"""Unit tests for the pure wiring-graph engine (ledgrab.api.graph_schema).

These exercise reference extraction, topology building, dependents, cycle and
dangling-reference detection without booting the app or any store.
"""

import json
import re
from dataclasses import dataclass, field

from ledgrab.api.graph_schema import (
    CONNECTION_SCHEMA,
    ENTITY_KINDS,
    build_topology,
    detect_cycles,
    extract_refs,
    find_dependents,
    graph_field_roots,
    is_editable,
    schema_for_kind,
    serialize_entity_for_graph,
    validate_connection,
    would_create_cycle,
)


# ── extract_refs ────────────────────────────────────────────────────────────


def test_extract_refs_top_level():
    assert extract_refs({"device_id": "dev_1"}, "device_id") == ["dev_1"]


def test_extract_refs_empty_and_missing_are_dropped():
    assert extract_refs({"device_id": ""}, "device_id") == []
    assert extract_refs({}, "device_id") == []
    assert extract_refs({"device_id": None}, "device_id") == []


def test_extract_refs_bindable_bound_vs_unbound():
    # Bound bindable serializes as a dict.
    assert extract_refs(
        {"brightness": {"value": 1.0, "source_id": "vs_1"}}, "brightness.source_id"
    ) == ["vs_1"]
    # Unbound bindable serializes as a plain number → no reference.
    assert extract_refs({"brightness": 0.5}, "brightness.source_id") == []
    # Bound-but-empty source_id → no reference.
    assert (
        extract_refs({"brightness": {"value": 1.0, "source_id": ""}}, "brightness.source_id") == []
    )


def test_extract_refs_list_field():
    entity = {"layers": [{"source_id": "a"}, {"source_id": ""}, {"other": "x"}]}
    assert extract_refs(entity, "layers[].source_id") == ["a"]


def test_extract_refs_deep_object_then_list():
    entity = {"calibration": {"lines": [{"picture_source_id": "p1"}, {"picture_source_id": "p2"}]}}
    assert extract_refs(entity, "calibration.lines[].picture_source_id") == ["p1", "p2"]


def test_extract_refs_nested_object_none_is_safe():
    assert extract_refs({"settings": None}, "settings.pattern_template_id") == []
    assert extract_refs(
        {"settings": {"pattern_template_id": "pt_1"}}, "settings.pattern_template_id"
    ) == ["pt_1"]


# ── registry consistency ─────────────────────────────────────────────────────


def test_registry_kinds_are_known():
    for cf in CONNECTION_SCHEMA:
        assert cf.target_kind in ENTITY_KINDS, cf.target_kind
        assert cf.source_kind in ENTITY_KINDS, cf.source_kind


def test_registry_has_no_duplicate_target_field_pairs():
    pairs = [(cf.target_kind, cf.field) for cf in CONNECTION_SCHEMA]
    assert len(pairs) == len(set(pairs)), "duplicate (target_kind, field) in CONNECTION_SCHEMA"


def test_schema_for_kind_filters_by_referrer():
    fields = {cf.field for cf in schema_for_kind("automation")}
    assert fields == {"scene_preset_id", "deactivation_scene_preset_id"}


# ── build_topology ───────────────────────────────────────────────────────────


def _sample_entities():
    return {
        "device": [{"id": "dev_1", "name": "Strip", "device_type": "wled"}],
        "picture_source": [{"id": "ps_1", "name": "Cap", "stream_type": "raw"}],
        "color_strip_source": [
            {"id": "css_1", "name": "CSS", "source_type": "picture", "picture_source_id": "ps_1"}
        ],
        "output_target": [
            {
                "id": "ot_1",
                "name": "TV",
                "target_type": "led",
                "device_id": "dev_1",
                "color_strip_source_id": "css_1",
            }
        ],
    }


def test_build_topology_nodes_and_edges():
    topo = build_topology(_sample_entities())

    assert {n["id"] for n in topo["nodes"]} == {"dev_1", "ps_1", "css_1", "ot_1"}
    edge_set = {(e["from"], e["to"], e["field"]) for e in topo["edges"]}
    assert ("ps_1", "css_1", "picture_source_id") in edge_set
    assert ("dev_1", "ot_1", "device_id") in edge_set
    assert ("css_1", "ot_1", "color_strip_source_id") in edge_set
    assert topo["issues"]["orphans"] == []
    assert topo["issues"]["broken_refs"] == []
    assert topo["issues"]["cycles"] == []


def test_build_topology_flags_orphan_and_broken_ref():
    entities = _sample_entities()
    entities["sync_clock"] = [{"id": "clk_1", "name": "Lonely"}]  # no edges → orphan
    entities["color_strip_source"][0]["audio_source_id"] = "ghost"  # dangling

    topo = build_topology(entities)

    assert "clk_1" in topo["issues"]["orphans"]
    broken = topo["issues"]["broken_refs"]
    assert {"ref": "ghost", "by": "css_1", "field": "audio_source_id"} in broken
    # The dangling ref must NOT appear as a real edge.
    assert all(e["from"] != "ghost" for e in topo["edges"])


def test_build_topology_detects_cycle():
    entities = {
        "value_source": [
            {"id": "vs_1", "name": "A", "source_type": "static", "value_source_id": "vs_2"},
            {"id": "vs_2", "name": "B", "source_type": "static", "value_source_id": "vs_1"},
        ]
    }
    topo = build_topology(entities)
    assert set(topo["issues"]["cycles"]) == {"vs_1", "vs_2"}


# ── detect_cycles ────────────────────────────────────────────────────────────


def test_detect_cycles_no_false_positive_on_diamond():
    # a→b, a→c, b→d, c→d  (DAG)
    edges = [
        {"from": "a", "to": "b"},
        {"from": "a", "to": "c"},
        {"from": "b", "to": "d"},
        {"from": "c", "to": "d"},
    ]
    assert detect_cycles(edges) == set()


def test_detect_cycles_marks_only_cycle_members():
    # x→a→b→a  (a,b in cycle; x is not)
    edges = [
        {"from": "x", "to": "a"},
        {"from": "a", "to": "b"},
        {"from": "b", "to": "a"},
    ]
    assert detect_cycles(edges) == {"a", "b"}


# ── would_create_cycle ───────────────────────────────────────────────────────


def test_would_create_cycle_detects_back_edge_and_self():
    edges = [{"from": "a", "to": "b"}]  # b depends on a (a→b)
    # Wiring a to consume b (edge b→a) closes the a→b→a loop.
    assert would_create_cycle(edges, source_id="b", target_id="a") is True
    # Wiring an unrelated pair is fine.
    assert would_create_cycle(edges, source_id="a", target_id="c") is False
    # Self-reference is always a cycle.
    assert would_create_cycle(edges, source_id="z", target_id="z") is True


# ── find_dependents ──────────────────────────────────────────────────────────


def test_find_dependents_returns_referrers():
    deps = find_dependents(_sample_entities(), "color_strip_source", "css_1")
    assert deps == [
        {"id": "ot_1", "kind": "output_target", "name": "TV", "field": "color_strip_source_id"}
    ]


def test_find_dependents_empty_when_unreferenced():
    assert find_dependents(_sample_entities(), "color_strip_source", "css_unused") == []


# ── validate_connection ──────────────────────────────────────────────────────


def test_validate_connection_accepts_valid_edit():
    ok, err = validate_connection(_sample_entities(), "output_target", "ot_1", "device_id", "dev_1")
    assert ok is True
    assert err is None


def test_validate_connection_detach_always_ok():
    ok, err = validate_connection(_sample_entities(), "output_target", "ot_1", "device_id", "")
    assert ok is True and err is None


def test_validate_connection_rejects_unknown_field():
    ok, err = validate_connection(_sample_entities(), "output_target", "ot_1", "nope_id", "dev_1")
    assert ok is False
    assert "Unknown connection field" in err


def test_validate_connection_rejects_missing_source():
    ok, err = validate_connection(_sample_entities(), "output_target", "ot_1", "device_id", "ghost")
    assert ok is False
    assert "not found" in err


def test_validate_connection_accepts_bindable_single_field():
    # Single-level bindable slots (e.g. brightness) ARE editable — only list
    # fields are rejected.
    entities = {
        "color_strip_source": [
            {"id": "css_1", "name": "X", "source_type": "effect", "brightness": 0.5}
        ],
        "value_source": [{"id": "vs_1", "name": "V", "source_type": "static"}],
    }
    ok, err = validate_connection(
        entities, "color_strip_source", "css_1", "brightness.source_id", "vs_1"
    )
    assert ok is True
    assert err is None


def test_validate_connection_rejects_list_field():
    # List slots can't be cycle-checked without an element index → rejected.
    entities = {
        "color_strip_source": [
            {
                "id": "css_1",
                "name": "X",
                "source_type": "composite",
                "layers": [{"source_id": "css_2"}],
            },
            {"id": "css_2", "name": "Y", "source_type": "picture"},
        ]
    }
    ok, err = validate_connection(
        entities, "color_strip_source", "css_1", "layers[].source_id", "css_2"
    )
    assert ok is False
    assert "not editable" in err


def test_validate_connection_rejects_color_bindable():
    # Colour bindings are structurally bindable but not graph-editable (a value
    # source can't drive a colour).
    entities = {
        "color_strip_source": [
            {"id": "css_1", "name": "X", "source_type": "single_color", "color": [255, 0, 0]}
        ],
        "value_source": [{"id": "vs_1", "name": "V", "source_type": "static"}],
    }
    ok, err = validate_connection(
        entities, "color_strip_source", "css_1", "color.source_id", "vs_1"
    )
    assert ok is False
    assert "not editable" in err


@dataclass
class _FakeRule:
    token: str = "SUPER_SECRET_WEBHOOK_TOKEN"


@dataclass
class _FakeAutomation:
    id: str = "auto_1"
    name: str = "A"
    enabled: bool = True
    scene_preset_id: str = "sp_1"
    rules: list = field(default_factory=lambda: [_FakeRule()])


# Keys that must NEVER appear in the /graph projection allowlist.
_SECRET_KEY_RE = re.compile(
    r"token|password|secret|credential|api[_-]?key|_key$|username|\burl\b|\bhost\b", re.I
)


def test_projection_roots_never_expose_secrets():
    # The /graph projection (graph_field_roots) is the leak boundary. Assert no
    # kind's allowlist contains a secret-bearing key — locks the boundary against
    # future schema drift (a new reference field whose root looks like a secret).
    for kind in ENTITY_KINDS:
        for root in graph_field_roots(kind):
            assert not _SECRET_KEY_RE.search(
                root
            ), f"{kind}: projected root {root!r} looks secret-bearing"


def test_serialize_entity_for_graph_drops_secrets():
    # The graph projection must strip everything except id/name/type + reference
    # roots — a deep asdict would otherwise leak the webhook token (a real,
    # auth-equivalent secret) in the /graph response.
    projected = serialize_entity_for_graph("automation", _FakeAutomation())
    assert projected["id"] == "auto_1"
    assert projected["name"] == "A"
    assert projected["scene_preset_id"] == "sp_1"  # reference root kept
    assert "rules" not in projected  # non-reference field dropped
    assert "enabled" not in projected
    assert "SUPER_SECRET_WEBHOOK_TOKEN" not in json.dumps(projected)


def test_is_editable_classifies_fields():
    by_field = {(c.target_kind, c.field): c for c in CONNECTION_SCHEMA}
    # Top-level reference and single-level BindableFloat → editable.
    assert is_editable(by_field[("output_target", "device_id")])
    assert is_editable(by_field[("color_strip_source", "brightness.source_id")])
    assert is_editable(by_field[("output_target", "transition.source_id")])
    # Colour binding, list slot, and double-nested → NOT editable.
    assert not is_editable(by_field[("color_strip_source", "color.source_id")])
    assert not is_editable(by_field[("color_strip_source", "layers[].source_id")])
    assert not is_editable(by_field[("output_target", "settings.brightness.source_id")])


def test_validate_connection_rejects_cycle():
    entities = {
        "value_source": [
            {"id": "vs_1", "name": "A", "source_type": "static", "value_source_id": ""},
            {"id": "vs_2", "name": "B", "source_type": "static", "value_source_id": "vs_1"},
        ]
    }
    # vs_2 already depends on vs_1 (edge vs_1→vs_2). Wiring vs_1 to consume vs_2
    # would close the loop.
    ok, err = validate_connection(entities, "value_source", "vs_1", "value_source_id", "vs_2")
    assert ok is False
    assert "cycle" in err.lower()