"""OpenLineage event emitter for airflow-correlator.

This module constructs and emits OpenLineage events to Correlator backend.

Event Types:
    - START: Task execution begins
    - COMPLETE: Task execution succeeds
    - FAIL: Task execution fails

The emitter handles:
    - Creating OpenLineage RunEvent objects
    - Batch emission of events to OpenLineage consumers
    - HTTP transport with error handling

Architecture:
    Listener captures task lifecycle → Emitter constructs events → HTTP POST to Correlator

OpenLineage Specification:
    - Core spec: https://openlineage.io/docs/spec/object-model
    - Run cycle: https://openlineage.io/docs/spec/run-cycle

Note:
    This is a skeleton implementation. Full functionality will be added after
    Task 1.2 research is complete.
"""

import logging
from typing import Any, Optional

from openlineage.client.event_v2 import RunEvent

from . import __version__

logger = logging.getLogger(__name__)

# Plugin version for producer field
PRODUCER = f"https://github.com/correlator-io/airflow-correlator/{__version__}"


def emit_events(
    events: list[RunEvent],
    endpoint: str,
    api_key: Optional[str] = None,
) -> None:
    """Emit batch of OpenLineage events to backend.

    Sends all events in a single HTTP POST using OpenLineage batch format.
    More efficient than individual emission (50x fewer requests for 50 events).

    Supports any OpenLineage-compatible backend.

    Args:
        events: List of OpenLineage RunEvents to emit.
        endpoint: OpenLineage API endpoint URL.
        api_key: Optional API key for authentication (X-API-Key header).

    Raises:
        ConnectionError: If unable to connect to endpoint.
        TimeoutError: If request times out.
        ValueError: If response indicates error (4xx/5xx status codes).
        NotImplementedError: Skeleton implementation - not yet functional.

    Example:
        >>> events = [start_event, *test_events, complete_event]
        >>> emit_events(events, "http://localhost:8080/api/v1/lineage/events")

    Note:
        - Uses OpenLineage batch format (array of events)
        - Handles 207 partial success gracefully (logs warning)
        - No retry logic (consistent with dbt-ol pattern)
        - Fire-and-forget: lineage emission doesn't block task execution
    """
    raise NotImplementedError(
        "emit_events() is not yet implemented. This is a skeleton release."
    )


def create_run_event(
    event_type: str,
    run_id: str,
    job_name: str,
    job_namespace: str,
    event_time: Optional[str] = None,
    inputs: Optional[list[dict[str, Any]]] = None,
    outputs: Optional[list[dict[str, Any]]] = None,
    producer: str = PRODUCER,
) -> dict[str, Any]:
    """Create an OpenLineage RunEvent dictionary.

    Constructs a complete OpenLineage event following the v1.0 specification.
    This is a simplified version for the skeleton release.

    Args:
        event_type: Event type - "START", "COMPLETE", "FAIL", or "ABORT".
        run_id: Unique identifier for this run (UUID format).
        job_name: Name of the job (e.g., "dag_id.task_id").
        job_namespace: Namespace for the job (e.g., "airflow").
        event_time: ISO 8601 timestamp. If None, uses current UTC time.
        inputs: Optional list of input dataset dictionaries.
        outputs: Optional list of output dataset dictionaries.
        producer: Producer URI identifying this plugin.

    Returns:
        OpenLineage event dictionary ready for emission.

    Raises:
        NotImplementedError: Skeleton implementation - not yet functional.

    Example:
        >>> event = create_run_event(
        ...     event_type="START",
        ...     run_id="550e8400-e29b-41d4-a716-446655440000",
        ...     job_namespace="airflow",
        ...     job_name="etl_dag.extract_task",
        ... )
        >>> event["eventType"]
        'START'
    """
    raise NotImplementedError(
        "create_run_event() is not yet implemented. This is a skeleton release."
    )
