board/main/desktop.c

#include <lwip/netdb.h>
#include <string.h>
#include <sys/param.h>

#include "esp_err.h"
#include "esp_event.h"
#include "esp_log.h"
#include "esp_netif.h"
#include "esp_system.h"
#include "esp_wifi.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "gui.c"
#include "light.c"
#include "lwip/err.h"
#include "lwip/sockets.h"
#include "lwip/sys.h"
#include "nvs_flash.h"
#include "ui_input.c"

#define UDP_PORT 23042

static const char *UDP_SERVER_TAG = "UDP_SERVER";

static bool desktop_connected = false;
static uint64_t last_desktop_ping_at = 0;
static struct sockaddr *desktop_addr = NULL;

static int sock = -1;
static uint8_t tx_buffer[128];

typedef struct desktop_value {
  uint8_t value;
  uint8_t max;
  uint8_t min;
} desktop_value_t;

static desktop_value_t display1_brightness = {
    .value = 20,
    .max = 100,
    .min = 0,
};
static desktop_value_t display2_brightness = {
    .value = 20,
    .max = 100,
    .min = 0,
};
static desktop_value_t computer_volume = {
    .value = 20,
    .max = 100,
    .min = 0,
};

static void udp_server_task(void *pvParameters) {
  char rx_buffer[1024];
  char addr_str[128];
  int addr_family = (int)pvParameters;
  int ip_protocol = 0;
  struct sockaddr_in dest_addr;

  while (1) {
    dest_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    dest_addr.sin_family = AF_INET;
    dest_addr.sin_port = htons(UDP_PORT);
    ip_protocol = IPPROTO_IP;

    sock = socket(addr_family, SOCK_DGRAM, ip_protocol);
    if (sock < 0) {
      ESP_LOGE(UDP_SERVER_TAG, "Unable to create socket: errno %d. sock: %d",
               errno, sock);
      break;
    }
    ESP_LOGI(UDP_SERVER_TAG, "Socket created");

    // Set timeout
    struct timeval timeout;
    timeout.tv_sec = 10;
    timeout.tv_usec = 0;
    setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof timeout);

    int err = bind(sock, (struct sockaddr *)&dest_addr, sizeof(dest_addr));
    if (err < 0) {
      ESP_LOGE(UDP_SERVER_TAG, "Socket unable to bind: errno %d. sock: %d",
               errno, sock);
      sock = -1;
      vTaskDelay(1000 / portTICK_PERIOD_MS);
      continue;
    }
    ESP_LOGI(UDP_SERVER_TAG, "Socket bound, port %d", UDP_PORT);

    struct sockaddr source_addr;  // Large enough for both IPv4 or IPv6
    socklen_t socklen = sizeof(source_addr);

    while (1) {
      // ESP_LOGI(UDP_SERVER_TAG, "Waiting for data");
      int len = recvfrom(sock, rx_buffer, sizeof(rx_buffer) - 1, 0,
                         &source_addr, &socklen);
      // Error occurred during receiving
      if (len < 0) {
        if (errno == EAGAIN) {
          continue;
        }
        ESP_LOGE(UDP_SERVER_TAG, "recvfrom failed: errno %d. len: %d", errno,
                 len);
      }
      // Data received
      else {
        // Get the sender's ip address as string
        inet_ntoa_r(((struct sockaddr_in *)&source_addr)->sin_addr, addr_str,
                    sizeof(addr_str) - 1);

        rx_buffer[len] = 0;  // Null-terminate whatever we received and treat
                             // like a string...

        switch (rx_buffer[0]) {
          case 1:
            last_desktop_ping_at = esp_timer_get_time();
            ESP_LOGD(UDP_SERVER_TAG, "Received ping from %s", addr_str);
            sendto(sock, rx_buffer, 1, 0, &source_addr, sizeof(source_addr));
            desktop_addr = &source_addr;
            break;

          case 2:
            set_display_ambient_light_colors(
                ((uint16_t)rx_buffer[1] << 8 | (uint16_t)rx_buffer[2]),
                (uint8_t *)&(rx_buffer[3]), len - 3);
            break;

          default:

            ESP_LOGI(UDP_SERVER_TAG, "%s", rx_buffer);
            break;
        }
        ESP_LOGD(UDP_SERVER_TAG, "Received %d bytes from %s:", len, addr_str);
      }

      if (sock != -1 && len < 0) {
        ESP_LOGE(UDP_SERVER_TAG, "Shutting down socket and restarting...");
        shutdown(sock, 0);
        close(sock);
        break;
      }
    }
  }
  vTaskDelete(NULL);
}

static uint8_t desktop_change_value(desktop_value_t *target, int8_t delta) {
  if (delta > 0) {
    if ((target->max - target->value) > delta) {
      target->value += delta;
    } else {
      target->value = target->max;
    }
  } else {
    if ((target->value - target->min) > -delta) {
      target->value += delta;
    } else {
      target->value = target->min;
    }
  }
  return target->value;
}

static uint8_t change_display_brightness(uint8_t display_index, int8_t delta) {
  if (desktop_addr == NULL) {
    ESP_LOGW(UDP_SERVER_TAG, "No desktop connected");
    return 0;
  }

  switch (display_index) {
    case 0: {
      uint8_t value = desktop_change_value(&display1_brightness, delta);

      tx_buffer[0] = 3;
      tx_buffer[1] = 0;
      tx_buffer[2] = value;
      int err =
          sendto(sock, tx_buffer, 3, 0, desktop_addr, sizeof(*desktop_addr));
      if (err < 0) {
        ESP_LOGE(UDP_SERVER_TAG, "Socket unable to send: errno %d. sock: %d",
                 errno, sock);
      }

      gui_change_display_brightness(display_index, value);
      return value;
    }

    case 1: {
      uint8_t value = desktop_change_value(&display1_brightness, delta);

      tx_buffer[0] = 3;
      tx_buffer[1] = 1;
      tx_buffer[2] = value;
      int err =
          sendto(sock, tx_buffer, 3, 0, desktop_addr, sizeof(*desktop_addr));
      if (err < 0) {
        ESP_LOGE(UDP_SERVER_TAG, "Socket unable to send: errno %d. sock: %d",
                 errno, sock);
      }

      gui_change_display_brightness(display_index, value);
      return value;
    }

    default:
      ESP_LOGE(UDP_SERVER_TAG, "Invalid display index: %d", display_index);
      return 0;
  }
}
static uint8_t change_volume(int8_t delta) {
  if (desktop_addr == NULL) {
    ESP_LOGW(UDP_SERVER_TAG, "No desktop connected");
    return 0;
  }

  uint8_t value = desktop_change_value(&computer_volume, delta);

  tx_buffer[0] = 4;
  tx_buffer[1] = value;
  int err = sendto(sock, tx_buffer, 2, 0, desktop_addr, sizeof(*desktop_addr));
  if (err < 0) {
    char addr_str[128];
    inet_ntoa_r(((struct sockaddr_in *)desktop_addr)->sin_addr, addr_str,
                sizeof(addr_str) - 1);
    ESP_LOGI(UDP_SERVER_TAG, "addr: %s", addr_str);
    ESP_LOGE(UDP_SERVER_TAG, "Socket unable to send: errno %d. sock: %d", errno,
             sock);
  }

  gui_change_volume_level(value);
  return value;
}

static void desktop_watch_input_task(void *arg) {
  s_ui_input_t input;
  for (;;) {
    if (xQueueReceive(ui_input_event, &input, portMAX_DELAY)) {
      switch (input.key) {
        case ui_input_key_display_0_brightness:
          change_display_brightness(0, input.value);
          break;

        case ui_input_key_display_1_brightness:
          change_display_brightness(1, input.value);
          break;

        case ui_input_key_computer_volume:
          change_volume(input.value);
          break;

        default:
          break;
      }
    }
  }
}

static void change_desktop_connection_status(bool connected) {
  desktop_connected = connected;
  if (connected) {
    gui_set_server_connected();
  } else {
    gui_set_server_disconnected();
  }
}

static void desktop_online_check_task(void *pvParameters) {
  while (1) {
    if (esp_timer_get_time() - last_desktop_ping_at > 5000000) {  // 2 seconds
      change_desktop_connection_status(false);
    } else {
      change_desktop_connection_status(true);
    }
    vTaskDelay(1000 / portTICK_PERIOD_MS);
  }
}

void udp_server_init(void) {
  xTaskCreate(udp_server_task, "udp_server", 4096, (void *)AF_INET, 5, NULL);
  xTaskCreate(desktop_online_check_task, "desktop_online_check", 1024, NULL, 10,
              NULL);
  xTaskCreate(desktop_watch_input_task, "desktop_watch_input", 4096, NULL, 7,
              NULL);
}