// File System Library
#include <FS.h>
// SPI Flash Syetem Library
#include <SPIFFS.h>

#include <WiFi.h>
#include <WiFiManager.h> // https://github.com/tzapu/WiFiManager
#include <ArduinoJson.h>

WiFiServer server(80);
// Define WiFiManager Object
WiFiManager wm;

// Flag for saving data
bool shouldSaveConfig = false;
 
// JSON configuration file
#define JSON_CONFIG_FILE "/test_config.json"
// Variables to hold data from custom textboxes
char testString[50] = "test value";
int testNumber = 1234;

// Variable to store the HTTP request
String header;

// Assign output variables to GPIO pins
const int output5 = 25;

#define TRIGGER_PIN 0

void saveConfigFile()
// Save Config in JSON format
{
  Serial.println(F("Saving configuration..."));
  
  // Create a JSON document
  StaticJsonDocument<512> json;
  json["testString"] = testString;
  json["testNumber"] = testNumber;
 
  // Open config file
  File configFile = SPIFFS.open(JSON_CONFIG_FILE, "w");
  if (!configFile)
  {
    // Error, file did not open
    Serial.println("failed to open config file for writing");
  }
 
  // Serialize JSON data to write to file
  serializeJsonPretty(json, Serial);
  if (serializeJson(json, configFile) == 0)
  {
    // Error writing file
    Serial.println(F("Failed to write to file"));
  }
  // Close file
  configFile.close();
}

bool loadConfigFile()
// Load existing configuration file
{
  // Uncomment if we need to format filesystem
  // SPIFFS.format();
 
  // Read configuration from FS json
  Serial.println("Mounting File System...");
 
  // May need to make it begin(true) first time you are using SPIFFS
  if (SPIFFS.begin(false) || SPIFFS.begin(true))
  {
    Serial.println("mounted file system");
    if (SPIFFS.exists(JSON_CONFIG_FILE))
    {
      // The file exists, reading and loading
      Serial.println("reading config file");
      File configFile = SPIFFS.open(JSON_CONFIG_FILE, "r");
      if (configFile)
      {
        Serial.println("Opened configuration file");
        StaticJsonDocument<512> json;
        DeserializationError error = deserializeJson(json, configFile);
        serializeJsonPretty(json, Serial);
        if (!error)
        {
          Serial.println("Parsing JSON");
 
          strcpy(testString, json["testString"]);
          testNumber = json["testNumber"].as<int>();
 
          return true;
        }
        else
        {
          // Error loading JSON data
          Serial.println("Failed to load json config");
        }
      }
    }
  }
  else
  {
    // Error mounting file system
    Serial.println("Failed to mount FS");
  }
 
  return false;
}

void saveConfigCallback()
// Callback notifying us of the need to save configuration
{
  Serial.println("Should save config");
  shouldSaveConfig = true;
}
 
void configModeCallback(WiFiManager *myWiFiManager)
// Called when config mode launched
{
  Serial.println("Entered Configuration Mode");
 
  Serial.print("Config SSID: ");
  Serial.println(myWiFiManager->getConfigPortalSSID());
 
  Serial.print("Config IP Address: ");
  Serial.println(WiFi.softAPIP());
}

void setup()
{
    // Change to true when testing to force configuration every time we run
  bool forceConfig = false;
 
  bool spiffsSetup = loadConfigFile();
  if (!spiffsSetup)
  {
    Serial.println(F("Forcing config mode as there is no saved config"));
    forceConfig = true;
  }

  pinMode(TRIGGER_PIN, INPUT);    
  
  WiFi.mode(WIFI_STA); // explicitly set mode, esp defaults to STA+AP

   // Setup Serial monitor
  Serial.begin(115200);
  delay(10);


 // Reset settings (only for development)
  //wm.resetSettings();
 
  // Set config save notify callback
  wm.setSaveConfigCallback(saveConfigCallback);
 
  // Set callback that gets called when connecting to previous WiFi fails, and enters Access Point mode
  wm.setAPCallback(configModeCallback);
 
  // Custom elements
 
  // Text box (String) - 50 characters maximum
  WiFiManagerParameter custom_text_box("key_text", "Enter your string here", testString, 50);
  
  // Need to convert numerical input to string to display the default value.
  char convertedValue[6];
  sprintf(convertedValue, "%d", testNumber); 
  
  // Text box (Number) - 7 characters maximum
  WiFiManagerParameter custom_text_box_num("key_num", "Enter your number here", convertedValue, 7); 
 
  // Add all defined parameters
  wm.addParameter(&custom_text_box);
  wm.addParameter(&custom_text_box_num);
 
  if (forceConfig)
    // Run if we need a configuration
  {
    if (!wm.startConfigPortal("NEWTEST_AP", "password"))
    {
      Serial.println("failed to connect and hit timeout");
      delay(3000);
      //reset and try again, or maybe put it to deep sleep
      ESP.restart();
      delay(5000);
    }
  }
  else
  {
    if (!wm.autoConnect("NEWTEST_AP"))
    {
      Serial.println("failed to connect and hit timeout");
      delay(3000);
      // if we still have not connected restart and try all over again
      ESP.restart();
      delay(5000);
    }
  }
 
  // If we get here, we are connected to the WiFi
 
  Serial.println("");
  Serial.println("WiFi connected");
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());
 
  // Lets deal with the user config values
 
  // Copy the string value
  strncpy(testString, custom_text_box.getValue(), sizeof(testString));
  Serial.print("testString: ");
  Serial.println(testString);
 
  //Convert the number value
  testNumber = atoi(custom_text_box_num.getValue());
  Serial.print("testNumber: ");
  Serial.println(testNumber);
 
 
  // Save the custom parameters to FS
  if (shouldSaveConfig)
  {
    saveConfigFile();
  }
  server.begin();
}

void loop()
{
  WiFiClient client = server.available(); // Listen for incoming clients

  if (client)
  {                                // If a new client connects,
    Serial.println("New Client."); // print a message out in the serial port
    String currentLine = "";       // make a String to hold incoming data from the client
    while (client.connected())
    { // loop while the client's connected
      if (client.available())
      {                         // if there's bytes to read from the client,
        char c = client.read(); // read a byte, then
        Serial.write(c);        // print it out the serial monitor
        header += c;
        if (c == '\n')
        { // if the byte is a newline character
          // if the current line is blank, you got two newline characters in a row.
          // that's the end of the client HTTP request, so send a response:
          if (currentLine.length() == 0)
          {
            // HTTP headers always start with a response code (e.g. HTTP/1.1 200 OK)
            // and a content-type so the client knows what's coming, then a blank line:
            client.println("HTTP/1.1 200 OK");
            client.println("Content-type:text/html");
            client.println("Connection: close");
            client.println();


            // Display the HTML web page
            client.println("<!DOCTYPE html><html>");
            client.println("<head><meta name=\"viewport\" content=\"width=device-width, initial-scale=1\">");
            client.println("<link rel=\"icon\" href=\"data:,\">");
            // CSS to style the on/off buttons
            // Feel free to change the background-color and font-size attributes to fit your preferences
            client.println("<style>html { font-family: Helvetica; display: inline-block; margin: 0px auto; text-align: center;}");
            client.println(".button { background-color: #195B6A; border: none; color: white; padding: 16px 40px;");
            client.println("text-decoration: none; font-size: 30px; margin: 2px; cursor: pointer;}");
            client.println(".button2 {background-color: #77878A;}</style></head>");

            // Web Page Heading
            client.println("<body><h1>ESP8266 Web Server</h1>");

            // Display current state, and ON/OFF buttons for GPIO 5
            // If the output5State is off, it displays the ON button
            client.println("</body></html>");

            // The HTTP response ends with another blank line
            client.println();
            // Break out of the while loop
            break;
          }
          else
          { // if you got a newline, then clear currentLine
            currentLine = "";
          }
        }
        else if (c != '\r')
        {                   // if you got anything else but a carriage return character,
          currentLine += c; // add it to the end of the currentLine
        }
      }
    }
    // Clear the header variable
    header = "";
    // Close the connection
    client.stop();
    Serial.println("Client disconnected.");
    Serial.println("");
  }
}