"""Extreme battery for sync-editor add/remove planners (#768 Bug C)."""

from __future__ import annotations

from core.sync.playlist_edit import plan_playlist_add, remove_one_occurrence


# ── plan_playlist_add: link must not duplicate ────────────────────────────

def test_link_to_existing_track_does_not_insert():
    # The reported loop: matching an unmatched source to a track already in
    # the playlist (an "extra") must NOT add a second copy.
    plan = plan_playlist_add(["a", "b", "nv72"], "nv72", is_link=True)
    assert plan["should_insert"] is False
    assert plan["new_ids"] == ["a", "b", "nv72"]  # unchanged


def test_link_to_absent_track_inserts():
    plan = plan_playlist_add(["a", "b"], "nv99", is_link=True, position=1)
    assert plan["should_insert"] is True
    assert plan["new_ids"] == ["a", "nv99", "b"]


def test_non_link_add_always_inserts_even_if_present():
    # A plain add (no source link) may legitimately duplicate.
    plan = plan_playlist_add(["a", "b"], "a", is_link=False)
    assert plan["should_insert"] is True
    assert plan["new_ids"].count("a") == 2


def test_add_appends_when_no_position():
    plan = plan_playlist_add(["a", "b"], "c", is_link=False)
    assert plan["new_ids"] == ["a", "b", "c"]


def test_add_clamps_out_of_range_position():
    assert plan_playlist_add(["a"], "c", is_link=False, position=99)["new_ids"] == ["a", "c"]
    assert plan_playlist_add(["a"], "c", is_link=False, position=-5)["new_ids"] == ["c", "a"]


def test_add_stringifies_ids():
    plan = plan_playlist_add([1, 2, 72], 72, is_link=True)
    assert plan["should_insert"] is False


# ── remove_one_occurrence: remove ONE, not all ────────────────────────────

def test_removes_only_one_of_duplicates():
    # The #768 delete bug: two copies (pos 72, 73) — removing must drop ONE.
    new_ids, removed = remove_one_occurrence(["a", "nv72", "nv72", "b"], "nv72")
    assert removed is True
    assert new_ids == ["a", "nv72", "b"]  # one copy survives


def test_removes_exact_position_when_given():
    new_ids, removed = remove_one_occurrence(["x", "x", "x"], "x", position=1)
    assert removed is True
    assert new_ids == ["x", "x"]


def test_falls_back_to_first_when_position_mismatches():
    new_ids, removed = remove_one_occurrence(["a", "b", "c"], "b", position=0)
    assert removed is True
    assert new_ids == ["a", "c"]


def test_remove_absent_id_reports_not_removed():
    new_ids, removed = remove_one_occurrence(["a", "b"], "zzz")
    assert removed is False
    assert new_ids == ["a", "b"]


def test_remove_single_occurrence():
    new_ids, removed = remove_one_occurrence(["a", "b", "c"], "b")
    assert (new_ids, removed) == (["a", "c"], True)


def test_remove_stringifies():
    new_ids, removed = remove_one_occurrence([1, 2, 2, 3], 2)
    assert removed and new_ids == ["1", "2", "3"]