/*
 * MTG RFID Companion - EC11 rotary encoder driver
 */

#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_log.h"
#include "driver/gpio.h"
#include "hw_pins.h"
#include "encoder.h"

static const char *TAG = "encoder";

static volatile int32_t s_delta = 0;
static volatile bool s_button_pressed = false;
static volatile uint32_t s_last_sw_tick = 0;

#define SW_DEBOUNCE_MS (35)

/* Quadrature decode: on each CLK edge, sample DT.
 * DT == CLK level  => one direction, != => other.
 * Physical wiring is corrected here if a knob feels inverted. */
#define DIR_CLK_HIGH (1)
/*
 * If the direction comes out reversed, flip this to -1.
 */
#define ENC_DIRECTION (1)

static void IRAM_ATTR encoder_isr(void *arg)
{
    uint32_t gpio = (uint32_t)(uintptr_t)arg;

    if (gpio == HW_ENC_CLK_GPIO) {
        int dt = gpio_get_level(HW_ENC_DT_GPIO);
        int clk = gpio_get_level(HW_ENC_CLK_GPIO);
        /* Increment on one edge per detent; using level comparison on both edges
         * doubles the count, so we only act when CLK transitions are detected as
         * ticks. To keep this robust we count on every edge and divide the
         * sense: signed direction * 1. */
        s_delta += (dt == clk) ? (ENC_DIRECTION) : (-ENC_DIRECTION);
    } else if (gpio == HW_ENC_SW_GPIO) {
        unsigned int now = (unsigned int)xTaskGetTickCountFromISR();
        if ((now - s_last_sw_tick) > pdMS_TO_TICKS(SW_DEBOUNCE_MS)) {
            s_last_sw_tick = now;
            s_button_pressed = true;
        }
    }
}

static esp_err_t config_pin(gpio_num_t pin, gpio_int_type_t intr_type)
{
    gpio_config_t cfg = {
        .pin_bit_mask = 1ULL << pin,
        .mode = GPIO_MODE_INPUT,
        .pull_up_en = GPIO_PULLUP_ENABLE,
        .pull_down_en = GPIO_PULLDOWN_DISABLE,
        .intr_type = intr_type,
    };
    return gpio_config(&cfg);
}

esp_err_t encoder_init(void)
{
    gpio_install_isr_service(ESP_INTR_FLAG_LEVEL1);

    ESP_ERROR_CHECK(config_pin(HW_ENC_CLK_GPIO, GPIO_INTR_POSEDGE));
    ESP_ERROR_CHECK(config_pin(HW_ENC_DT_GPIO, GPIO_INTR_DISABLE));
    ESP_ERROR_CHECK(config_pin(HW_ENC_SW_GPIO, GPIO_INTR_NEGEDGE));

    ESP_ERROR_CHECK(gpio_isr_handler_add(HW_ENC_CLK_GPIO, encoder_isr, (void *)(uintptr_t)HW_ENC_CLK_GPIO));
    ESP_ERROR_CHECK(gpio_isr_handler_add(HW_ENC_SW_GPIO, encoder_isr, (void *)(uintptr_t)HW_ENC_SW_GPIO));

    ESP_LOGI(TAG, "EC11 encoder ready (CLK=%d DT=%d SW=%d)",
             HW_ENC_CLK_GPIO, HW_ENC_DT_GPIO, HW_ENC_SW_GPIO);
    return ESP_OK;
}

bool encoder_has_delta(void)
{
    return s_delta != 0;
}

int32_t encoder_get_delta(void)
{
    return (int32_t)s_delta;
}

int32_t encoder_get_delta_and_reset(void)
{
    int32_t v = (int32_t)s_delta;
    s_delta = 0;
    return v;
}

bool encoder_button_pressed(void)
{
    return s_button_pressed;
}

void encoder_clear_button(void)
{
    s_button_pressed = false;
}