"""Dry-run preview of source-owned dependency edges (STATE-WP-0094-T05 follow-up).

``diff_against_hub`` is pure, so these tests need no database: hub state is
passed as data. They pin that the preview uses the same rules as receiving.
"""
from pathlib import Path

from api.services import forge_projection as fp
from tests.test_forge_dependency_edges import _source, _write

TGT_WP = "11111111-1111-1111-1111-111111111111"
TGT_T01 = "22222222-2222-2222-2222-222222222222"
OWNER = "forge:edge-source"


def _derive(tmp_path: Path, frontmatter_deps: str, **kw):
    _write(tmp_path, _source(frontmatter_deps, **kw))
    return fp.derive_from_checkout(tmp_path, "edge-source", "b" * 40)


def _hub(derived):
    """Hub already holds every derived workplan and task under derived UUIDs."""
    workplans = [{"id": w.uuid, "slug": w.record_id.lower(), "status": w.status,
                  "flavor": w.flavor, "backing_relative_path": w.relative_path}
                 for w in derived.workplans]
    tasks = {w.uuid: [{"id": t.uuid, "record_id": t.record_id, "title": t.title,
                       "status": t.status} for t in w.tasks] for w in derived.workplans}
    return workplans, tasks


def _ids(derived):
    wp = {w.record_id: w.uuid for w in derived.workplans}
    tasks = {t.record_id: t.uuid for w in derived.workplans for t in w.tasks}
    return wp, tasks


def test_preview_absent_without_hub_edges(tmp_path):
    derived = _derive(tmp_path, "depends_on: [TGT-WP-0001]\n")
    workplans, tasks = _hub(derived)
    diff = fp.diff_against_hub(derived, workplans, tasks)
    assert diff.edges is None
    assert "edges" not in diff.to_dict()


def test_preview_lists_create_unresolved_and_external(tmp_path):
    derived = _derive(tmp_path, "depends_on: [TGT-WP-0001, TGT-WP-0001-T01]\n")
    workplans, tasks = _hub(derived)
    wp, tk = _ids(derived)
    # The sibling edge already exists as an externally authored (C-20/API) row.
    external = {"id": "e1", "from_workplan_id": wp["SRC-WP-0001"],
                "from_task_id": tk["SRC-WP-0001-T01"], "to_workplan_id": wp["SRC-WP-0002"],
                "to_task_id": None, "relationship_type": "blocks", "source_owner": None}
    diff = fp.diff_against_hub(
        derived, workplans, tasks, hub_edges=[external],
        edge_targets={"TGT-WP-0001": [TGT_WP], "TGT-WP-0001-T01": [TGT_T01],
                      "SRC-WP-0002": [wp["SRC-WP-0002"]]},
    )
    e = diff.edges
    created = {(c["from"], c["target"], c["relationship_type"]) for c in e["create"]}
    assert created == {("SRC-WP-0001", "TGT-WP-0001", "blocks"),
                       ("SRC-WP-0001", "TGT-WP-0001-T01", "starts_after")}
    assert [(x["from"], x["target"]) for x in e["external"]] == [("SRC-WP-0001-T01", "SRC-WP-0002")]
    # T02 declares a missing target; the closed T03 declares nothing.
    assert [(u["from"], u["reason"]) for u in e["unresolved"]] == [("SRC-WP-0001-T02", "missing")]
    assert e["remove"] == [] and e["retain"] == []
    assert not diff.clean
    out = diff.to_dict()
    assert out["edge_counts"] == {"create": 2, "remove": 0, "retain": 0, "unresolved": 1, "external": 1}


def test_preview_removes_only_undeclared_owned_edges(tmp_path):
    derived = _derive(tmp_path, "", t02_target="SRC-WP-0002")
    workplans, tasks = _hub(derived)
    wp, tk = _ids(derived)
    targets = {"SRC-WP-0002": [wp["SRC-WP-0002"]]}
    owned_live = {"id": "o1", "from_workplan_id": wp["SRC-WP-0001"],
                  "from_task_id": tk["SRC-WP-0001-T01"], "to_workplan_id": wp["SRC-WP-0002"],
                  "to_task_id": None, "relationship_type": "blocks", "source_owner": OWNER}
    owned_live_t02 = {**owned_live, "id": "o2", "from_task_id": tk["SRC-WP-0001-T02"]}
    owned_gone = {"id": "o3", "from_workplan_id": wp["SRC-WP-0001"], "from_task_id": None,
                  "to_workplan_id": TGT_WP, "to_task_id": None, "relationship_type": "blocks",
                  "source_owner": OWNER}
    foreign_gone = {**owned_gone, "id": "x1", "source_owner": "forge:other"}
    null_gone = {**owned_gone, "id": "x2", "source_owner": None}
    diff = fp.diff_against_hub(
        derived, workplans, tasks,
        hub_edges=[owned_live, owned_live_t02, owned_gone, foreign_gone, null_gone],
        edge_targets=targets,
    )
    e = diff.edges
    assert [r["id"] for r in e["remove"]] == ["o3"]
    assert e["create"] == [] and e["external"] == [] and e["unresolved"] == []
    assert not diff.clean


def test_preview_holds_owned_edges_of_unresolved_side_and_is_clean_when_settled(tmp_path):
    derived = _derive(tmp_path, "depends_on: [TGT-WP-0001]\n")
    workplans, tasks = _hub(derived)
    wp, tk = _ids(derived)
    owned = [
        {"id": "o1", "from_workplan_id": wp["SRC-WP-0001"], "from_task_id": None,
         "to_workplan_id": TGT_WP, "to_task_id": None, "relationship_type": "blocks",
         "source_owner": OWNER},
        {"id": "o2", "from_workplan_id": wp["SRC-WP-0001"], "from_task_id": tk["SRC-WP-0001-T01"],
         "to_workplan_id": wp["SRC-WP-0002"], "to_task_id": None, "relationship_type": "blocks",
         "source_owner": OWNER},
        # Owned edge of T02, whose declared target is now ambiguous: retained.
        {"id": "o3", "from_workplan_id": wp["SRC-WP-0001"], "from_task_id": tk["SRC-WP-0001-T02"],
         "to_workplan_id": TGT_WP, "to_task_id": None, "relationship_type": "blocks",
         "source_owner": OWNER},
    ]
    diff = fp.diff_against_hub(
        derived, workplans, tasks, hub_edges=owned,
        edge_targets={"TGT-WP-0001": [TGT_WP], "SRC-WP-0002": [wp["SRC-WP-0002"]],
                      "MISSING-WP-0009": ["a", "b"]},
    )
    e = diff.edges
    assert e["create"] == [] and e["remove"] == []
    assert [r["id"] for r in e["retain"]] == ["o3"]
    assert e["unresolved"][0]["reason"] == "ambiguous"
    assert e["unresolved"][0]["candidates"] == ["a", "b"]
    assert diff.clean  # unresolved/retained/external alone do not change the hub


def test_preview_resolves_targets_created_in_the_same_receipt(tmp_path):
    derived = _derive(tmp_path, "")
    workplans, tasks = _hub(derived)
    wp, tk = _ids(derived)
    # The hub lacks SRC-WP-0002 entirely; the receipt would create it.
    workplans = [w for w in workplans if w["slug"] != "src-wp-0002"]
    diff = fp.diff_against_hub(derived, workplans, tasks, hub_edges=[], edge_targets={})
    created = [(c["from"], c["to_workplan_id"]) for c in diff.edges["create"]]
    assert created == [("SRC-WP-0001-T01", wp["SRC-WP-0002"])]
    assert any(m["record_id"] == "SRC-WP-0002" for m in diff.missing)


def test_preview_flags_self_edge(tmp_path):
    derived = _derive(tmp_path, "depends_on: [SRC-WP-0001]\n")
    workplans, tasks = _hub(derived)
    wp, _ = _ids(derived)
    diff = fp.diff_against_hub(
        derived, workplans, tasks, hub_edges=[],
        edge_targets={"SRC-WP-0001": [wp["SRC-WP-0001"]], "SRC-WP-0002": [wp["SRC-WP-0002"]]},
    )
    assert ("SRC-WP-0001", "self") in {(u["from"], u["reason"]) for u in diff.edges["unresolved"]}


def test_classifier_never_collapses_duplicate_keys():
    key = ("wp", None, "tgt", None, "blocks")
    rows = [(key, "owned", OWNER), (key, "api", None)]
    # Declared: the owned row satisfies it; the API duplicate is not reported.
    plan = fp.classify_source_edges({key: {}}, set(), rows, OWNER)
    assert plan == {"create": [], "external": [], "remove": [], "retain": []}
    # Undeclared: only the owned row is removed, whatever the row order.
    for ordered in (rows, rows[::-1]):
        plan = fp.classify_source_edges({}, set(), ordered, OWNER)
        assert plan["remove"] == [(key, "owned")]