/*******************************************************************************
 * @file    led_control.c
 * @brief   LED direct control driver
 *
 * k_timer based 2-color LED (green/orange) pattern control
 * Simple on/off states use immediate GPIO, complex patterns use state machine
 ******************************************************************************/
#include <zephyr/kernel.h>
#include <zephyr/drivers/gpio.h>
#include <zephyr/devicetree.h>
#include "led_control.h"
#include "debug_print.h"

/* Devicetree LED specs */
#define LED_BLE_NODE      DT_NODELABEL(led_ble)
#define FUNCTION_LED_NODE DT_NODELABEL(function_led)

static const struct gpio_dt_spec led_ble      = GPIO_DT_SPEC_GET(LED_BLE_NODE, gpios);
static const struct gpio_dt_spec function_led = GPIO_DT_SPEC_GET(FUNCTION_LED_NODE, gpios);

/* Color constants */
#define COLOR_NONE      0
#define COLOR_GREEN     1
#define COLOR_ORANGE    2

/* Error pattern constants (State 7) */
#define ERROR_BLINK_ON_MS       166
#define ERROR_BLINK_OFF_MS      166
#define ERROR_BLINK_COUNT       3
#define ERROR_PAUSE_MS          1000

/* Pattern table */
typedef struct {
    uint32_t on_ms;
    uint32_t off_ms;
    uint8_t  color;
    bool     repeat;
} led_pattern_t;

static const led_pattern_t m_patterns[LED_STATE_COUNT] = {
    [LED_STATE_OFF]              = { 0,    0,    COLOR_NONE,   false },
    [LED_STATE_POWER_ON]         = { 2000, 0,    COLOR_GREEN,  false },
    [LED_STATE_POWER_OFF]        = { 2000, 0,    COLOR_GREEN,  false },
    [LED_STATE_ADVERTISING]      = { 500,  500,  COLOR_GREEN,  true  },
    [LED_STATE_DETACH_WARNING]   = { 1000, 3000, COLOR_GREEN,  true  },
    [LED_STATE_ALIGN_SEARCHING]  = { 1000, 1000, COLOR_ORANGE, true  },
    [LED_STATE_ALIGN_COMPLETE]   = { 0,    0,    COLOR_GREEN,  false },
    [LED_STATE_ERROR]            = { 0,    0,    COLOR_ORANGE, true  },
};

/* Module variables */
static struct k_timer m_led_timer;

static led_state_t m_current_state = LED_STATE_OFF;
static bool        m_phase_on;

/* Error pattern state machine */
static uint8_t m_error_blink_cnt;
static uint8_t m_error_phase;

/* GPIO helpers */
static inline void led_ble_on(void)  { gpio_pin_set_dt(&led_ble, 1); }
static inline void led_ble_off(void) { gpio_pin_set_dt(&led_ble, 0); }
static inline void function_led_on(void)  { gpio_pin_set_dt(&function_led, 1); }
static inline void function_led_off(void) { gpio_pin_set_dt(&function_led, 0); }

static void led_all_off(void)
{
    led_ble_off();
    function_led_off();
}

static void led_color_on(uint8_t color)
{
    led_all_off();
    if (color == COLOR_GREEN)       led_ble_on();
    else if (color == COLOR_ORANGE) function_led_on();
}

/* Timer helper */
static void timer_start_ms(uint32_t ms)
{
    if (ms == 0) return;
    k_timer_start(&m_led_timer, K_MSEC(ms), K_NO_WAIT);
}

/* Error pattern state machine */
static void error_pattern_start(void)
{
    m_error_blink_cnt = 0;
    m_error_phase = 0;
    led_color_on(COLOR_ORANGE);
    timer_start_ms(ERROR_BLINK_ON_MS);
}

static void error_pattern_tick(void)
{
    switch (m_error_phase)
    {
        case 0: // ON period done -> OFF
            led_all_off();
            m_error_phase = 1;
            timer_start_ms(ERROR_BLINK_OFF_MS);
            break;
        case 1: // OFF period done
            m_error_blink_cnt++;
            if (m_error_blink_cnt < ERROR_BLINK_COUNT) {
                m_error_phase = 0;
                led_color_on(COLOR_ORANGE);
                timer_start_ms(ERROR_BLINK_ON_MS);
            } else {
                m_error_phase = 2;
                timer_start_ms(ERROR_PAUSE_MS);
            }
            break;
        case 2: // Pause done -> restart
            m_error_blink_cnt = 0;
            m_error_phase = 0;
            led_color_on(COLOR_ORANGE);
            timer_start_ms(ERROR_BLINK_ON_MS);
            break;
        default:
            break;
    }
}

/* Timer callback */
static void led_timer_handler(struct k_timer *timer)
{
    ARG_UNUSED(timer);

    if (m_current_state == LED_STATE_ERROR)
    {
        error_pattern_tick();
        return;
    }

    const led_pattern_t *p = &m_patterns[m_current_state];

    if (m_phase_on)
    {
        // ON -> OFF transition
        led_all_off();
        m_phase_on = false;

        if (p->off_ms > 0)
        {
            timer_start_ms(p->off_ms);
        }
        else if (!p->repeat)
        {
            if (m_current_state == LED_STATE_POWER_OFF) {
                led_all_off();
                m_current_state = LED_STATE_OFF;
            }
            // POWER_ON: stays lit, no timer
        }
    }
    else
    {
        // OFF -> ON transition
        if (p->repeat)
        {
            led_color_on(p->color);
            m_phase_on = true;
            timer_start_ms(p->on_ms);
        }
    }
}

/* Public functions */
void led_init(void)
{
    gpio_pin_configure_dt(&led_ble, GPIO_OUTPUT_INACTIVE);
    gpio_pin_configure_dt(&function_led, GPIO_OUTPUT_INACTIVE);
    led_all_off();

    k_timer_init(&m_led_timer, led_timer_handler, NULL);

    m_current_state = LED_STATE_OFF;
}

void led_set_state(led_state_t state)
{
    if (state >= LED_STATE_COUNT) return;


    k_timer_stop(&m_led_timer);
    led_all_off();

    m_current_state = state;
    m_phase_on = false;

    const led_pattern_t *p = &m_patterns[state];

    switch (state) {
    case LED_STATE_OFF:
        break;
    case LED_STATE_ERROR:
        error_pattern_start();
        break;
    default:
        led_color_on(p->color);
        m_phase_on = true;

        if (p->on_ms > 0)
        {
            timer_start_ms(p->on_ms);
        }
        break;
    }
}

led_state_t led_get_state(void)
{
    return m_current_state;
}

void led_ble_solid(void)
{
    k_timer_stop(&m_led_timer);
    led_all_off();
    led_ble_on();
    m_current_state = LED_STATE_OFF;  // no pattern running
}