#include <assert.h>
#include <fcntl.h>
#include <stdint.h>
#include <stdio.h>
#include <linux/gpio.h>
#include <sys/ioctl.h>
#include <time.h>

#include "gpio.h"
#include "timespec.h"
#include "ping_pong.h"

#define LAST_PONG_TIMEOUT (PING_INTERVAL * 3)

/*
  17 red (11)
  27 green (13)
  22 blue (15)
*/

/*
  19 switch (35)
  26 switch (37)
 */

#define RED   0b001
#define GREEN 0b010
#define BLUE  0b100

int gpio_open(const char * path,
	      struct gpio_state * gpio_state)
{
  gpio_state->chip_fd = open(path, O_RDWR);
  if (gpio_state->chip_fd == -1) {
    perror("open gpio");
    return -1;
  }

  struct gpio_v2_line_request request_leds = {
    .offsets = { 17, 27, 22 },
    .consumer = "timer-leds",
    .config = {
      .flags = GPIO_V2_LINE_FLAG_OUTPUT,
    },
    .num_lines = 3,
  };
  int ret1 = ioctl(gpio_state->chip_fd, GPIO_V2_GET_LINE_IOCTL, &request_leds);
  if (ret1 == -1) {
    gpio_state->chip_fd = -1;
    perror("GPIO_V2_GET_LINE_IOCTL timer-leds");
    return -1;
  }
  gpio_state->led_request_fd = request_leds.fd;

  struct gpio_v2_line_request request_switch = {
    .offsets = { 19, 26 },
    .consumer = "timer-switch",
    .config = {
      .flags = GPIO_V2_LINE_FLAG_INPUT | GPIO_V2_LINE_FLAG_BIAS_PULL_UP,
    },
    .num_lines = 2,
  };
  int ret2 = ioctl(gpio_state->chip_fd, GPIO_V2_GET_LINE_IOCTL, &request_switch);
  if (ret2 == -1) {
    gpio_state->chip_fd = -1;
    perror("GPIO_V2_GET_LINE_IOCTL timer-switch");
    return -1;
  }
  gpio_state->switch_request_fd = request_switch.fd;

  return 0;
}

void gpio_set_values(struct gpio_state * gpio_state, uint64_t bits)
{
  if (gpio_state->chip_fd == -1) {
    return;
  }

  struct gpio_v2_line_values values = {
    .bits = bits,
    .mask = 0b111,
  };

  int ret = ioctl(gpio_state->led_request_fd, GPIO_V2_LINE_SET_VALUES_IOCTL, &values);
  assert(ret != -1);
}

uint64_t gpio_get_values(struct gpio_state * gpio_state)
{
  if (gpio_state->chip_fd == -1) {
    return 0;
  }

  struct gpio_v2_line_values values = {
    .mask = 0b11,
  };

  int ret = ioctl(gpio_state->switch_request_fd, GPIO_V2_LINE_GET_VALUES_IOCTL, &values);
  assert(ret != -1);

  return (~values.bits) & 0b11;
}

void gpio_set_values_from_link_states(struct gpio_state * gpio_state,
				      struct link_state * link_states,
				      int link_states_length)
{
  struct timespec now;
  int ret = clock_gettime(CLOCK_MONOTONIC_RAW, &now);
  assert(ret != -1);

  int error = 0;

  for (int i = 0; i < link_states_length; i++) {
    struct timespec delta = timespec_sub(&now, &link_states[i].last_pong);
    if (delta.tv_sec >= LAST_PONG_TIMEOUT) {
      printf("[%d] gpio pong timeout %ld\n", i, delta.tv_sec);
      error |= 1 << (i % 2);
    } else {
      printf("[%d] gpio pong ok %ld\n", i, delta.tv_sec);
    }
  }

  if (error == 0) {
    gpio_set_values(gpio_state, GREEN);
  } else {
    int color = 0;
    if (error & 0b01) color |= RED;
    if (error & 0b10) color |= BLUE;
    gpio_set_values(gpio_state, color);
  }
}

/*
int main()
{
  struct gpio_state gpio_state;
  gpio_open("/dev/gpiochip0", &gpio_state);
  set_gpio_values(&gpio_state, 0b000);
}
*/