import unittest

from h8536.emulator import MemoryMap, P9DDR, P9DR
from h8536.emulator.peripherals import P9Bus


class P9BusTest(unittest.TestCase):
    def test_bit7_input_uses_queued_then_default_low_response(self):
        memory = MemoryMap(b"\x00" * 4)
        memory.write8(P9DDR, 0x13)
        memory.write8(P9DR, 0x80)
        memory.p9_bus.queue_input_bits([1])

        self.assertEqual(memory.read8(P9DDR), 0x13)
        self.assertEqual(memory.read8(P9DR) & 0x80, 0x80)
        self.assertEqual(memory.read8(P9DR) & 0x80, 0x00)
        self.assertEqual(memory.registers[P9DR - 0xFE80], 0x80)

    def test_bit7_output_reads_latch(self):
        memory = MemoryMap(b"\x00" * 4)
        memory.write8(P9DDR, 0x93)
        memory.write8(P9DR, 0x80)

        self.assertEqual(memory.read8(P9DDR), 0x93)
        self.assertEqual(memory.read8(P9DR) & 0x80, 0x80)
        self.assertEqual(memory.registers[P9DR - 0xFE80], 0x80)

    def test_strobe_rising_edges_capture_output_bits_and_byte_candidates(self):
        bus = P9Bus()
        bus.write_ddr(0x93)
        for bit in (1, 0, 1, 0, 0, 1, 0, 1):
            bus.write_dr(0x80 if bit else 0x00)
            bus.write_dr((0x80 if bit else 0x00) | 0x02)
            bus.write_dr(0x80 if bit else 0x00)

        self.assertEqual(bus.transmitted_bits, [1, 0, 1, 0, 0, 1, 0, 1])
        self.assertEqual(bus.byte_candidates, [0xA5])
        self.assertEqual([event.edge for event in bus.strobe_edges[:2]], ["rising", "falling"])


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