"""Tests for the Ketten-Builder and Status-Engine."""

import pytest

from tracker.core.chains import build_suffix_references, build_chains
from tracker.db.session import get_connection


@pytest.fixture
def db():
    conn = get_connection()
    yield conn
    conn.close()


class TestSuffixReferences:
    def test_build_suffix_references(self, db):
        """Should create referenzen for suffix-linked Vorlagen."""
        count = build_suffix_references(db)
        # We know there are 166 suffix Vorlagen, so we should get references
        total = db.execute(
            "SELECT COUNT(*) as cnt FROM referenzen WHERE typ = 'suffix'"
        ).fetchone()["cnt"]
        assert total > 0, "No suffix references created"

    def test_suffix_reference_links_correct(self, db):
        """Verify that suffix references link child -> parent correctly."""
        build_suffix_references(db)
        # Check a known suffix pair
        row = db.execute("""
            SELECT r.quelle_id, r.ziel_id,
                   q.aktenzeichen as q_az, z.aktenzeichen as z_az
            FROM referenzen r
            JOIN vorlagen q ON r.quelle_id = q.id
            JOIN vorlagen z ON r.ziel_id = z.id
            WHERE r.typ = 'suffix'
            LIMIT 5
        """).fetchall()

        for r in row:
            # The quelle (child) should have a suffix, the ziel (parent) should not or have lower suffix
            assert r["q_az"] is not None


class TestChainBuilder:
    def test_build_chains(self, db):
        """Should create ketten for Anträge and Anfragen."""
        build_suffix_references(db)
        count = build_chains(db)
        assert count > 0, "No chains built"

        # Verify chains exist in DB
        total = db.execute("SELECT COUNT(*) as cnt FROM ketten").fetchone()["cnt"]
        assert total > 0

    def test_chain_has_glieder(self, db):
        """Each chain should have at least one Glied (the Ursprung)."""
        build_suffix_references(db)
        build_chains(db)

        orphans = db.execute("""
            SELECT k.id FROM ketten k
            LEFT JOIN ketten_glieder kg ON k.id = kg.kette_id
            WHERE kg.kette_id IS NULL
        """).fetchall()

        assert len(orphans) == 0, f"Found {len(orphans)} chains without Glieder"

    def test_chain_status_is_set(self, db):
        """Every chain should have a status."""
        build_suffix_references(db)
        build_chains(db)

        no_status = db.execute(
            "SELECT COUNT(*) as cnt FROM ketten WHERE status IS NULL"
        ).fetchone()["cnt"]

        assert no_status == 0, f"Found {no_status} chains without status"

    def test_chain_types(self, db):
        """Chains should only be antrag or anfrage."""
        build_suffix_references(db)
        build_chains(db)

        types = db.execute(
            "SELECT DISTINCT typ FROM ketten"
        ).fetchall()
        type_names = {r["typ"] for r in types}
        assert type_names <= {"antrag", "anfrage"}, f"Unexpected chain types: {type_names}"