"""ci-ai-bot — schlanker Gitea-Webhook-Dienst (interaktiver KI-Bot).

Empfängt Gitea-Webhooks und reagiert sofort (Antwort in Sekunden, nicht über die
CI-Pipeline). Wiederverwendet die ci-ai-Module:
  - scripts/llm.py       → LLM-Backend (Jetson-Ollama, provider-agnostisch)
  - scripts/gitea_api.py → Diff/Thread holen, Kommentare posten
  - scripts/ai_review.py → derselbe Review-Prompt wie die CI-Variante

Events:
  - issue_comment (created) mit `@<BOT_NAME>` → Chat/Q&A im Thread-Kontext (neue Antwort)
  - pull_request (opened/synchronized/reopened) → automatisches PR-Review (idempotent)

Läuft auf dem Pi im web_network neben Gitea: Gitea-API intern über http://gitea:3000,
LLM über die Jetson-LAN-IP. Kein Runner, kein Clone, kein Hairpin.

Env: BOT_NAME, WEBHOOK_SECRET, GITEA_TOKEN, GITEA_API, AI_PROVIDER, AI_MODEL, AI_BASE_URL.
"""
import hashlib
import hmac
import json
import os
import sys

from fastapi import BackgroundTasks, FastAPI, Request, Response

sys.path.insert(0, os.path.join(os.path.dirname(__file__), "scripts"))
import ai_review  # noqa: E402  (reuse SYSTEM/PROMPT/filter_diff/MARKER/DIFF_CAP)
import gitea_api  # noqa: E402
import llm  # noqa: E402

BOT_NAME = os.environ.get("BOT_NAME", "ci-ai")
SECRET = os.environ.get("WEBHOOK_SECRET", "")
THREAD_CAP = 18000
DIFF_CAP = 18000

CHAT_SYSTEM = (
    "Du bist ein hilfreicher KI-Assistent in Gitea-Pull-Requests/Issues. Antworte auf "
    "Deutsch, knapp und konkret, auf Basis des Threads und (falls PR) des Diffs. "
    "Erfinde nichts, was nicht im Kontext steht."
)

app = FastAPI(title="ci-ai-bot")


@app.get("/healthz")
def healthz():
    return {"status": "ok", "bot": BOT_NAME}


def _verify(body: bytes, signature: str) -> bool:
    if not SECRET:
        return True
    mac = hmac.new(SECRET.encode(), body, hashlib.sha256).hexdigest()
    return hmac.compare_digest(mac, signature or "")


def handle_comment(event: dict) -> None:
    """@mention → eine Chat-Antwort (neuer Kommentar, mit Thread-/Diff-Kontext)."""
    comment = (event.get("comment") or {}).get("body") or ""
    if f"@{BOT_NAME}" not in comment:
        return
    owner, name = event["repository"]["full_name"].split("/", 1)
    issue = event["issue"]
    index = issue["number"]
    question = comment.split(f"@{BOT_NAME}", 1)[1].strip() or "Fasse den Stand zusammen."

    thread = gitea_api.get_issue_thread(owner, name, index)[:THREAD_CAP]
    prompt = f"Frage an dich: {question}\n\n--- Thread ---\n{thread}"
    if issue.get("pull_request"):
        try:
            diff = ai_review.filter_diff(gitea_api.get_pr_diff(owner, name, index))[:DIFF_CAP]
            if diff:
                prompt += f"\n\n--- Diff ---\n{diff}"
        except Exception:
            pass

    answer = llm.complete(CHAT_SYSTEM, prompt, max_tokens=1200)
    gitea_api.post_comment(owner, name, index, f"🤖 {answer}")
    print(f"[bot] chat reply on {owner}/{name}#{index}", flush=True)


def handle_pr(event: dict) -> None:
    """PR opened/synchronized → idempotentes KI-Review (gleicher Prompt wie CI)."""
    if event.get("action") not in ("opened", "synchronized", "reopened"):
        return
    owner, name = event["repository"]["full_name"].split("/", 1)
    pr = event["pull_request"]
    index = pr["number"]
    diff = ai_review.filter_diff(gitea_api.get_pr_diff(owner, name, index))[: ai_review.DIFF_CAP]
    if not diff:
        return
    answer = llm.complete(
        ai_review.SYSTEM,
        ai_review.PROMPT.format(title=pr.get("title", ""), body=(pr.get("body") or "")[:1000], diff=diff),
        max_tokens=1800,
    )
    gitea_api.upsert_comment(owner, name, index, ai_review.MARKER, f"## 🤖 KI-Review\n\n{answer}")
    print(f"[bot] review on {owner}/{name}#{index}", flush=True)


@app.post("/webhook")
async def webhook(request: Request, background: BackgroundTasks):
    body = await request.body()
    if not _verify(body, request.headers.get("X-Gitea-Signature", "")):
        return Response(status_code=401, content="bad signature")
    event = json.loads(body or b"{}")
    etype = request.headers.get("X-Gitea-Event", "")
    # Antworte SOFORT mit 200; die LLM-Arbeit läuft im Hintergrund (Gitea-Timeout-Schutz).
    if etype == "issue_comment" and event.get("action") == "created":
        background.add_task(handle_comment, event)
    elif etype == "pull_request":
        background.add_task(handle_pr, event)
    return {"ok": True, "event": etype}