#include "gpio.h"

#include <stdbool.h>

#include "ch32v003fun.h"
#include "systick.h"

#define LED_BLINK_SLOW 1000     // Warning blink interval (ms)
#define LED_BLINK_FAST 500      // Error blink interval (ms)
#define LED_BREATH_PERIOD 2000  // Breathing effect period (ms)
#define STATE_STABILITY 500     // Minimum time before state change (ms)

#define LED_G (1 << 4)
#define LED_B (1 << 3)

typedef struct {
  uint32_t last_update;
  uint32_t stable_since;
  led_state_t current_state;
  led_state_t target_state;
  uint8_t blink_state;
  uint32_t last_blink;
} led_status_t;

static led_status_t led_status = {0};

void gpio_init(void) {
  // Enable clock for GPIOB
  RCC->APB2PCENR |= RCC_APB2Periph_GPIOB;

  // GPIOB: Pins 3 and 4 as Output, Push-Pull, 10MHz
  GPIOB->CFGLR &= ~((0xF << (4 * 3)) | (0xF << (4 * 4)));
  GPIOB->CFGLR |= ((GPIO_Speed_10MHz | GPIO_CNF_OUT_PP) << (4 * 3)) |
                  ((GPIO_Speed_10MHz | GPIO_CNF_OUT_PP) << (4 * 4));

  // GPIOB: Pin 9 as Output, Push-Pull, 10MHz
  GPIOB->CFGHR &= ~(0xF << (4 * (9 - 8)));
  GPIOB->CFGHR |= (GPIO_Speed_10MHz | GPIO_CNF_OUT_PP) << (4 * (9 - 8));

  led_status.current_state = LED_STATE_OFF;
  led_status.target_state = LED_STATE_OFF;

  GPIOB->BSHR = LED_G | LED_B;
}

void led_status_set(led_state_t state) {
  uint32_t now = millis();

  // stability timer upd on state change
  if (led_status.target_state != state) {
    led_status.stable_since = now;
    led_status.target_state = state;
  }
}

static inline void leds(bool g, bool b) {
  uint32_t val = (g ? LED_G << 16 : LED_G) | (b ? LED_B << 16 : LED_B);
  GPIOB->BSHR = val;
}

void led_status_process(void) {
  uint32_t now = millis();

  if (now - led_status.stable_since < STATE_STABILITY) {
    return;
  }

  switch (led_status.target_state) {
    case LED_STATE_OFF:
      GPIOB->BSHR = LED_G | LED_B;
      break;

    case LED_STATE_ON:
      leds(1, 0);  // green on, blue off
      break;

    case LED_STATE_WARNING:
      if (now - led_status.last_blink >= LED_BLINK_SLOW) {
        led_status.blink_state = !led_status.blink_state;
        led_status.last_blink = now;
        leds(led_status.blink_state, 0);
      }
      break;

    case LED_STATE_ERROR:
      if (now - led_status.last_blink >= LED_BLINK_FAST) {
        led_status.blink_state = !led_status.blink_state;
        led_status.last_blink = now;
        leds(led_status.blink_state, !led_status.blink_state);
      }
      break;

    case LED_STATE_BUSY:
      bool blue_on = (now % LED_BREATH_PERIOD) < LED_BREATH_PERIOD / 2;
      leds(0, blue_on);
      break;
  }
}