"""Tests for the observation and context-building layer (context.py).

All tests are offline — httpx is mocked so no live state-hub required.
"""
from __future__ import annotations

from pathlib import Path
from unittest.mock import MagicMock, patch

import pytest

from context import (
    build_context,
    fetch_state,
    load_constitution,
    CONSTITUTION_PATH,
    API_BASE,
)


# ---------------------------------------------------------------------------
# fetch_state
# ---------------------------------------------------------------------------

class TestFetchState:
    def _mock_response(self, data: dict, status: int = 200):
        resp = MagicMock()
        resp.status_code = status
        resp.json.return_value = data
        resp.raise_for_status = MagicMock()
        return resp

    def test_fetch_state_calls_summary_endpoint(self):
        state_data = {"totals": {"tasks": {"todo": 5}}, "topics": []}
        with patch("httpx.get") as mock_get:
            mock_get.return_value = self._mock_response(state_data)
            result = fetch_state(domain=None)
        mock_get.assert_called_once()
        call_url = mock_get.call_args[0][0]
        assert "/state/summary" in call_url

    def test_fetch_state_with_domain_calls_domain_endpoint(self):
        domain_data = {"domain": "custodian", "workstreams": []}
        with patch("httpx.get") as mock_get:
            mock_get.return_value = self._mock_response(domain_data)
            result = fetch_state(domain="custodian")
        call_url = mock_get.call_args[0][0]
        assert "custodian" in call_url

    def test_fetch_state_returns_dict(self):
        state_data = {"totals": {}, "topics": []}
        with patch("httpx.get") as mock_get:
            mock_get.return_value = self._mock_response(state_data)
            result = fetch_state()
        assert isinstance(result, dict)

    def test_fetch_state_handles_connection_error(self):
        with patch("httpx.get") as mock_get:
            mock_get.side_effect = Exception("Connection refused")
            result = fetch_state()
        # Graceful degradation: returns empty dict, does not raise
        assert result == {}

    def test_fetch_state_handles_non_200(self):
        resp = MagicMock()
        resp.raise_for_status.side_effect = Exception("503 Service Unavailable")
        with patch("httpx.get") as mock_get:
            mock_get.return_value = resp
            result = fetch_state()
        assert result == {}

    def test_fetch_state_custom_api_base(self):
        with patch("httpx.get") as mock_get:
            mock_get.return_value = self._mock_response({})
            fetch_state(api_base="http://localhost:9999")
        call_url = mock_get.call_args[0][0]
        assert "localhost:9999" in call_url


# ---------------------------------------------------------------------------
# load_constitution
# ---------------------------------------------------------------------------

class TestLoadConstitution:
    def test_load_constitution_returns_non_empty_string(self):
        text = load_constitution()
        assert isinstance(text, str)
        assert len(text) > 100

    def test_load_constitution_contains_key_clauses(self):
        text = load_constitution()
        assert "Custodian" in text
        assert "Forbidden" in text or "forbidden" in text.lower()

    def test_constitution_path_exists(self):
        assert CONSTITUTION_PATH.exists(), (
            f"Constitution not found at {CONSTITUTION_PATH}. "
            "The path is hardcoded relative to this file — check context.py."
        )

    def test_load_constitution_with_missing_file(self, tmp_path, monkeypatch):
        """If constitution is missing, return a minimal fallback, not an exception."""
        import context as ctx_module
        monkeypatch.setattr(ctx_module, "CONSTITUTION_PATH",
                            tmp_path / "nonexistent.md")
        text = load_constitution()
        assert isinstance(text, str)
        # Should return fallback, not crash
        assert len(text) > 0


# ---------------------------------------------------------------------------
# build_context
# ---------------------------------------------------------------------------

class TestBuildContext:
    def _minimal_state(self) -> dict:
        return {
            "totals": {
                "tasks": {"todo": 3, "done": 10},
                "workstreams": {"active": 2, "completed": 5},
                "decisions": {"open": 0},
            },
            "blocking_decisions": [],
            "blocked_tasks": [],
            "open_workstreams": [],
        }

    def test_build_context_returns_string(self):
        ctx = build_context(self._minimal_state(), "## Constitution\nBe safe.")
        assert isinstance(ctx, str)

    def test_build_context_includes_constitution(self):
        ctx = build_context(self._minimal_state(), "## Constitution\nBe safe.")
        assert "Be safe" in ctx

    def test_build_context_includes_task_counts(self):
        ctx = build_context(self._minimal_state(), "")
        assert "3" in ctx  # todo count

    def test_build_context_mentions_blocked_tasks_when_present(self):
        state = self._minimal_state()
        state["blocked_tasks"] = [
            {"id": "t1", "title": "Deploy postgres", "blocking_reason": "no cluster"}
        ]
        ctx = build_context(state, "")
        assert "Deploy postgres" in ctx or "blocked" in ctx.lower()

    def test_build_context_mentions_blocking_decisions_when_present(self):
        state = self._minimal_state()
        state["blocking_decisions"] = [
            {"id": "d1", "title": "Which DB?", "type": "pending"}
        ]
        ctx = build_context(state, "")
        assert "Which DB?" in ctx or "decision" in ctx.lower()

    def test_build_context_with_empty_state_does_not_crash(self):
        ctx = build_context({}, "some constitution")
        assert isinstance(ctx, str)

    def test_build_context_includes_json_response_instruction(self):
        """The prompt must instruct the LLM to return a JSON block."""
        ctx = build_context(self._minimal_state(), "")
        assert "```json" in ctx or "JSON" in ctx