import unittest
from dataclasses import dataclass, field
from datetime import datetime, timezone

from dns_sync.adapters import (
    CERTIFICATES,
    DNS_RECORDS,
    PROXY_HOSTS,
    Capability,
    CapabilityOperation,
    DiscoveredObject,
    Endpoint,
    NormalizedObject,
    ObjectReference,
    Observation,
)
from dns_sync.orchestrator import discover_reconcile_plan
from dns_sync.reconciliation import ReconciliationConflict
from dns_sync.persistence import SQLiteStateStore


T1 = datetime(
    2026, 9, 20, 8, 0, tzinfo=timezone.utc
)
T2 = datetime(
    2026, 9, 20, 9, 0, tzinfo=timezone.utc
)


@dataclass
class FakeAdapter:
    endpoint: Endpoint
    capabilities: frozenset[Capability]
    discovered: dict[str, list[DiscoveredObject]] = field(
        default_factory=dict
    )
    failures: dict[str, str] = field(
        default_factory=dict
    )

    def connect(self) -> None:
        return None

    def discover(
        self,
        object_type: str,
    ) -> list[DiscoveredObject]:
        if object_type in self.failures:
            raise RuntimeError(
                self.failures[object_type]
            )
        return list(
            self.discovered.get(
                object_type,
                [],
            )
        )


def capability_set(
    *object_types: str,
    apply: bool = False,
) -> frozenset[Capability]:
    rows = {
        Capability(
            object_type,
            CapabilityOperation.DISCOVER,
        )
        for object_type in object_types
    }

    if apply:
        rows.update(
            Capability(
                object_type,
                CapabilityOperation.APPLY,
            )
            for object_type in object_types
        )

    return frozenset(rows)


def normalized_certificate(
    local_key: str,
    *,
    valid_from: str,
    expires_on: str,
) -> NormalizedObject:
    return NormalizedObject(
        object_type=CERTIFICATES,
        logical_key="app.example.com",
        local_key=local_key,
        payload={
            "domain_names": ["app.example.com"],
            "provider": "other",
            "valid_from": valid_from,
            "expires_on": expires_on,
        },
    )


def discovered_certificate(
    local_key: str,
    *,
    valid_from: str,
    expires_on: str,
) -> DiscoveredObject:
    return DiscoveredObject(
        object_type=CERTIFICATES,
        local_key=local_key,
        payload={
            "domain_names": ["app.example.com"],
            "provider": "other",
            "valid_from": valid_from,
            "expires_on": expires_on,
        },
    )


def normalized_proxy(
    local_key: str,
) -> NormalizedObject:
    return NormalizedObject(
        object_type=PROXY_HOSTS,
        logical_key="app.example.com",
        local_key=local_key,
        payload={
            "domain_names": ["app.example.com"],
            "forward_scheme": "http",
            "forward_host": "backend.internal",
            "forward_port": 8080,
            "enabled": True,
        },
    )


class ObservationAuthorityTests(unittest.TestCase):
    def test_failed_newer_certificate_cache_cannot_override_live_certificate(self):
        live_endpoint = Endpoint(
            "npm",
            "192.168.1.3:81",
        )
        failed_endpoint = Endpoint(
            "npm",
            "192.168.1.4:81",
        )

        live = FakeAdapter(
            endpoint=live_endpoint,
            capabilities=capability_set(
                CERTIFICATES,
            ),
            discovered={
                CERTIFICATES: [
                    discovered_certificate(
                        "20",
                        valid_from=(
                            "2026-09-15T00:00:00+00:00"
                        ),
                        expires_on=(
                            "2026-12-15T00:00:00+00:00"
                        ),
                    )
                ]
            },
        )

        failed = FakeAdapter(
            endpoint=failed_endpoint,
            capabilities=capability_set(
                CERTIFICATES,
                apply=True,
            ),
            failures={
                CERTIFICATES: "offline"
            },
        )

        cached_newer = normalized_certificate(
            "99",
            valid_from=(
                "2026-09-19T00:00:00+00:00"
            ),
            expires_on=(
                "2026-12-19T00:00:00+00:00"
            ),
        )

        with SQLiteStateStore(":memory:") as store:
            store.replace_observations(
                failed_endpoint.identity,
                CERTIFICATES,
                [
                    Observation(
                        failed_endpoint.identity,
                        cached_newer,
                        T1,
                    )
                ],
                T1,
            )

            result = discover_reconcile_plan(
                [
                    live,
                    failed,
                ],
                store,
                target_ip="192.168.1.101",
                run_at=T2,
            )

        certificates = [
            object
            for object in result.desired
            if object.object_type == CERTIFICATES
        ]

        self.assertEqual(
            len(certificates),
            1,
        )
        self.assertEqual(
            certificates[0].payload["valid_from"],
            "2026-09-15T00:00:00+00:00",
        )

        # The failed target advertised APPLY, but it must not
        # receive a certificate mutation plan this run.
        self.assertEqual(
            result.plans,
            (),
        )

        self.assertTrue(
            any(
                observation.endpoint_id
                == failed_endpoint.identity
                and observation.object.local_key == "99"
                for observation in result.observations
            )
        )

    def test_persisted_newer_certificate_cannot_regress_to_older_live_certificate(
        self,
    ):
        endpoint = Endpoint(
            "npm",
            "192.168.1.3:81",
        )

        live = FakeAdapter(
            endpoint=endpoint,
            capabilities=capability_set(
                CERTIFICATES,
                apply=True,
            ),
            discovered={
                CERTIFICATES: [
                    discovered_certificate(
                        "20",
                        valid_from=(
                            "2026-09-15T00:00:00+00:00"
                        ),
                        expires_on=(
                            "2026-12-15T00:00:00+00:00"
                        ),
                    )
                ]
            },
        )

        persisted = normalized_certificate(
            "99",
            valid_from=(
                "2026-09-19T00:00:00+00:00"
            ),
            expires_on=(
                "2026-12-19T00:00:00+00:00"
            ),
        )

        persisted = NormalizedObject(
            object_type=persisted.object_type,
            logical_key=persisted.logical_key,
            payload=dict(persisted.payload),
        )

        with SQLiteStateStore(":memory:") as store:
            store.replace_desired_state(
                CERTIFICATES,
                [persisted],
                T1,
            )

            result = discover_reconcile_plan(
                [live],
                store,
                target_ip="192.168.1.101",
                run_at=T2,
            )

            stored = store.load_desired_state(
                CERTIFICATES
            )

        certificates = [
            object
            for object in result.desired
            if object.object_type == CERTIFICATES
        ]

        self.assertEqual(len(certificates), 1)
        self.assertEqual(
            certificates[0].payload["valid_from"],
            "2026-09-19T00:00:00+00:00",
        )
        self.assertEqual(
            certificates[0].payload["expires_on"],
            "2026-12-19T00:00:00+00:00",
        )

        self.assertEqual(len(stored), 1)
        self.assertEqual(
            stored[0].object,
            persisted,
        )

        self.assertEqual(len(result.plans), 1)
        self.assertEqual(
            result.plans[0].endpoint_id,
            endpoint.identity,
        )
        self.assertEqual(
            len(result.plans[0].actions),
            1,
        )
        self.assertEqual(
            result.plans[0].actions[0].operation.value,
            "replace",
        )
        self.assertEqual(
            result.plans[0].actions[0].desired,
            persisted,
        )

    def test_expired_certificate_on_disabled_proxy_is_removed_from_desired(
        self,
    ):
        endpoint = Endpoint(
            "npm",
            "192.168.1.3:81",
        )

        adapter = FakeAdapter(
            endpoint=endpoint,
            capabilities=capability_set(
                CERTIFICATES,
                PROXY_HOSTS,
            ),
            discovered={
                CERTIFICATES: [
                    DiscoveredObject(
                        object_type=CERTIFICATES,
                        local_key="56",
                        payload={
                            "domain_names": [
                                "admin.trunavigate.org"
                            ],
                            "provider": "letsencrypt",
                            "valid_from": None,
                            "expires_on": (
                                "2026-06-22T03:40:57.000Z"
                            ),
                        },
                    )
                ],
                PROXY_HOSTS: [
                    DiscoveredObject(
                        object_type=PROXY_HOSTS,
                        local_key="29",
                        payload={
                            "domain_names": [
                                "admin.trunavigate.org"
                            ],
                            "forward_scheme": "http",
                            "forward_host": "192.168.1.4",
                            "forward_port": 3283,
                            "enabled": False,
                        },
                        references=(
                            ObjectReference(
                                relation="certificate",
                                object_type=CERTIFICATES,
                                local_key="56",
                            ),
                        ),
                    )
                ],
            },
        )

        with SQLiteStateStore(":memory:") as store:
            result = discover_reconcile_plan(
                [adapter],
                store,
                target_ip="192.168.1.101",
                run_at=T2,
            )

        certificates = [
            object
            for object in result.desired
            if object.object_type == CERTIFICATES
        ]
        proxies = [
            object
            for object in result.desired
            if object.object_type == PROXY_HOSTS
        ]

        self.assertEqual(certificates, [])
        self.assertEqual(len(proxies), 1)
        self.assertEqual(
            proxies[0].logical_key,
            "admin.trunavigate.org",
        )
        self.assertEqual(
            proxies[0].references,
            (),
        )

    def test_expired_certificate_on_enabled_proxy_fails_closed(
        self,
    ):
        endpoint = Endpoint(
            "npm",
            "192.168.1.3:81",
        )

        adapter = FakeAdapter(
            endpoint=endpoint,
            capabilities=capability_set(
                CERTIFICATES,
                PROXY_HOSTS,
            ),
            discovered={
                CERTIFICATES: [
                    DiscoveredObject(
                        object_type=CERTIFICATES,
                        local_key="56",
                        payload={
                            "domain_names": [
                                "active.example.com"
                            ],
                            "provider": "letsencrypt",
                            "valid_from": None,
                            "expires_on": (
                                "2026-06-22T03:40:57.000Z"
                            ),
                        },
                    )
                ],
                PROXY_HOSTS: [
                    DiscoveredObject(
                        object_type=PROXY_HOSTS,
                        local_key="29",
                        payload={
                            "domain_names": [
                                "active.example.com"
                            ],
                            "forward_scheme": "http",
                            "forward_host": "192.168.1.4",
                            "forward_port": 3283,
                            "enabled": True,
                        },
                        references=(
                            ObjectReference(
                                relation="certificate",
                                object_type=CERTIFICATES,
                                local_key="56",
                            ),
                        ),
                    )
                ],
            },
        )

        with SQLiteStateStore(":memory:") as store:
            with self.assertRaisesRegex(
                ReconciliationConflict,
                "Enabled proxy host references an expired certificate",
            ):
                discover_reconcile_plan(
                    [adapter],
                    store,
                    target_ip="192.168.1.101",
                    run_at=T2,
                )

    def test_all_failed_sources_preserve_persisted_desired_without_planning(self):
        npm_endpoint = Endpoint(
            "npm",
            "192.168.1.3:81",
        )

        npm = FakeAdapter(
            endpoint=npm_endpoint,
            capabilities=capability_set(
                PROXY_HOSTS,
                apply=True,
            ),
            failures={
                PROXY_HOSTS: "offline"
            },
        )

        cached_proxy = normalized_proxy("12")

        previous_dns = NormalizedObject(
            object_type=DNS_RECORDS,
            logical_key="app.example.com",
            payload={
                "hostname": "app.example.com",
                "ip_address": "192.168.1.101",
            },
        )

        with SQLiteStateStore(":memory:") as store:
            store.replace_observations(
                npm_endpoint.identity,
                PROXY_HOSTS,
                [
                    Observation(
                        npm_endpoint.identity,
                        cached_proxy,
                        T1,
                    )
                ],
                T1,
            )

            store.replace_desired_state(
                DNS_RECORDS,
                [previous_dns],
                T1,
            )

            result = discover_reconcile_plan(
                [npm],
                store,
                target_ip="192.168.1.101",
                run_at=T2,
            )

            persisted_dns = store.load_desired_state(
                DNS_RECORDS
            )

        self.assertEqual(
            result.desired,
            (),
        )
        self.assertEqual(
            result.plans,
            (),
        )

        self.assertEqual(
            len(persisted_dns),
            1,
        )
        self.assertEqual(
            persisted_dns[0].object,
            previous_dns,
        )


if __name__ == "__main__":
    unittest.main()