"""Unit tests for db.py, files.py, and config.py: DB helpers, name/position counters, settings merge."""

import sqlite3
from collections.abc import Iterator
from pathlib import Path

import pytest

import db
import files
from config import deep_merge


@pytest.fixture(autouse=True)
def reset_counters() -> Iterator[None]:
    db.COUNTERS.clear()
    yield
    db.COUNTERS.clear()


@pytest.fixture
def test_db(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> Iterator[sqlite3.Connection]:
    """Temporary SQLite database with full schema applied."""
    monkeypatch.setattr(db, "DB_PATH", tmp_path / "test.db")
    monkeypatch.setattr(files, "DATA_DIR", tmp_path)
    monkeypatch.setattr(files, "IMAGES_DIR", tmp_path / "images")
    files.init_dirs()
    db.init_db()
    connection = db.conn()
    yield connection
    connection.close()


# ── deep_merge ────────────────────────────────────────────────────────────────


def test_deep_merge_basic() -> None:
    result = deep_merge({"a": 1, "b": 2}, {"b": 3, "c": 4})
    assert result == {"a": 1, "b": 3, "c": 4}


def test_deep_merge_nested() -> None:
    base = {"x": {"a": 1, "b": 2}}
    override = {"x": {"b": 99, "c": 3}}
    result = deep_merge(base, override)
    assert result == {"x": {"a": 1, "b": 99, "c": 3}}


def test_deep_merge_list_replacement() -> None:
    base = {"items": [1, 2, 3]}
    override = {"items": [4, 5]}
    result = deep_merge(base, override)
    assert result["items"] == [4, 5]


def test_deep_merge_does_not_mutate_base() -> None:
    base = {"a": {"x": 1}}
    deep_merge(base, {"a": {"x": 2}})
    assert base["a"]["x"] == 1


# ── uid / now ────────────────────────────────────────────────────────────────


def test_uid_unique() -> None:
    assert db.uid() != db.uid()


def test_uid_is_string() -> None:
    result = db.uid()
    assert isinstance(result, str)
    assert len(result) == 36  # UUID4 format


def test_now_is_string() -> None:
    result = db.now()
    assert isinstance(result, str)
    assert "T" in result  # ISO format


# ── next_name ────────────────────────────────────────────────────────────────


def test_next_name_increments() -> None:
    assert db.next_name("Room") == "Room 1"
    assert db.next_name("Room") == "Room 2"
    assert db.next_name("Room") == "Room 3"


def test_next_name_independent_prefixes() -> None:
    assert db.next_name("Room") == "Room 1"
    assert db.next_name("Shelf") == "Shelf 1"
    assert db.next_name("Room") == "Room 2"


# ── next_pos / next_root_pos ────────────────────────────────────────────────


def test_next_root_pos_empty(test_db: sqlite3.Connection) -> None:
    pos = db.next_root_pos(test_db, "rooms")
    assert pos == 1


def test_next_root_pos_with_rows(test_db: sqlite3.Connection) -> None:
    ts = db.now()
    test_db.execute("INSERT INTO rooms VALUES (?,?,?,?)", ["r1", "Room 1", 1, ts])
    test_db.execute("INSERT INTO rooms VALUES (?,?,?,?)", ["r2", "Room 2", 2, ts])
    test_db.commit()
    assert db.next_root_pos(test_db, "rooms") == 3


def test_next_pos_empty(test_db: sqlite3.Connection) -> None:
    ts = db.now()
    test_db.execute("INSERT INTO rooms VALUES (?,?,?,?)", ["r1", "Room", 1, ts])
    test_db.commit()
    pos = db.next_pos(test_db, "cabinets", "room_id", "r1")
    assert pos == 1


def test_next_pos_with_children(test_db: sqlite3.Connection) -> None:
    ts = db.now()
    test_db.execute("INSERT INTO rooms VALUES (?,?,?,?)", ["r1", "Room", 1, ts])
    test_db.execute("INSERT INTO cabinets VALUES (?,?,?,?,?,?,?,?)", ["c1", "r1", "C1", None, None, None, 1, ts])
    test_db.execute("INSERT INTO cabinets VALUES (?,?,?,?,?,?,?,?)", ["c2", "r1", "C2", None, None, None, 2, ts])
    test_db.commit()
    pos = db.next_pos(test_db, "cabinets", "room_id", "r1")
    assert pos == 3


# ── init_db ────────────────────────────────────────────────────────────────────


def test_init_db_creates_tables(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    monkeypatch.setattr(db, "DB_PATH", tmp_path / "test.db")
    db.init_db()
    connection = sqlite3.connect(tmp_path / "test.db")
    tables = {row[0] for row in connection.execute("SELECT name FROM sqlite_master WHERE type='table'").fetchall()}
    connection.close()
    assert {"rooms", "cabinets", "shelves", "books"}.issubset(tables)


# ── init_dirs ─────────────────────────────────────────────────────────────────


def test_init_dirs_creates_images_dir(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    monkeypatch.setattr(files, "DATA_DIR", tmp_path)
    monkeypatch.setattr(files, "IMAGES_DIR", tmp_path / "images")
    files.init_dirs()
    assert (tmp_path / "images").is_dir()