// Simple encryption utilities - only what's needed for the hook
const ENCRYPTION_PASSWORD_KEY_PREFIX = "realestate_app";
const ENCRYPTION_SKIP_KEY_PREFIX = "realestate_app_skip";

// Generate user-specific localStorage key
export function getUserEncryptionKey(userId: string): string {
  return `${ENCRYPTION_PASSWORD_KEY_PREFIX}_user_${userId}`;
}

// Generate user-specific skip key
export function getUserSkipKey(userId: string): string {
  return `${ENCRYPTION_SKIP_KEY_PREFIX}_user_${userId}`;
}

export function MakeNewDate(
  input: string | number,
  timezone: string = "T00:00:00.000Z",
): Date {
  if (typeof input === "string") {
    if (input.length === 10) {
      // If it's a 10-character string (YYYY-MM-DD), append T00:00:00.000Z for consistent UTC midnight parsing
      const d = new Date(input + timezone);
      return d;
    } else if (input.length === 13) {
      // If it's a 13-character string, try to parse as timestamp
      const timestamp = parseInt(input, 10);
      if (isNaN(timestamp)) {
        throw new Error("Invalid 13-character timestamp string");
      }
      const tDate = new Date(timestamp);
      const d = MakeNewDate(tDate.toISOString().split("T")[0]);
      return d;
    } else {
      throw new Error(
        "String input must be exactly 10 characters (YYYY-MM-DD) or 13 characters (timestamp)",
      );
    }
  } else if (typeof input === "number") {
    // If it's a number (timestamp), use it directly
    const tDate = new Date(input);
    const d = MakeNewDate(tDate.toISOString().split("T")[0]);
    return d;
  } else {
    throw new Error("MakeNewDate expects a string or number input");
  }
}

export function getDate(dateTime: Date): number {
  const d = MakeNewDate(dateTime.getTime());
  d.setDate(d.getDate() + 1);
  return d.getDate();
}

export function getMonth(dateTime: Date): number {
  const d = MakeNewDate(dateTime.getTime());
  d.setDate(d.getDate() + 1);
  return d.getMonth();
}

export function getYear(dateTime: Date): number {
  const d = MakeNewDate(dateTime.getTime());
  d.setDate(d.getDate() + 1);
  return d.getFullYear();
}

export function getDay(dateTime: Date): number {
  const d = MakeNewDate(dateTime.getTime());
  d.setDate(d.getDate() + 1);
  return d.getDay();
}

export async function createPublicId(guid: string): Promise<string> {
  const encoder = new TextEncoder();
  const data = encoder.encode(guid);
  const hashBuffer = await crypto.subtle.digest("SHA-256", data);
  return btoa(String.fromCharCode(...new Uint8Array(hashBuffer)))
    .replace(/[+/=]/g, "")
    .substring(0, 22); // Truncate for shorter ID
}

// Utility: derive an AES key from a password using PBKDF2
export async function deriveKey(
  password: string,
  salt: Uint8Array,
): Promise<CryptoKey> {
  const enc = new TextEncoder();
  const passKey = await globalThis.crypto.subtle.importKey(
    "raw",
    enc.encode(password),
    "PBKDF2",
    false,
    ["deriveKey"],
  );
  // Derive a 256-bit AES-GCM key
  return globalThis.crypto.subtle.deriveKey(
    {
      name: "PBKDF2",
      salt: new Uint8Array(salt),
      iterations: 100_000,
      hash: "SHA-256",
    },
    passKey,
    { name: "AES-GCM", length: 256 },
    false,
    ["encrypt", "decrypt"],
  );
}

// Utility: random salt/IV generation
export function getRandomBytes(length: number): Uint8Array {
  const arr = new Uint8Array(length);
  globalThis.crypto.getRandomValues(arr);
  return arr;
}

// Encrypt data using password
export async function encryptData(
  data: string,
  password: string,
): Promise<string | null> {
  if (!data || !password) {
    return null;
  }

  try {
    const salt = getRandomBytes(16);
    const iv = getRandomBytes(12);
    const key = await deriveKey(password, salt);
    const enc = new TextEncoder().encode(data);
    const ciphertext = new Uint8Array(
      await globalThis.crypto.subtle.encrypt(
        { name: "AES-GCM", iv: new Uint8Array(iv) },
        key,
        new Uint8Array(enc),
      ),
    );

    // Bundle data as base64
    const bundle = JSON.stringify({
      salt: btoa(String.fromCharCode(...salt)),
      iv: btoa(String.fromCharCode(...iv)),
      data: btoa(String.fromCharCode(...ciphertext)),
    });

    return bundle;
  } catch (error) {
    console.error("Encryption failed:", error);
    return null;
  }
}

// Decrypt data using password
export async function decryptData(
  encryptedBundle: string,
  password: string,
): Promise<string | null> {
  if (!encryptedBundle || !password) {
    return null;
  }

  try {
    const { salt, iv, data } = JSON.parse(encryptedBundle);

    const saltBytes = Uint8Array.from(atob(salt), (c) => c.charCodeAt(0));
    const ivBytes = Uint8Array.from(atob(iv), (c) => c.charCodeAt(0));
    const cipherBytes = Uint8Array.from(atob(data), (c) => c.charCodeAt(0));
    const key = await deriveKey(password, saltBytes);

    const decryptedBytes = await globalThis.crypto.subtle.decrypt(
      { name: "AES-GCM", iv: new Uint8Array(ivBytes) },
      key,
      new Uint8Array(cipherBytes),
    );

    return new TextDecoder().decode(decryptedBytes);
  } catch (error) {
    console.error("Decryption failed:", error);
    return null;
  }
}

// Retrieve encryption password from localStorage
export function getEncryptionPassword(userId: string): string | null {
  if (!userId) return null;

  try {
    const userKey = getUserEncryptionKey(userId);
    return globalThis.localStorage?.getItem(userKey) || null;
  } catch (error) {
    console.warn(
      "Failed to access localStorage for encryption password:",
      error,
    );
    return null;
  }
}

// Encrypt data using stored password for a specific user (convenience function)
export async function encryptDataWithStoredPassword(
  userId: string,
  data: string,
): Promise<string | null> {
  if (!userId) {
    console.warn("Cannot encrypt data: userId is required");
    return null;
  }

  const password = getEncryptionPassword(userId);
  if (!password) {
    console.warn(`No encryption password stored for user ${userId}`);
    return null;
  }
  const encryptedBundle = await encryptData(data, password);
  if (!encryptedBundle) {
    return null;
  }
  return btoa(encryptedBundle);
}

// Decrypt data using stored password for a specific user (convenience function)
export async function decryptDataWithStoredPassword(
  userId: string,
  encryptedBundle: string,
): Promise<string | null> {
  if (!userId) {
    console.warn("Cannot decrypt data: userId is required");
    return null;
  }

  const password = getEncryptionPassword(userId);
  if (!password) {
    console.warn(`No encryption password stored for user ${userId}`);
    return null;
  }
  if (!encryptedBundle) {
    return null;
  }
  const decodedBundle = atob(encryptedBundle);
  return await decryptData(decodedBundle, password);
}

// Decrypt data using stored password for a specific user (convenience function)
export async function tryDecryptDataWith(
  password: string,
  encryptedBundle: string,
): Promise<string | null> {
  if (!password) {
    console.warn("Cannot decrypt data: password is required");
    return null;
  }

  if (!encryptedBundle) {
    return null;
  }
  const decodedBundle = atob(encryptedBundle);
  return await decryptData(decodedBundle, password);
}