"""Tests for the event-lifecycle detection service (T52).

Per Phase 3, after each narrated turn we ask a classifier whether any
active events transitioned (started, completed, cancelled). The bias is
strongly toward an empty result — most turns do NOT resolve or start a
known event, and the turn-flow caller (T61) only appends an
event_started/completed/cancelled record when this service yields one.

These tests cover:

* The classifier returning a single transition is honored end-to-end.
* An empty ``active_events`` list short-circuits before any LLM call,
  so callers that hold no live events pay zero classifier cost.
* Three rounds of malformed JSON exhaust ``classify``'s retries and we
  fall back to the empty default — graceful degradation per §3.3.
"""

from __future__ import annotations

import json

import pytest

from chat.llm.mock import MockLLMClient
from chat.services.event_lifecycle import (
    EventLifecycleDecision,
    detect_event_transitions,
)


@pytest.mark.asyncio
async def test_detects_one_transition_happy_path():
    canned = json.dumps(
        {
            "transitions": [
                {
                    "event_id": "evt_1",
                    "new_status": "completed",
                    "reason": "they arrived at the park",
                }
            ]
        }
    )
    mock = MockLLMClient(canned=[canned])
    result = await detect_event_transitions(
        mock,
        classifier_model="x",
        narrative_text="They walked through the park gate, finally there.",
        active_events=[
            {
                "event_id": "evt_1",
                "kind": "date_at_park",
                "status": "active",
                "props": {},
            }
        ],
    )
    assert isinstance(result, EventLifecycleDecision)
    assert len(result.transitions) == 1
    assert result.transitions[0].event_id == "evt_1"
    assert result.transitions[0].new_status == "completed"
    assert result.transitions[0].reason == "they arrived at the park"


@pytest.mark.asyncio
async def test_empty_active_events_short_circuits_without_classifier_call():
    """No active events -> no classifier call.

    The mock has an empty canned list; any ``generate`` call would raise
    ``IndexError`` from ``list.pop(0)``. The test passing proves the
    short-circuit holds.
    """
    mock = MockLLMClient(canned=[])
    result = await detect_event_transitions(
        mock,
        classifier_model="x",
        narrative_text="Just a quiet moment between them.",
        active_events=[],
    )
    assert isinstance(result, EventLifecycleDecision)
    assert result.transitions == []


@pytest.mark.asyncio
async def test_classifier_failure_returns_empty_default():
    """``classify`` retries 3 times; after all fail it returns the empty
    default so the turn flow keeps moving (§3.3 graceful degradation)."""
    mock = MockLLMClient(canned=["bad", "bad", "bad"])
    result = await detect_event_transitions(
        mock,
        classifier_model="x",
        narrative_text="Some text the classifier will choke on.",
        active_events=[
            {
                "event_id": "evt_1",
                "kind": "date_at_park",
                "status": "active",
                "props": {},
            }
        ],
    )
    assert isinstance(result, EventLifecycleDecision)
    assert result.transitions == []