import unittest
import sys
import os
import gzip
from io import BytesIO

# Add scripts directory to path so we can import web_dashboard
sys.path.append(os.path.dirname(os.path.abspath(__file__)))

from web_dashboard import app

class TestWebDashboardCompression(unittest.TestCase):
    def setUp(self):
        self.app = app.test_client()
        self.app.testing = True

    def test_gzip_compression_enabled(self):
        """Test that the response is gzipped when Accept-Encoding contains gzip and content is large."""
        # Ensure we hit a route that returns > 500 bytes (e.g. dashboard with README)
        response = self.app.get('/', headers={'Accept-Encoding': 'gzip'})

        self.assertEqual(response.headers.get('Content-Encoding'), 'gzip', "Response should be gzipped")
        self.assertIn('Vary', response.headers)
        self.assertIn('Accept-Encoding', response.headers['Vary'])

        # Verify content is actually compressed
        try:
            gzip.GzipFile(fileobj=BytesIO(response.data)).read()
        except OSError:
            self.fail("Response content is not valid gzip data")

    def test_no_compression_without_header(self):
        """Test that the response is NOT gzipped when Accept-Encoding is missing."""
        response = self.app.get('/')
        self.assertIsNone(response.headers.get('Content-Encoding'), "Response should not be gzipped without header")

    def test_no_compression_for_small_response(self):
        """Test that small responses are not gzipped."""
        # /health returns a small JSON
        response = self.app.get('/health', headers={'Accept-Encoding': 'gzip'})
        self.assertIsNone(response.headers.get('Content-Encoding'), "Small response should not be gzipped")

if __name__ == '__main__':
    unittest.main()