import io
import os
import pty
import select
import termios
import unittest

from gaze_link import GazeLink, center_to_gaze, crc16_ccitt, encode_frame, open_pi_uart


class GazeLinkTests(unittest.TestCase):
    def test_crc_standard_vector_and_esp32_fixture(self):
        self.assertEqual(crc16_ccitt(b"123456789"), 0x29B1)
        # Generated by the current C++ gaze::encode used on the ESP32 boards.
        self.assertEqual(
            encode_frame(0x1234, 655, 774, True).hex(),
            "a55a010134128f020603fa76",
        )

    def test_stream_and_sequence_wrap(self):
        stream = io.BytesIO()
        link = GazeLink(stream)
        link.sequence = 0xFFFF
        self.assertEqual(link.send(500, 500, False), 0xFFFF)
        self.assertEqual(link.send(0, 1000, True), 0)
        self.assertEqual(len(stream.getvalue()), 24)
        self.assertEqual(stream.getvalue()[12:14], b"\xA5\x5A")

    def test_box_center_and_invalid_inputs(self):
        self.assertEqual(center_to_gaze((0, 0, 319, 239), 320, 240), (498, 497))
        with self.assertRaises(ValueError):
            center_to_gaze((0, 0, 320, 239), 320, 240)
        with self.assertRaises(ValueError):
            encode_frame(0, 1001, 0, True)

    def test_serial_port_sends_115200_baud_frame(self):
        master, slave = pty.openpty()
        try:
            link = open_pi_uart(os.ttyname(slave))
            try:
                settings = termios.tcgetattr(slave)
                self.assertEqual(settings[4:6], [termios.B115200, termios.B115200])
                link.send(200, 500, True)
                self.assertTrue(select.select([master], [], [], 1)[0])
                self.assertEqual(os.read(master, 12), encode_frame(0, 200, 500, True))
            finally:
                link.stream.close()
        finally:
            os.close(slave)
            os.close(master)


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