"""Tests for SSU2 ACK bitfield tracking."""

import pytest


class TestSSU2Bitfield:
    def test_set_and_get(self):
        from i2p_transport.ssu2_bitfield import SSU2Bitfield

        bf = SSU2Bitfield()
        bf.set(0)
        bf.set(5)
        bf.set(100)
        assert bf.get(0) is True
        assert bf.get(5) is True
        assert bf.get(100) is True

    def test_get_unset(self):
        from i2p_transport.ssu2_bitfield import SSU2Bitfield

        bf = SSU2Bitfield()
        bf.set(10)
        assert bf.get(0) is False
        assert bf.get(9) is False
        assert bf.get(11) is False
        assert bf.get(255) is False

    def test_highest(self):
        from i2p_transport.ssu2_bitfield import SSU2Bitfield

        bf = SSU2Bitfield()
        assert bf.get_highest() == -1

        bf.set(3)
        assert bf.get_highest() == 3

        bf.set(50)
        assert bf.get_highest() == 50

        bf.set(25)  # Set a lower one; highest should not change
        assert bf.get_highest() == 50

    def test_shift_offset(self):
        from i2p_transport.ssu2_bitfield import SSU2Bitfield

        bf = SSU2Bitfield()
        bf.set(0)
        bf.set(1)
        bf.set(5)
        bf.set(10)

        bf.shift_offset(5)
        # Packets 0, 1 should be gone; 5 and 10 should remain
        assert bf.get(0) is False
        assert bf.get(1) is False
        assert bf.get(5) is True
        assert bf.get(10) is True

    def test_to_ack_blocks(self):
        from i2p_transport.ssu2_bitfield import SSU2Bitfield

        bf = SSU2Bitfield()
        # Contiguous: 0,1,2,3,4
        for i in range(5):
            bf.set(i)

        blocks = bf.to_ack_blocks()
        # All contiguous: should be a single (5, 0) ack block
        assert len(blocks) >= 1
        total_acked = sum(a for a, _ in blocks)
        assert total_acked == 5

    def test_from_ack_blocks(self):
        from i2p_transport.ssu2_bitfield import SSU2Bitfield

        # through=9, blocks: 3 acked (9,8,7), 2 nacked (6,5), 5 acked (4,3,2,1,0)
        blocks = [(3, 2), (5, 0)]
        bf = SSU2Bitfield.from_ack_blocks(through=9, blocks=blocks)

        assert bf.get(9) is True
        assert bf.get(8) is True
        assert bf.get(7) is True
        assert bf.get(6) is False
        assert bf.get(5) is False
        assert bf.get(4) is True
        assert bf.get(3) is True
        assert bf.get(2) is True
        assert bf.get(1) is True
        assert bf.get(0) is True

    def test_roundtrip(self):
        from i2p_transport.ssu2_bitfield import SSU2Bitfield

        bf = SSU2Bitfield()
        # Set some packet numbers with gaps
        for pn in [0, 1, 2, 5, 6, 10, 11, 12]:
            bf.set(pn)

        through = bf.get_highest()
        blocks = bf.to_ack_blocks()
        bf2 = SSU2Bitfield.from_ack_blocks(through, blocks)

        # Verify all set bits match
        for pn in range(through + 1):
            assert bf.get(pn) == bf2.get(pn), f"Mismatch at packet {pn}"

    def test_sparse_bitfield(self):
        from i2p_transport.ssu2_bitfield import SSU2Bitfield

        bf = SSU2Bitfield()
        # Every 10th packet
        for i in range(0, 100, 10):
            bf.set(i)

        assert bf.get_highest() == 90
        assert len(bf) == 10

        for i in range(100):
            if i % 10 == 0:
                assert bf.get(i) is True
            else:
                assert bf.get(i) is False

    def test_contains(self):
        from i2p_transport.ssu2_bitfield import SSU2Bitfield

        bf = SSU2Bitfield()
        bf.set(42)
        assert 42 in bf
        assert 43 not in bf

    def test_len(self):
        from i2p_transport.ssu2_bitfield import SSU2Bitfield

        bf = SSU2Bitfield()
        assert len(bf) == 0
        bf.set(0)
        bf.set(10)
        bf.set(20)
        assert len(bf) == 3