//todo:
// - more accurate TX/RX indication (for security concern), e.g. favicon is served static, thus not display TX/RX arrow.
// - Login and apikey access for next version

#include "wifi.h"
#include "upsCfg.h"

#ifndef UPSIO_H
#include "upsIo.h"
#endif

//#include <AsyncTCP.h> //for esp32
#include <ESPAsyncTCP.h>  //for esp8266
#include <ESPAsyncWebServer.h>

const char* http_username = "admin";
const char* http_password = "admin123";

String base64Decode(const String& input) {
  const char b64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  String out;
  int buf = 0, bits = 0;
  for (size_t i = 0; i < input.length(); i++) {
    char c = input[i];
    if (c == '=') break;
    const char* p = strchr(b64, c);
    if (!p) continue;
    buf = (buf << 6) | (p - b64);
    bits += 6;
    if (bits >= 8) {
      bits -= 8;
      out += (char)((buf >> bits) & 0xFF);
      buf &= (1 << bits) - 1;
    }
  }
  return out;
}

bool checkAuth(AsyncWebServerRequest *request) {
  if (!request->hasHeader("Authorization")) return false;
  String auth = request->header("Authorization");
  if (!auth.startsWith("Basic ")) return false;
  String b64 = auth.substring(6);
  b64.trim();
  String decoded = base64Decode(b64);
  int sep = decoded.indexOf(':');
  if (sep < 0) return false;
  String user = decoded.substring(0, sep);
  String pass = decoded.substring(sep + 1);
  return user.equals(http_username) && pass.equals(http_password);
}

int8_t wifiStatePrev = 99;

bool configChanged = false;

AsyncWebServer server(80);

void applyConfigs() {
  autoPowerOn = (cfgAutoOn >= AUTO_POWER_ON);  //auto power on

  //cfgChargeMode: charge mode:
  switch (cfgChargeMode) {
    case CHARGE_MODE_ALWAYS:
      {
        chargeAlwaysActive = true;
      }
      break;
    case CHARGE_MODE_RANGE_90_100:
      {
        chargeAlwaysActive = false;
        chargeToFull = true;
        chargePercentageForStop = 100;
        chargePercentageForResume = 90;
      }
      break;
    case CHARGE_MODE_RANGE_85_100:
      {
        chargeAlwaysActive = false;
        chargeToFull = true;
        chargePercentageForStop = 100;
        chargePercentageForResume = 85;
      }
      break;
    case CHARGE_MODE_RANGE_80_100:
      {
        chargeAlwaysActive = false;
        chargeToFull = true;
        chargePercentageForStop = 100;
        chargePercentageForResume = 80;
      }
      break;
    case CHARGE_MODE_RANGE_90_95:
      {
        chargeAlwaysActive = false;
        chargeToFull = false;
        chargePercentageForStop = 95;
        chargePercentageForResume = 90;
      }
      break;
    case CHARGE_MODE_RANGE_85_95:
      {
        chargeAlwaysActive = false;
        chargeToFull = true;
        chargePercentageForStop = 95;
        chargePercentageForResume = 85;
      }
      break;
    case CHARGE_MODE_RANGE_80_95:
      {
        chargeAlwaysActive = false;
        chargeToFull = true;
        chargePercentageForStop = 95;
        chargePercentageForResume = 80;
      }
      break;
    case CHARGE_MODE_RANGE_85_90:
      {
        chargeAlwaysActive = false;
        chargeToFull = true;
        chargePercentageForStop = 90;
        chargePercentageForResume = 85;
      }
      break;
    case CHARGE_MODE_RANGE_80_90:
      {
        chargeAlwaysActive = false;
        chargeToFull = true;
        chargePercentageForStop = 90;
        chargePercentageForResume = 80;
      }
      break;
    case CHARGE_MODE_RANGE_80_85:
      {
        chargeAlwaysActive = false;
        chargeToFull = true;
        chargePercentageForStop = 85;
        chargePercentageForResume = 80;
      }
      break;
  }

  //cfgInputLostTriggerChargeMode:
  switch (cfgInputLostTriggerChargeMode) {
    case INPUT_LOST_TRIGGER_CHARGE_NONE:
      {
        chargeAfterInputLost = false;
      }
      break;
    case INPUT_LOST_TRIGGER_CHARGE_ACTIVE_FULL_ALWAYS:
      {
        chargeAfterInputLost = true;
        fullChargeAfterInputLost = true;
      }
      break;
    case INPUT_LOST_TRIGGER_CHARGE_ACTIVE_FULL_95:
      {
        chargeAfterInputLost = true;
        fullChargeAfterInputLost = false;
        triggerFullChargeAfterInputLostAtPercentage = 95;
      }
      break;
    case INPUT_LOST_TRIGGER_CHARGE_ACTIVE_FULL_90:
      {
        chargeAfterInputLost = true;
        fullChargeAfterInputLost = false;
        triggerFullChargeAfterInputLostAtPercentage = 90;
      }
      break;
    case INPUT_LOST_TRIGGER_CHARGE_ACTIVE_FULL_85:
      {
        chargeAfterInputLost = true;
        fullChargeAfterInputLost = false;
        triggerFullChargeAfterInputLostAtPercentage = 85;
      }
      break;
    case INPUT_LOST_TRIGGER_CHARGE_ACTIVE_FULL_80:
      {
        chargeAfterInputLost = true;
        fullChargeAfterInputLost = false;
        triggerFullChargeAfterInputLostAtPercentage = 80;
      }
      break;
  }

  //cfgChargeOvervoltageProtection:
  chargeOvervoltageProtection = (cfgChargeOvervoltageProtection > 0);
  //cfgChargeAutomaticReducer:
  chargeReduceAtBatteryFull = (cfgChargeAutomaticReducer > 0);
}

bool getShutdownSuggestionFlag() {
  if (cfgShutdownSuggestion == SHUTDOWN_SUGGESTION_DISABLED) return false;
  if (!startupReady) return false;
  switch (cfgShutdownSuggestion) {
    case SHUTDOWN_SUGGESTION_ON_BATT:
      {
        return powerOutputActive && !inputVoltageKeepup;
      }
      break;
    case SHUTDOWN_SUGGESTION_ON_BATT_75:
      {
        return powerOutputActive && !inputVoltageKeepup && (batteryLevel <= 3);
      }
      break;
    case SHUTDOWN_SUGGESTION_ON_BATT_50:
      {
        return powerOutputActive && !inputVoltageKeepup && (batteryLevel <= 2);
      }
      break;
    case SHUTDOWN_SUGGESTION_ON_BATT_25:
      {
        return powerOutputActive && !inputVoltageKeepup && (batteryLevel <= 1);
      }
      break;
    case SHUTDOWN_SUGGESTION_ON_BATT_CRITICAL:
      {
        return powerOutputActive && !inputVoltageKeepup && (batteryLevel <= 1) && isUpsBatteryCritical();
      }
      break;
    default:
      {
        return false;
      }
  }

  return false;
}

void handleGetState(AsyncWebServerRequest *request) {
  if (!checkAuth(request)) {
    setNetworkIndicatorInTransmission(true, false);
    AsyncWebServerResponse *response = request->beginResponse(401, "application/json", "{\"success\":0}");
    // response->addHeader("WWW-Authenticate", "Basic realm=\"UPS Login\""); // Removed to prevent native browser prompt
    request->send(response);
    setNetworkIndicatorInTransmission(true, true);
    return;
  }
  setNetworkIndicatorInTransmission(true, false);
  bool isRefresh = true;
  String v = "";
  uint8_t i = 0;

  if (request->hasParam("on")) {
    isRefresh = false;
    v = request->getParam("on")->value();
    bool tgtState = v != "0";
    Serial.print("Switch request: ");
    Serial.println(tgtState);
    if (tgtState != powerOutputActive) {
      setOutputPowerState(tgtState);
      Serial.println("Switching...");
    }
  }

  if (request->hasParam("auto")) {
    isRefresh = false;
    v = request->getParam("auto")->value();
    uint8_t tmpAutoOnMode = v.toInt();
    if ((tmpAutoOnMode != cfgAutoOn) && (tmpAutoOnMode <= AUTO_POWER_PERSIST)) {
      cfgAutoOn = tmpAutoOnMode;
      configChanged = true;
    }
  }

  if (request->hasParam("shutdown")) {
    isRefresh = false;
    v = request->getParam("shutdown")->value();
    uint16_t tSec = v.toInt();
    if (tSec > 999) tSec = 999;
    uint32_t nanoT = ((uint32_t)tSec) * 1000000UL;
    if (nanoT < 999999) nanoT = 999999;
    bool ok = setPersistentShutdown(nanoT);
    if ((cfgShutdownInSeconds != tSec && ok)) {
      cfgShutdownInSeconds = tSec;
      configChanged = true;
    }
    Serial.print("Timed Shutdown request: ");
    Serial.println(tSec);
    //Serial.println(ok);
  }

  if (request->hasParam("shutlv")) {
    isRefresh = false;
    v = request->getParam("shutlv")->value();
    int16_t lv = v.toInt();
    if (lv >= SHUTDOWN_SUGGESTION_DISABLED && lv <= SHUTDOWN_SUGGESTION_ON_BATT_CRITICAL) {
      if (lv != cfgShutdownSuggestion) {
        cfgShutdownSuggestion = lv;
        configChanged = true;
        Serial.print("Shutdown level changed: ");
        Serial.println(lv);
      }
    } else {
      Serial.print("Invalid shutdown level: ");
      Serial.println(v);
    }
  }

  //battery management params:
  //cfgChargeMode (charge mode):
  if (request->hasParam("cm")) {
    isRefresh = false;
    v = request->getParam("cm")->value();
    i = v.toInt();
    if (i <= CHARGE_MODE_RANGE_80_85) {
      cfgChargeMode = i;
      configChanged = true;
      Serial.print("CM: ");
      Serial.println(i);
    }
  }

  //cfgInputLostTriggerChargeMode (charge on input lost):
  if (request->hasParam("coil")) {
    isRefresh = false;
    v = request->getParam("coil")->value();
    i = v.toInt();
    if (i <= INPUT_LOST_TRIGGER_CHARGE_ACTIVE_FULL_80) {
      cfgInputLostTriggerChargeMode = i;
      configChanged = true;
      Serial.print("COIL: ");
      Serial.println(i);
    }
  }

  //cfgChargeOvervoltageProtection (charge overvoltage protection):
  if (request->hasParam("covp")) {
    isRefresh = false;
    v = request->getParam("covp")->value();
    i = v.toInt();
    if (i > 1) i = 1;
    if (i != cfgChargeOvervoltageProtection) {
      cfgChargeOvervoltageProtection = i;
      configChanged = true;
      Serial.print("COVP: ");
      Serial.println(i);
    }
  }
  //reset "On-Going Full Charge" triggered after input lost (reset ongoing full charge):
  if (request->hasParam("rofc")) {
    isRefresh = false;
    v = request->getParam("rofc")->value();
    i = v.toInt();
    if (i > 0 && needFullChargeOnce) {
      resetOnGoingFullChargeAfterLineLost();
      Serial.print("ROFC: ");
      Serial.println(i);
    }
  }

  //cfgChargeAutomaticReducer (charge automatic reducer)
  if (request->hasParam("car")) {
    isRefresh = false;
    v = request->getParam("car")->value();
    i = v.toInt();
    if (i > 1) i = 1;
    if (i != cfgChargeAutomaticReducer) {
      cfgChargeAutomaticReducer = i;
      configChanged = true;
      Serial.print("CAR: ");
      Serial.println(i);
    }
  }

  DynamicJsonDocument jsonDoc(1536);
  String jsonResponse;
  //String stateOn = isUpsOn()?"1":"0";
  //String autoOn = String(cfgAutoOn);
  //String voltageValue = String(batteryVoltage, 2);
  //2 battery, 1 Input line or AC, 0 OFF
  //String lineActive = isUpsPoweredFromBattery()?"2":isInputLinePowered()?"1":isUpsOn()?"2":"0";
  uint8_t lineActiveState = isUpsPoweredFromBattery() ? 2 : isInputLinePowered() ? 1
                                                          : isUpsOn()            ? 2
                                                                                 : 0;
  //String batt = String(batteryLevel);
  //String battMax = "4";
  //  String battBlink = IsUpsChargingOrBlink()?"1":"0";
  //  String chargeLv = IsUpsChargingOrBlink()?(String(UpsBattMinimalLevelUnderChargingOrBlink())):(String(UpsBatteryLevel()));
  //  String battCritical = IsUpsBatteryCritical()?"1":"0";
  //  String isTimedShut = timedShutdownFlag?"1":"0";
  //  String onShutRemaining = String(GetShutdownCountdown());
  //  String shutdownSuggest = GetShutdownSuggestionFlag()?"1":"0";
  //  String shutdownSuggestMode = String(cfgShutdownSuggestion);
  //  String shutdownLastPeriod = String(timeShutdownLastPeriod);

  //json vars:
  jsonDoc["success"] = isRefresh ? 2 : 1;
  jsonDoc["on"] = powerOutputActive ? 1 : 0;
  ;
  jsonDoc["state"] = isUpsOn() ? 1 : 0;
  jsonDoc["v"] = String(batteryVoltage, 2);
  jsonDoc["batt"] = batteryLevel;
  jsonDoc["battP"] = batteryPercentage;
  jsonDoc["line"] = lineActiveState;

  jsonDoc["auto"] = cfgAutoOn;
  jsonDoc["battBlink"] = isUpsBatteryIndicatorChargingOrBlink() ? 1 : 0;
  jsonDoc["battCritical"] = isUpsBatteryCritical() ? 1 : 0;
  jsonDoc["chargeLv"] = getRawBatteryLevelFromPercentage(batteryPercentage);  //real level
  jsonDoc["batt"] = batteryLevel;                                             //staged level
  jsonDoc["battMax"] = 4;
  jsonDoc["timedShutdown"] = (persistentShutdown && powerOutputActive) ? 1 : 0;
  jsonDoc["shutdownRemain"] = getPersistentShutdownTick() / 1000000;
  jsonDoc["shutdownSuggestMode"] = cfgShutdownSuggestion;
  jsonDoc["shutdownSuggest"] = getShutdownSuggestionFlag() ? 1 : 0;  //internal flag raised if cfgShutdownSuggestion fullfill the condition
  jsonDoc["shutLastTimer"] = cfgShutdownInSeconds;
  //charge configuration:
  jsonDoc["chgError"] = chargeError;         //error state
  jsonDoc["charging"] = getChargingState();  //on charging state
  jsonDoc["chgMode"] = cfgChargeMode;
  jsonDoc["chgOVP"] = cfgChargeOvervoltageProtection;  //over voltage protection
  jsonDoc["chgReducer"] = cfgChargeAutomaticReducer;
  jsonDoc["chgFullTrig"] = cfgInputLostTriggerChargeMode;
  jsonDoc["chgOFC"] = needFullChargeOnce ? 1 : 0;  //when input lost and "Ongoing Full Charge" flag triggered

  jsonDoc["vSub"] = String(batteryVoltageUnfiltered, 2);
  jsonDoc["chgSwitch"] = isChargeActive ? 1 : 0;
  jsonDoc["inputUV"] = inputUnderVoltage ? 1 : 0;
  jsonDoc["inputVExist"] = inputVoltageKeepup ? 1 : 0;
  jsonDoc["btn"] = buttonState ? 1 : 0;
  jsonDoc["btnShort"] = buttonShortPress ? 1 : 0;
  jsonDoc["btnLong"] = buttonLongPress ? 1 : 0;
  jsonDoc["keepPower"] = keepPowerState ? 1 : 0;
  jsonDoc["display"] = displayActive ? 1 : 0;
  jsonDoc["rssi"] = rssi;
  jsonDoc["chargeAllowed"] = chargeAllowed ? 1 : 0;

  serializeJson(jsonDoc, jsonResponse);
  request->send(200, "application/json", jsonResponse);

  setNetworkIndicatorInTransmission(true, true);
}

void onRootRequest(AsyncWebServerRequest *request) {
  setNetworkIndicatorInTransmission(true, false);
  Serial.println("onRootRequest");
  bool isOK = false;
  if (spiffsOk) {
    if (LittleFS.exists("/index.html")) {
      isOK = true;
      request->send(LittleFS, "/index.html", "text/html");
      setNetworkIndicatorInTransmission(true, true);
    }
  }
  if (!isOK) {
    request->send(404, "text/text", "404: Not Found");
    setNetworkIndicatorInTransmission(true, true);
  }
}

void upsServerInit() {

  bool b = initConfigs();
  if (b) {
    loadCfg();
    applyConfigs();
  }

  //transfer configuration to ups library:
  if (cfgAutoOn >= AUTO_POWER_ON) {
    autoPowerOn = true;
    restartAutoPowerOn();
  } else {
    autoPowerOn = false;
  }

  //for favicon
  server.serveStatic("/favicon.ico", LittleFS, "/favicon.ico");
  server.serveStatic("*/favicon.ico", LittleFS, "/favicon.ico");

  //login endpoint: validate credentials
  server.on("/login", HTTP_GET, [](AsyncWebServerRequest *request) {
    setNetworkIndicatorInTransmission(true, false);
    if (!checkAuth(request)) {
      request->send(401, "application/json", "{\"success\":0}");
    } else {
      request->send(200, "application/json", "{\"success\":1}");
    }
    setNetworkIndicatorInTransmission(true, true);
  });

  //logout endpoint: clear basic auth by returning 401
  server.on("/logout", HTTP_GET, [](AsyncWebServerRequest *request) {
    setNetworkIndicatorInTransmission(true, false);
    AsyncWebServerResponse *response = request->beginResponse(401, "application/json", "{\"success\":0,\"message\":\"Logged out\"}");
    request->send(response);
    setNetworkIndicatorInTransmission(true, true);
  });

  //for RESTapi
  server.on("/state", HTTP_GET, handleGetState);

  //root
  server.on("/", onRootRequest);
  server.on("/*", onRootRequest);
  //Redirect all not-found requests to the root
  server.onNotFound(onRootRequest);

  server.begin();
  Serial.println("Server is running!");
}

void upsServerRoutine() {
  WiFiManagerRoutine();

  //updating wifi state:
  if (wifiCurrentState != wifiStatePrev) {
    wifiStatePrev = wifiCurrentState;
    setNetworkState(wifiStatePrev);
  }

  //update signal:
  indicatorNetworkSignalLevel = wifiSignalLevel;

  //manage auto on mode:
  if (cfgAutoOn == AUTO_POWER_PERSIST) {
    if (inputVoltageKeepup && inputVoltageOK) {
      if (restartAutoPowerOn()) Serial.println("Automatic ON restarted");
    }
  }

  //if button long pressed -------------------------------------------
  if (buttonLongPressIgnore && buttonLongPress) {
    buttonLongPressIgnore = true;
    Serial.println("Long Pressed Button Action is Reserved!");
    //(not used)
  }
  //------------------------------------------------------------------

  //saving configuration:
  if (configChanged) {
    configChanged = false;
    saveCfg();
    applyConfigs();
  }
}