#include "blk_box_drivers/inputs.hpp"

#include "bottom_half.h"
#include "pins.h"
#include "driver/i2c.h"
#include "driver/gpio.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_log.h"
#include "esp_err.h"

static const char *TAG = "INPUTS";

static TaskHandle_t expander_task_handle = NULL;

static i2c_master_dev_handle_t expander_i2c_dev_handle;

const static uint8_t REG_WHOAMI = 0x01;
const static uint8_t REG_SW_VERSION = 0x02;
const static uint8_t REG_EVENT_QUEUE_POP = 0x10;
const static uint8_t REG_EVENT_QUEUE_LEN = 0x11;
const static uint8_t REG_STATE_BUTTONS = 0x20;
const static uint8_t REG_STATE_SWITCHES = 0x21;
const static uint8_t REG_STATE_KEYPAD = 0x22;
const static uint8_t REG_STATE_TOUCH = 0x23;
const static uint8_t REG_STATE_RFID = 0x24;
const static uint8_t REG_STATE_HALL = 0x25;
const static uint8_t REG_STATE_CLOSE = 0x26;
const static uint8_t REG_RESET = 0x30;
const static uint8_t REG_HALL_SENSITIVITY = 0x31;
const static uint8_t REG_CLOSE_SENSITIVITY = 0x32;
const static uint8_t REG_SWITCH_TOUCH_EVENT = 0x33;

/// The global data for the expander peripheral.
class ExpanderPeripheral {
    // TODO: change these to private
    // or even make this class hidden
    public: 
    SemaphoreHandle_t state_mutex;
    InputsState state;

    // channels
    QueueHandle_t button_press_events;
    QueueHandle_t button_release_events;
    QueueHandle_t switch_flip_events;
    QueueHandle_t switch_touch_events;
    QueueHandle_t touch_events;
    QueueHandle_t keypad_press_events;
    QueueHandle_t keypad_release_events;
};

ExpanderPeripheral expander_peripheral_singleton;

// forward declarations
static void get_events();
static void handle_event(uint8_t event);
static void handle_button_switch_event(uint8_t event);
static void handle_keypad_event(uint8_t event);
static void handle_touch_event(uint8_t event);
static void handle_rfid_event(uint8_t event);
static void handle_close_hal_event(uint8_t event);
static void expander_task(void *arg);

// ISR handler
static void IRAM_ATTR expander_isr_handler(void *arg) {
    BaseType_t xHigherPriorityTaskWoken = pdFALSE;

    if (expander_task_handle != NULL) {
        vTaskNotifyGiveFromISR(expander_task_handle, &xHigherPriorityTaskWoken);
    }

    if (xHigherPriorityTaskWoken == pdTRUE) {
        portYIELD_FROM_ISR();
    }
}

void init_expander() {
    ESP_LOGI(TAG, "Initializing expander...");

    i2c_device_config_t dev_config = {
        .dev_addr_length = I2C_ADDR_BIT_LEN_7,
        .device_address = EXPANDER_I2C_ADDR,
        .scl_speed_hz = EXPANDER_I2C_SPEED,
        .scl_wait_us = 0, // default
        .flags = {
            .disable_ack_check = 0,
        }
    };

    // setup interrupt on BOTTOM_PIN_INTERUPT
    gpio_config_t io_conf = {
        .pin_bit_mask = (1ULL << BOTTOM_PIN_INTERUPT),
        .mode = GPIO_MODE_INPUT,
        .pull_up_en = GPIO_PULLUP_ENABLE,
        .pull_down_en = GPIO_PULLDOWN_DISABLE,
        .intr_type = GPIO_INTR_NEGEDGE
    };

    ESP_ERROR_CHECK(gpio_config(&io_conf));

    // Install ISR service (only call once in your program)
    ESP_ERROR_CHECK(gpio_install_isr_service(0));

    // Attach the ISR to the expander pin
    ESP_ERROR_CHECK(gpio_isr_handler_add(BOTTOM_PIN_INTERUPT, expander_isr_handler, NULL));

    // verify the expander connection status by reading the WHOAMI register
    uint8_t read_buf[2] = {0};

    i2c_master_write_read_device(I2C_NUM_0, BOTTOM_I2C_ADDR, &REG_WHOAMI, 1, read_buf, 1, 1000);

    if (read_buf[0] != EXPANDER_WHOAMI_VALUE) {
        ESP_LOGE(TAG, "WHOAMI mismatch, expected 0x%02X, got 0x%02X", EXPANDER_WHOAMI_VALUE, read_buf[0]);
        return;
    }

    ESP_LOGD(TAG, "Expander WHOAMI check passed");

    ESP_ERROR_CHECK(i2c_master_transmit_receive(expander_i2c_dev_handle, &REG_SW_VERSION, 1, read_buf, 2, EXPANDER_TIMEOUT_MS));

    // init the peripheral struct
    expander_peripheral_singleton.state_mutex = xSemaphoreCreateMutex();
    expander_peripheral_singleton.button_press_events= xQueueCreate(EXPANDER_EVENT_QUEUE_SIZE, sizeof(Button));
    expander_peripheral_singleton.button_release_events= xQueueCreate(EXPANDER_EVENT_QUEUE_SIZE, sizeof(Button));
    expander_peripheral_singleton.switch_flip_events= xQueueCreate(EXPANDER_EVENT_QUEUE_SIZE, sizeof(SwitchFlip));
    expander_peripheral_singleton.switch_touch_events= xQueueCreate(EXPANDER_EVENT_QUEUE_SIZE, sizeof(SwitchTouch));
    expander_peripheral_singleton.touch_events= xQueueCreate(EXPANDER_EVENT_QUEUE_SIZE, sizeof(TouchedReleased));
    expander_peripheral_singleton.keypad_press_events= xQueueCreate(EXPANDER_KEYPAD_QUEUE_SIZE, sizeof(KeypadKey));
    expander_peripheral_singleton.keypad_release_events= xQueueCreate(EXPANDER_KEYPAD_QUEUE_SIZE, sizeof(KeypadKey));

    ESP_LOGI(TAG, "Expander initialized! SW version: v%d.%d", read_buf[0], read_buf[1]);

    // Create the expander background worker task
    BaseType_t task_created = xTaskCreate(
        expander_task,
        "expander_task",
        4096,
        NULL,
        tskIDLE_PRIORITY + 1,
        &expander_task_handle
    );

    if (task_created != pdPASS) {
        ESP_LOGE(TAG, "Failed to create expander task");
    }
}

static void expander_task(void *arg) {
    (void)arg;

    while (true) {
        get_events();

        // Wait for interrupt notification (signal is sent when INT falls)
        ulTaskNotifyTake(pdTRUE, portMAX_DELAY);
    }
}

static void get_events() {
    uint8_t recv;
    while (gpio_get_level(PIN_EXPANDER_INT) == 0) {
        ESP_ERROR_CHECK(i2c_master_transmit_receive(expander_i2c_dev_handle, &REG_EVENT_QUEUE_POP, 1, &recv, 1, EXPANDER_TIMEOUT_MS));
        handle_event(recv);
    }
}

static void handle_event(uint8_t event) {
    const uint8_t BUTTON_SWITCH = 0b000;
    const uint8_t KEYPAD = 0b001;
    const uint8_t TOUCH = 0b010;
    const uint8_t RFID = 0b011;

    ESP_LOGD(TAG, "Expander event: 0b%08b (0x%02X)", event, event);

    if (event == 0) {
        ESP_LOGE(TAG, "We read from event queue while it was empty!");
        return;
    }

    uint8_t type_bits = event >> 5;

    switch (type_bits) {
        case BUTTON_SWITCH:
            handle_button_switch_event(event);
            break;
        case KEYPAD:
            handle_keypad_event(event);
            break;
        case TOUCH:
            handle_touch_event(event);
            break;
        case RFID:
            handle_rfid_event(event);
            break;
        default:
            handle_close_hal_event(event);
            break;
    }
}

static void handle_button_switch_event(uint8_t event) {
    const uint8_t PRESSED_NOT_RELEASED_BIT = 0b10000;
    const uint8_t SWITCH_NOT_BUTTON_BIT = 0b01000;
    const uint8_t SWITCH_UP_NOT_DOWN_BIT = 0b00100;
    const uint8_t NUMBER_MASK = 0b00011;

    bool pressed = (event & PRESSED_NOT_RELEASED_BIT) != 0;
    uint8_t number = event & NUMBER_MASK;

    if ((event & SWITCH_NOT_BUTTON_BIT) != 0) {
        // For now, we support two position switches by only looking at the switch up events
        bool switch_up = (event & SWITCH_UP_NOT_DOWN_BIT) != 0;
        if (!switch_up) {
            return;
        }

        Switch sw = static_cast<Switch>(number);
        SwitchFlip sw_flip = SwitchFlip(sw, pressed);
        xQueueSendToBack(expander_peripheral_singleton.switch_flip_events, &sw_flip, 0);
        xSemaphoreTake(expander_peripheral_singleton.state_mutex, portMAX_DELAY);
        if (pressed) {
            // set
            expander_peripheral_singleton.state.switch_state |= 1 << number;
        } else {
            // clear
            expander_peripheral_singleton.state.switch_state &= ~(1 << number);
        }
        xSemaphoreGive(expander_peripheral_singleton.state_mutex);
    } else {
        // button
        Button button = static_cast<Button>(number);
        if (pressed) {
            xQueueSendToBack(expander_peripheral_singleton.button_press_events, &button, 0);
            xSemaphoreTake(expander_peripheral_singleton.state_mutex, portMAX_DELAY);
            expander_peripheral_singleton.state.button_state |= 1 << number;
            xSemaphoreGive(expander_peripheral_singleton.state_mutex);
        } else {
            xQueueSendToBack(expander_peripheral_singleton.button_release_events, &button, 0);
            xSemaphoreTake(expander_peripheral_singleton.state_mutex, portMAX_DELAY);
            expander_peripheral_singleton.state.button_state &= ~(1 << number);
            xSemaphoreGive(expander_peripheral_singleton.state_mutex);
        }
    }
}

static void handle_keypad_event(uint8_t event) {
    const uint8_t PRESSED_NOT_RELEASED_BIT = 0b10000;
    const uint8_t KEY_MASK = 0b1111;

    bool pressed = (event & PRESSED_NOT_RELEASED_BIT) != 0;
    uint8_t number = event & KEY_MASK;
    KeypadKey key = static_cast<KeypadKey>(number);

    // starcode system gets first dibs
    // TODO: do starcode inbetweener
    // if starcode_handle_keypad(key, pressed).await {
    //     return;
    // }

    if (pressed) {
        xQueueSendToBack(expander_peripheral_singleton.keypad_press_events, &key, 0);
        xSemaphoreTake(expander_peripheral_singleton.state_mutex, portMAX_DELAY);
        expander_peripheral_singleton.state.keypad_state |= 1 << number;
        xSemaphoreGive(expander_peripheral_singleton.state_mutex);
    } else {
        xQueueSendToBack(expander_peripheral_singleton.keypad_release_events, &key, 0);
        xSemaphoreTake(expander_peripheral_singleton.state_mutex, portMAX_DELAY);
        expander_peripheral_singleton.state.keypad_state &= ~(1 << number);
        xSemaphoreGive(expander_peripheral_singleton.state_mutex);
    }
}

static void handle_touch_event(uint8_t event) {
    const uint8_t TOUCHED_NOT_UNTOUCHED_BIT = 0b10000;
    const uint8_t SENSOR_MASK = 0b0111;
    const uint8_t FINGERPRINT_BIT = 0b0100;

    bool touched = (event & TOUCHED_NOT_UNTOUCHED_BIT) != 0;
    uint8_t sensor = event & SENSOR_MASK;

    if ((sensor & FINGERPRINT_BIT) != 0) {
        TouchedReleased touch_state = static_cast<TouchedReleased>(touched);
        xQueueSendToBack(expander_peripheral_singleton.touch_events, &touch_state, 0);
    } else {
        Switch sw = static_cast<Switch>(sensor);
        SwitchTouch sw_touch = SwitchTouch(sw, touched);
        xQueueSendToBack(expander_peripheral_singleton.switch_touch_events, &sw_touch, 0);
    }

    xSemaphoreTake(expander_peripheral_singleton.state_mutex, portMAX_DELAY);
    if (touched) {
        expander_peripheral_singleton.state.touch_state |= 1 << sensor;
    } else {
        expander_peripheral_singleton.state.touch_state &= ~(1 << sensor);
    }
    xSemaphoreGive(expander_peripheral_singleton.state_mutex);
}

static void handle_rfid_event(uint8_t event) {
    // TODO: impl
    (void)event;
}

static void handle_close_hal_event(uint8_t event) {
    // TODO: impl
    (void)event;
}

// InputsController implementations

/// Clears all events waiting in the queues.
void InputsController::clear_all_events() {
    xQueueReset(expander_peripheral_singleton.button_press_events);
    xQueueReset(expander_peripheral_singleton.button_release_events);
    xQueueReset(expander_peripheral_singleton.switch_flip_events);
    xQueueReset(expander_peripheral_singleton.switch_touch_events);
    xQueueReset(expander_peripheral_singleton.touch_events);
    xQueueReset(expander_peripheral_singleton.keypad_press_events);
    xQueueReset(expander_peripheral_singleton.keypad_release_events);
}

InputsState InputsController::get_input_state() {
    xSemaphoreTake(expander_peripheral_singleton.state_mutex, portMAX_DELAY);
    InputsState state_copy = expander_peripheral_singleton.state;
    xSemaphoreGive(expander_peripheral_singleton.state_mutex);
    return state_copy;
}

/// Returns `true` iff there is a button press event waiting.
bool InputsController::has_button_press() {
    return uxQueueMessagesWaiting(expander_peripheral_singleton.button_press_events) > 0;
}

/// Gets the next button press event (if any).
std::optional<Button> InputsController::get_button_press() {
    Button b;
    if (xQueueReceive(expander_peripheral_singleton.button_press_events, &b, 0) == pdTRUE) {
        return b;
    }
    return std::nullopt;
}

/// Gets the next button press event, waiting if neccesary.
Button InputsController::wait_button_press() {
    Button b;
    xQueueReceive(expander_peripheral_singleton.button_press_events, &b, portMAX_DELAY);
    return b;
}

/// Gets the current state of the buttons.
uint8_t InputsController::button_state() {
    xSemaphoreTake(expander_peripheral_singleton.state_mutex, portMAX_DELAY);
    uint8_t value = expander_peripheral_singleton.state.button_state;
    xSemaphoreGive(expander_peripheral_singleton.state_mutex);
    return value;
}

/// Returns `true` iff there is a button release event waiting.
bool InputsController::has_button_release() {
    return uxQueueMessagesWaiting(expander_peripheral_singleton.button_release_events) > 0;
}

/// Gets the next button release event (if any).
std::optional<Button> InputsController::get_button_release() {
    Button b;
    if (xQueueReceive(expander_peripheral_singleton.button_release_events, &b, 0) == pdTRUE) {
        return b;
    }
    return std::nullopt;
}

/// Gets the next button release event, waiting if neccesary.
Button InputsController::wait_button_release() {
    Button b;
    xQueueReceive(expander_peripheral_singleton.button_release_events, &b, portMAX_DELAY);
    return b;
}

/// Returns `true` iff there is a switch flip event waiting.
bool InputsController::has_switch_flip() {
    return uxQueueMessagesWaiting(expander_peripheral_singleton.switch_flip_events) > 0;
}

/// Gets the next switch flip event (if any).
std::optional<SwitchFlip> InputsController::get_switch_flip() {
    SwitchFlip s;
    if (xQueueReceive(expander_peripheral_singleton.switch_flip_events, &s, 0) == pdTRUE) {
        return s;
    }
    return std::nullopt;
}

/// Gets the next switch flip event, waiting if neccesary.
SwitchFlip InputsController::wait_switch_flip() {
    SwitchFlip s;
    xQueueReceive(expander_peripheral_singleton.switch_flip_events, &s, portMAX_DELAY);
    return s;
}

/// Gets the current state of the switches.
uint8_t InputsController::switch_state() {
    xSemaphoreTake(expander_peripheral_singleton.state_mutex, portMAX_DELAY);
    uint8_t value = expander_peripheral_singleton.state.switch_state;
    xSemaphoreGive(expander_peripheral_singleton.state_mutex);
    return value;
}

/// Returns `true` iff there is a switch touch event waiting.
bool InputsController::has_switch_touch() {
    return uxQueueMessagesWaiting(expander_peripheral_singleton.switch_touch_events) > 0;
}

/// Gets the next switch touch event (if any).
std::optional<SwitchTouch> InputsController::get_switch_touch() {
    SwitchTouch s;
    if (xQueueReceive(expander_peripheral_singleton.switch_touch_events, &s, 0) == pdTRUE) {
        return s;
    }
    return std::nullopt;
}

/// Gets the next switch touch event, waiting if neccesary.
SwitchTouch InputsController::wait_switch_touch() {
    SwitchTouch s;
    xQueueReceive(expander_peripheral_singleton.switch_touch_events, &s, portMAX_DELAY);
    return s;
}

/// Gets the current state of the touch sensors.
uint8_t InputsController::switch_touch_state() {
    xSemaphoreTake(expander_peripheral_singleton.state_mutex, portMAX_DELAY);
    uint8_t value = expander_peripheral_singleton.state.touch_state;
    xSemaphoreGive(expander_peripheral_singleton.state_mutex);
    return value;
}

/// Returns `true` iff there is a keypad press event waiting.
bool InputsController::has_keypad_press() {
    return uxQueueMessagesWaiting(expander_peripheral_singleton.keypad_press_events) > 0;
}

/// Gets the next keypad press event (if any).
std::optional<KeypadKey> InputsController::get_keypad_press() {
    KeypadKey k;
    if (xQueueReceive(expander_peripheral_singleton.keypad_press_events, &k, 0) == pdTRUE) {
        return k;
    }
    return std::nullopt;
}

/// Gets the next keypad press event, waiting if neccesary.
KeypadKey InputsController::wait_keypad_press() {
    KeypadKey k;
    xQueueReceive(expander_peripheral_singleton.keypad_press_events, &k, portMAX_DELAY);
    return k;
}

/// Returns `true` iff there is a keypad release event waiting.
bool InputsController::has_keypad_release() {
    return uxQueueMessagesWaiting(expander_peripheral_singleton.keypad_release_events) > 0;
}

/// Gets the next keypad release event (if any).
std::optional<KeypadKey> InputsController::get_keypad_release() {
    KeypadKey k;
    if (xQueueReceive(expander_peripheral_singleton.keypad_release_events, &k, 0) == pdTRUE) {
        return k;
    }
    return std::nullopt;
}

/// Gets the next keypad release event, waiting if neccesary.
KeypadKey InputsController::wait_keypad_release() {
    KeypadKey k;
    xQueueReceive(expander_peripheral_singleton.keypad_release_events, &k, portMAX_DELAY);
    return k;
}

/// Gets the current state of the keypad.
uint16_t InputsController::keypad_state() {
    xSemaphoreTake(expander_peripheral_singleton.state_mutex, portMAX_DELAY);
    uint16_t value = expander_peripheral_singleton.state.keypad_state;
    xSemaphoreGive(expander_peripheral_singleton.state_mutex);
    return value;
}