rmi-backend/.github/scripts/ai_review.py

#!/usr/bin/env python3
"""Post an AI-generated review comment on a pull request from a diff file.

Environment variables:
    AI_REVIEW_API_KEY     API key for the chat-completions endpoint.
    AI_REVIEW_MODEL       Model string (default: openrouter/openai/gpt-4o-mini).
    AI_REVIEW_BASE_URL    Base URL for the endpoint (default: https://openrouter.ai/api/v1).
    GITHUB_TOKEN          GitHub token used to post the PR comment.
    PR_NUMBER             Pull request number to comment on.

Usage:
    python3 .github/scripts/ai_review.py /path/to/pr.diff
"""

from __future__ import annotations

import json
import os
import sys
from pathlib import Path

import httpx

DEFAULT_MODEL = "openrouter/openai/gpt-4o-mini"
DEFAULT_BASE_URL = "https://openrouter.ai/api/v1"
MAX_DIFF_CHARS = 30_000

SYSTEM_PROMPT = (
    "You are a senior code reviewer for a FastAPI crypto-intelligence backend. "
    "Review the provided diff for correctness, security, maintainability, and "
    "conformance to the project standards. Keep the response concise, actionable, "
    "and focused on the most important issues. If the diff is large, prioritize "
    "architecture and security concerns."
)


def _call_llm(diff_text: str) -> str:
    api_key = os.environ.get("AI_REVIEW_API_KEY")
    if not api_key:
        return "AI_REVIEW_API_KEY not set; skipping AI review."

    base_url = os.environ.get("AI_REVIEW_BASE_URL", DEFAULT_BASE_URL).rstrip("/")
    model = os.environ.get("AI_REVIEW_MODEL", DEFAULT_MODEL)

    payload = {
        "model": model,
        "messages": [
            {"role": "system", "content": SYSTEM_PROMPT},
            {"role": "user", "content": f"Pull request diff:\n\n```diff\n{diff_text}\n```"},
        ],
        "temperature": 0.2,
        "max_tokens": 2_000,
    }

    data = json.dumps(payload).encode("utf-8")
    headers = {
        "Authorization": f"Bearer {api_key}",
        "Content-Type": "application/json",
    }

    try:
        with httpx.Client(timeout=120) as client:
            resp = client.post(f"{base_url}/chat/completions", content=data, headers=headers)
            result = resp.json()
    except httpx.HTTPError as exc:
        return f"AI review API request failed: {exc}"
    except Exception as exc:
        return f"AI review API request failed: {exc}"

    try:
        return result["choices"][0]["message"]["content"]
    except (KeyError, IndexError, TypeError):
        return f"AI review returned unexpected response: {result}"


def _post_comment(body: str) -> None:
    pr_number = os.environ.get("PR_NUMBER")
    token = os.environ.get("GITHUB_TOKEN")
    repo = os.environ.get("GITHUB_REPOSITORY")
    if not pr_number or not token or not repo:
        print("PR_NUMBER/GITHUB_TOKEN/GITHUB_REPOSITORY not set; printing review to stdout.")
        print(body)
        return

    payload = json.dumps({"body": body}).encode("utf-8")
    headers = {
        "Authorization": f"Bearer {token}",
        "Accept": "application/vnd.github+json",
        "Content-Type": "application/json",
    }
    try:
        with httpx.Client(timeout=60) as client:
            resp = client.post(
                f"https://api.github.com/repos/{repo}/issues/{pr_number}/comments",
                content=payload,
                headers=headers,
            )
            print(f"Posted AI review comment: {resp.status_code}")
    except httpx.HTTPError as exc:
        print(f"Failed to post comment: {exc}", file=sys.stderr)
    except Exception as exc:
        print(f"Failed to post comment: {exc}", file=sys.stderr)


def main() -> int:
    diff_path = Path(sys.argv[1]) if len(sys.argv) > 1 else None
    if diff_path:
        diff_text = diff_path.read_text(encoding="utf-8", errors="ignore")
    else:
        diff_text = sys.stdin.read()

    if not diff_text.strip():
        print("No diff provided; skipping AI review.")
        return 0

    if len(diff_text) > MAX_DIFF_CHARS:
        diff_text = diff_text[:MAX_DIFF_CHARS] + "\n\n... [diff truncated for token limits]"

    review = _call_llm(diff_text)
    _post_comment(review)
    return 0


if __name__ == "__main__":
    raise SystemExit(main())