#!/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 time

import pytest
from fastapi import status


@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_process")
    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_process, str)
    assert "/" in settings.rate_limit_process
    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
    from fastapi import Request

    # 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 app.main import app
    from slowapi.errors import RateLimitExceeded

    # 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_process)
    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