"""Round 24: sidebar drag auto-scroll.

Dragging a playlist (or tracks) near the top/bottom edge of the sidebar's
playlist tree scrolls the tree so off-screen rows can be reached. Same root
cause and fix as the track table's Round 13: our dragMoveEvent accepts the
event itself, so Qt's built-in autoscroll never runs. The direction helper
(autoscroll_direction) is shared with the table and already covered by
test_round13.
"""

from PyQt6.QtCore import QPoint

from lintunes.models import Library, Track
from lintunes.library_manager import LibraryManager
from lintunes.gui.sidebar import PlaylistTree


def _tree(qapp, tmp_path, playlists=0):
    library = Library(tracks={1: Track(track_id=1, name="One")})
    manager = LibraryManager(library, tmp_path)
    tree = PlaylistTree(manager)
    for i in range(playlists):
        manager.create_playlist(f"playlist {i}")
    # Small viewport: enough rows that the scrollbar gets a real range (the
    # view re-derives the range itself, so a manual setRange doesn't stick;
    # show() forces the polish/layout pass that computes it).
    tree.resize(200, 100)
    tree.show()
    return tree


class TestAutoscrollTick:
    def test_tick_scrolls_by_direction(self, qapp, tmp_path):
        tree = _tree(qapp, tmp_path, playlists=60)
        bar = tree.verticalScrollBar()
        assert bar.maximum() > 20  # real range from the rows
        bar.setValue(10)

        tree._autoscroll_dir = 1
        tree._autoscroll_tick()
        assert bar.value() == 11

        tree._autoscroll_dir = -1
        tree._autoscroll_tick()
        assert bar.value() == 10

    def test_tick_stops_at_the_end(self, qapp, tmp_path):
        tree = _tree(qapp, tmp_path, playlists=60)
        bar = tree.verticalScrollBar()
        bar.setValue(bar.maximum())  # already at the bottom

        tree._autoscroll_dir = 1
        tree._autoscroll_timer.start()
        tree._autoscroll_tick()

        assert bar.value() == bar.maximum()
        assert not tree._autoscroll_timer.isActive()


class TestUpdateAutoscroll:
    def test_edge_starts_timer(self, qapp, tmp_path):
        tree = _tree(qapp, tmp_path)
        tree.resize(200, 300)
        tree._update_autoscroll(QPoint(10, 5), accepted=True)
        assert tree._autoscroll_dir == -1
        assert tree._autoscroll_timer.isActive()

    def test_rejected_drop_keeps_timer_off(self, qapp, tmp_path):
        tree = _tree(qapp, tmp_path)
        tree.resize(200, 300)
        tree._update_autoscroll(QPoint(10, 5), accepted=False)
        assert tree._autoscroll_dir == 0
        assert not tree._autoscroll_timer.isActive()

    def test_stop_autoscroll_resets(self, qapp, tmp_path):
        tree = _tree(qapp, tmp_path)
        tree._autoscroll_dir = 1
        tree._autoscroll_timer.start()
        tree._stop_autoscroll()
        assert tree._autoscroll_dir == 0
        assert tree._autoscroll_pos is None
        assert not tree._autoscroll_timer.isActive()