"""Tests for SSU2 transport protocol types."""

import os
import struct

import pytest


class TestSSU2Header:
    def test_construct(self):
        from i2p_transport.ssu2 import SSU2Header
        h = SSU2Header(dest_conn_id=0xDEADBEEF, pkt_num=42,
                       header_type=0, version=2)
        assert h.dest_conn_id == 0xDEADBEEF
        assert h.pkt_num == 42

    def test_short_header_roundtrip(self):
        from i2p_transport.ssu2 import SSU2Header
        h = SSU2Header(dest_conn_id=12345, pkt_num=100,
                       header_type=0, version=2)
        data = h.to_bytes()
        h2 = SSU2Header.from_bytes(data)
        assert h2.dest_conn_id == 12345
        assert h2.pkt_num == 100

    def test_header_size(self):
        from i2p_transport.ssu2 import SSU2Header
        h = SSU2Header(dest_conn_id=0, pkt_num=0, header_type=0, version=2)
        data = h.to_bytes()
        assert len(data) == 16  # dest_id(8) + pkt_num(4) + type(1) + version(1) + net_id(2)


class TestSSU2Block:
    def test_construct(self):
        from i2p_transport.ssu2 import SSU2Block, BlockType
        block = SSU2Block(block_type=BlockType.DATA, payload=b"test")
        assert block.block_type == BlockType.DATA
        assert block.payload == b"test"

    def test_roundtrip(self):
        from i2p_transport.ssu2 import SSU2Block, BlockType
        block = SSU2Block(block_type=BlockType.DATA, payload=os.urandom(64))
        data = block.to_bytes()
        block2 = SSU2Block.from_bytes(data)
        assert block2.block_type == block.block_type
        assert block2.payload == block.payload

    def test_ack_block(self):
        from i2p_transport.ssu2 import SSU2Block, BlockType
        # ACK: ack_through(4) + num_ranges(1) + ranges
        ack_payload = struct.pack("!IB", 100, 0)
        block = SSU2Block(BlockType.ACK, ack_payload)
        data = block.to_bytes()
        block2 = SSU2Block.from_bytes(data)
        assert block2.block_type == BlockType.ACK

    def test_address_block(self):
        from i2p_transport.ssu2 import SSU2Block, BlockType
        block = SSU2Block(BlockType.ADDRESS, b"\x04\x01\x02\x03\x04\x30\x39")
        data = block.to_bytes()
        block2 = SSU2Block.from_bytes(data)
        assert block2.block_type == BlockType.ADDRESS

    def test_termination_block(self):
        from i2p_transport.ssu2 import SSU2Block, BlockType
        block = SSU2Block(BlockType.TERMINATION, struct.pack("!BQ", 0, 50))
        data = block.to_bytes()
        block2 = SSU2Block.from_bytes(data)
        assert block2.block_type == BlockType.TERMINATION

    def test_padding_block(self):
        from i2p_transport.ssu2 import SSU2Block, BlockType
        block = SSU2Block(BlockType.PADDING, os.urandom(32))
        data = block.to_bytes()
        block2 = SSU2Block.from_bytes(data)
        assert block2.block_type == BlockType.PADDING

    def test_multiple_blocks(self):
        import io
        from i2p_transport.ssu2 import SSU2Block, BlockType
        b1 = SSU2Block(BlockType.DATA, b"first")
        b2 = SSU2Block(BlockType.DATA, b"second")
        buf = b1.to_bytes() + b2.to_bytes()
        stream = io.BytesIO(buf)
        r1 = SSU2Block.from_stream(stream)
        r2 = SSU2Block.from_stream(stream)
        assert r1.payload == b"first"
        assert r2.payload == b"second"


class TestSSU2SessionState:
    def test_initial_state(self):
        from i2p_transport.ssu2 import SSU2SessionState, SSU2State
        state = SSU2SessionState()
        assert state.state == SSU2State.UNKNOWN

    def test_token_request_flow(self):
        from i2p_transport.ssu2 import SSU2SessionState, SSU2State
        state = SSU2SessionState()
        state.send_token_request()
        assert state.state == SSU2State.TOKEN_REQUEST_SENT

    def test_session_request_flow(self):
        from i2p_transport.ssu2 import SSU2SessionState, SSU2State
        state = SSU2SessionState()
        state.send_session_request()
        assert state.state == SSU2State.SESSION_REQUEST_SENT

    def test_established(self):
        from i2p_transport.ssu2 import SSU2SessionState, SSU2State
        state = SSU2SessionState()
        state.send_session_request()
        state.receive_session_created()
        assert state.state == SSU2State.SESSION_CONFIRMED
        state.confirm()
        assert state.state == SSU2State.ESTABLISHED

    def test_terminate(self):
        from i2p_transport.ssu2 import SSU2SessionState, SSU2State
        state = SSU2SessionState()
        state.send_session_request()
        state.receive_session_created()
        state.confirm()
        state.terminate()
        assert state.state == SSU2State.TERMINATED

    def test_peer_test(self):
        from i2p_transport.ssu2 import SSU2SessionState
        state = SSU2SessionState()
        state.send_session_request()
        state.receive_session_created()
        state.confirm()
        state.start_peer_test()
        assert state.peer_test_active

    def test_path_validation(self):
        from i2p_transport.ssu2 import SSU2SessionState
        state = SSU2SessionState()
        state.send_session_request()
        state.receive_session_created()
        state.confirm()
        nonce = state.start_path_validation()
        assert nonce is not None
        assert state.path_challenge_pending