#include "sensors.h"
#include "board_config.h"
#include "esp_log.h"
#include "esp_task_wdt.h"
#include "driver/gpio.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/queue.h"
#include "i2c.h"
#include "storage.h"
#include <sys/param.h>

// make the compiler shut up about casting an int to a void
#define INT2VOIDP(i) (void*)(uintptr_t)(i)


static const char* TAG = "SENS";

#ifdef BOARD_V5
// V5 physical connectors:
//   J1 = IO27 → SAFETY
//   J2 = IO14 → JACK
//   J3 = IO23 → n/c (AUX)   (J3 unreliable on the V5 board, moved DRIVE off)
//   J4 = IO19 → DRIVE
// Array order matches sensor_t: SAFETY, DRIVE, JACK, AUX2
uint8_t sensor_pins[N_SENSORS] = {GPIO_NUM_27, GPIO_NUM_19, GPIO_NUM_14, GPIO_NUM_23};
#else // BOARD_V4
uint8_t sensor_pins[N_SENSORS] = {GPIO_NUM_27, GPIO_NUM_14, GPIO_NUM_16, GPIO_NUM_19};
#endif

volatile int16_t sensor_count[N_SENSORS] = {0};
/* Bumped directly in the ISR on every edge — does not require sensors_check()
 * to run, so it works even while bring-up pauses the FSM task. */
volatile uint32_t sensor_isr_edge_count[N_SENSORS] = {0};
static volatile uint64_t sensor_last_isr_time[N_SENSORS] = {0};
static volatile bool sensor_stable_state[N_SENSORS] = {false};
static QueueHandle_t sensor_event_queue = NULL;


static volatile bool last_raw_state[N_SENSORS] = {false};

// Safety sensor debouncing
static volatile bool is_safe = true;
static volatile uint64_t safety_low_start_time = 0;
static volatile uint64_t safety_high_start_time = 0;
#define SAFETY_BREAK_DEBOUNCE_US   get_param_value_t(PARAM_SAFETY_BREAK_US).u32
#define SAFETY_MAKE_DEBOUNCE_US    get_param_value_t(PARAM_SAFETY_MAKE_US).u32

#define DEBOUNCE_TIME_US    2000   // 2 ms debounce (adjust per switch)
#define DEBOUNCE_TICKS      pdMS_TO_TICKS(DEBOUNCE_TIME_MS)

typedef struct {
    uint8_t sensor_id;
    bool level;
} sensor_event_t;

// ISR: Minimal work – just record timestamp and forward to queue
static void IRAM_ATTR sensor_isr_handler(void* arg) {
    uint32_t gpio_num = (uint32_t)arg;
    uint8_t i;
    for (i = 0; i < N_SENSORS; i++) {
        if (sensor_pins[i] == gpio_num) break;
    }
    if (i == N_SENSORS) return;

    uint64_t now = esp_timer_get_time();
    sensor_last_isr_time[i] = now;

    sensor_isr_edge_count[i]++;

    sensor_event_t evt = {.sensor_id = i, .level = !gpio_get_level(gpio_num)};
    BaseType_t xHigherPriorityTaskWoken = pdFALSE;
    xQueueSendFromISR(sensor_event_queue, &evt, &xHigherPriorityTaskWoken);
    if (xHigherPriorityTaskWoken) portYIELD_FROM_ISR();
}

esp_err_t sensors_init() {
	
	 uint64_t pin_mask = 0;
	 for (uint8_t i = 0; i < N_SENSORS; i++) pin_mask |= (1ULL << sensor_pins[i]);

	/* Belt-and-suspenders: force each sensor pin into digital-GPIO mode with
	 * pull-up explicitly applied. gpio_config()'s pull_up_en is known to be
	 * shadowed by RTC-subsystem settings on RTC-capable pins (IO27, 32, 33,
	 * 34–39). gpio_reset_pin() detaches any lingering RTC/peripheral mux,
	 * and the explicit gpio_set_pull_mode() call goes through the right
	 * path regardless of which sub-block owns the pin. */
	for (uint8_t i = 0; i < N_SENSORS; i++) {
	    gpio_reset_pin(sensor_pins[i]);
	}

	 gpio_config_t io_conf = {
        .pin_bit_mask = pin_mask,
        .mode = GPIO_MODE_INPUT,
        .pull_up_en = GPIO_PULLUP_ENABLE,
        .pull_down_en = GPIO_PULLDOWN_DISABLE,
        .intr_type = GPIO_INTR_ANYEDGE,
    };
    ESP_ERROR_CHECK(gpio_config(&io_conf));

    for (uint8_t i = 0; i < N_SENSORS; i++) {
        ESP_ERROR_CHECK(gpio_set_pull_mode(sensor_pins[i], GPIO_PULLUP_ONLY));
    }

    sensor_event_queue = xQueueCreate(16, sizeof(sensor_event_t));
    if (!sensor_event_queue) {
        ESP_LOGE(TAG, "Failed to create sensor queue");
        return ESP_FAIL;
    }

    // Install ISR service
    ESP_ERROR_CHECK(gpio_install_isr_service(0));

    for (uint8_t i = 0; i < N_SENSORS; i++) {
        ESP_ERROR_CHECK(gpio_isr_handler_add(sensor_pins[i], sensor_isr_handler, INT2VOIDP(sensor_pins[i])));
    	sensor_stable_state[i] = !gpio_get_level(sensor_pins[i]);
    }
	
    //static uint64_t last_processed_time[N_SENSORS] = {0};

    // Initialize stable state
    for (uint8_t i = 0; i < N_SENSORS; i++) {
        bool level = !gpio_get_level(sensor_pins[i]);
        sensor_stable_state[i] = level;
        last_raw_state[i] = level;
        //last_processed_time[i] = esp_timer_get_time();
    }
    
    // Initialize safety sensor
    bool safety_current = !gpio_get_level(sensor_pins[SENSOR_SAFETY]);
    if (safety_current) {
        safety_low_start_time = esp_timer_get_time();
        safety_high_start_time = 0;
    } else {
        safety_low_start_time = 0;
        safety_high_start_time = esp_timer_get_time();
    }
    
    return ESP_OK;
}

void sensors_check() {
    /* Drain ALL queued events with a non-blocking receive. Previously this
     * was a single blocking receive with a 10 ms timeout, which (a) chewed up
     * half the FSM tick window waiting on quiet sensors, and (b) consumed
     * only one edge per tick — encoder bursts above 50 Hz overflowed the
     * 16-entry queue and undercounted distance. Now each tick consumes the
     * full queue contents and applies a per-sensor debounce. */
    sensor_event_t evt;
    static uint64_t last_counted_us[N_SENSORS] = {0};
    while (xQueueReceive(sensor_event_queue, &evt, 0) == pdTRUE) {
        uint8_t i = evt.sensor_id;
        if (i >= N_SENSORS) continue;

        /* Use the ISR-captured level (snapshot at edge time) rather than a
         * fresh GPIO read here — by the time the FSM tick drains the queue,
         * the line may have toggled again and a re-read would miss the
         * transition we're processing. */
        bool current_raw = evt.level;

        /* Software debounce on non-safety sensors. The safety sensor has its
         * own asymmetric debouncer below, so we don't double-count there. */
        uint64_t now = esp_timer_get_time();
        if (i != SENSOR_SAFETY) {
            if (now - last_counted_us[i] < DEBOUNCE_TIME_US) continue;
        }
        last_counted_us[i] = now;

        sensor_stable_state[i] = current_raw;
        if (current_raw != last_raw_state[i]) {
            sensor_count[i]++;
        }
        last_raw_state[i] = current_raw;
    }
    
    // Handle safety sensor debouncing with asymmetric timing
    bool safety_current = !gpio_get_level(sensor_pins[SENSOR_SAFETY]);
    uint64_t now = esp_timer_get_time();
    
    if (safety_current) {
        // Safety sensor is LOW (active)
        if (safety_low_start_time == 0) {
            // First time going low, start timing
            safety_low_start_time = now;
            safety_high_start_time = 0;
            ESP_LOGI(TAG, "Safety sensor went LOW, starting make timer");
        } else if (!is_safe && (now - safety_low_start_time >= SAFETY_MAKE_DEBOUNCE_US)) {
            is_safe = true;
            ESP_LOGW(TAG, "SAFETY MADE - Relays enabled");
        }
    } else {
        // Safety sensor is HIGH (inactive)
        if (safety_high_start_time == 0) {
            // First time going high, start timing
            safety_high_start_time = now;
            safety_low_start_time = 0;
            ESP_LOGI(TAG, "Safety sensor went HIGH, starting break timer");
        } else if (is_safe && (now - safety_high_start_time >= SAFETY_BREAK_DEBOUNCE_US)) {
            is_safe = false;
            /* Kill all bridges but leave the sensor rail up — we still
             * want to observe the safety input. */
            i2c_relays_idle();
            ESP_LOGI(TAG, "SAFETY BREAK - Relays disabled");
        }
    }
    
    esp_task_wdt_reset();
}

int8_t pack_sensors() {
	int8_t ret = 0;
	for(uint8_t i=0; i<MIN(4, N_SENSORS); i++) {
		if(sensor_stable_state[i]) ret |= 0x01<<i;
		if(last_raw_state[i]) ret |= 0x01<<(i+4);
	}
	return ret;
}

// Public API
bool get_sensor(sensor_t i) {
    return sensor_stable_state[i];
}

bool get_is_safe(void) {
    return is_safe;
}

int16_t get_sensor_counter(sensor_t i) {
    return sensor_count[i];
}

void set_sensor_counter(sensor_t i, int16_t to) {
    sensor_count[i] = to;
}

uint32_t get_sensor_isr_edges(sensor_t i) {
    if (i >= N_SENSORS) return 0;
    return sensor_isr_edge_count[i];
}