"""galaxis-agent webhook server."""
import hashlib
import hmac
import json
import logging
import os
import re

from fastapi import FastAPI, Request, HTTPException
from slowapi import Limiter
from slowapi.util import get_remote_address
from slowapi.errors import RateLimitExceeded
from slowapi.middleware import SlowAPIMiddleware

logger = logging.getLogger(__name__)

app = FastAPI(title="galaxis-agent")
limiter = Limiter(key_func=get_remote_address)
app.state.limiter = limiter
app.add_middleware(SlowAPIMiddleware)


def verify_gitea_signature(payload: bytes, signature: str, secret: str) -> bool:
    """Verify Gitea webhook HMAC-SHA256 signature."""
    expected = hmac.new(secret.encode(), payload, hashlib.sha256).hexdigest()
    return hmac.compare_digest(expected, signature)


def generate_thread_id(repo: str, issue_id: int) -> str:
    """Generate deterministic thread ID from issue."""
    raw = hashlib.sha256(f"gitea-issue:{repo}:{issue_id}".encode()).hexdigest()
    return f"{raw[:8]}-{raw[8:12]}-{raw[12:16]}-{raw[16:20]}-{raw[20:32]}"


def parse_gitea_event(event_type: str, payload: dict) -> dict:
    """Gitea webhook 페이로드를 파싱하여 처리 대상인지 판단한다."""
    repo = payload.get("repository", {})
    repo_name = repo.get("name", "")
    full_name = repo.get("full_name", "")
    repo_owner = full_name.split("/")[0] if "/" in full_name else ""

    base = {
        "should_process": False,
        "issue_number": 0,
        "repo_name": repo_name,
        "repo_owner": repo_owner,
        "message": "",
        "event_type": event_type,
        "title": "",
    }

    if event_type == "issue_comment":
        action = payload.get("action", "")
        if action != "created":
            return base
        comment_body = payload.get("comment", {}).get("body", "")
        issue = payload.get("issue", {})
        if "@agent" not in comment_body.lower():
            return base
        message = re.sub(r"@agent\b", "", comment_body, flags=re.IGNORECASE).strip()
        base.update({
            "should_process": True,
            "issue_number": issue.get("number", 0),
            "message": message,
            "title": issue.get("title", ""),
        })
        return base

    if event_type == "issues":
        label = payload.get("label", {})
        if label.get("name") == "agent-fix":
            issue = payload.get("issue", {})
            base.update({
                "should_process": True,
                "issue_number": issue.get("number", 0),
                "message": issue.get("body", ""),
                "title": issue.get("title", ""),
            })
        return base

    if event_type == "pull_request":
        action = payload.get("action", "")
        if action == "review_requested":
            pr = payload.get("pull_request", {})
            base.update({
                "should_process": True,
                "issue_number": pr.get("number", 0),
                "message": pr.get("body", ""),
                "title": pr.get("title", ""),
            })
        return base

    return base


@app.get("/health")
async def health():
    return {"status": "ok"}


@app.post("/webhooks/gitea")
@limiter.limit("10/minute")
async def gitea_webhook(request: Request):
    """Gitea webhook endpoint with event parsing and task dispatch."""
    payload_bytes = await request.body()
    signature = request.headers.get("X-Gitea-Signature", "")
    secret = os.environ.get("GITEA_WEBHOOK_SECRET", "")

    if not verify_gitea_signature(payload_bytes, signature, secret):
        raise HTTPException(status_code=401, detail="Invalid signature")

    payload = json.loads(payload_bytes)
    event_type = request.headers.get("X-Gitea-Event", "")

    event = parse_gitea_event(event_type, payload)
    if not event["should_process"]:
        return {"status": "ignored"}

    thread_id = generate_thread_id(event["repo_name"], event["issue_number"])

    from agent.message_store import get_message_store
    from agent.task_queue import get_task_queue
    task_queue = await get_task_queue()

    if await task_queue.has_running_task(thread_id):
        store = await get_message_store()
        await store.push_message(thread_id, {
            "role": "human",
            "content": event["message"],
        })
        return {"status": "queued_message", "thread_id": thread_id}

    task_id = await task_queue.enqueue(
        thread_id=thread_id,
        source="gitea",
        payload={
            "issue_number": event["issue_number"],
            "repo_owner": event["repo_owner"],
            "repo_name": event["repo_name"],
            "message": event["message"],
            "title": event["title"],
            "event_type": event["event_type"],
        },
    )
    return {"status": "enqueued", "task_id": task_id, "thread_id": thread_id}