/*
** Demo of memory depletion during
** ESP8266WebServer responses,  based on 
** ESP8266WebServer->HelloServer example.
** Pat Deegan, 2015
** 
** Repeated GETs to /inline will show 
** memory depletion on Serial, starting with
** Resp #1
** Free heap: 33728 @ 18s.
** Free heap: 33768 @ 18s.
** Free heap: 33896 @ 18s.
** Free heap: 33528 @ 18s.
** Resp #2
** Free heap: 33536 @ 18s.
** Free heap: 33576 @ 18s.
** Free heap: 33704 @ 18s.
** Free heap: 33336 @ 19s.
** ...
** and finally, after 50 requests
**
** Resp #48
** Free heap: 24704 @ 33s.
** Free heap: 24744 @ 33s.
** Free heap: 24872 @ 33s.
** Free heap: 24504 @ 33s.
** Resp #49
** Free heap: 24512 @ 33s.
** Free heap: 24552 @ 33s.
** Free heap: 24680 @ 33s.
** ...
** after 1 minute or so from the first request,
** memory will start returning to the heap
** without intervention in blocks of 192 bytes:
** 
** Free heap: 24872 @ 79s.
** Free heap: 25064 @ 79s.
** Free heap: 25256 @ 79s.
** Free heap: 25448 @ 79s.
** ... all the way to
** Free heap: 33896 @ 93s.
** Free heap: 34088 @ 93s.
** Free heap: 34312 @ 93s.
*/

#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <ESP8266WebServer.h>
#include <ESP8266mDNS.h>

const char* ssid = "........"
const char* password = "........";

ESP8266WebServer server(80);
uint32_t lastFreeHeap = 0;

const int led = 13;

void showFreeHeap()
{
   uint32_t freeNow = ESP.getFreeHeap();
   if (freeNow != lastFreeHeap)
   {
     lastFreeHeap = freeNow;
     Serial.print("Free heap: ");
     Serial.print(freeNow);
     Serial.print(" @ " );
     Serial.print(millis()/1000);
     Serial.println("s.");
     
   }
}

void handleRoot() {
  digitalWrite(led, 1);
  server.send(200, "text/plain", "hello from esp8266!");
  digitalWrite(led, 0);
}

void handleNotFound(){
  digitalWrite(led, 1);
  String message = "File Not Found\n\n";
  message += "URI: ";
  message += server.uri();
  message += "\nMethod: ";
  message += (server.method() == HTTP_GET)?"GET":"POST";
  message += "\nArguments: ";
  message += server.args();
  message += "\n";
  for (uint8_t i=0; i<server.args(); i++){
    message += " " + server.argName(i) + ": " + server.arg(i) + "\n";
  }
  server.send(404, "text/plain", message);
  digitalWrite(led, 0);
}

#define RESP_SIZE 3500
char ho[RESP_SIZE + 1];

uint16_t respNumber = 0;
void setup(void){


    memset(ho, 'h', RESP_SIZE);
    ho[RESP_SIZE] = 0;
  
  pinMode(led, OUTPUT);
  digitalWrite(led, 0);
  Serial.begin(115200);
  WiFi.begin(ssid, password);
  Serial.println("");

  Serial.println(WiFi.localIP());
  // Wait for connection
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.print("Connected to ");
  Serial.println(ssid);
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());

  if (MDNS.begin("esp8266")) {
    Serial.println("MDNS responder started");
  }

  server.on("/", handleRoot);

  server.on("/inline", [](){

    Serial.print("Resp #");
    Serial.println(respNumber++);
    
    server.send(200, "text/plain", "");
    server.sendContent(ho);
  });

  server.onNotFound(handleNotFound);

  server.begin();
  Serial.println("HTTP server started");
}

void loop(void){
  server.handleClient();
  
  showFreeHeap();
}