"""Tests for backend.claude_client — deterministic helpers (no LLM calls).

These test JSON extraction and history sanitisation only. No API keys needed.
"""
import sys
from pathlib import Path

sys.path.insert(0, str(Path(__file__).resolve().parent.parent))

from backend.claude_client import _extract_json_object, _sanitise_history


# ---------------------------------------------------------------------------
# _extract_json_object
# ---------------------------------------------------------------------------

class TestExtractJsonObject:
    def test_plain_json(self):
        assert _extract_json_object('{"a": 1}') == '{"a": 1}'

    def test_with_preamble(self):
        raw = 'Here is the JSON: {"a": 1}'
        assert _extract_json_object(raw) == '{"a": 1}'

    def test_with_code_fence(self):
        raw = '```json\n{"a": 1}\n```'
        assert _extract_json_object(raw) == '{"a": 1}'

    def test_with_trailing_prose(self):
        raw = '{"a": 1} I hope this helps!'
        assert _extract_json_object(raw) == '{"a": 1}'

    def test_nested_braces(self):
        raw = '{"outer": {"inner": 2}}'
        result = _extract_json_object(raw)
        assert result == '{"outer": {"inner": 2}}'

    def test_no_braces_returns_stripped(self):
        raw = "no json here"
        assert _extract_json_object(raw) == "no json here"


# ---------------------------------------------------------------------------
# _sanitise_history
# ---------------------------------------------------------------------------

class TestSanitiseHistory:
    def test_empty_returns_empty(self):
        assert _sanitise_history(None) == []
        assert _sanitise_history([]) == []

    def test_drops_leading_assistant(self):
        history = [
            {"role": "assistant", "content": "Welcome!"},
            {"role": "user", "content": "Hi"},
        ]
        result = _sanitise_history(history)
        assert result[0]["role"] == "user"
        assert result[0]["content"] == "Hi"

    def test_merges_consecutive_same_role(self):
        history = [
            {"role": "user", "content": "Hello"},
            {"role": "user", "content": "Can you help?"},
            {"role": "assistant", "content": "Sure!"},
        ]
        result = _sanitise_history(history)
        assert len(result) == 2
        assert "Hello" in result[0]["content"]
        assert "Can you help?" in result[0]["content"]

    def test_skips_invalid_roles(self):
        history = [
            {"role": "user", "content": "Hi"},
            {"role": "system", "content": "Internal"},
            {"role": "assistant", "content": "Hello!"},
        ]
        result = _sanitise_history(history)
        assert len(result) == 2
        assert result[0]["role"] == "user"
        assert result[1]["role"] == "assistant"