"""Schlanke Gitea-API-Helfer (stdlib only).

- PR-Diff holen
- Kommentare IDEMPOTENT posten: ein versteckter HTML-Marker identifiziert den
  Bot-Kommentar; existiert er schon, wird er editiert statt neu angelegt
  (kein Zuspammen bei jedem Push).

Env-Vars:
  GITEA_API     Basis-URL der API, Default https://git.eulernest.eu/api/v1
  GITEA_TOKEN   Token fürs Kommentieren (Actions-Auto-Token ODER PAT).
                Fallback: GITEA_BOT_TOKEN.
"""
import json
import os
import urllib.error
import urllib.request

_BASE = os.environ.get("GITEA_API", "https://git.eulernest.eu/api/v1").rstrip("/")
_TOKEN = os.environ.get("GITEA_TOKEN") or os.environ.get("GITEA_BOT_TOKEN", "")


def _request(method: str, path: str, *, data=None, raw: bool = False):
    url = f"{_BASE}{path}"
    headers = {}
    if _TOKEN:
        headers["Authorization"] = f"token {_TOKEN}"
    body = None
    if data is not None:
        body = json.dumps(data).encode("utf-8")
        headers["Content-Type"] = "application/json"
    req = urllib.request.Request(url, data=body, headers=headers, method=method)
    try:
        with urllib.request.urlopen(req, timeout=60) as resp:
            content = resp.read().decode("utf-8", "replace")
            if raw:
                return content
            return json.loads(content) if content.strip() else None
    except urllib.error.HTTPError as exc:
        detail = exc.read().decode("utf-8", "replace")
        raise SystemExit(f"[gitea] {method} {path} -> HTTP {exc.code}: {detail[:400]}")
    except urllib.error.URLError as exc:
        raise SystemExit(f"[gitea] {method} {path} fehlgeschlagen: {exc.reason}")


def get_pr_diff(owner: str, repo: str, index: int) -> str:
    """Unified Diff eines PRs (Gitea unterstützt den .diff-Suffix)."""
    return _request("GET", f"/repos/{owner}/{repo}/pulls/{index}.diff", raw=True)


def upsert_comment(owner: str, repo: str, index: int, marker: str, body: str) -> int:
    """Legt einen Kommentar an ODER editiert den vorhandenen mit gleichem Marker.

    PR-Kommentare sind in Gitea Issue-Kommentare (gleicher Endpunkt).
    """
    full = f"{body}\n\n{marker}"
    existing = _request("GET", f"/repos/{owner}/{repo}/issues/{index}/comments") or []
    for comment in existing:
        if marker in (comment.get("body") or ""):
            _request(
                "PATCH",
                f"/repos/{owner}/{repo}/issues/comments/{comment['id']}",
                data={"body": full},
            )
            return comment["id"]
    created = _request(
        "POST",
        f"/repos/{owner}/{repo}/issues/{index}/comments",
        data={"body": full},
    )
    return created["id"]