"""
IssueSink adapter interface and implementations.

IssueSink is the outbound boundary between activity-core and task backends
(issue-core, etc.). It receives TaskSpec objects and returns TaskRef objects.

Active sink is selected by ISSUE_SINK_TYPE env var: "rest" (default) | "null".
"""

from __future__ import annotations

import logging
import os
import uuid
from abc import ABC, abstractmethod

import httpx

from activity_core.rules.models import TaskRef, TaskSpec

logger = logging.getLogger(__name__)

ISSUE_CORE_URL = os.environ.get("ISSUE_CORE_URL", "http://127.0.0.1:8765")
ISSUE_CORE_API_KEY_ENV = "ISSUE_CORE_API_KEY"
ISSUE_SINK_TYPE = os.environ.get("ISSUE_SINK_TYPE", "rest")


class IssueSink(ABC):
    @abstractmethod
    def emit(self, task_spec: TaskSpec) -> TaskRef: ...


class IssueCoreRestSink(IssueSink):
    """POSTs to issue-core REST API.

    Config: ISSUE_CORE_URL and ISSUE_CORE_API_KEY env vars (shared key with
    the issue-core server).
    """

    def __init__(
        self,
        base_url: str = ISSUE_CORE_URL,
        api_key: str | None = None,
    ) -> None:
        self._base_url = base_url.rstrip("/")
        if api_key is not None:
            self._api_key = api_key.strip()
        else:
            self._api_key = os.environ.get(ISSUE_CORE_API_KEY_ENV, "").strip()

    def _auth_headers(self) -> dict[str, str]:
        if not self._api_key:
            raise RuntimeError(
                f"{ISSUE_CORE_API_KEY_ENV} is not set. "
                "Required when ISSUE_SINK_TYPE=rest."
            )
        return {"Authorization": f"Bearer {self._api_key}"}

    def emit(self, task_spec: TaskSpec) -> TaskRef:
        payload = {
            "title": task_spec.title,
            "description": task_spec.description,
            "target_repo": task_spec.target_repo,
            "priority": task_spec.priority,
            "labels": task_spec.labels,
            "due_in_days": task_spec.due_in_days,
            "source_type": task_spec.source_type,
            "source_id": task_spec.source_id,
            "triggering_event_id": (
                str(task_spec.triggering_event_id)
                if task_spec.triggering_event_id is not None
                else None
            ),
            "activity_definition_id": task_spec.activity_definition_id,
        }
        resp = httpx.post(
            f"{self._base_url}/issues/",
            json=payload,
            headers=self._auth_headers(),
            timeout=10.0,
        )
        resp.raise_for_status()
        data = resp.json()
        return TaskRef(
            external_id=data["issue_id"],
            backend_url=data.get("issue_url"),
            backend=data.get("backend", ""),
        )


class NullSink(IssueSink):
    """Discards tasks and returns synthetic TaskRefs. For testing."""

    def emit(self, task_spec: TaskSpec) -> TaskRef:
        synthetic_id = f"null-{uuid.uuid4()}"
        logger.debug("NullSink: discarding task %r → %s", task_spec.title, synthetic_id)
        return TaskRef(external_id=synthetic_id, backend="null")


def get_issue_sink() -> IssueSink:
    """Factory: returns the configured IssueSink based on ISSUE_SINK_TYPE."""
    sink_type = ISSUE_SINK_TYPE.lower()
    if sink_type == "null":
        return NullSink()
    return IssueCoreRestSink()