import os
import sys
import requests
from flask import Flask, request
from prometheus_client import generate_latest, Gauge, CollectorRegistry
import time

app = Flask(__name__)

# Create a CollectorRegistry
registry = CollectorRegistry()

# Create a Prometheus metric for the latest release
github_latest_release_metric = Gauge(
    'github_latest_release',
    'Latest release version of a GitHub repository',
    ['repo', 'version'],
    registry=registry,
)

# GitHub API token (replace with your actual token)
github_api_token = os.environ.get('GITHUB_TOKEN')

if github_api_token is None:
    sys.exit("Env variable GITHUB_TOKEN not found!")

# Function to fetch the latest release version or the latest tag from GitHub
def get_latest_version(repo_url):
    api_url = f"https://api.github.com/repos/{repo_url}/releases/latest"
    headers = {
        'Authorization': f'Bearer {github_api_token}',
        'Accept': 'application/vnd.github.v3+json'
    }
    response = requests.get(api_url, headers=headers)

    # If the repository has releases, get the latest release version
    if response.status_code == 200:
        data = response.json()
        return data["tag_name"]
    
    # If the repository doesn't have releases, get the latest tag
    if response.status_code == 404:
        api_url = f"https://api.github.com/repos/{repo_url}/tags"
        response = requests.get(api_url, headers=headers)
        data = response.json()
        if data:
            return data[0]["name"]
    
    # If both release and tag information is not available, return None
    return None

@app.route('/metrics')
def metrics():
    # Get the GitHub repository URL from the query parameter
    repo_url = request.args.get('repo')
    if not repo_url:
        return "Error: Please provide a 'repo' parameter.", 400
    
    try:
        latest_version = get_latest_version(repo_url)
        
        if latest_version:
            print(f"Latest version: {latest_version}")
            
            # Reset the metric to its initial state
            github_latest_release_metric.clear()
            
            # Set the metric value to 1 with appropriate labels
            github_latest_release_metric.labels(repo=repo_url, version=latest_version).set(1)
    except Exception as e:
        print(f"Error: {e}")
    
    return generate_latest(registry)

if __name__ == '__main__':
    # Start the web service on port 8000
    app.run(host='0.0.0.0', port=8000)