import json
import time
from datetime import timedelta

import pytest
from django.utils import timezone
from rest_framework.test import APIClient

from apps.notifications import services, views
from apps.notifications.services import RedisNotificationStore
from apps.notifications.tests.test_services import FakePubSub, FakeRedis
from apps.users.models import User


@pytest.fixture()
def fake_redis(monkeypatch):
    redis = FakeRedis()
    monkeypatch.setattr(services, "redis_client", redis)
    return redis


@pytest.fixture()
def user(db):
    return User.objects.create_user(mobile="09121111111", password="secret123")


@pytest.fixture()
def second_user(db):
    return User.objects.create_user(mobile="09122222222", password="secret123")


def _read_sse_chunks(response, count):
    iterator = iter(response.streaming_content)
    chunks = []
    for _ in range(count):
        chunk = next(iterator)
        if isinstance(chunk, bytes):
            chunk = chunk.decode("utf-8")
        chunks.append(chunk)
    response.close()
    return chunks


def _parse_sse_data(chunk: str) -> dict:
    for line in chunk.splitlines():
        if line.startswith("data: "):
            return json.loads(line.removeprefix("data: "))
    raise AssertionError("SSE payload did not include data")


def test_stream_token_endpoint_returns_short_lived_token(user):
    client = APIClient()
    client.force_authenticate(user=user)

    response = client.post("/api/notifications/stream-token/")

    assert response.status_code == 200
    assert response.data["token"]
    assert response.data["expires_in"] > 0


def test_stream_endpoint_rejects_missing_and_expired_token(user, settings):
    client = APIClient()

    missing = client.get("/api/notifications/stream/")
    assert missing.status_code == 401

    settings.NOTIFICATION_STREAM_TOKEN_LIFETIME_SECONDS = 1
    token = views._issue_stream_token_for_user(str(user.id))
    time.sleep(1.1)

    expired = client.get(f"/api/notifications/stream/?token={token}")
    assert expired.status_code == 401


def test_stream_endpoint_sends_only_current_users_notifications(
    fake_redis, user, second_user, monkeypatch
):
    RedisNotificationStore.add(str(user.id), {"title": "For current user"})
    RedisNotificationStore.add(str(second_user.id), {"title": "For another user"})
    pubsub = FakePubSub()
    monkeypatch.setattr(RedisNotificationStore, "get_pubsub", classmethod(lambda cls: pubsub))
    token = views._issue_stream_token_for_user(str(user.id))

    client = APIClient()
    response = client.get(
        f"/api/notifications/stream/?token={token}",
        HTTP_ACCEPT="text/event-stream",
    )
    retry_line, connected_chunk = _read_sse_chunks(response, 2)

    assert response.status_code == 200
    assert retry_line.startswith("retry:")
    connected = _parse_sse_data(connected_chunk)
    assert connected["unread_count"] == 1
    assert [item["title"] for item in connected["notifications"]] == ["For current user"]


def test_stream_endpoint_emits_heartbeat(fake_redis, user, settings, monkeypatch):
    pubsub = FakePubSub()
    monkeypatch.setattr(RedisNotificationStore, "get_pubsub", classmethod(lambda cls: pubsub))
    settings.NOTIFICATION_SSE_HEARTBEAT_SECONDS = 1

    first_now = timezone.now()
    tick_values = iter(
        [
            first_now,
            first_now,
            first_now + timedelta(seconds=2),
            first_now + timedelta(seconds=2),
            first_now + timedelta(seconds=2),
            first_now + timedelta(seconds=2),
        ]
    )
    last_tick = first_now + timedelta(seconds=2)

    def fake_now():
        return next(tick_values, last_tick)

    monkeypatch.setattr(views.timezone, "now", fake_now)
    view = views.NotificationStreamView()
    stream = view._build_stream(str(user.id))

    chunks = [next(stream) for _ in range(4)]
    stream.close()

    assert "event: ping" in chunks[3]


def test_notification_list_and_seen_endpoints_work(fake_redis, user):
    notification = RedisNotificationStore.add(
        str(user.id),
        {"title": "Deploy succeeded", "type": "deploy"},
    )

    client = APIClient()
    client.force_authenticate(user=user)

    list_response = client.get("/api/notifications/list/?type=deploy")
    assert list_response.status_code == 200
    assert list_response.data["count"] == 1
    assert list_response.data["unread_count"] == 1
    assert list_response.data["notifications"][0]["title"] == "Deploy succeeded"

    seen_response = client.post("/api/notifications/seen/", {"id": notification["id"]}, format="json")
    assert seen_response.status_code == 200
    assert seen_response.data["marked_read"] is True
    assert seen_response.data["notification"]["is_seen"] is True


def test_notification_delete_endpoint_removes_notification(fake_redis, user):
    notification = RedisNotificationStore.add(
        str(user.id),
        {"title": "Delete me", "type": "deploy"},
    )

    client = APIClient()
    client.force_authenticate(user=user)

    response = client.delete(f"/api/notifications/{notification['id']}/")

    assert response.status_code == 200
    assert response.data["deleted"] is True
    assert response.data["notification_id"] == notification["id"]
    assert RedisNotificationStore.get(str(user.id), notification["id"]) is None