/******************************************************************************
 * @file    app_shake_wake.c
 * @brief   PA3 vibration-switch wake detector.
 *
 * The fitted switch is normally closed to ground.  A vibration opens the
 * contact, so PA3 goes high, then returns low when the contact closes again.
 * A wake is accepted only after the high level has been stable for the
 * re-arm interval and is generated on the following high-to-low transition.
 ******************************************************************************/

#include "app_shake_wake.h"
#include "board_pin.h"
#include "asm/gpio.h"

typedef struct {
    AppShakeWakeAllowedFn allowed;
    AppShakeWakeTriggerFn trigger;
    uint8_t enable;
    uint8_t armed;
    uint8_t trigger_pending;
    uint8_t high_ticks;
} AppShakeWakeCtx_t;

static AppShakeWakeCtx_t s_shake;

static void shake_reset_detection(void)
{
    s_shake.armed = 0;
    s_shake.trigger_pending = 0;
    s_shake.high_ticks = 0;
}

static void shake_pin_init(void)
{
#if BOARD_SHAKE_ENABLE
    gpio_set_die(BOARD_SHAKE_PIN, 1);
    gpio_direction_input(BOARD_SHAKE_PIN);
    gpio_set_pull_up(BOARD_SHAKE_PIN, 1);
    gpio_set_pull_down(BOARD_SHAKE_PIN, 0);
#endif
}

void app_shake_wake_init(AppShakeWakeAllowedFn allowed,
                         AppShakeWakeTriggerFn trigger)
{
    s_shake.allowed = allowed;
    s_shake.trigger = trigger;
    s_shake.enable = 0;
    shake_reset_detection();
    shake_pin_init();
}

void app_shake_wake_set_enable(uint8_t enable)
{
    s_shake.enable = !!enable;
    shake_reset_detection();
}

void app_shake_wake_reset(void)
{
    shake_reset_detection();
}

void app_shake_wake_poll(void)
{
    uint8_t pin_high;
    uint8_t rearm_ticks;

    if (!s_shake.enable) {
        shake_reset_detection();
        return;
    }

#if BOARD_SHAKE_ENABLE
    pin_high = (uint8_t)(gpio_read(BOARD_SHAKE_PIN) == BOARD_SHAKE_ACTIVE_LEVEL);
#else
    pin_high = 0;
#endif
    rearm_ticks = (uint8_t)(BOARD_SHAKE_REARM_MS / BOARD_SHAKE_POLL_MS);
    if (!rearm_ticks) {
        rearm_ticks = 1;
    }

    if (pin_high) {
        if (s_shake.high_ticks < rearm_ticks) {
            s_shake.high_ticks++;
        }
        if (s_shake.high_ticks >= rearm_ticks) {
            s_shake.armed = 1;
        }
        return;
    }

    /* The contact has closed again: this is the verified wake edge. */
    s_shake.high_ticks = 0;
    if (s_shake.armed) {
        s_shake.armed = 0;
        s_shake.trigger_pending = 1;
    }

    if (!s_shake.trigger_pending) {
        return;
    }
    s_shake.trigger_pending = 0;
    if (!s_shake.allowed || !s_shake.allowed()) {
        shake_reset_detection();
        return;
    }
    if (s_shake.trigger) {
        s_shake.trigger();
    }
}