import yaml
import json
import requests
import sys
import os
from urllib.parse import urljoin

def load_yaml(path):
    with open(path, 'r') as f:
        return yaml.safe_load(f)

def fetch_index(repo_url):
    index_url = urljoin(repo_url + '/', 'index.yaml')
    print(f"Fetching index from {index_url}...")
    try:
        r = requests.get(index_url)
        r.raise_for_status()
        return yaml.safe_load(r.text)
    except Exception as e:
        print(f"Error fetching {index_url}: {e}")
        return None

def main():
    if len(sys.argv) < 2:
        print("Usage: python helm_sync.py <path_to_chartfile.yaml> [output_lock_file]")
        sys.exit(1)

    chartfile_path = sys.argv[1]
    lockfile_path = sys.argv[2] if len(sys.argv) > 2 else chartfile_path.replace('.yaml', '.lock.json')

    print(f"Reading {chartfile_path}...")
    chartfile = load_yaml(chartfile_path)

    repos = {r['name']: r['url'] for r in chartfile.get('repositories', [])}
    indices = {}

    lock_data = {"charts": {}}

    for req in chartfile.get('requires', []):
        chart_ref = req['chart']
        version = req['version']
        
        if '/' not in chart_ref:
            print(f"Invalid chart reference: {chart_ref}. Expected repo/name.")
            continue
            
        repo_name, chart_name = chart_ref.split('/', 1)
        
        if repo_name not in repos:
            print(f"Repository '{repo_name}' not found for chart {chart_ref}")
            continue
            
        repo_url = repos[repo_name]
        
        if repo_name not in indices:
            indices[repo_name] = fetch_index(repo_url)
            
        index = indices[repo_name]
        if not index:
            print(f"Skipping {chart_ref} due to missing index.")
            continue
            
        entries = index.get('entries', {}).get(chart_name, [])
        
        # Find exact version
        matched_entry = None
        for entry in entries:
            if entry['version'] == version:
                matched_entry = entry
                break
        
        if not matched_entry:
            print(f"Version {version} not found for chart {chart_ref}")
            continue
            
        # Resolve URL
        urls = matched_entry.get('urls', [])
        if not urls:
            print(f"No URLs found for {chart_ref} version {version}")
            continue
            
        # URL can be relative or absolute
        chart_url = urls[0]
        if not chart_url.startswith('http'):
            chart_url = urljoin(repo_url + '/', chart_url)
            
        digest = matched_entry.get('digest')
        
        print(f"Resolved {chart_ref} {version} -> {chart_url}")
        
        lock_data["charts"][chart_ref] = {
            "version": version,
            "url": chart_url,
            "digest": digest
        }

    print(f"Writing lockfile to {lockfile_path}...")
    with open(lockfile_path, 'w') as f:
        json.dump(lock_data, f, indent=2, sort_keys=True)
        f.write('\n')

if __name__ == "__main__":
    main()