# Python imports
import base64
import nh3
from plane.utils.exception_logger import log_exception

# Maximum allowed size for binary data (10MB)
MAX_SIZE = 10 * 1024 * 1024

# Suspicious patterns for binary data content
SUSPICIOUS_BINARY_PATTERNS = [
    "<html",
    "<!doctype",
    "<script",
    "javascript:",
    "data:",
    "<iframe",
]


def validate_binary_data(data):
    """
    Validate that binary data appears to be valid document format and doesn't contain malicious content.

    Args:
        data (bytes or str): The binary data to validate, or base64-encoded string

    Returns:
        tuple: (is_valid: bool, error_message: str or None)
    """
    if not data:
        return True, None  # Empty is OK

    # Handle base64-encoded strings by decoding them first
    if isinstance(data, str):
        try:
            binary_data = base64.b64decode(data)
        except Exception:
            return False, "Invalid base64 encoding"
    else:
        binary_data = data

    # Size check - 10MB limit
    if len(binary_data) > MAX_SIZE:
        return False, "Binary data exceeds maximum size limit (10MB)"

    # Basic format validation
    if len(binary_data) < 4:
        return False, "Binary data too short to be valid document format"

    # Check for suspicious text patterns (HTML/JS)
    try:
        decoded_text = binary_data.decode("utf-8", errors="ignore")[:200]
        if any(
            pattern in decoded_text.lower() for pattern in SUSPICIOUS_BINARY_PATTERNS
        ):
            return False, "Binary data contains suspicious content patterns"
    except Exception:
        pass  # Binary data might not be decodable as text, which is fine

    return True, None


def validate_html_content(html_content: str):
    """
    Sanitize HTML content using nh3.
    Returns a tuple: (is_valid, error_message, clean_html)
    """
    if not html_content:
        return True, None, None

    # Size check - 10MB limit (consistent with binary validation)
    if len(html_content.encode("utf-8")) > MAX_SIZE:
        return False, "HTML content exceeds maximum size limit (10MB)", None

    try:
        clean_html = nh3.clean(html_content)
        return True, None, clean_html
    except Exception as e:
        log_exception(e)
        return False, "Failed to sanitize HTML", None