"""
tests/test_risk_timeline.py

Unit tests for build_timeline() in risk_attribution.py:
  - Buckets multiple same-type events in same time window into one item
  - Includes incident escalation events
  - Respects max_items limit
  - Sorts newest-first
"""
import sys, os
sys.path.insert(0, os.path.join(os.path.dirname(__file__), "../services/router"))

import datetime
import pytest
from risk_attribution import build_timeline


def _now() -> str:
    return datetime.datetime.utcnow().isoformat()


def _ts(minutes_ago: int) -> str:
    return (datetime.datetime.utcnow() - datetime.timedelta(minutes=minutes_ago)).isoformat()


_POLICY = {
    "timeline": {
        "enabled": True,
        "lookback_hours": 24,
        "max_items": 30,
        "include_types": ["deploy", "incident", "slo", "followup", "alert_loop", "release_gate",
                          "dependency", "drift", "alert"],
        "time_bucket_minutes": 5,
    },
}


class TestBuildTimeline:
    def test_empty_input(self):
        result = build_timeline([], _POLICY)
        assert result == []

    def test_single_event(self):
        events = [{"ts": _ts(10), "type": "deploy", "label": "Deploy: canary", "refs": {}}]
        result = build_timeline(events, _POLICY)
        assert len(result) == 1
        assert result[0]["type"] == "deploy"
        assert result[0]["label"] == "Deploy: canary"

    def test_newest_first(self):
        events = [
            {"ts": _ts(60), "type": "deploy", "label": "Old deploy", "refs": {}},
            {"ts": _ts(10), "type": "incident", "label": "New incident", "refs": {}},
        ]
        result = build_timeline(events, _POLICY)
        assert result[0]["type"] == "incident"   # newest first
        assert result[1]["type"] == "deploy"

    def test_buckets_same_type_same_window(self):
        """Multiple deploy alerts in the same 5-min window → coalesced to 1 item with xN."""
        now = datetime.datetime.utcnow()
        # All within the same 5-min bucket
        base = now.replace(second=0, microsecond=0)
        bucket_start = base - datetime.timedelta(minutes=base.minute % 5)
        events = [
            {"ts": (bucket_start + datetime.timedelta(seconds=i)).isoformat(),
             "type": "deploy", "label": "Deploy alert", "refs": {"alert_ref": f"alrt_{i}"}}
            for i in range(4)
        ]
        result = build_timeline(events, _POLICY)
        # Should be coalesced into 1 item
        deploy_items = [e for e in result if e["type"] == "deploy"]
        assert len(deploy_items) == 1
        assert "×4" in deploy_items[0]["label"]

    def test_different_types_not_bucketed_together(self):
        now = datetime.datetime.utcnow()
        bucket_start = now.replace(second=0, microsecond=0)
        bucket_start -= datetime.timedelta(minutes=bucket_start.minute % 5)
        events = [
            {"ts": bucket_start.isoformat(), "type": "deploy",
             "label": "Deploy", "refs": {}},
            {"ts": bucket_start.isoformat(), "type": "incident",
             "label": "Incident", "refs": {}},
        ]
        result = build_timeline(events, _POLICY)
        assert len(result) == 2

    def test_max_items_respected(self):
        events = [
            {"ts": _ts(i * 6), "type": "alert", "label": f"Alert {i}", "refs": {}}
            for i in range(50)
        ]
        policy = {**_POLICY, "timeline": {**_POLICY["timeline"], "max_items": 5}}
        result = build_timeline(events, policy)
        assert len(result) == 5

    def test_include_types_filter(self):
        events = [
            {"ts": _ts(10), "type": "deploy", "label": "Deploy", "refs": {}},
            {"ts": _ts(20), "type": "unknown_type", "label": "Unknown", "refs": {}},
        ]
        policy = {**_POLICY, "timeline": {**_POLICY["timeline"], "include_types": ["deploy"]}}
        result = build_timeline(events, policy)
        assert all(e["type"] == "deploy" for e in result)

    def test_incident_escalation_included(self):
        events = [
            {"ts": _ts(5), "type": "incident",
             "label": "Incident escalated: inc_001",
             "refs": {"incident_id": "inc_001"}},
        ]
        result = build_timeline(events, _POLICY)
        assert len(result) == 1
        assert "inc_001" in str(result[0]["refs"])

    def test_timeline_disabled(self):
        policy = {**_POLICY, "timeline": {**_POLICY["timeline"], "enabled": False}}
        events = [{"ts": _ts(5), "type": "deploy", "label": "D", "refs": {}}]
        result = build_timeline(events, policy)
        assert result == []

    def test_refs_preserved(self):
        events = [{
            "ts": _ts(5),
            "type": "deploy",
            "label": "Canary deploy",
            "refs": {"alert_ref": "alrt_xyz", "service": "gateway"},
        }]
        result = build_timeline(events, _POLICY)
        assert len(result) == 1
        refs = result[0]["refs"]
        # refs can be dict or list of tuples; we just need to verify alert_ref is present
        assert "alrt_xyz" in str(refs)

    def test_bucketed_item_refs_merged(self):
        """When items coalesce, refs from multiple events are merged (up to 5)."""
        now = datetime.datetime.utcnow()
        bucket_start = now.replace(second=0, microsecond=0)
        bucket_start -= datetime.timedelta(minutes=bucket_start.minute % 5)
        events = [
            {"ts": (bucket_start + datetime.timedelta(seconds=i)).isoformat(),
             "type": "deploy",
             "label": "Deploy",
             "refs": {"alert_ref": f"alrt_{i}"}}
            for i in range(3)
        ]
        result = build_timeline(events, _POLICY)
        assert len(result) == 1
        # Refs should contain at least one alert_ref
        refs_str = str(result[0]["refs"])
        assert "alrt_" in refs_str