"""Tests for the F4 ledger -> schema_linking.json deterministic projection."""
import json

from tht.config import DatabaseConfig
from tht.decisions import append_decision
from tht.session.store import create_session, set_schema_linking, sync_schema_linking


def _db():
    return DatabaseConfig(
        database="testdb", user="u", password="p",  # noqa: S106
        **{"schema": "public"},
    )


def test_projection_from_ledger(tmp_path):
    m = create_session("domanda X", _db(), tmp_path)
    sid = m.id
    sdir = tmp_path / sid
    # seed a prior schema_linking with a join to prove joins are preserved
    set_schema_linking(sid, {"question": "domanda X", "candidates": [], "joins": [
        {"from": "dim_patient.cod_paz", "to": "fact_x.cod_paz"}], "excluded": []}, tmp_path)
    append_decision(sdir, type="table_promoted", subject="dim_patient")
    append_decision(sdir, type="column_promoted", subject="dim_patient.cod_paz")
    append_decision(sdir, type="column_promoted", subject="dim_patient.nome")
    append_decision(sdir, type="table_excluded", subject="fact_sost")

    sync_schema_linking(sid, tmp_path)

    data = json.loads((sdir / "schema_linking.json").read_text())
    tabs = {(c["kind"], c["name"], c["decision"]) for c in data["candidates"]}
    assert ("table", "dim_patient", "promoted") in tabs
    assert ("column", "dim_patient.cod_paz", "promoted") in tabs
    assert ("column", "dim_patient.nome", "promoted") in tabs
    assert {"kind": "table", "name": "fact_sost"} in [
        {"kind": e["kind"], "name": e["name"]} for e in data["excluded"]]
    assert data["joins"], "existing joins must be preserved"


def test_projection_last_decision_wins(tmp_path):
    m = create_session("domanda Y", _db(), tmp_path)
    sid = m.id
    sdir = tmp_path / sid
    append_decision(sdir, type="table_promoted", subject="dim_x")
    append_decision(sdir, type="table_excluded", subject="dim_x")

    sync_schema_linking(sid, tmp_path)

    data = json.loads((sdir / "schema_linking.json").read_text())
    assert data["candidates"] == []
    assert [e["name"] for e in data["excluded"]] == ["dim_x"]


def test_projection_defaults_question_from_manifest(tmp_path):
    m = create_session("domanda Z", _db(), tmp_path)
    sid = m.id

    path = sync_schema_linking(sid, tmp_path)

    data = json.loads(path.read_text())
    assert data["question"] == "domanda Z"
    assert data["candidates"] == []
    assert data["excluded"] == []