import json
import tempfile
from pathlib import Path

import pytest

from lintunes.storage.conflict_resolver import resolve_conflicts


def _write_json(path: Path, data: dict):
    with open(path, "w") as f:
        json.dump(data, f)


def _read_json(path: Path) -> dict:
    with open(path) as f:
        return json.load(f)


class TestConflictResolver:
    def test_no_conflicts(self, tmp_path):
        data_dir = tmp_path / ".lintunes"
        data_dir.mkdir()
        _write_json(data_dir / "library.json", {"1": {"track_id": 1, "name": "Song"}})
        resolve_conflicts(data_dir)
        # Should not crash, data should be unchanged
        result = _read_json(data_dir / "library.json")
        assert result["1"]["name"] == "Song"

    def test_nonexistent_dir(self, tmp_path):
        # Should not crash
        resolve_conflicts(tmp_path / "nonexistent")

    def test_merge_play_counts(self, tmp_path):
        data_dir = tmp_path / ".lintunes"
        data_dir.mkdir()

        original = {
            "1": {"track_id": 1, "name": "Song", "play_count": 5, "skip_count": 2}
        }
        conflict = {
            "1": {"track_id": 1, "name": "Song", "play_count": 8, "skip_count": 1}
        }

        _write_json(data_dir / "library.json", original)
        _write_json(
            data_dir / "library.sync-conflict-20240101-120000-ABCDEFG.json",
            conflict,
        )

        resolve_conflicts(data_dir)

        result = _read_json(data_dir / "library.json")
        assert result["1"]["play_count"] == 8  # max(5, 8)
        assert result["1"]["skip_count"] == 2  # max(2, 1)

    def test_merge_loved_or(self, tmp_path):
        data_dir = tmp_path / ".lintunes"
        data_dir.mkdir()

        original = {"1": {"track_id": 1, "loved": False}}
        conflict = {"1": {"track_id": 1, "loved": True}}

        _write_json(data_dir / "library.json", original)
        _write_json(
            data_dir / "library.sync-conflict-20240101-120000-ABCDEFG.json",
            conflict,
        )

        resolve_conflicts(data_dir)

        result = _read_json(data_dir / "library.json")
        assert result["1"]["loved"] is True

    def test_merge_date_added_earliest(self, tmp_path):
        data_dir = tmp_path / ".lintunes"
        data_dir.mkdir()

        original = {"1": {"track_id": 1, "date_added": "2022-06-01T00:00:00"}}
        conflict = {"1": {"track_id": 1, "date_added": "2020-01-15T00:00:00"}}

        _write_json(data_dir / "library.json", original)
        _write_json(
            data_dir / "library.sync-conflict-20240101-120000-ABCDEFG.json",
            conflict,
        )

        resolve_conflicts(data_dir)

        result = _read_json(data_dir / "library.json")
        assert result["1"]["date_added"] == "2020-01-15T00:00:00"

    def test_merge_new_track_from_conflict(self, tmp_path):
        data_dir = tmp_path / ".lintunes"
        data_dir.mkdir()

        original = {"1": {"track_id": 1, "name": "Song A"}}
        conflict = {
            "1": {"track_id": 1, "name": "Song A"},
            "2": {"track_id": 2, "name": "Song B"},
        }

        _write_json(data_dir / "library.json", original)
        _write_json(
            data_dir / "library.sync-conflict-20240101-120000-ABCDEFG.json",
            conflict,
        )

        resolve_conflicts(data_dir)

        result = _read_json(data_dir / "library.json")
        assert "2" in result
        assert result["2"]["name"] == "Song B"

    def test_playlist_merge_union(self, tmp_path):
        data_dir = tmp_path / ".lintunes"
        playlists_dir = data_dir / "playlists"
        playlists_dir.mkdir(parents=True)

        original = {"name": "My Playlist", "track_ids": [1, 2, 3], "settings": {}}
        conflict = {"name": "My Playlist", "track_ids": [2, 3, 4, 5], "settings": {}}

        orig_path = playlists_dir / "PL1.json"
        conf_path = playlists_dir / "PL1.sync-conflict-20240101-120000-ABCDEFG.json"

        _write_json(orig_path, original)
        _write_json(conf_path, conflict)

        resolve_conflicts(data_dir)

        result = _read_json(orig_path)
        # All track IDs should be present (union)
        assert set(result["track_ids"]) == {1, 2, 3, 4, 5}

    def test_conflicts_archived(self, tmp_path):
        data_dir = tmp_path / ".lintunes"
        data_dir.mkdir()

        _write_json(data_dir / "library.json", {"1": {"track_id": 1}})
        conf_path = data_dir / "library.sync-conflict-20240101-120000-ABCDEFG.json"
        _write_json(conf_path, {"1": {"track_id": 1}})

        resolve_conflicts(data_dir)

        assert not conf_path.exists()
        resolved_dir = data_dir / ".resolved"
        assert resolved_dir.exists()
        archived = list(resolved_dir.iterdir())
        assert len(archived) == 1