using System;
using System.IO;
using System.Threading.Tasks;
using System.Windows;
using Microsoft.Win32;
using ytLive.Helpers;
using ytLive.Services;

namespace ytLive.ViewModels;

public partial class MainViewModel : ViewModelBase
{
    private string? _recordFolder;
    public string RecordFolderDisplay => _recordFolder ?? DefaultRecordFolder();
    private string? _activeRecordPath;
    private DateTime _recordStartTime;
    private TimeSpan _recordLength;

    private string? StartRecordFile()
    {
        try
        {
            var folder = _recordFolder ?? DefaultRecordFolder();
            Directory.CreateDirectory(folder);
            var name = RecordingFile.BuildStartName(DateTime.Now) + ".mp4";
            var path = Path.Combine(folder, name);
            _activeRecordPath = path;
            return path;
        }
        catch (Exception ex)
        {
            AppLog.Write(ex, "Recording: failed to prepare output path");
            return null;
        }
    }

    private async Task FinalizeRecordingAsync()
    {
        var startPath = _activeRecordPath;
        _activeRecordPath = null;
        if (string.IsNullOrEmpty(startPath)) return;
        try
        {
            while (_framePump.IsRunning) await Task.Delay(50);

            if (!File.Exists(startPath))
            {
                AppLog.Write($"Recording: output not found for rename: {startPath}");
                return;
            }
            _recordLength = _liveElapsed;
            var autoStem = RecordingFile.BuildFinalName(_recordStartTime, _recordLength);
            var dir = Path.GetDirectoryName(startPath)!;

            // Manual rename modal: give the creator a chance to name the recording.
            // CREATOR RULING 2026-09-26: Cancel means DISCARD, not "save under the
            // default name". This used to fall through and File.Move anyway, so a
            // cancelled dialog silently kept the recording — Cancel was a lie.
            var dialog = new RenameRecordingDialog(autoStem);
            var creatorSaved = dialog.ShowDialog() == true;

            var result = CompleteRecordingSave(
                startPath, dir, autoStem, dialog.ResultFileName, creatorSaved);
            switch (result.Outcome)
            {
                case RecordingSaveOutcome.Saved:
                    AppLog.Write($"Recording saved: {result.FinalPath}");
                    _notifications.Info("Recording saved",
                        Path.GetFileName(result.FinalPath!) +
                        " — you can rename it in your videos folder at any time.");
                    break;
                case RecordingSaveOutcome.Discarded:
                    AppLog.Write($"Recording discarded by creator: {startPath}");
                    _notifications.Info("Recording discarded",
                        "The recording was deleted and nothing was saved.");
                    break;
                case RecordingSaveOutcome.DiscardFailed:
                    // A "discarded" recording still sitting on disk is worse than no
                    // report at all — name the file and the folder so it can be found.
                    AppLog.Write($"Recording discard failed: {startPath}");
                    _notifications.Error("Recording discarded?",
                        $"Could not delete {Path.GetFileName(startPath)} — it is still in {dir}.");
                    break;
            }
        }
        catch (Exception ex)
        {
            AppLog.Write(ex, "Recording: rename-on-stop failed");
            _notifications.Error("Recording saved",
                $"The recording was written but couldn't be renamed: {Path.GetFileName(startPath)}");
        }
    }

    /// <summary>What happened to the footage once the save dialog was answered, plus
    /// where it landed (<c>FinalPath</c> is set only for <see cref="RecordingSaveOutcome.Saved"/>).</summary>
    internal readonly record struct RecordingSaveResult(RecordingSaveOutcome Outcome, string? FinalPath);

    /// <summary>What happened to the footage once the save dialog was answered.</summary>
    internal enum RecordingSaveOutcome
    {
        Saved,
        Discarded,
        DiscardFailed,
    }

    /// <summary>The commit-or-discard decision behind the recording save dialog, split out
    /// so it can be tested against real files without a frame pump (CREATOR RULING
    /// 2026-09-26). <paramref name="creatorSaved"/> is the dialog's DialogResult:
    /// <c>false</c> — Cancel, Escape, or the X — DELETES the footage; only an explicit
    /// Save (including Enter on the pre-filled default) moves it to its final name.</summary>
    internal static RecordingSaveResult CompleteRecordingSave(
        string startPath, string dir, string autoStem, string? chosenStem, bool creatorSaved)
    {
        if (!creatorSaved)
        {
            if (!File.Exists(startPath)) return new RecordingSaveResult(RecordingSaveOutcome.Discarded, null);
            try
            {
                File.Delete(startPath);
                return new RecordingSaveResult(RecordingSaveOutcome.Discarded, null);
            }
            catch (Exception)
            {
                return new RecordingSaveResult(RecordingSaveOutcome.DiscardFailed, startPath);
            }
        }

        // A blank name still means "keep the auto name" (the dialog says so), but
        // only on an explicit Save. Enter with the pre-filled default lands here too.
        var stem = string.IsNullOrWhiteSpace(chosenStem) ? autoStem : chosenStem!;
        var finalPath = UniquePath(Path.Combine(dir, stem + ".mp4"));
        File.Move(startPath, finalPath);
        return new RecordingSaveResult(RecordingSaveOutcome.Saved, finalPath);
    }

    private static string UniquePath(string path)
    {
        if (!File.Exists(path)) return path;
        var dir = Path.GetDirectoryName(path)!;
        var name = Path.GetFileNameWithoutExtension(path);
        var ext = Path.GetExtension(path);
        for (var i = 2; ; i++)
        {
            var candidate = Path.Combine(dir, $"{name}-{i}{ext}");
            if (!File.Exists(candidate)) return candidate;
        }
    }

    private void ChooseRecordFolder()
    {
        var dialog = new Microsoft.Win32.OpenFolderDialog
        {
            Title = "Choose a folder for local recordings",
            InitialDirectory = _recordFolder ?? DefaultRecordFolder(),
        };
        if (dialog.ShowDialog() == true)
        {
            _recordFolder = dialog.FolderName;
            _layoutStore.SaveRecordFolder(_recordFolder);
            OnPropertyChanged(nameof(RecordFolderDisplay));
            _notifications.Info("Record folder set", _recordFolder);
        }
    }

    private void ResetRecordFolder()
    {
        _recordFolder = null;
        _layoutStore.SaveRecordFolder(null);
        OnPropertyChanged(nameof(RecordFolderDisplay));
        _notifications.Info("Record folder reset", RecordFolderDisplay);
    }

    internal static string DefaultRecordFolder()
    {
        var downloads = Path.Combine(
            Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), "Downloads");
        return Directory.Exists(downloads)
            ? downloads
            : Environment.GetFolderPath(Environment.SpecialFolder.MyVideos);
    }
}