#!/usr/bin/env python3
"""
Download all available CVE data from NVD
"""

import os
import requests
import zipfile
from pathlib import Path
from tqdm import tqdm
import time

def download_file_with_retry(url, target_file, filename, max_retries=5):
    """Helper function to download files with retry logic for unstable connections."""
    for attempt in range(1, max_retries + 1):
        try:
            if attempt > 1:
                print(f"[INFO] Retrying download for {filename} (Attempt {attempt}/{max_retries})...")
            else:
                print(f"[INFO] Downloading {filename}...")
                
            headers = {
                'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36'
            }
            response = requests.get(url, stream=True, headers=headers, timeout=60)
            response.raise_for_status()
            
            total_size = int(response.headers.get('content-length', 0))
            
            with open(target_file, 'wb') as f:
                with tqdm(total=total_size, unit='B', unit_scale=True, desc=filename) as pbar:
                    for chunk in response.iter_content(chunk_size=8192):
                        if chunk:
                            f.write(chunk)
                            pbar.update(len(chunk))
            
            print(f"[INFO] Successfully downloaded: {target_file}")
            return True
            
        except BaseException as e:
            if isinstance(e, KeyboardInterrupt):
                print(f"\n[INFO] Download interrupted by user. Cleaning up {filename}...")
            else:
                print(f"[ERROR] Failed to download {filename} on attempt {attempt}: {e}")
            
            # Clean up the partial file if it exists so we don't think it's completed
            if target_file.exists():
                try:
                    target_file.unlink()
                except Exception as cleanup_error:
                    print(f"[ERROR] Could not remove partial file {target_file}: {cleanup_error}")
            
            if isinstance(e, KeyboardInterrupt):
                raise  # Stop entirely if user pressed Ctrl+C
                
            if attempt < max_retries:
                time.sleep(2 * attempt)  # Wait a bit before retrying
            else:
                print(f"[ERROR] Reached maximum retries for {filename}. Skipping.")
                return False

def download_cve_data():
    """Download all available CVE data from NVD"""
    
    # Get the directory of this script
    script_dir = Path(__file__).resolve().parent
    target_dir = script_dir.parent / "data" / "CVE" / "zip"
    target_dir.mkdir(parents=True, exist_ok=True)
    
    # NVD CVE base URL (current feeds)
    base_url = "https://nvd.nist.gov/feeds/json/cve/2.0"
    
    # Get current year
    import datetime
    current_year = datetime.datetime.now().year
    
    print(f"[INFO] Downloading CVE data from 2002 to {current_year}...")
    
    # Download CVE data for each year
    for year in range(2002, current_year + 1):
        filename = f"nvdcve-2.0-{year}.json.zip"
        url = f"{base_url}/{filename}"
        target_file = target_dir / filename
        
        if target_file.exists():
            # Basic sanity check: if the file is too small, redownload it
            if target_file.stat().st_size > 1000:
                print(f"[INFO] {filename} already exists, skipping...")
                continue
            else:
                print(f"[INFO] {filename} exists but seems too small/corrupted, redownloading...")
                
        download_file_with_retry(url, target_file, filename)
    
    # Also download the modified CVE feed (contains recent updates)
    modified_filename = "nvdcve-2.0-modified.json.zip"
    modified_url = f"{base_url}/{modified_filename}"
    modified_target_file = target_dir / modified_filename
    
    if modified_target_file.exists() and modified_target_file.stat().st_size > 1000:
        print(f"[INFO] {modified_filename} already exists, skipping...")
    else:
        download_file_with_retry(modified_url, modified_target_file, modified_filename)
    
    print(f"[INFO] Download complete! Files saved to: {target_dir}")

if __name__ == "__main__":
    download_cve_data()