fix filenames using single quotes (#3)

* refactor

* support filenames that use single quotes

BlackDetect.cs

@@ -0,0 +1,42 @@
+namespace MkChap;
+
+public class BlackDetect : FFprobeBase
+{
+    public static async Task<string> Detect(string? inputFile, double minBlackSeconds, double ratioBlackPixels,
+        double blackPixelThreshold)
+    {
+        if (string.IsNullOrWhiteSpace(inputFile))
+        {
+            return string.Empty;
+        }
+
+        inputFile = FixFileName(inputFile);
+        return await GetFFprobeOutput(new List<string>
+        {
+            "-f", "lavfi",
+            "-i",
+            $"movie={inputFile},blackdetect=d={minBlackSeconds}:pic_th={ratioBlackPixels}:pix_th={blackPixelThreshold}[out0]",
+            "-show_entries", "frame_tags=lavfi.black_start,lavfi.black_end",
+            "-of", "default=nw=1",
+            "-v", "panic"
+        });
+    }
+
+    private static string FixFileName(string inputFile)
+    {
+        // rework filename in a format that works on windows
+        if (OperatingSystem.IsWindows())
+        {
+            // \ is escape, so use / for directory separators
+            inputFile = inputFile.Replace(@"\", "/");
+
+            // colon after drive letter needs to be escaped
+            inputFile = inputFile.Replace(":/", @"\:/");
+        }
+
+        // escape apostrophes
+        inputFile = inputFile.Replace("'", @"\\\'");
+
+        return inputFile;
+    }
+}

ChapterWriter.cs

@@ -0,0 +1,114 @@
+using System.Diagnostics;
+using System.Text;
+using MkChap.Models;
+
+namespace MkChap;
+
+public class ChapterWriter
+{
+    public static async Task WriteToFile(string? inputFile, string outputFile, List<Chapter> chapters)
+    {
+        if (string.IsNullOrWhiteSpace(inputFile))
+        {
+            return;
+        }
+
+        var ffMetadata = GetFFMetadata(chapters);
+        var metadataFile = string.Empty;
+
+        try
+        {
+            metadataFile = await WriteFFMetadata(ffMetadata);
+            await WriteMetadataToFile(inputFile, outputFile, metadataFile);
+        }
+        finally
+        {
+            try
+            {
+                if (File.Exists(metadataFile))
+                {
+                    File.Delete(metadataFile);
+                }
+            }
+            catch
+            {
+                // do nothing
+            }
+        }
+    }
+
+    private static string GetFFMetadata(List<Chapter> chapters)
+    {
+        var sb = new StringBuilder();
+
+        sb.Append(";FFMETADATA1\n");
+        sb.Append('\n');
+
+        for (var i = 0; i < chapters.Count; i++)
+        {
+            sb.Append(chapters[i].GetMetadata(i + 1));
+        }
+
+        return sb.ToString();
+    }
+
+    private static async Task<string> WriteFFMetadata(string ffMetadata)
+    {
+        var file = Path.GetTempFileName();
+        await File.WriteAllTextAsync(file, ffMetadata);
+        return file;
+    }
+
+    private static async Task WriteMetadataToFile(string inputFile, string outputFile, string metadataFile)
+    {
+        if (inputFile == outputFile)
+        {
+            var extension = Path.GetExtension(inputFile);
+            var tempFile = Path.ChangeExtension(Path.GetTempFileName(), extension);
+            await PerformWrite(inputFile, tempFile, metadataFile);
+            File.Move(tempFile, outputFile, true);
+        }
+        else
+        {
+            await PerformWrite(inputFile, outputFile, metadataFile);
+        }
+    }
+
+    private static async Task PerformWrite(string inputFile, string outputFile, string metadataFile)
+    {
+        var process = new Process
+        {
+            StartInfo = new ProcessStartInfo
+            {
+                FileName = "ffmpeg",
+                UseShellExecute = false,
+                RedirectStandardError = false,
+                RedirectStandardOutput = false
+            }
+        };
+
+        var arguments = new List<string>
+        {
+            "-hide_banner",
+            "-v", "error",
+            "-i", inputFile,
+            "-i", metadataFile,
+            "-map_metadata", "1",
+            "-map_chapters", "1",
+            "-codec", "copy",
+            "-y", outputFile
+        };
+
+        foreach (var arg in arguments)
+        {
+            process.StartInfo.ArgumentList.Add(arg);
+        }
+
+        process.Start();
+
+        await process.WaitForExitAsync();
+
+        // ReSharper disable once MethodHasAsyncOverload
+        process.WaitForExit();
+    }
+}

Duration.cs

@@ -0,0 +1,30 @@
+using System.Globalization;
+using LanguageExt;
+
+namespace MkChap;
+
+public class Duration : FFprobeBase
+{
+    public static async Task<Option<TimeSpan>> GetDuration(string? inputFile)
+    {
+        if (string.IsNullOrWhiteSpace(inputFile))
+        {
+            return Option<TimeSpan>.None;
+        }
+
+        var output = await GetFFprobeOutput(new List<string>
+        {
+            "-v", "panic",
+            "-show_entries", "format=duration",
+            "-of", "default=nw=1:nokey=1",
+            inputFile
+        });
+
+        if (double.TryParse(output, NumberStyles.Number, NumberFormatInfo.InvariantInfo, out var value))
+        {
+            return TimeSpan.FromSeconds(value);
+        }
+
+        return Option<TimeSpan>.None;
+    }
+}

FFprobeBase.cs

@@ -0,0 +1,18 @@
+using CliWrap;
+using CliWrap.Buffered;
+
+namespace MkChap;
+
+public abstract class FFprobeBase
+{
+    protected static async Task<string> GetFFprobeOutput(IEnumerable<string> arguments)
+    {
+        var result = await Cli.Wrap("ffprobe")
+            .WithArguments(arguments)
+            .WithValidation(CommandResultValidation.None)
+            .WithStandardErrorPipe(PipeTarget.ToStream(Stream.Null))
+            .ExecuteBufferedAsync();
+
+        return result.StandardOutput;
+    }
+}

MkChap.csproj

@@ -9,6 +9,7 @@
     </PropertyGroup>
 
     <ItemGroup>
+      <PackageReference Include="CliWrap" Version="3.6.6" />
       <PackageReference Include="CommandLineParser" Version="2.9.1" />
       <PackageReference Include="LanguageExt.Core" Version="4.4.7" />
     </ItemGroup>

Models/AnalysisResult.cs

@@ -0,0 +1,3 @@
+namespace MkChap.Models;
+
+public record AnalysisResult(List<BlackSection> BlackSections, List<Chapter> Chapters);

Models/BlackSection.cs

@@ -0,0 +1,7 @@
+namespace MkChap.Models;
+
+public record BlackSection(TimeSpan Start, TimeSpan Finish, State State)
+{
+    public TimeSpan Duration => Finish - Start;
+    public TimeSpan Midpoint() => Start + (Finish - Start) / 2.0;
+};

Models/Chapter.cs

@@ -0,0 +1,21 @@
+using System.Globalization;
+using System.Text;
+
+namespace MkChap.Models;
+
+public record Chapter(TimeSpan Start, TimeSpan Finish)
+{
+    public string GetMetadata(int num)
+    {
+        var sb = new StringBuilder();
+
+        sb.Append("[CHAPTER]\n");
+        sb.Append("TIMEBASE=1/1000\n");
+        sb.Append($"START={Start.TotalMilliseconds.ToString(NumberFormatInfo.InvariantInfo)}\n");
+        sb.Append($"END={Finish.TotalMilliseconds.ToString(NumberFormatInfo.InvariantInfo)}\n");
+        sb.Append($"title=Chapter {num}\n");
+        sb.Append('\n');
+
+        return sb.ToString();
+    }
+}

Models/State.cs

@@ -0,0 +1,8 @@
+namespace MkChap.Models;
+
+public enum State
+{
+    TooShort,
+    OutsideOfWindows,
+    Ok
+}

Models/Window.cs

@@ -0,0 +1,6 @@
+namespace MkChap.Models;
+
+public record Window(TimeSpan Start, TimeSpan Finish)
+{
+    public bool Contains(TimeSpan time) => time >= Start && time <= Finish;
+}