"""Tests for governance/policy.py — Policy Engine.

NOTE: This module exists only in darkplex-core. Tests written against the module API.
"""

import os
import tempfile
import pytest
from pathlib import Path

# We need yaml for creating test fixtures
import yaml


def _write_policy(tmpdir, filename, data):
    path = Path(tmpdir) / filename
    path.write_text(yaml.dump(data))
    return path


class TestRule:
    def setup_method(self):
        import sys
        sys.path.insert(0, str(Path.home() / "repos" / "darkplex-core"))
        from governance.policy import Rule
        self.Rule = Rule

    def test_matches_simple(self):
        r = self.Rule(name="r1", conditions={"agent": "claudia"}, effect="allow")
        assert r.matches({"agent": "claudia"})

    def test_no_match(self):
        r = self.Rule(name="r1", conditions={"agent": "claudia"}, effect="allow")
        assert not r.matches({"agent": "other"})

    def test_missing_key(self):
        r = self.Rule(name="r1", conditions={"agent": "claudia"}, effect="allow")
        assert not r.matches({})

    def test_list_condition(self):
        r = self.Rule(name="r1", conditions={"action": ["read", "write"]}, effect="allow")
        assert r.matches({"action": "read"})
        assert not r.matches({"action": "delete"})

    def test_multiple_conditions(self):
        r = self.Rule(name="r1", conditions={"agent": "claudia", "action": "send"}, effect="deny")
        assert r.matches({"agent": "claudia", "action": "send"})
        assert not r.matches({"agent": "claudia", "action": "read"})


class TestPolicyEngine:
    def setup_method(self):
        import sys
        sys.path.insert(0, str(Path.home() / "repos" / "darkplex-core"))
        from governance.policy import PolicyEngine
        self.PolicyEngine = PolicyEngine

    def test_empty_dir(self, tmp_path):
        engine = self.PolicyEngine(policies_dir=str(tmp_path))
        assert engine.policies == []

    def test_nonexistent_dir(self, tmp_path):
        engine = self.PolicyEngine(policies_dir=str(tmp_path / "nope"))
        assert engine.policies == []

    def test_load_policy(self, tmp_path):
        _write_policy(tmp_path, "test.yaml", {
            "name": "test-policy",
            "description": "Test",
            "version": "1.0.0",
            "rules": [
                {"name": "deny-external", "conditions": {"target": "external"}, "effect": "deny", "priority": 10},
            ],
        })
        engine = self.PolicyEngine(policies_dir=str(tmp_path))
        assert len(engine.policies) == 1
        assert engine.policies[0].name == "test-policy"
        assert len(engine.policies[0].rules) == 1

    def test_evaluate_no_match(self, tmp_path):
        _write_policy(tmp_path, "test.yaml", {
            "name": "p", "description": "", "version": "1",
            "rules": [{"name": "r1", "conditions": {"agent": "x"}, "effect": "deny"}],
        })
        engine = self.PolicyEngine(policies_dir=str(tmp_path))
        result = engine.evaluate({"agent": "y"})
        assert result["verdict"] == "allow"

    def test_evaluate_match_deny(self, tmp_path):
        _write_policy(tmp_path, "test.yaml", {
            "name": "p", "description": "", "version": "1",
            "rules": [{"name": "r1", "conditions": {"target": "external"}, "effect": "deny", "priority": 5}],
        })
        engine = self.PolicyEngine(policies_dir=str(tmp_path))
        result = engine.evaluate({"target": "external"})
        assert result["verdict"] == "deny"

    def test_priority_ordering(self, tmp_path):
        _write_policy(tmp_path, "test.yaml", {
            "name": "p", "description": "", "version": "1",
            "rules": [
                {"name": "allow-all", "conditions": {"agent": "claudia"}, "effect": "allow", "priority": 1},
                {"name": "deny-ext", "conditions": {"agent": "claudia"}, "effect": "deny", "priority": 10},
            ],
        })
        engine = self.PolicyEngine(policies_dir=str(tmp_path))
        result = engine.evaluate({"agent": "claudia"})
        assert result["verdict"] == "deny"  # higher priority wins

    def test_reload(self, tmp_path):
        engine = self.PolicyEngine(policies_dir=str(tmp_path))
        assert len(engine.policies) == 0
        _write_policy(tmp_path, "new.yaml", {
            "name": "new", "description": "", "version": "1", "rules": [],
        })
        engine.reload()
        assert len(engine.policies) == 1

    def test_skips_schema_yaml(self, tmp_path):
        _write_policy(tmp_path, "schema.yaml", {"name": "schema"})
        _write_policy(tmp_path, "real.yaml", {
            "name": "real", "description": "", "version": "1", "rules": [],
        })
        engine = self.PolicyEngine(policies_dir=str(tmp_path))
        assert len(engine.policies) == 1
        assert engine.policies[0].name == "real"