#include "webinterface.h"
#include <Arduino.h>
#include <Preferences.h>
#include <Update.h>
#include <WebServer.h>
#include <WiFi.h>

namespace
{
constexpr char default_access_point_password[] = "telemetry";
constexpr char settings_namespace[] = "telemetry";
constexpr char default_callsign[] = "D1234";
constexpr int default_min_speed = 80;
constexpr int default_max_speed = 150;
constexpr unsigned int default_active_time_seconds = 90;

String default_access_point_name()
{
#ifdef DEVICE_SAILPLANE
  return String("Sailplane-") + default_callsign;
#else
  return "Winde-Telemetry";
#endif
}

WebServer server(80);
Preferences preferences;
TelemetrySettings *active_settings = nullptr;
bool restart_after_update = false;
bool update_failed = false;
bool access_point_restart_pending = false;

String html_escape(const String &value)
{
  String escaped = value;
  escaped.replace("&", "&amp;");
  escaped.replace("<", "&lt;");
  escaped.replace(">", "&gt;");
  escaped.replace("\"", "&quot;");
  escaped.replace("'", "&#39;");
  return escaped;
}

void send_page(const String &message = String())
{
  String page;
  page.reserve(2600);
  page += F("<!doctype html><html lang='de'><head><meta charset='utf-8'>"
            "<meta name='viewport' content='width=device-width,initial-scale=1'>"
            "<title>Winden-Telemetry</title><style>"
            "body{font-family:sans-serif;max-width:38rem;margin:2rem auto;padding:0 1rem}"
            "label{display:block;margin-top:1rem}input{box-sizing:border-box;width:100%;padding:.6rem;font-size:1rem}"
            "button{margin-top:1rem;padding:.65rem 1rem;font-size:1rem}"
            ".msg{padding:.6rem;background:#e5f4e8}small{color:#555}"
            "</style></head><body><h1>Winden-Telemetry</h1>");
  if (message.length() > 0)
  {
    page += F("<p class='msg'>");
    page += html_escape(message);
    page += F("</p>");
  }
  page += F("<form method='post' action='/settings'>"
            "<label>WLAN-Name<input name='ap_name' maxlength='32' required value='");
  page += html_escape(active_settings->access_point_name);
  page += F("'></label><label>WLAN-Passwort<input name='ap_password' type='password' minlength='8' maxlength='63' required value='");
  page += html_escape(active_settings->access_point_password);
  page += F("'></label><label>Callsign<input name='callsign' maxlength='16' required value='");
  page += html_escape(active_settings->callsign);
  page += F("'></label><label>Min Speed (km/h)<input name='min' type='number' min='0' max='300' required value='");
  page += String(active_settings->min_speed);
  page += F("'></label><label>Max Speed (km/h)<input name='max' type='number' min='1' max='300' required value='");
  page += String(active_settings->max_speed);
  page += F("'></label><label>Uebertragungszeit (Sekunden)<input name='active_time' type='number' min='1' max='600' required value='");
  page += String(active_settings->active_time_seconds);
  page += F("'></label><button type='submit'>Speichern</button></form>"
            "<h2>Firmware aktualisieren</h2><form method='post' action='/update' enctype='multipart/form-data'>"
            "<input name='firmware' type='file' accept='.bin' required><button type='submit'>Upload starten</button>"
            "</form><p><small>Access Point: ");
  page += html_escape(active_settings->access_point_name);
  page += F("</small></p></body></html>");
  server.send(200, "text/html; charset=utf-8", page);
}

bool parse_settings(TelemetrySettings &settings)
{
  String callsign = server.arg("callsign");
  String access_point_name = server.arg("ap_name");
  String access_point_password = server.arg("ap_password");
  int min_speed = server.arg("min").toInt();
  int max_speed = server.arg("max").toInt();
  int active_time_seconds = server.arg("active_time").toInt();
  callsign.trim();
  access_point_name.trim();
  access_point_password.trim();
  if (access_point_name.length() == 0 || access_point_name.length() > 32 || access_point_password.length() < 8 || access_point_password.length() > 63 || callsign.length() == 0 || callsign.length() > 16 || min_speed < 0 || max_speed > 300 ||
      min_speed >= max_speed || active_time_seconds < 1 || active_time_seconds > 600)
    return false;

  settings.callsign = callsign;
  settings.access_point_name = access_point_name;
  settings.access_point_password = access_point_password;
  settings.min_speed = min_speed;
  settings.max_speed = max_speed;
  settings.active_time_seconds = active_time_seconds;
  return true;
}

void handle_root()
{
  send_page();
}

void handle_settings()
{
  TelemetrySettings updated = *active_settings;
  if (!parse_settings(updated))
  {
    server.send(400, "text/plain; charset=utf-8", "Ungueltige Einstellungen");
    return;
  }

  active_settings->callsign = updated.callsign;
  active_settings->access_point_name = updated.access_point_name;
  active_settings->access_point_password = updated.access_point_password;
  active_settings->min_speed = updated.min_speed;
  active_settings->max_speed = updated.max_speed;
  active_settings->active_time_seconds = updated.active_time_seconds;
  preferences.putString("callsign", active_settings->callsign);
  preferences.putString("ap_name", active_settings->access_point_name);
  preferences.putString("ap_password", active_settings->access_point_password);
  preferences.putInt("min", active_settings->min_speed);
  preferences.putInt("max", active_settings->max_speed);
  preferences.putUInt("active_time", active_settings->active_time_seconds);
  send_page("Einstellungen gespeichert.");
  access_point_restart_pending = true;
}

void handle_update_upload()
{
  HTTPUpload &upload = server.upload();
  if (upload.status == UPLOAD_FILE_START)
  {
    restart_after_update = false;
    update_failed = false;
    Serial.printf("Firmware-Upload: %s\n", upload.filename.c_str());
    if (!Update.begin(UPDATE_SIZE_UNKNOWN))
    {
      update_failed = true;
      Update.printError(Serial);
    }
  }
  else if (upload.status == UPLOAD_FILE_WRITE)
  {
    if (Update.write(upload.buf, upload.currentSize) != upload.currentSize)
    {
      update_failed = true;
      Update.printError(Serial);
    }
  }
  else if (upload.status == UPLOAD_FILE_END)
  {
    if (Update.end(true))
    {
      restart_after_update = true;
      Serial.printf("Firmware-Upload abgeschlossen: %u Bytes\n", upload.totalSize);
    }
    else
    {
      update_failed = true;
      Update.printError(Serial);
    }
  }
}

void handle_update_result()
{
  if (!update_failed && restart_after_update)
  {
    server.send(200, "text/plain; charset=utf-8", "Upload erfolgreich. Neustart...");
    if (restart_after_update)
    {
      delay(500);
      ESP.restart();
    }
  }
  else
    server.send(500, "text/plain; charset=utf-8", "Firmware-Upload fehlgeschlagen");
}
} // namespace

bool webinterface_begin(TelemetrySettings &settings)
{
  active_settings = &settings;
  preferences.begin(settings_namespace, false);
  settings.callsign = preferences.getString("callsign", default_callsign);
  settings.access_point_name = preferences.getString("ap_name", default_access_point_name());
  settings.access_point_password = preferences.getString("ap_password", default_access_point_password);
  settings.min_speed = preferences.getInt("min", default_min_speed);
  settings.max_speed = preferences.getInt("max", default_max_speed);
    settings.active_time_seconds = preferences.getUInt("active_time", default_active_time_seconds);
  if (settings.access_point_name.length() == 0 || settings.access_point_name.length() > 32 || settings.access_point_password.length() < 8 || settings.access_point_password.length() > 63 || settings.callsign.length() == 0 || settings.min_speed < 0 || settings.min_speed >= settings.max_speed ||
      settings.max_speed > 300 || settings.active_time_seconds < 1 || settings.active_time_seconds > 600)
  {
    settings.callsign = default_callsign;
    settings.access_point_name = default_access_point_name();
    settings.access_point_password = default_access_point_password;
    settings.min_speed = default_min_speed;
    settings.max_speed = default_max_speed;
    settings.active_time_seconds = default_active_time_seconds;
  }

  WiFi.mode(WIFI_AP);
  bool ap_started = WiFi.softAP(settings.access_point_name, settings.access_point_password);
  if (!ap_started)
    return false;

  server.on("/", HTTP_GET, handle_root);
  server.on("/settings", HTTP_POST, handle_settings);
  server.on("/update", HTTP_POST, handle_update_result, handle_update_upload);
  server.begin();
  Serial.print("Webinterface: http://");
  Serial.println(WiFi.softAPIP());
  return true;
}

void webinterface_handle(void)
{
  server.handleClient();
  if (access_point_restart_pending)
  {
    access_point_restart_pending = false;
    WiFi.softAPdisconnect(true);
    delay(100);
    if (!WiFi.softAP(active_settings->access_point_name, active_settings->access_point_password))
      Serial.println("Access Point konnte nicht neu gestartet werden");
  }
}

const TelemetrySettings &webinterface_settings(void)
{
  return *active_settings;
}