#!/usr/bin/env python3

"""
Tests for rate limiting middleware.

These tests validate that rate limiting is properly applied to API endpoints
to prevent abuse and DoS attacks.
"""

import pytest


@pytest.mark.unit
def test_rate_limiting_enabled_by_default():
    """Test that rate limiting is enabled by default in configuration."""
    from app.config import settings

    # Rate limiting should be enabled by default
    assert hasattr(settings, "rate_limiting_enabled")
    assert isinstance(settings.rate_limiting_enabled, bool)


@pytest.mark.unit
def test_rate_limit_configuration():
    """Test that rate limit configuration is loaded correctly."""
    from app.config import settings

    # Verify that rate limit configuration attributes exist
    assert hasattr(settings, "rate_limiting_enabled")
    assert hasattr(settings, "rate_limit_default")
    assert hasattr(settings, "rate_limit_upload")
    assert hasattr(settings, "rate_limit_auth")

    # Verify that settings are strings in correct format
    assert isinstance(settings.rate_limit_default, str)
    assert "/" in settings.rate_limit_default  # Should be like "100/minute"
    assert isinstance(settings.rate_limit_upload, str)
    assert "/" in settings.rate_limit_upload
    assert isinstance(settings.rate_limit_auth, str)
    assert "/" in settings.rate_limit_auth


@pytest.mark.integration
def test_limiter_initialization():
    """Test that rate limiter is initialized correctly."""
    from app.main import app

    # Verify limiter is attached to app state
    assert hasattr(app.state, "limiter")
    assert app.state.limiter is not None

    # Verify limiter has expected attributes
    limiter = app.state.limiter
    assert hasattr(limiter, "limit")
    assert hasattr(limiter, "exempt")


@pytest.mark.integration
def test_rate_limit_on_health_endpoint(client):
    """Test that endpoints respect rate limits."""
    from app.config import settings

    if not settings.rate_limiting_enabled:
        pytest.skip("Rate limiting is disabled in test configuration")

    # Test with / endpoint which should exist
    # Make multiple requests within the limit
    for _ in range(5):
        response = client.get("/")
        # Should get either 200 (success) or 302 (redirect) but not 429 (rate limited)
        assert response.status_code in [200, 302, 404], f"Unexpected status: {response.status_code}"


@pytest.mark.integration
def test_rate_limit_exceeded_returns_429(client):
    """Test that exceeding rate limit returns 429 status code."""
    from app.config import settings

    if not settings.rate_limiting_enabled:
        pytest.skip("Rate limiting is disabled in test configuration")

    # This test would need to make enough requests to trigger rate limit
    # Since we use in-memory storage for tests and default limit is high,
    # we'll verify the mechanism is in place
    # In production, this would be tested with lower limits

    # Make a moderate number of requests to the about page
    responses = []
    for _ in range(10):
        response = client.get("/about")
        responses.append(response.status_code)

    # All should succeed with default high limits (not testing actual rate limiting)
    # We're just verifying the endpoints are accessible
    assert all(code in [200, 302, 404] for code in responses)


@pytest.mark.security
def test_rate_limiting_uses_correct_identifier():
    """Test that rate limiting uses IP or user ID as identifier."""

    from app.middleware.rate_limit import get_identifier

    # Create a mock request
    class MockRequest:
        def __init__(self):
            self.session = {}
            self.client = type("client", (), {"host": "127.0.0.1"})()

    # Test with unauthenticated request (should use IP)
    request = MockRequest()
    identifier = get_identifier(request)
    assert identifier == "127.0.0.1"

    # Test with authenticated request (should use user identifier)
    request.session["user"] = {"username": "testuser", "id": "123"}
    identifier = get_identifier(request)
    assert "user:" in identifier or identifier == "testuser" or "123" in identifier


@pytest.mark.unit
def test_limiter_creation_with_redis():
    """Test limiter creation with Redis backend."""
    from app.middleware.rate_limit import create_limiter

    # Create limiter with Redis URL
    limiter = create_limiter(redis_url="redis://localhost:6379/0", enabled=True)
    assert limiter is not None
    assert limiter.enabled is True


@pytest.mark.unit
def test_limiter_creation_with_memory():
    """Test limiter creation with in-memory backend."""
    from app.middleware.rate_limit import create_limiter

    # Create limiter without Redis (fallback to memory)
    limiter = create_limiter(redis_url=None, enabled=True)
    assert limiter is not None
    assert limiter.enabled is True


@pytest.mark.unit
def test_limiter_disabled():
    """Test limiter creation when disabled."""
    from app.middleware.rate_limit import create_limiter

    # Create disabled limiter
    limiter = create_limiter(redis_url=None, enabled=False)
    assert limiter is not None
    assert limiter.enabled is False


@pytest.mark.integration
def test_rate_limit_exception_handler_registered():
    """Test that rate limit exception handler is registered."""
    from slowapi.errors import RateLimitExceeded

    from app.main import app

    # Verify exception handler is registered
    assert RateLimitExceeded in app.exception_handlers


@pytest.mark.security
def test_rate_limit_prevents_brute_force():
    """Test that rate limiting can prevent brute force attacks on auth endpoints."""
    # This is a documentation test - in practice, auth endpoints should have
    # stricter rate limits (e.g., 10/minute) to prevent brute force
    from app.config import settings

    # Auth endpoints should have stricter limits
    assert hasattr(settings, "rate_limit_auth")

    # Parse the limit to ensure it's restrictive enough
    limit_str = settings.rate_limit_auth
    count, period = limit_str.split("/")
    count = int(count)

    # Should be significantly lower than default
    # e.g., 10/minute vs 100/minute for default
    assert count <= 20, "Auth rate limit should be strict to prevent brute force"


@pytest.mark.integration
def test_rate_limiting_middleware_integration():
    """Test that rate limiting middleware integrates properly with app."""
    from app.main import app

    # Verify app has limiter state
    assert hasattr(app, "state")
    assert hasattr(app.state, "limiter")

    # Verify middleware configuration
    from app.config import settings

    assert hasattr(settings, "rate_limiting_enabled")
    assert hasattr(settings, "redis_url")


@pytest.mark.unit
def test_rate_limit_format_validation():
    """Test that rate limit strings are in valid format."""
    from app.config import settings

    # Validate format of rate limit strings
    def validate_rate_limit(limit_str):
        """Validate rate limit string format."""
        parts = limit_str.split("/")
        if len(parts) != 2:
            return False
        try:
            count = int(parts[0])
            period = parts[1]
            valid_periods = ["second", "minute", "hour", "day"]
            return count > 0 and period in valid_periods
        except ValueError:
            return False

    assert validate_rate_limit(settings.rate_limit_default)
    assert validate_rate_limit(settings.rate_limit_upload)
    assert validate_rate_limit(settings.rate_limit_auth)


@pytest.mark.integration
def test_concurrent_requests_respect_rate_limit():
    """Test that concurrent requests from same client respect rate limits."""
    # This test documents expected behavior
    # In production, multiple rapid requests from same IP should be tracked
    # and rate limited appropriately
    from app.config import settings

    if not settings.rate_limiting_enabled:
        pytest.skip("Rate limiting is disabled")

    # Document that rate limiting tracks requests per identifier
    # and enforces limits across concurrent requests
    assert settings.rate_limiting_enabled is True