"""Pipe-level regressions for the native preferences harness response reader."""
import os
import select
import unittest
from unittest.mock import patch

from native_preferences import ResponseReader


class ResponseReaderTests(unittest.TestCase):
    def setUp(self):
        readFd, writeFd = os.pipe()
        self.stream = os.fdopen(readFd, encoding="utf-8")
        self.writer = os.fdopen(writeFd, "wb", buffering=0)
        self.addCleanup(self.stream.close)
        self.addCleanup(self.writer.close)
        self.reader = ResponseReader(self.stream)

    def test_batched_preview_and_save(self):
        self.writer.write(b'{"Preview": true}\n{"Save": true}\n')
        self.assertEqual(self.reader.request(), {"Preview": True})
        self.assertFalse(select.select([self.stream], [], [], 0)[0])
        self.assertEqual(self.reader.request(timeout=0), {"Save": True})

    def test_missing_response_times_out(self):
        with self.assertRaises(TimeoutError):
            self.reader.request(timeout=0.01)

    def test_partial_response_times_out_and_can_resume(self):
        self.writer.write(b'{"Name": "\xc3')
        with self.assertRaises(TimeoutError):
            self.reader.request(timeout=0.01)
        self.writer.write(b'\xa9"}\n')
        self.assertEqual(self.reader.request(), {"Name": "\u00e9"})

    def test_partial_reads_share_one_deadline(self):
        self.writer.write(b'{"Save":')
        with patch("native_preferences.time.monotonic", side_effect=[10, 10, 16]):
            with self.assertRaises(TimeoutError):
                self.reader.request(timeout=5)

    def test_eof_is_reported_after_complete_responses(self):
        self.writer.write(b'{"Save": true}\n{"Close":')
        self.writer.close()
        self.assertEqual(self.reader.request(), {"Save": True})
        with self.assertRaises(EOFError):
            self.reader.request()

    def test_remaining_output_includes_read_ahead_and_pipe_bytes(self):
        self.writer.write(b'{"Preview": true}\n{"Name": "\xc3')
        self.assertEqual(self.reader.request(), {"Preview": True})
        self.writer.write(b'\xa9"}\n')
        self.writer.close()
        self.assertEqual(self.reader.read_remaining(), '{"Name": "\u00e9"}\n')
        self.assertEqual(self.reader.read_remaining(), "")


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