import os
import re
import json
import logging
from werkzeug.utils import secure_filename
from flask import current_app

ALLOWED_EXTENSIONS = {"pdf", "jpg", "jpeg", "png", "svg", "docx", "doc", "xlsx", "xls", "wav", "mp3", "m4a", "ogg"}
MAX_SIZE_PDF_DOCS = 1 * 1024 * 1024 * 1024    # 1GB
MAX_SIZE_IMAGES = 500 * 1024 * 1024           # 500MB
MAX_SIZE_AUDIO = 100 * 1024 * 1024            # 100MB


def allowed_file(filename):
    return "." in filename and filename.rsplit(".", 1)[1].lower() in ALLOWED_EXTENSIONS


def check_file_size(file):
    try:
        # Store current position
        current_pos = file.tell()
        
        # Check size
        file.seek(0, os.SEEK_END)
        size = file.tell()
        
        # Return to original position
        file.seek(current_pos)
        
        extension = file.filename.rsplit('.', 1)[-1].lower()
        if extension in {"pdf", "docx"} and size > MAX_SIZE_PDF_DOCS:
            return False, f"File {file.filename} exceeds 1GB size limit"
        elif extension in {"jpg", "jpeg", "png"} and size > MAX_SIZE_IMAGES:
            return False, f"Image {file.filename} exceeds 500MB size limit"
        elif extension in {"wav", "mp3", "m4a", "ogg"} and size > MAX_SIZE_AUDIO:
            return False, f"Audio file {file.filename} exceeds 100MB size limit"
        return True, None
    except Exception as e:
        logging.error(f"Error checking file size: {e}", exc_info=True)
        return False, f"Error checking file size: {str(e)}"


def save_data_to_storage(filename, data):
    try:
        upload_folder = current_app.config.get("UPLOAD_FOLDER", "uploads")
        if not os.path.exists(upload_folder):
            os.makedirs(upload_folder, exist_ok=True)
        filename = filename.rsplit(".", 1)[0]
        filepath = os.path.join(upload_folder, f"{filename}.json")
        with open(filepath, "w") as file:
            json.dump(data, file)
    except Exception as e:
        logging.error(f"Exception during save: {e}")


def get_data_from_storage(filename):
    try:
        upload_folder = current_app.config.get("UPLOAD_FOLDER", "uploads")
        filepath = os.path.join(upload_folder, f"{filename}.json")
        if not os.path.exists(filepath):
            return None
        with open(filepath, "r") as file:
            data = json.load(file)
        return data
    except Exception as e:
        logging.error(f"Error loading data: {e}")
        return None