import pytest
import uuid


def unique_email(prefix: str = "counter") -> str:
    """Generate a unique email for tests sharing the same database."""
    return f"{prefix}-{uuid.uuid4().hex[:8]}@example.com"


async def create_user_and_get_headers(client, email: str = None) -> dict:
    """Create a user and return auth headers for authenticated requests."""
    if email is None:
        email = unique_email()
    response = await client.post(
        "/api/auth/register",
        json={"email": email, "password": "testpass123"},
    )
    token = response.json()["access_token"]
    return {"Authorization": f"Bearer {token}"}


# Protected endpoint tests - without auth
@pytest.mark.asyncio
async def test_get_counter_requires_auth(client):
    response = await client.get("/api/counter")
    assert response.status_code in [401, 403]


@pytest.mark.asyncio
async def test_increment_counter_requires_auth(client):
    response = await client.post("/api/counter/increment")
    assert response.status_code in [401, 403]


@pytest.mark.asyncio
async def test_get_counter_invalid_token(client):
    response = await client.get(
        "/api/counter",
        headers={"Authorization": "Bearer invalidtoken"},
    )
    assert response.status_code == 401


@pytest.mark.asyncio
async def test_increment_counter_invalid_token(client):
    response = await client.post(
        "/api/counter/increment",
        headers={"Authorization": "Bearer invalidtoken"},
    )
    assert response.status_code == 401


# Authenticated counter tests
@pytest.mark.asyncio
async def test_get_counter_authenticated(client):
    auth_headers = await create_user_and_get_headers(client)
    response = await client.get("/api/counter", headers=auth_headers)
    assert response.status_code == 200
    assert "value" in response.json()


@pytest.mark.asyncio
async def test_increment_counter(client):
    auth_headers = await create_user_and_get_headers(client)
    
    # Get current value
    before = await client.get("/api/counter", headers=auth_headers)
    before_value = before.json()["value"]
    
    # Increment
    response = await client.post("/api/counter/increment", headers=auth_headers)
    assert response.status_code == 200
    assert response.json()["value"] == before_value + 1


@pytest.mark.asyncio
async def test_increment_counter_multiple(client):
    auth_headers = await create_user_and_get_headers(client)
    
    # Get starting value
    before = await client.get("/api/counter", headers=auth_headers)
    start = before.json()["value"]
    
    # Increment 3 times
    await client.post("/api/counter/increment", headers=auth_headers)
    await client.post("/api/counter/increment", headers=auth_headers)
    response = await client.post("/api/counter/increment", headers=auth_headers)
    
    assert response.json()["value"] == start + 3


@pytest.mark.asyncio
async def test_get_counter_after_increment(client):
    auth_headers = await create_user_and_get_headers(client)
    
    before = await client.get("/api/counter", headers=auth_headers)
    start = before.json()["value"]
    
    await client.post("/api/counter/increment", headers=auth_headers)
    await client.post("/api/counter/increment", headers=auth_headers)
    
    response = await client.get("/api/counter", headers=auth_headers)
    assert response.json()["value"] == start + 2


# Counter is shared between users
@pytest.mark.asyncio
async def test_counter_shared_between_users(client):
    headers1 = await create_user_and_get_headers(client, unique_email("share1"))
    
    # Get starting value
    before = await client.get("/api/counter", headers=headers1)
    start = before.json()["value"]
    
    await client.post("/api/counter/increment", headers=headers1)
    await client.post("/api/counter/increment", headers=headers1)
    
    # Second user sees the increments
    headers2 = await create_user_and_get_headers(client, unique_email("share2"))
    response = await client.get("/api/counter", headers=headers2)
    assert response.json()["value"] == start + 2
    
    # Second user increments
    await client.post("/api/counter/increment", headers=headers2)
    
    # First user sees the increment
    response = await client.get("/api/counter", headers=headers1)
    assert response.json()["value"] == start + 3