import os
import urllib.request
import urllib.error
import hashlib
import sys
import ssl
import time

# Configuration - PncyssD Resource Manifest
RESOURCES = [
    {
        "url": "https://grainy-gradients.vercel.app/noise.svg",
        "filename": "noise.svg",
        "dir": "src/assets",
        "md5": None  # Skip check for dynamic/external resources if hash unknown, or fill if known
    }
]

def get_remote_file_size(url):
    try:
        req = urllib.request.Request(url, method='HEAD', headers={'User-Agent': 'Mozilla/5.0'})
        ctx = ssl.create_default_context()
        ctx.check_hostname = False
        ctx.verify_mode = ssl.CERT_NONE
        with urllib.request.urlopen(req, context=ctx, timeout=10) as response:
            return int(response.headers.get('Content-Length', 0))
    except:
        return 0

def calculate_md5(filepath):
    hash_md5 = hashlib.md5()
    with open(filepath, "rb") as f:
        for chunk in iter(lambda: f.read(4096), b""):
            hash_md5.update(chunk)
    return hash_md5.hexdigest()

def download_file_with_resume(url, directory, filename, expected_md5=None):
    if not os.path.exists(directory):
        os.makedirs(directory)
    
    filepath = os.path.join(directory, filename)
    temp_filepath = filepath + ".part"
    
    total_size = get_remote_file_size(url)
    downloaded_size = 0
    
    if os.path.exists(temp_filepath):
        downloaded_size = os.path.getsize(temp_filepath)
    
    # Check if file already exists and is complete
    if os.path.exists(filepath):
        if expected_md5:
            current_md5 = calculate_md5(filepath)
            if current_md5 == expected_md5:
                print(f"[SKIP] {filename} already exists and matches MD5.")
                return True
            else:
                print(f"[WARN] {filename} exists but MD5 mismatch. Re-downloading.")
        else:
            # If no MD5 provided, check size if possible, or just skip if it exists
            if total_size > 0 and os.path.getsize(filepath) == total_size:
                 print(f"[SKIP] {filename} already exists (size match).")
                 return True

    headers = {'User-Agent': 'Mozilla/5.0'}
    if downloaded_size > 0:
        headers['Range'] = f'bytes={downloaded_size}-'
        print(f"[RESUME] Resuming {filename} from {downloaded_size} bytes...")
    else:
        print(f"[START] Downloading {filename}...")

    req = urllib.request.Request(url, headers=headers)
    ctx = ssl.create_default_context()
    ctx.check_hostname = False
    ctx.verify_mode = ssl.CERT_NONE

    try:
        with urllib.request.urlopen(req, context=ctx, timeout=20) as response:
            mode = 'ab' if downloaded_size > 0 else 'wb'
            with open(temp_filepath, mode) as f:
                while True:
                    chunk = response.read(8192)
                    if not chunk:
                        break
                    f.write(chunk)
                    downloaded_size += len(chunk)
                    
                    # Simple progress bar
                    if total_size > 0:
                        percent = (downloaded_size / total_size) * 100
                        sys.stdout.write(f"\rProgress: [{('=' * int(percent // 2)).ljust(50)}] {percent:.1f}%")
                        sys.stdout.flush()
        
        print() # Newline after progress
        
        # Verify MD5 if provided
        if expected_md5:
            if calculate_md5(temp_filepath) != expected_md5:
                print(f"\n[ERROR] MD5 verification failed for {filename}")
                return False
        
        os.rename(temp_filepath, filepath)
        print(f"[SUCCESS] Saved to {filepath}")
        return True

    except urllib.error.HTTPError as e:
        if e.code == 416: # Range Not Satisfiable (likely already complete)
            print(f"\n[INFO] File likely already complete.")
            if os.path.exists(temp_filepath):
                os.rename(temp_filepath, filepath)
            return True
        print(f"\n[ERROR] HTTP Error: {e}")
        return False
    except Exception as e:
        print(f"\n[ERROR] Failed to download {url}: {e}")
        return False

def main():
    print("=== PncyssD Static Resource Downloader ===")
    print("Features: MD5 Check, Resume Capability, Progress Bar")
    print("==========================================")
    
    success_count = 0
    for res in RESOURCES:
        if download_file_with_resume(res["url"], res["dir"], res["filename"], res.get("md5")):
            success_count += 1
            
    print(f"\nTotal: {len(RESOURCES)}, Success: {success_count}")

if __name__ == "__main__":
    main()