    ASSERT(ev == BTN_EVENT_PARK, "short press + quiet: BTN_EVENT_PARK");
}

static void test_long_press_no_park(void)
{
    uint32_t now = 0;
    hw_button_init();

    /* Press for BTN_LONG_MIN_MS + 100 ms (long press) */
    _tick_n(&now, BTN_DEBOUNCE_MS + BTN_LONG_MIN_MS + 100, true);
    /* Release and wait */
    hw_btn_event_t ev = _tick_n(&now, BTN_COMMIT_MS + 10, false);
    /* Lone LONG press has no defined gesture */
    ASSERT(ev == BTN_EVENT_NONE, "lone long press: no event");
}

static void test_rearm_combo_fires(void)
{
    uint32_t now = 0;
    hw_button_init();

    /* Press 1: SHORT (30 ms hold + release) */
    _tick_n(&now, BTN_DEBOUNCE_MS + 10, true);
    _tick_n(&now, 1, false);
    /* Brief gap between presses (< BTN_COMMIT_MS so no PARK fires) */
    _tick_n(&now, 100, false);

    /* Press 2: SHORT */
    _tick_n(&now, BTN_DEBOUNCE_MS + 10, true);
    _tick_n(&now, 1, false);
    _tick_n(&now, 100, false);

    /* Press 3: LONG — combo fires on release */
    _tick_n(&now, BTN_DEBOUNCE_MS + BTN_LONG_MIN_MS + 50, true);
    hw_btn_event_t ev = BTN_EVENT_NONE;
    hw_button_inject(false);
    for (int i = 0; i < 5; i++) {
        hw_btn_event_t e = hw_button_tick(now++);
        if (e != BTN_EVENT_NONE) ev = e;
    }
    ASSERT(ev == BTN_EVENT_REARM_COMBO, "SHORT+SHORT+LONG: BTN_EVENT_REARM_COMBO");
}

static void test_rearm_combo_resets_buffer(void)
{
    uint32_t now = 0;
    hw_button_init();

    /* Fire combo once */
    _tick_n(&now, BTN_DEBOUNCE_MS + 10, true); _tick_n(&now, 100, false);
    _tick_n(&now, BTN_DEBOUNCE_MS + 10, true); _tick_n(&now, 100, false);
    _tick_n(&now, BTN_DEBOUNCE_MS + BTN_LONG_MIN_MS + 50, true);
    hw_button_inject(false);
    hw_btn_event_t ev = BTN_EVENT_NONE;
    for (int i = 0; i < 5; i++) {
        hw_btn_event_t e = hw_button_tick(now++);
        if (e != BTN_EVENT_NONE) ev = e;
    }
    ASSERT(ev == BTN_EVENT_REARM_COMBO, "first combo fires");

    /* After combo, a lone short press should produce PARK */
    _tick_n(&now, BTN_DEBOUNCE_MS + 10, true);
    _tick_n(&now, 1, false);
    ev = BTN_EVENT_NONE;
    hw_button_inject(false);
    for (uint32_t i = 0; i < BTN_COMMIT_MS + 10; i++) {
        hw_btn_event_t e = hw_button_tick(now++);
        if (e != BTN_EVENT_NONE) ev = e;
    }
    ASSERT(ev == BTN_EVENT_PARK, "after combo: short press fires PARK");
}

static void test_seq_timeout_clears_buffer(void)
{
    uint32_t now = 0;
    hw_button_init();

    /* TWO short presses — seq_len=2 (no PARK since it's not a lone SHORT).
     * Then wait BTN_SEQ_TIMEOUT_MS — buffer should be abandoned silently. */
    _tick_n(&now, BTN_DEBOUNCE_MS + 10, true);
    _tick_n(&now, 1, false);
    _tick_n(&now, 100, false);   /* gap between presses (< BTN_COMMIT_MS) */
    _tick_n(&now, BTN_DEBOUNCE_MS + 10, true);
    _tick_n(&now, 1, false);

    /* Wait BTN_SEQ_TIMEOUT_MS — seq_len=2 buffer expires silently */
    hw_btn_event_t ev = _tick_n(&now, BTN_SEQ_TIMEOUT_MS + 10, false);
    ASSERT(ev == BTN_EVENT_NONE, "seq timeout (seq_len=2): buffer cleared, no event");

    /* Fresh lone short press should produce PARK as a new sequence */
    _tick_n(&now, BTN_DEBOUNCE_MS + 10, true);
    _tick_n(&now, 1, false);
    ev = BTN_EVENT_NONE;
    hw_button_inject(false);
    for (uint32_t i = 0; i < BTN_COMMIT_MS + 10; i++) {
        hw_btn_event_t e = hw_button_tick(now++);
        if (e != BTN_EVENT_NONE) ev = e;
    }
    ASSERT(ev == BTN_EVENT_PARK, "after timeout: fresh short press fires PARK");
}

static void test_is_pressed_tracks_held(void)
{
    uint32_t now = 0;
    hw_button_init();

    ASSERT(!hw_button_is_pressed(), "initially not pressed");
    _tick_n(&now, BTN_DEBOUNCE_MS + 1, true);
    ASSERT(hw_button_is_pressed(), "after debounce: is_pressed true");
    _tick_n(&now, 1, false);
    ASSERT(!hw_button_is_pressed(), "after release: is_pressed false");
}

static void test_short_press_before_commit_no_park(void)
{
    uint32_t now = 0;
    hw_button_init();

    /* Press and release */
    _tick_n(&now, BTN_DEBOUNCE_MS + 10, true);
    _tick_n(&now, 1, false);

    /* Wait less than BTN_COMMIT_MS — no PARK yet */
    hw_btn_event_t ev = BTN_EVENT_NONE;
    hw_button_inject(false);
    for (uint32_t i = 0; i < BTN_COMMIT_MS - 50; i++) {
        hw_btn_event_t e = hw_button_tick(now++);
        if (e != BTN_EVENT_NONE) ev = e;
    }
    ASSERT(ev == BTN_EVENT_NONE, "before commit window: no PARK yet");
}

static void test_two_shorts_no_park(void)
{
    uint32_t now = 0;
    hw_button_init();

    /* Two short presses close together — seq_len=2 does not trigger PARK */
    _tick_n(&now, BTN_DEBOUNCE_MS + 10, true); _tick_n(&now, 1, false);
    _tick_n(&now, 100, false);
    _tick_n(&now, BTN_DEBOUNCE_MS + 10, true); _tick_n(&now, 1, false);

    hw_btn_event_t ev = BTN_EVENT_NONE;
    hw_button_inject(false);
    for (uint32_t i = 0; i < BTN_COMMIT_MS + 10; i++) {
        hw_btn_event_t e = hw_button_tick(now++);
        if (e != BTN_EVENT_NONE) ev = e;
    }
    ASSERT(ev == BTN_EVENT_NONE, "two shorts + quiet: no PARK (seq_len=2, not lone SHORT)");
}

/* ---- main ---- */
int main(void)
{
    printf("=== test_hw_button ===\n");

    test_idle_no_event();
    test_debounce_bounce_ignored();
    test_debounce_confirmed();
    test_short_press_park();
    test_long_press_no_park();
    test_rearm_combo_fires();
    test_rearm_combo_resets_buffer();
    test_seq_timeout_clears_buffer();
    test_is_pressed_tracks_held();
    test_short_press_before_commit_no_park();
    test_two_shorts_no_park();

    printf("\nResults: %d passed, %d failed\n", g_pass, g_fail);
    return g_fail ? 1 : 0;
}