"""GitHub tools — PR diffs, repo info."""

import os
import re
from typing import Optional


async def github_pr_diff(pr_url: str) -> dict:
    """Fetch a GitHub PR's diff and metadata.

    Args:
        pr_url: Full GitHub PR URL (e.g. https://github.com/owner/repo/pull/123)
    """
    import httpx

    # Parse owner/repo/number from URL
    match = re.match(r"https?://github\.com/([^/]+)/([^/]+)/pull/(\d+)", pr_url)
    if not match:
        return {"error": f"Invalid PR URL format: {pr_url}"}

    owner, repo, number = match.group(1), match.group(2), match.group(3)
    api_base = f"https://api.github.com/repos/{owner}/{repo}/pulls/{number}"

    headers = {"Accept": "application/vnd.github.v3+json"}
    token = os.environ.get("GITHUB_TOKEN")
    if token:
        headers["Authorization"] = f"token {token}"

    async with httpx.AsyncClient(timeout=20) as client:
        # Get PR metadata
        meta_res = await client.get(api_base, headers=headers)
        if meta_res.status_code != 200:
            return {"error": f"GitHub API {meta_res.status_code}: {meta_res.text[:200]}"}
        meta = meta_res.json()

        # Get diff
        diff_headers = {**headers, "Accept": "application/vnd.github.v3.diff"}
        diff_res = await client.get(api_base, headers=diff_headers)
        diff = diff_res.text if diff_res.status_code == 200 else "Could not fetch diff"

        # Truncate large diffs
        if len(diff) > 20000:
            diff = diff[:20000] + "\n\n[diff truncated — too large]"

        return {
            "title": meta.get("title"),
            "author": meta.get("user", {}).get("login"),
            "state": meta.get("state"),
            "additions": meta.get("additions"),
            "deletions": meta.get("deletions"),
            "changed_files": meta.get("changed_files"),
            "base_branch": meta.get("base", {}).get("ref"),
            "head_branch": meta.get("head", {}).get("ref"),
            "description": (meta.get("body") or "")[:1000],
            "diff": diff,
        }


async def github_repo_info(repo_url: str) -> dict:
    """Get basic info about a GitHub repository.

    Args:
        repo_url: GitHub repo URL (e.g. https://github.com/owner/repo)
    """
    import httpx

    match = re.match(r"https?://github\.com/([^/]+)/([^/]+)", repo_url)
    if not match:
        return {"error": f"Invalid repo URL: {repo_url}"}

    owner, repo = match.group(1), match.group(2)
    headers = {"Accept": "application/vnd.github.v3+json"}
    token = os.environ.get("GITHUB_TOKEN")
    if token:
        headers["Authorization"] = f"token {token}"

    async with httpx.AsyncClient(timeout=15) as client:
        res = await client.get(
            f"https://api.github.com/repos/{owner}/{repo}",
            headers=headers,
        )
        if res.status_code != 200:
            return {"error": f"GitHub API {res.status_code}"}

        data = res.json()
        return {
            "name": data.get("full_name"),
            "description": data.get("description"),
            "language": data.get("language"),
            "stars": data.get("stargazers_count"),
            "forks": data.get("forks_count"),
            "open_issues": data.get("open_issues_count"),
            "topics": data.get("topics", []),
            "default_branch": data.get("default_branch"),
            "updated_at": data.get("updated_at"),
        }