"""Parse Gitea webhook payloads into typed `ForgeEvent`s.

Only the fields the orchestrator acts on are extracted; unknown payloads
and event types return None so the webhook layer can ignore them.

Gitea sends the event kind in the `X-Gitea-Event` header and the payload
as JSON. The relevant kinds:

- `issues` with `action == "assigned"`  -> IssueAssigned
- `issue_comment` with `action == "created"` -> CommentCreated
- `pull_request` with `action == "closed"` -> PullRequestClosed
"""

from __future__ import annotations

from typing import Any

from .model import CommentCreated, ForgeEvent, IssueAssigned, PullRequestClosed


def _repo_owner(payload: dict[str, Any]) -> tuple[str, str]:
    repo = payload.get("repository") or {}
    owner = (repo.get("owner") or {}).get("login", "")
    return str(owner), str(repo.get("name", ""))


def parse_event(event_kind: str, payload: dict[str, Any]) -> ForgeEvent | None:
    """Map (X-Gitea-Event, payload) to a `ForgeEvent`, or None to ignore."""
    if event_kind == "issues":
        return _parse_issue(payload)
    if event_kind == "issue_comment":
        return _parse_comment(payload)
    if event_kind == "pull_request":
        return _parse_pull_request(payload)
    return None


def _parse_issue(payload: dict[str, Any]) -> IssueAssigned | None:
    if payload.get("action") != "assigned":
        return None
    owner, repo = _repo_owner(payload)
    issue = payload.get("issue") or {}
    assignees = tuple(
        str(a.get("login", "")) for a in (issue.get("assignees") or [])
    )
    labels = tuple(str(l.get("name", "")) for l in (issue.get("labels") or []))
    return IssueAssigned(
        owner=owner,
        repo=repo,
        issue_number=int(issue.get("number", 0)),
        title=str(issue.get("title", "")),
        body=str(issue.get("body", "") or ""),
        assignees=assignees,
        labels=labels,
    )


def _parse_comment(payload: dict[str, Any]) -> CommentCreated | None:
    if payload.get("action") != "created":
        return None
    owner, repo = _repo_owner(payload)
    issue = payload.get("issue") or {}
    comment = payload.get("comment") or {}
    return CommentCreated(
        owner=owner,
        repo=repo,
        issue_number=int(issue.get("number", 0)),
        comment_id=int(comment.get("id", 0)),
        author=str((comment.get("user") or {}).get("login", "")),
        body=str(comment.get("body", "") or ""),
        is_pull=bool(issue.get("pull_request")),
    )


def _parse_pull_request(payload: dict[str, Any]) -> PullRequestClosed | None:
    if payload.get("action") != "closed":
        return None
    owner, repo = _repo_owner(payload)
    pr = payload.get("pull_request") or {}
    return PullRequestClosed(
        owner=owner,
        repo=repo,
        pr_number=int(pr.get("number", 0)),
        merged=bool(pr.get("merged", False)),
    )