"""TDD — IdentityPlugin.schema() and protocol conformance.

Covers:
- schema() returns a valid DomainSchema
- domain field is "identity"
- Two dimensions: "identities" and "relationships"
- Both dimensions are independently mergeable
- "identities" dimension uses SetSchema keyed by handle
- "relationships" dimension uses SetSchema keyed by (from, edge_type, to)
- merge_mode is "three_way"
- Plugin satisfies MuseDomainPlugin protocol (runtime isinstance check)
- Plugin satisfies AddressedMergePlugin protocol (has merge_ops)
- Plugin satisfies HarmonyPlugin protocol (has conflict_fingerprint)
- drift() delegates to snapshot + diff correctly
- apply() returns live_state unchanged (post-processing no-op for now)
"""
from __future__ import annotations

import pathlib

import pytest

from muse.domain import (
    DriftReport,
    LiveState,
    MergeResult,
    MuseDomainPlugin,
    AddressedMergePlugin,
    SnapshotManifest,
    StateDelta,
    StateSnapshot,
)
from muse.plugins.identity.plugin import IdentityPlugin
from muse.core.types import long_id


@pytest.fixture
def plugin() -> IdentityPlugin:
    return IdentityPlugin()


# ── DomainSchema ──────────────────────────────────────────────────────────────

class TestSchema:
    def test_domain_is_identity(self, plugin: IdentityPlugin) -> None:
        assert plugin.schema()["domain"] == "identity"

    def test_description_non_empty(self, plugin: IdentityPlugin) -> None:
        assert plugin.schema()["description"]

    def test_has_two_dimensions(self, plugin: IdentityPlugin) -> None:
        dims = plugin.schema()["dimensions"]
        assert len(dims) == 2

    def test_identities_dimension_exists(self, plugin: IdentityPlugin) -> None:
        names = {d["name"] for d in plugin.schema()["dimensions"]}
        assert "identities" in names

    def test_relationships_dimension_exists(self, plugin: IdentityPlugin) -> None:
        names = {d["name"] for d in plugin.schema()["dimensions"]}
        assert "relationships" in names

    def test_both_dimensions_independently_mergeable(self, plugin: IdentityPlugin) -> None:
        for dim in plugin.schema()["dimensions"]:
            assert dim["independent_merge"] is True

    def test_identities_dimension_is_set_schema(self, plugin: IdentityPlugin) -> None:
        dim = next(d for d in plugin.schema()["dimensions"] if d["name"] == "identities")
        assert dim["schema"]["kind"] == "set"

    def test_relationships_dimension_is_set_schema(self, plugin: IdentityPlugin) -> None:
        dim = next(d for d in plugin.schema()["dimensions"] if d["name"] == "relationships")
        assert dim["schema"]["kind"] == "set"

    def test_merge_mode_is_three_way(self, plugin: IdentityPlugin) -> None:
        assert plugin.schema()["merge_mode"] == "three_way"

    def test_schema_version_is_string(self, plugin: IdentityPlugin) -> None:
        assert isinstance(plugin.schema()["schema_version"], str)


# ── Protocol conformance ──────────────────────────────────────────────────────

class TestProtocolConformance:
    def test_satisfies_muse_domain_plugin(self, plugin: IdentityPlugin) -> None:
        assert isinstance(plugin, MuseDomainPlugin)

    def test_satisfies_addressed_merge_plugin(self, plugin: IdentityPlugin) -> None:
        assert isinstance(plugin, AddressedMergePlugin)

    def test_has_conflict_fingerprint_harmony(self, plugin: IdentityPlugin) -> None:
        assert callable(getattr(plugin, "conflict_fingerprint", None))

    def test_has_all_six_required_methods(self, plugin: IdentityPlugin) -> None:
        for method in ("snapshot", "diff", "merge", "drift", "apply", "schema"):
            assert callable(getattr(plugin, method, None)), f"missing: {method}"

    def test_has_merge_ops(self, plugin: IdentityPlugin) -> None:
        assert callable(getattr(plugin, "merge_ops", None))


# ── drift() ───────────────────────────────────────────────────────────────────

class TestDrift:
    def test_no_drift_when_tree_matches_commit(self, plugin: IdentityPlugin, tmp_path: pathlib.Path) -> None:
        snap = plugin.snapshot(tmp_path)
        report = plugin.drift(snap, tmp_path)
        assert report.has_drift is False

    def test_drift_detected_on_new_file(self, plugin: IdentityPlugin, tmp_path: pathlib.Path) -> None:
        snap = plugin.snapshot(tmp_path)
        (tmp_path / "identities").mkdir()
        (tmp_path / "identities" / "gabriel.json").write_bytes(b'{"handle":"gabriel"}')
        report = plugin.drift(snap, tmp_path)
        assert report.has_drift is True

    def test_drift_report_has_summary(self, plugin: IdentityPlugin, tmp_path: pathlib.Path) -> None:
        snap = plugin.snapshot(tmp_path)
        (tmp_path / "identities").mkdir()
        (tmp_path / "identities" / "alice.json").write_bytes(b'{"handle":"alice"}')
        report = plugin.drift(snap, tmp_path)
        assert hasattr(report, "summary")

    def test_no_drift_summary_indicates_clean(self, plugin: IdentityPlugin, tmp_path: pathlib.Path) -> None:
        snap = plugin.snapshot(tmp_path)
        report = plugin.drift(snap, tmp_path)
        # summary should convey "nothing changed"
        assert not report.has_drift


# ── apply() ───────────────────────────────────────────────────────────────────

class TestApply:
    def test_apply_returns_live_state(self, plugin: IdentityPlugin, tmp_path: pathlib.Path) -> None:
        snap = plugin.snapshot(tmp_path)
        delta: StateDelta = {"ops": [], "summary": "", "domain": "identity"}
        result = plugin.apply(delta, tmp_path)
        assert result == tmp_path

    def test_apply_with_manifest_returns_manifest(self, plugin: IdentityPlugin) -> None:
        manifest = SnapshotManifest(
            files={"identities/alice.json": long_id("a" * 64)},
            domain="identity",
            directories=[],
        )
        delta: StateDelta = {"ops": [], "summary": "", "domain": "identity"}
        result = plugin.apply(delta, manifest)
        assert result == manifest