using System.IO;

namespace EmbyToolbox.Services;

/// <summary>
/// Сценарии для запоминания последних каталогов в диалогах открытия/сохранения.
/// </summary>
public enum RecentPathScenario
{
    SeriesRenamer,
    ConversionAddFiles,
    ConversionAddFolder,
    Merge,
    VideoInfoOpenFile,
    SettingsTempFolder,
    SettingsOutputFolder,
    TrackExtractDestination
}

/// <summary>
/// Запоминает последние каталоги по сценариям и общий каталог; сохраняет вместе с <see cref="AppSettings"/>.
/// </summary>
public sealed class RecentPathService
{
    private readonly AppSettingsService _settingsService;

    private string? _lastSeriesRenamerFolder;
    private string? _lastConversionFilesFolder;
    private string? _lastConversionFolder;
    private string? _lastMergeFolder;
    private string? _lastVideoInfoFolder;
    private string? _lastTempFolder;
    private string? _lastOutputFolder;
    private string? _lastTrackExtractDestinationFolder;
    private string? _lastCommonFolder;

    public RecentPathService(AppSettingsService settingsService)
    {
        _settingsService = settingsService;
    }

    public void HydrateFrom(AppSettings settings)
    {
        _lastSeriesRenamerFolder = settings.LastSeriesRenamerFolder;
        _lastConversionFilesFolder = settings.LastConversionFilesFolder;
        _lastConversionFolder = settings.LastConversionFolder;
        _lastMergeFolder = settings.LastMergeFolder;
        _lastVideoInfoFolder = settings.LastVideoInfoFolder;
        _lastTempFolder = settings.LastTempFolder;
        _lastOutputFolder = settings.LastOutputFolder;
        _lastTrackExtractDestinationFolder = settings.LastTrackExtractDestinationFolder;
        _lastCommonFolder = settings.LastCommonFolder;
    }

    public void ApplyTo(AppSettings target)
    {
        target.LastSeriesRenamerFolder = _lastSeriesRenamerFolder;
        target.LastConversionFilesFolder = _lastConversionFilesFolder;
        target.LastConversionFolder = _lastConversionFolder;
        target.LastMergeFolder = _lastMergeFolder;
        target.LastVideoInfoFolder = _lastVideoInfoFolder;
        target.LastTempFolder = _lastTempFolder;
        target.LastOutputFolder = _lastOutputFolder;
        target.LastTrackExtractDestinationFolder = _lastTrackExtractDestinationFolder;
        target.LastCommonFolder = _lastCommonFolder;
    }

    /// <param name="extraFolderFallbackBeforeDefault">
    /// Дополнительный существующий каталог перед стандартным «Видео» (для TEMP: текущий выбранный каталог из настроек).
    /// </param>
    public string GetInitialDirectory(RecentPathScenario scenario, string? extraFolderFallbackBeforeDefault = null)
    {
        foreach (var candidate in GetCandidateChain(scenario, extraFolderFallbackBeforeDefault))
        {
            if (IsUsableExistingDirectory(candidate))
            {
                return candidate!;
            }
        }

        return Environment.GetFolderPath(Environment.SpecialFolder.MyVideos);
    }

    public void RememberChosenFiles(RecentPathScenario scenario, IReadOnlyList<string> chosenFilePaths)
    {
        if (chosenFilePaths.Count == 0)
        {
            return;
        }

        var dir = NormalizeExistingDirectory(Path.GetDirectoryName(chosenFilePaths[0]));
        if (dir is null)
        {
            return;
        }

        SetScenarioFolder(scenario, dir);
        _lastCommonFolder = dir;
        Persist();
    }

    public string? GetNormalizedRememberedFolderPath(RecentPathScenario scenario)
    {
        var folder = GetScenarioStored(scenario);
        if (string.IsNullOrWhiteSpace(folder))
        {
            return null;
        }

        try
        {
            return Path.GetFullPath(folder.Trim());
        }
        catch
        {
            return null;
        }
    }

    public void RememberChosenFolder(RecentPathScenario scenario, string folderPathOrFile)
    {
        var dir = NormalizeExistingDirectory(folderPathOrFile);
        if (dir is null)
        {
            return;
        }

        SetScenarioFolder(scenario, dir);
        _lastCommonFolder = dir;
        Persist();
    }

    private IEnumerable<string?> GetCandidateChain(RecentPathScenario scenario, string? extraFolderFallbackBeforeDefault)
    {
        yield return GetScenarioStored(scenario);
        yield return _lastCommonFolder;
        if (!string.IsNullOrWhiteSpace(extraFolderFallbackBeforeDefault))
        {
            yield return NormalizePathOnly(extraFolderFallbackBeforeDefault);
        }
    }

    private string? GetScenarioStored(RecentPathScenario scenario) =>
        scenario switch
        {
            RecentPathScenario.SeriesRenamer => _lastSeriesRenamerFolder,
            RecentPathScenario.ConversionAddFiles => _lastConversionFilesFolder,
            RecentPathScenario.ConversionAddFolder => _lastConversionFolder,
            RecentPathScenario.Merge => _lastMergeFolder,
            RecentPathScenario.VideoInfoOpenFile => _lastVideoInfoFolder,
            RecentPathScenario.SettingsTempFolder => _lastTempFolder,
            RecentPathScenario.SettingsOutputFolder => _lastOutputFolder,
            RecentPathScenario.TrackExtractDestination => _lastTrackExtractDestinationFolder,
            _ => null
        };

    private void SetScenarioFolder(RecentPathScenario scenario, string normalizedDirectory)
    {
        switch (scenario)
        {
            case RecentPathScenario.SeriesRenamer:
                _lastSeriesRenamerFolder = normalizedDirectory;
                break;
            case RecentPathScenario.ConversionAddFiles:
                _lastConversionFilesFolder = normalizedDirectory;
                break;
            case RecentPathScenario.ConversionAddFolder:
                _lastConversionFolder = normalizedDirectory;
                break;
            case RecentPathScenario.Merge:
                _lastMergeFolder = normalizedDirectory;
                break;
            case RecentPathScenario.VideoInfoOpenFile:
                _lastVideoInfoFolder = normalizedDirectory;
                break;
            case RecentPathScenario.SettingsTempFolder:
                _lastTempFolder = normalizedDirectory;
                break;
            case RecentPathScenario.SettingsOutputFolder:
                _lastOutputFolder = normalizedDirectory;
                break;
            case RecentPathScenario.TrackExtractDestination:
                _lastTrackExtractDestinationFolder = normalizedDirectory;
                break;
            default:
                throw new ArgumentOutOfRangeException(nameof(scenario), scenario, null);
        }
    }

    private void Persist()
    {
        var disk = _settingsService.Load();
        ApplyTo(disk);
        _settingsService.Save(disk);
    }

    private static string? NormalizeExistingDirectory(string? path)
    {
        if (string.IsNullOrWhiteSpace(path))
        {
            return null;
        }

        try
        {
            var full = Path.GetFullPath(path.Trim());
            return Directory.Exists(full) ? full : null;
        }
        catch
        {
            return null;
        }
    }

    private static string? NormalizePathOnly(string? path)
    {
        if (string.IsNullOrWhiteSpace(path))
        {
            return null;
        }

        try
        {
            return Path.GetFullPath(path.Trim());
        }
        catch
        {
            return null;
        }
    }

    private static bool IsUsableExistingDirectory(string? path)
    {
        if (string.IsNullOrWhiteSpace(path))
        {
            return false;
        }

        try
        {
            return Directory.Exists(Path.GetFullPath(path.Trim()));
        }
        catch
        {
            return false;
        }
    }
}