#include <WiFi.h>
#include <HTTPClient.h>
#include <ArduinoJson.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <SparkFun_Qwiic_Keypad_Arduino_Library.h>
#include "config.h" // Include private configuration

// Hardware configuration
const int RELAY_PINS[6] = {13, 12, 14, 27, 26, 25}; // Relay pins for doors 1-6
const int DOOR_OPEN_TIME = 5000; // 5 seconds in milliseconds

// I2C devices
LiquidCrystal_I2C lcd(0x27, 16, 2); // LCD with I2C address 0x27
KEYPAD keypad; // Qwiic Keypad

// State variables
String currentCode = "";
bool processingLoan = false;
int failedAttempts = 0;
unsigned long lockoutEndTime = 0;
const int MAX_FAILED_ATTEMPTS = 3;
const unsigned long LOCKOUT_DURATION = 30000; // 30 seconds in milliseconds

void setup() {
  Serial.begin(115200);
  
  // Initialize I2C
  Wire.begin();
  
  // Initialize LCD
  lcd.init();
  lcd.backlight();
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Starte...");
  
  // Initialize keypad
  if (!keypad.begin()) {
    Serial.println("Keypad not connected!");
    lcd.clear();
    lcd.print("Keypad Fehler!");
    while (1);
  }
  
  // Initialize relay pins (active LOW for most relay modules)
  for (int i = 0; i < 6; i++) {
    pinMode(RELAY_PINS[i], OUTPUT);
    digitalWrite(RELAY_PINS[i], HIGH); // Keep doors locked initially
  }
  
  // Connect to WiFi
  connectToWiFi();
  
  // Ready message
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Code eingeben:");
  lcd.setCursor(0, 1);
  lcd.print(""); // Code will appear here
  
  Serial.println("System ready!");
}

void loop() {
  // Check for lockout timeout
  if (lockoutEndTime > 0) {
    if (millis() < lockoutEndTime) {
      // Still in lockout period
      unsigned long remainingSeconds = (lockoutEndTime - millis()) / 1000;
      lcd.setCursor(0, 1);
      lcd.print("Warte ");
      lcd.print(remainingSeconds);
      lcd.print("s     ");
      delay(1000);
      return;
    } else {
      // Lockout period ended
      lockoutEndTime = 0;
      failedAttempts = 0;
      resetState();
    }
  }
  
  // Check if keypad button was pressed
  keypad.updateFIFO();
  char button = keypad.getButton();
  
  if (button != 0 && !processingLoan) {
    handleKeypadInput(button);
  }
  
  // Check WiFi connection
  if (WiFi.status() != WL_CONNECTED) {
    connectToWiFi();
  }
}

void handleKeypadInput(char button) {
  if (button == '#') {
    // Submit code
    if (currentCode.length() == 6) {
      processLoanCode(currentCode);
    } else {
      showError("Code muss 6-stellig sein!");
      currentCode = "";
      updateCodeDisplay();
    }
  } else if (button == '*') {
    // Clear current input
    currentCode = "";
    updateCodeDisplay();
    lcd.setCursor(0, 0);
    lcd.print("Code eingeben:  ");
  } else {
    // Add digit to code
    if (currentCode.length() < 6) {
      currentCode += button;
      updateCodeDisplay();
    }
  }
}

void updateCodeDisplay() {
  lcd.setCursor(0, 1);
  // Display asterisks for entered digits
  String display = "";
  for (int i = 0; i < currentCode.length(); i++) {
    display += "*";
  }
  // Pad with spaces
  while (display.length() < 16) {
    display += " ";
  }
  lcd.print(display);
}

void processLoanCode(String code) {
  processingLoan = true;
  
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Verarbeite...");
  
  Serial.println("Processing loan code: " + code);
  
  // Get loan information from backend
  String lockers = "";
  bool isReturn = false;
  
  if (!getLoanInfo(code, lockers, isReturn)) {
    failedAttempts++;
    
    if (failedAttempts >= MAX_FAILED_ATTEMPTS) {
      // Start lockout period
      lockoutEndTime = millis() + LOCKOUT_DURATION;
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("Zu viele Fehler!");
      lcd.setCursor(0, 1);
      lcd.print("Gesperrt 30s");
      delay(2000);
      return;
    } else {
      showError("Ungültiger Code!");
      lcd.setCursor(0, 1);
      lcd.print("Versuch ");
      lcd.print(failedAttempts);
      lcd.print("/");
      lcd.print(MAX_FAILED_ATTEMPTS);
      delay(2000);
    }
    
    resetState();
    return;
  }
  
  // Code was correct - reset failed attempts
  failedAttempts = 0;
  
  // Parse locker numbers
  DynamicJsonDocument doc(512);
  DeserializationError error = deserializeJson(doc, lockers);
  
  if (error) {
    Serial.println("JSON parsing failed!");
    showError("System Fehler!");
    resetState();
    return;
  }
  
  // Display action type
  lcd.clear();
  lcd.setCursor(0, 0);
  if (isReturn) {
    lcd.print("Rückgabe");
  } else {
    lcd.print("Ausleihe");
  }
  
  // Open doors one by one
  JsonArray lockerArray = doc.as<JsonArray>();
  int doorCount = 0;
  
  for (JsonVariant locker : lockerArray) {
    int doorNumber = locker.as<int>();
    if (doorNumber >= 1 && doorNumber <= 6) {
      doorCount++;
      openDoor(doorNumber);
    }
  }
  
  if (doorCount == 0) {
    showError("Keine Fächer!");
    resetState();
    return;
  }
  
  // Update loan status in backend
  if (isReturn) {
    setReturnDate(code);
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Rückgabe OK!");
  } else {
    setTakeDate(code);
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Ausleihe OK!");
  }
  
  lcd.setCursor(0, 1);
  lcd.print("Vielen Dank!");
  
  delay(3000);
  resetState();
}

bool getLoanInfo(String loanCode, String &lockers, bool &isReturn) {
  if (WiFi.status() != WL_CONNECTED) {
    Serial.println("WiFi not connected!");
    return false;
  }
  
  HTTPClient http;
  String url = String(BACKEND_URL) + "/get-loan-by-code/" + API_KEY + "/" + loanCode;
  
  http.begin(url);
  int httpCode = http.GET();
  
  if (httpCode != 200) {
    Serial.println("HTTP error: " + String(httpCode));
    http.end();
    return false;
  }
  
  String payload = http.getString();
  http.end();
  
  // Parse response
  DynamicJsonDocument doc(1024);
  DeserializationError error = deserializeJson(doc, payload);
  
  if (error) {
    Serial.println("JSON parsing failed!");
    return false;
  }
  
  // Check if loan was found
  if (!doc.containsKey("data")) {
    Serial.println("No data in response");
    return false;
  }
  
  JsonObject data = doc["data"];
  
  // Get lockers array as string
  lockers = data["lockers"].as<String>();
  
  // Check if this is a return (returned_date is null) or pickup (returned_date is set)
  // If returned_date is null, this is a return action
  // If take_date is null, this is a pickup action
  isReturn = !data["returned_date"].isNull();
  
  // Actually, based on API: if returned_date is null, user is returning items
  // If take_date is null, user is taking items
  if (data["take_date"].isNull()) {
    isReturn = false; // User is taking items
  } else if (data["returned_date"].isNull()) {
    isReturn = true; // User is returning items
  } else {
    // Both dates set - loan already completed
    Serial.println("Loan already completed");
    return false;
  }
  
  Serial.println("Loan info retrieved. Lockers: " + lockers + ", isReturn: " + String(isReturn));
  return true;
}

void openDoor(int doorNumber) {
  if (doorNumber < 1 || doorNumber > 6) {
    return;
  }
  
  int pinIndex = doorNumber - 1;
  
  lcd.setCursor(0, 1);
  lcd.print("Öffne Fach ");
  lcd.print(doorNumber);
  lcd.print("   ");
  
  Serial.println("Opening door " + String(doorNumber));
  
  // Activate relay (LOW = on for most relay modules)
  digitalWrite(RELAY_PINS[pinIndex], LOW);
  
  // Keep door open for specified time
  delay(DOOR_OPEN_TIME);
  
  // Deactivate relay (close door)
  digitalWrite(RELAY_PINS[pinIndex], HIGH);
  
  Serial.println("Door " + String(doorNumber) + " closed");
}

bool setReturnDate(String loanCode) {
  if (WiFi.status() != WL_CONNECTED) {
    return false;
  }
  
  HTTPClient http;
  String url = String(BACKEND_URL) + "/set-return-date/" + API_KEY + "/" + loanCode;
  
  http.begin(url);
  int httpCode = http.POST("");
  
  bool success = (httpCode == 200);
  http.end();
  
  Serial.println("Set return date: " + String(success ? "success" : "failed"));
  return success;
}

bool setTakeDate(String loanCode) {
  if (WiFi.status() != WL_CONNECTED) {
    return false;
  }
  
  HTTPClient http;
  String url = String(BACKEND_URL) + "/set-take-date/" + API_KEY + "/" + loanCode;
  
  http.begin(url);
  int httpCode = http.POST("");
  
  bool success = (httpCode == 200);
  http.end();
  
  Serial.println("Set take date: " + String(success ? "success" : "failed"));
  return success;
}

void showError(String message) {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("FEHLER:");
  lcd.setCursor(0, 1);
  lcd.print(message);
  Serial.println("Error: " + message);
  delay(2000);
}

void resetState() {
  currentCode = "";
  processingLoan = false;
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Code eingeben:");
  lcd.setCursor(0, 1);
  lcd.print("");
}

void connectToWiFi() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Verbinde WiFi...");
  
  Serial.print("Connecting to WiFi");
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
  
  int attempts = 0;
  while (WiFi.status() != WL_CONNECTED && attempts < 20) {
    delay(500);
    Serial.print(".");
    lcd.setCursor(0, 1);
    for (int i = 0; i < (attempts % 16); i++) {
      lcd.print(".");
    }
    attempts++;
  }
  
  if (WiFi.status() == WL_CONNECTED) {
    Serial.println("\nConnected to WiFi!");
    Serial.println("IP: " + WiFi.localIP().toString());
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("WiFi verbunden!");
    delay(1500);
  } else {
    Serial.println("\nFailed to connect to WiFi!");
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("WiFi Fehler!");
    delay(2000);
  }
}