using System;
using System.IO;
using Xunit;
using ytLive.ViewModels;

namespace ytLive.Tests;

/// <summary>
/// The post-recording save dialog (CREATOR RULING 2026-09-26).
/// <para>Reported symptom: clicking Cancel in the save prompt still saved the
/// recording under the default name — Cancel behaved like "accept the default". The
/// creator's intent is explicit: <b>Enter accepts the default file name and saves;
/// Cancel cancels the save and discards the footage.</b></para>
/// <para>The bug was in the caller, not the modal — <c>FinalizeRecordingAsync</c> ran
/// <c>File.Move</c> unconditionally, so <c>ShowDialog() == false</c> fell straight
/// through into the save. These tests drive the extracted commit-or-discard decision
/// against real files in a temp folder, which is what would have caught it.</para>
/// </summary>
public sealed class RecordingSaveDialogTests : IDisposable
{
    private readonly string _dir = Path.Combine(
        Path.GetTempPath(), "ytLive-recsave-" + Guid.NewGuid().ToString("N")[..8]);

    private const string AutoStem = "ty-20260926-1405-0130";
    private const string StartStem = "ty-20260926-1405-0000";
    private const string Bytes = "fake-mp4-payload";

    public RecordingSaveDialogTests() => Directory.CreateDirectory(_dir);

    public void Dispose()
    {
        try { Directory.Delete(_dir, recursive: true); } catch { /* best-effort */ }
    }

    /// <summary>The reported bug: Cancel must leave NOTHING in the videos folder — not
    /// the temp start-name file, and not a renamed copy of it either.</summary>
    [Fact]
    public void Cancel_DiscardsTheFootage_AndLeavesNothingOnDisk()
    {
        var start = WriteStartFile();

        var result = CompleteRecordingSave(start, _dir, AutoStem, chosenStem: null, creatorSaved: false);

        Assert.Equal(MainViewModel.RecordingSaveOutcome.Discarded, result.Outcome);
        Assert.False(File.Exists(start), "Cancel must delete the temp recording, not move it");
        Assert.Empty(Directory.GetFiles(_dir));
    }

    /// <summary>Enter on the pre-filled default is a Save — the file lands under the
    /// auto name with its bytes intact (the creator's other half of the ruling).</summary>
    [Fact]
    public void EnterOnTheDefault_KeepsTheAutoName_AndSavesTheFootage()
    {
        var start = WriteStartFile();

        var result = CompleteRecordingSave(start, _dir, AutoStem, AutoStem, creatorSaved: true);

        Assert.Equal(MainViewModel.RecordingSaveOutcome.Saved, result.Outcome);
        var expected = Path.Combine(_dir, AutoStem + ".mp4");
        Assert.Equal(expected, result.FinalPath);
        Assert.False(File.Exists(start), "Save renames the temp file — it must not be left behind");
        Assert.Equal(Bytes, File.ReadAllText(expected));
        Assert.Single(Directory.GetFiles(_dir));
    }

    /// <summary>A cleared name box on an explicit Save still means "keep the auto
    /// name" (the dialog promises this) — Cancel is the only way to discard.</summary>
    [Fact]
    public void SaveWithABlankName_StillFallsBackToTheAutoName()
    {
        var start = WriteStartFile();

        var result = CompleteRecordingSave(start, _dir, AutoStem, "   ", creatorSaved: true);

        Assert.Equal(MainViewModel.RecordingSaveOutcome.Saved, result.Outcome);
        Assert.True(File.Exists(Path.Combine(_dir, AutoStem + ".mp4")));
    }

    /// <summary>An explicit Save with a chosen name honours that name.</summary>
    [Fact]
    public void SaveWithAChosenName_UsesThatName()
    {
        var start = WriteStartFile();

        var result = CompleteRecordingSave(start, _dir, AutoStem, "my-stream", creatorSaved: true);

        Assert.Equal("my-stream.mp4", Path.GetFileName(result.FinalPath!));
    }

    /// <summary>Never clobber an earlier recording: a second save with the same name
    /// gets uniquified rather than overwriting the first.</summary>
    [Fact]
    public void SaveWithACollidingName_UniquifiesInsteadOfOverwriting()
    {
        var first = WriteStartFile();
        Assert.Equal(
            MainViewModel.RecordingSaveOutcome.Saved,
            CompleteRecordingSave(first, _dir, AutoStem, AutoStem, true).Outcome);

        var second = WriteStartFile();
        var result = CompleteRecordingSave(second, _dir, AutoStem, AutoStem, true);

        Assert.Equal(AutoStem + "-2.mp4", Path.GetFileName(result.FinalPath!));
        Assert.Equal(2, Directory.GetFiles(_dir).Length);
    }

    private static MainViewModel.RecordingSaveResult CompleteRecordingSave(
        string startPath, string dir, string autoStem, string? chosenStem, bool creatorSaved)
        => MainViewModel.CompleteRecordingSave(startPath, dir, autoStem, chosenStem, creatorSaved);

    private string WriteStartFile()
    {
        var start = Path.Combine(_dir, StartStem + ".mp4");
        File.WriteAllText(start, Bytes);
        return start;
    }
}