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/*
* Usurpation – wearable device main logic
*
* Copyright (C) 2019 Gediminas Jakutis
* Copyright (C) 2019 Ramūnas Mažeikis
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; version 2.1
* of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
*/
#include <ESP8266WiFi.h>
#include <WiFiUdp.h>
#include <stdlib.h>
#include <stddef.h>
static char udppacketbuffer[32] = {0};
static char *udppacketcursor = NULL;
static const unsigned int internal_led = 2;
static unsigned int led_state = 0;
static const char servermagic[] = "I love coffee!";
static const char clientmagic[] = "I love tea!";
IPAddress ip;
WiFiUDP Udp;
unsigned int toggle_led(const int ip);
static void discover_client(void);
static int wifi_connect(const char * const ssid, const char * const password, const char doblink, const int ledpin);
static void discover_client(void);
static void udp_init_packet(IPAddress ip, const int port);
static void udp_push(const void * const data, const size_t size);
static int udp_flush(void);
static void blink_led(const int pin, const int ontime, const int offtime);
void setup(void)
{
extern const char * const ssid;
extern const char * const password;
pinMode(internal_led, OUTPUT);
toggle_led(internal_led);
wifi_connect(ssid, password, 1, internal_led);
discover_client();
}
/* the logic is a placeholder right now */
void loop(void)
{
/* sleep length to use */
static unsigned int delta = 2000;
delay(delta);
udp_init_packet(ip, 6996);
Udp.begin(6996);
udp_push(clientmagic, sizeof(clientmagic));
}
/* toggle the bult-in led and return current state */
unsigned int toggle_led(const int pin)
{
led_state = !led_state;
/* as the cathode of the builtin diode is connected to the MCU's pin,
* while the anode is connected to Vcc, to turn it off, we need to set
* the pin to HIGH.
*/
digitalWrite(pin, led_state ? LOW : HIGH);
return led_state;
}
static int wifi_connect(const char * const ssid, const char * const password, const char doblink, const int ledpin)
{
size_t i = 30;
WiFi.forceSleepWake();
yield();
WiFi.persistent(0);
WiFi.mode(WIFI_STA);
WiFi.begin(ssid, password);
do {
if (doblink) {
blink_led(ledpin, 250, 250);
} else {
delay (500);
}
} while (WiFi.status() != WL_CONNECTED);
return 0;
}
static void discover_client(void)
{
IPAddress bcastip(255, 255, 255, 255);
static const char servermagic[] = "I love coffee!";
static const char clientmagic[] = "I love tea!";
char buffer[32] = {0};
size_t done = 0;
do {
udp_init_packet(bcastip, 6996);
udp_push(servermagic, sizeof(servermagic));
udp_flush();
delay(5);
while (Udp.parsePacket()) {
if (Udp.available() >= sizeof(clientmagic)) {
Udp.read(buffer, sizeof(clientmagic));
if (!(strcmp(clientmagic, buffer))) {
ip = Udp.remoteIP();
++done;
}
}
}
delay(95);
} while (!done);
}
static void udp_init_packet(IPAddress ip, const int port)
{
Udp.beginPacket(ip, port);
memset(udppacketbuffer, 0, sizeof(udppacketbuffer));
udppacketcursor = udppacketbuffer;
}
static void udp_push(const void * const data, const size_t size)
{
memcpy(udppacketcursor, data, size);
udppacketcursor += size;
}
static int udp_flush(void)
{
Udp.write((const uint8_t *) udppacketbuffer, udppacketcursor - udppacketbuffer);
return Udp.endPacket();
}
static void blink_led(const int pin, const int ontime, const int offtime)
{
toggle_led(pin);
delay(ontime);
toggle_led(pin);
delay(offtime);
}
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