"""
PIOE GitHub Client

Tracks trending repositories and star velocity for AI/Robotics/CV projects.
"""
import httpx
from datetime import datetime, timedelta
from typing import Optional


class GitHubClient:
    """
    Client for GitHub API to discover trending repositories.
    Tracks star velocity and contributor growth.
    """
    
    BASE_URL = "https://api.github.com"
    
    # Search queries for relevant topics
    SEARCH_TOPICS = [
        "computer-vision",
        "robotics", 
        "machine-learning",
        "deep-learning",
        "ros",
        "pytorch",
        "transformers",
        "llm"
    ]
    
    def __init__(self, token: Optional[str] = None, max_results: int = 30):
        self.token = token
        self.max_results = max_results
        self._headers = {
            "Accept": "application/vnd.github+json",
            "X-GitHub-Api-Version": "2022-11-28"
        }
        if token:
            self._headers["Authorization"] = f"Bearer {token}"
    
    async def fetch_trending(self, topics: Optional[list[str]] = None) -> list[dict]:
        """
        Fetch recently popular repositories in target topics.
        
        Returns list of normalized opportunity dicts.
        """
        topics = topics or self.SEARCH_TOPICS
        opportunities = []
        
        # Get repos created or updated in last 7 days with high stars
        week_ago = (datetime.utcnow() - timedelta(days=7)).strftime("%Y-%m-%d")
        
        for topic in topics[:5]:  # Limit to avoid rate limiting
            try:
                repos = await self._search_repos(topic, week_ago)
                opportunities.extend(repos)
            except Exception as e:
                print(f"GitHub search error for {topic}: {e}")
        
        # Deduplicate by URL
        seen_urls = set()
        unique = []
        for opp in opportunities:
            if opp["url"] not in seen_urls:
                seen_urls.add(opp["url"])
                unique.append(opp)
        
        return unique[:self.max_results]
    
    async def _search_repos(self, topic: str, since_date: str) -> list[dict]:
        """Search for repositories by topic."""
        query = f"topic:{topic} pushed:>{since_date} stars:>50"
        
        async with httpx.AsyncClient() as client:
            response = await client.get(
                f"{self.BASE_URL}/search/repositories",
                params={
                    "q": query,
                    "sort": "stars",
                    "order": "desc",
                    "per_page": 10
                },
                headers=self._headers,
                timeout=30,
                follow_redirects=True
            )
            response.raise_for_status()
        
        data = response.json()
        return self._parse_repos(data.get("items", []), topic)
    
    def _parse_repos(self, repos: list, topic: str) -> list[dict]:
        """Parse GitHub repos into normalized opportunities."""
        opportunities = []
        
        for repo in repos:
            try:
                opportunity = {
                    "title": f"[GitHub] {repo['full_name']}: {repo.get('description', '')[:100]}",
                    "raw_text": repo.get("description", "") or "",
                    "url": repo["html_url"],
                    "source_type": "github",
                    "source_name": f"GitHub/{topic}",
                    "published_at": self._parse_date(repo.get("created_at")),
                    "social_engagement": repo.get("stargazers_count", 0),
                    "metadata": {
                        "owner": repo["owner"]["login"],
                        "stars": repo.get("stargazers_count", 0),
                        "forks": repo.get("forks_count", 0),
                        "language": repo.get("language"),
                        "topics": repo.get("topics", []),
                        "open_issues": repo.get("open_issues_count", 0),
                        "updated_at": repo.get("updated_at")
                    }
                }
                opportunities.append(opportunity)
            except Exception as e:
                print(f"Error parsing repo: {e}")
        
        return opportunities
    
    async def fetch_gsoc_repos(self) -> list[dict]:
        """Fetch Google Summer of Code related repositories."""
        async with httpx.AsyncClient() as client:
            response = await client.get(
                f"{self.BASE_URL}/search/repositories",
                params={
                    "q": "topic:gsoc OR topic:google-summer-of-code",
                    "sort": "updated",
                    "per_page": 20
                },
                headers=self._headers,
                timeout=30,
                follow_redirects=True
            )
            response.raise_for_status()
        
        data = response.json()
        repos = self._parse_repos(data.get("items", []), "gsoc")
        
        # Mark as open source opportunity
        for repo in repos:
            repo["title"] = f"[GSoC] {repo['title'].replace('[GitHub] ', '')}"
        
        return repos
    
    def _parse_date(self, date_str: Optional[str]) -> Optional[datetime]:
        """Parse GitHub date format."""
        if not date_str:
            return None
        try:
            return datetime.fromisoformat(date_str.replace("Z", "+00:00"))
        except Exception:
            return None