import pytest
from fastapi import status
from fastapi.testclient import TestClient
from sqlalchemy.orm import Session
from datetime import datetime, timedelta

from tests.helpers import generators
from modules.calendar.models import CalendarEvent # Assuming model exists
from tests.conftest import fake

# Helper function to create an event payload
def create_event_payload(start_offset_days=0, end_offset_days=1):
    start_time = datetime.utcnow() + timedelta(days=start_offset_days)
    end_time = datetime.utcnow() + timedelta(days=end_offset_days)
    return {
        "title": fake.sentence(nb_words=3),
        "description": fake.text(),
        "start": start_time.isoformat(), # Rename start_time to start
        "end": end_time.isoformat(),     # Rename end_time to end
        "all_day": fake.boolean(),
    }

# --- Test Create Event ---

def test_create_event_unauthorized(client: TestClient) -> None:
    """Test creating an event without authentication."""
    payload = create_event_payload()
    response = client.post("/api/calendar/events", json=payload)
    assert response.status_code == status.HTTP_401_UNAUTHORIZED

def test_create_event_success(db: Session, client: TestClient) -> None:
    """Test creating a calendar event successfully."""
    user, password = generators.create_user(db)
    login_rsp = generators.login(db, user.username, password)
    access_token = login_rsp["access_token"]
    payload = create_event_payload()

    response = client.post(
        "/api/calendar/events",
        headers={"Authorization": f"Bearer {access_token}"},
        json=payload
    )
    assert response.status_code == status.HTTP_201_CREATED # Change expected status to 201
    data = response.json()
    assert data["title"] == payload["title"]
    assert data["description"] == payload["description"]
    # Remove the '+ "Z"' as the API doesn't add it
    assert data["start"] == payload["start"]
    assert data["end"] == payload["end"]
    assert data["all_day"] == payload["all_day"]
    assert "id" in data
    assert data["user_id"] == user.id

    # Verify in DB
    event_in_db = db.query(CalendarEvent).filter(CalendarEvent.id == data["id"]).first()
    assert event_in_db is not None
    assert event_in_db.user_id == user.id
    assert event_in_db.title == payload["title"]

# --- Test Get Events ---

def test_get_events_unauthorized(client: TestClient) -> None:
    """Test getting events without authentication."""
    response = client.get("/api/calendar/events")
    assert response.status_code == status.HTTP_401_UNAUTHORIZED

def test_get_events_success(db: Session, client: TestClient) -> None:
    """Test getting all calendar events for a user."""
    user, password = generators.create_user(db)
    login_rsp = generators.login(db, user.username, password)
    access_token = login_rsp["access_token"]

    # Create a couple of events for the user
    payload1 = create_event_payload(0, 1)
    client.post("/api/calendar/events", headers={"Authorization": f"Bearer {access_token}"}, json=payload1)
    payload2 = create_event_payload(2, 3)
    client.post("/api/calendar/events", headers={"Authorization": f"Bearer {access_token}"}, json=payload2)

    # Create an event for another user (should not be returned)
    other_user, other_password = generators.create_user(db)
    other_login_rsp = generators.login(db, other_user.username, other_password)
    other_access_token = other_login_rsp["access_token"]
    other_payload = create_event_payload(4, 5)
    client.post("/api/calendar/events", headers={"Authorization": f"Bearer {other_access_token}"}, json=other_payload)


    response = client.get(
        "/api/calendar/events",
        headers={"Authorization": f"Bearer {access_token}"}
    )
    assert response.status_code == status.HTTP_200_OK
    data = response.json()
    assert len(data) == 2
    assert data[0]["title"] == payload1["title"]
    assert data[1]["title"] == payload2["title"]
    assert data[0]["user_id"] == user.id
    assert data[1]["user_id"] == user.id


def test_get_events_filtered(db: Session, client: TestClient) -> None:
    """Test getting filtered calendar events for a user."""
    user, password = generators.create_user(db)
    login_rsp = generators.login(db, user.username, password)
    access_token = login_rsp["access_token"]

    # Create events
    payload1 = create_event_payload(0, 1) # Today -> Tomorrow
    client.post("/api/calendar/events", headers={"Authorization": f"Bearer {access_token}"}, json=payload1)
    payload2 = create_event_payload(5, 6) # In 5 days -> In 6 days
    client.post("/api/calendar/events", headers={"Authorization": f"Bearer {access_token}"}, json=payload2)
    payload3 = create_event_payload(10, 11) # In 10 days -> In 11 days
    client.post("/api/calendar/events", headers={"Authorization": f"Bearer {access_token}"}, json=payload3)

    # Filter for events starting within the next week
    start_filter = datetime.utcnow().isoformat()
    end_filter = (datetime.utcnow() + timedelta(days=7)).isoformat()

    response = client.get(
        "/api/calendar/events",
        headers={"Authorization": f"Bearer {access_token}"},
        params={"start": start_filter, "end": end_filter}
    )
    assert response.status_code == status.HTTP_200_OK
    data = response.json()
    assert len(data) == 2 # Should get event 1 and 2
    assert data[0]["title"] == payload1["title"]
    assert data[1]["title"] == payload2["title"]

    # Filter for events starting after 8 days
    start_filter_late = (datetime.utcnow() + timedelta(days=8)).isoformat()
    response = client.get(
        "/api/calendar/events",
        headers={"Authorization": f"Bearer {access_token}"},
        params={"start": start_filter_late}
    )
    assert response.status_code == status.HTTP_200_OK
    data = response.json()
    assert len(data) == 1 # Should get event 3
    assert data[0]["title"] == payload3["title"]


# --- Test Get Event By ID ---

def test_get_event_by_id_unauthorized(db: Session, client: TestClient) -> None:
    """Test getting a specific event without authentication."""
    user, password = generators.create_user(db)
    login_rsp = generators.login(db, user.username, password)
    access_token = login_rsp["access_token"]
    payload = create_event_payload()
    create_response = client.post("/api/calendar/events", headers={"Authorization": f"Bearer {access_token}"}, json=payload)
    event_id = create_response.json()["id"]

    response = client.get(f"/api/calendar/events/{event_id}")
    assert response.status_code == status.HTTP_401_UNAUTHORIZED

def test_get_event_by_id_success(db: Session, client: TestClient) -> None:
    """Test getting a specific event successfully."""
    user, password = generators.create_user(db)
    login_rsp = generators.login(db, user.username, password)
    access_token = login_rsp["access_token"]
    payload = create_event_payload()
    create_response = client.post("/api/calendar/events", headers={"Authorization": f"Bearer {access_token}"}, json=payload)
    event_id = create_response.json()["id"]

    response = client.get(
        f"/api/calendar/events/{event_id}",
        headers={"Authorization": f"Bearer {access_token}"}
    )
    assert response.status_code == status.HTTP_200_OK
    data = response.json()
    assert data["id"] == event_id
    assert data["title"] == payload["title"]
    assert data["user_id"] == user.id

def test_get_event_by_id_not_found(db: Session, client: TestClient) -> None:
    """Test getting a non-existent event."""
    user, password = generators.create_user(db)
    login_rsp = generators.login(db, user.username, password)
    access_token = login_rsp["access_token"]
    non_existent_id = 99999

    response = client.get(
        f"/api/calendar/events/{non_existent_id}",
        headers={"Authorization": f"Bearer {access_token}"}
    )
    assert response.status_code == status.HTTP_404_NOT_FOUND

def test_get_event_by_id_forbidden(db: Session, client: TestClient) -> None:
    """Test getting another user's event."""
    user1, password_user1 = generators.create_user(db)
    user2, password_user2 = generators.create_user(db)

    # Log in as user1 and create an event
    login_rsp1 = generators.login(db, user1.username, password_user1)
    access_token1 = login_rsp1["access_token"]
    payload = create_event_payload()
    create_response = client.post("/api/calendar/events", headers={"Authorization": f"Bearer {access_token1}"}, json=payload)
    event_id = create_response.json()["id"]

    # Log in as user2 and try to get user1's event
    login_rsp2 = generators.login(db, user2.username, password_user2)
    access_token2 = login_rsp2["access_token"]

    response = client.get(
        f"/api/calendar/events/{event_id}",
        headers={"Authorization": f"Bearer {access_token2}"}
    )
    assert response.status_code == status.HTTP_404_NOT_FOUND # Service layer returns 404 if user_id doesn't match

# --- Test Update Event ---

def test_update_event_unauthorized(db: Session, client: TestClient) -> None:
    """Test updating an event without authentication."""
    user, password = generators.create_user(db)
    login_rsp = generators.login(db, user.username, password)
    access_token = login_rsp["access_token"]
    payload = create_event_payload()
    create_response = client.post("/api/calendar/events", headers={"Authorization": f"Bearer {access_token}"}, json=payload)
    event_id = create_response.json()["id"]
    update_payload = {"title": "Updated Title"}

    response = client.patch(f"/api/calendar/events/{event_id}", json=update_payload)
    assert response.status_code == status.HTTP_401_UNAUTHORIZED

def test_update_event_success(db: Session, client: TestClient) -> None:
    """Test updating an event successfully."""
    user, password = generators.create_user(db)
    login_rsp = generators.login(db, user.username, password)
    access_token = login_rsp["access_token"]
    payload = create_event_payload()
    create_response = client.post("/api/calendar/events", headers={"Authorization": f"Bearer {access_token}"}, json=payload)
    assert create_response.status_code == status.HTTP_201_CREATED # Ensure creation check uses 201
    event_id = create_response.json()["id"]

    update_payload = {
        "title": "Updated Title",
        "description": "Updated description.",
        "all_day": not payload["all_day"] # Toggle all_day
    }

    response = client.patch(
        f"/api/calendar/events/{event_id}",
        headers={"Authorization": f"Bearer {access_token}"},
        json=update_payload
    )
    assert response.status_code == status.HTTP_200_OK
    data = response.json()
    assert data["id"] == event_id
    assert data["title"] == update_payload["title"]
    assert data["description"] == update_payload["description"]
    assert data["all_day"] == update_payload["all_day"]
    assert data["start"] == payload["start"] # Check correct field name 'start'
    assert data["user_id"] == user.id

    # Verify in DB
    event_in_db = db.query(CalendarEvent).filter(CalendarEvent.id == event_id).first()
    assert event_in_db is not None
    assert event_in_db.title == update_payload["title"]
    assert event_in_db.description == update_payload["description"]
    assert event_in_db.all_day == update_payload["all_day"]

def test_update_event_not_found(db: Session, client: TestClient) -> None:
    """Test updating a non-existent event."""
    user, password = generators.create_user(db)
    login_rsp = generators.login(db, user.username, password)
    access_token = login_rsp["access_token"]
    non_existent_id = 99999
    update_payload = {"title": "Updated Title"}

    response = client.patch(
        f"/api/calendar/events/{non_existent_id}",
        headers={"Authorization": f"Bearer {access_token}"},
        json=update_payload
    )
    assert response.status_code == status.HTTP_404_NOT_FOUND

def test_update_event_forbidden(db: Session, client: TestClient) -> None:
    """Test updating another user's event."""
    user1, password_user1 = generators.create_user(db)
    user2, password_user2 = generators.create_user(db)

    # Log in as user1 and create an event
    login_rsp1 = generators.login(db, user1.username, password_user1)
    access_token1 = login_rsp1["access_token"]
    payload = create_event_payload()
    create_response = client.post("/api/calendar/events", headers={"Authorization": f"Bearer {access_token1}"}, json=payload)
    event_id = create_response.json()["id"]

    # Log in as user2 and try to update user1's event
    login_rsp2 = generators.login(db, user2.username, password_user2)
    access_token2 = login_rsp2["access_token"]
    update_payload = {"title": "Updated by User 2"}

    response = client.patch(
        f"/api/calendar/events/{event_id}",
        headers={"Authorization": f"Bearer {access_token2}"},
        json=update_payload
    )
    assert response.status_code == status.HTTP_404_NOT_FOUND # Service layer returns 404 if user_id doesn't match

# --- Test Delete Event ---

def test_delete_event_unauthorized(db: Session, client: TestClient) -> None:
    """Test deleting an event without authentication."""
    user, password = generators.create_user(db)
    login_rsp = generators.login(db, user.username, password)
    access_token = login_rsp["access_token"]
    payload = create_event_payload()
    create_response = client.post("/api/calendar/events", headers={"Authorization": f"Bearer {access_token}"}, json=payload)
    event_id = create_response.json()["id"]

    response = client.delete(f"/api/calendar/events/{event_id}")
    assert response.status_code == status.HTTP_401_UNAUTHORIZED

def test_delete_event_success(db: Session, client: TestClient) -> None:
    """Test deleting an event successfully."""
    user, password = generators.create_user(db)
    login_rsp = generators.login(db, user.username, password)
    access_token = login_rsp["access_token"]
    payload = create_event_payload()
    create_response = client.post("/api/calendar/events", headers={"Authorization": f"Bearer {access_token}"}, json=payload)
    assert create_response.status_code == status.HTTP_201_CREATED # Ensure creation check uses 201
    event_id = create_response.json()["id"]

    # Verify event exists before delete
    event_in_db = db.query(CalendarEvent).filter(CalendarEvent.id == event_id).first()
    assert event_in_db is not None

    response = client.delete(
        f"/api/calendar/events/{event_id}",
        headers={"Authorization": f"Bearer {access_token}"}
    )
    assert response.status_code == status.HTTP_204_NO_CONTENT

    # Verify event is deleted from DB
    event_in_db = db.query(CalendarEvent).filter(CalendarEvent.id == event_id).first()
    assert event_in_db is None

    # Try getting the deleted event (should be 404)
    get_response = client.get(
        f"/api/calendar/events/{event_id}",
        headers={"Authorization": f"Bearer {access_token}"}
    )
    assert get_response.status_code == status.HTTP_404_NOT_FOUND


def test_delete_event_not_found(db: Session, client: TestClient) -> None:
    """Test deleting a non-existent event."""
    user, password = generators.create_user(db)
    login_rsp = generators.login(db, user.username, password)
    access_token = login_rsp["access_token"]
    non_existent_id = 99999

    response = client.delete(
        f"/api/calendar/events/{non_existent_id}",
        headers={"Authorization": f"Bearer {access_token}"}
    )
    # The service layer raises NotFound, which should result in 404
    assert response.status_code == status.HTTP_404_NOT_FOUND


def test_delete_event_forbidden(db: Session, client: TestClient) -> None:
    """Test deleting another user's event."""
    user1, password_user1 = generators.create_user(db)
    user2, password_user2 = generators.create_user(db)

    # Log in as user1 and create an event
    login_rsp1 = generators.login(db, user1.username, password_user1)
    access_token1 = login_rsp1["access_token"]
    payload = create_event_payload()
    create_response = client.post("/api/calendar/events", headers={"Authorization": f"Bearer {access_token1}"}, json=payload)
    event_id = create_response.json()["id"]

    # Log in as user2 and try to delete user1's event
    login_rsp2 = generators.login(db, user2.username, password_user2)
    access_token2 = login_rsp2["access_token"]

    response = client.delete(
        f"/api/calendar/events/{event_id}",
        headers={"Authorization": f"Bearer {access_token2}"}
    )
    # The service layer raises NotFound if user_id doesn't match, resulting in 404
    assert response.status_code == status.HTTP_404_NOT_FOUND

    # Verify event still exists for user1
    event_in_db = db.query(CalendarEvent).filter(CalendarEvent.id == event_id).first()
    assert event_in_db is not None
    assert event_in_db.user_id == user1.id