from __future__ import annotations

import pytest

from langbot.pkg.box.backend import CLISandboxBackend, _MAX_RAW_OUTPUT_BYTES


class TestClipCapturedBytes:
    def test_within_limit_unchanged(self):
        data = b'hello world'
        result = CLISandboxBackend._clip_captured_bytes(data, total_size=len(data), limit=1024)
        assert result == 'hello world'

    def test_exceeding_limit_clips_and_appends_notice(self):
        captured = b'A' * 100
        total_size = 200
        result = CLISandboxBackend._clip_captured_bytes(captured, total_size=total_size, limit=100)
        assert result.startswith('A' * 100)
        assert 'raw output clipped at 100 bytes' in result
        assert '100 bytes discarded' in result

    def test_exact_limit_not_clipped(self):
        data = b'B' * 100
        result = CLISandboxBackend._clip_captured_bytes(data, total_size=100, limit=100)
        assert result == 'B' * 100
        assert 'clipped' not in result

    def test_default_limit_is_module_constant(self):
        data = b'x' * 10
        result = CLISandboxBackend._clip_captured_bytes(data, total_size=10)
        assert result == 'x' * 10
        assert _MAX_RAW_OUTPUT_BYTES == 1_048_576

    def test_invalid_utf8_replaced(self):
        data = b'ok\xff\xfetail'
        result = CLISandboxBackend._clip_captured_bytes(data, total_size=len(data), limit=1024)
        assert 'ok' in result
        assert 'tail' in result