diff --git a/CronTimer/CronEventArgs.cs b/CronTimer/CronEventArgs.cs
new file mode 100644
index 0000000..df87ec1
--- /dev/null
+++ b/CronTimer/CronEventArgs.cs
@@ -0,0 +1,6 @@
+using System;
+
+public class CronTimerEventArgs : EventArgs
+{
+ public DateTime At { get; set; }
+}
diff --git a/CronTimer/CronTimer.cs b/CronTimer/CronTimer.cs
new file mode 100644
index 0000000..00357a8
--- /dev/null
+++ b/CronTimer/CronTimer.cs
@@ -0,0 +1,78 @@
+using System;
+using System.Threading;
+using NCrontab;
+
+public class CronTimer
+{
+ public const string UTC = "Etc/UTC";
+
+ static readonly TimeSpan InfiniteTimeSpan = TimeSpan.FromMilliseconds(Timeout.Infinite); // net 3.5
+
+ readonly CrontabSchedule schedule;
+ readonly TimeZoneInfo tzi;
+ readonly string id;
+ readonly Timer t;
+
+ public string tz { get; }
+ public string Expression { get; }
+ public event EventHandler<CronTimerEventArgs> OnOccurence;
+
+ public DateTime Next { get; private set; }
+
+ public CronTimer(string expression, string tz = UTC, bool includingSeconds = false)
+ {
+ Expression = expression;
+ this.tz = tz;
+ id = TimeZoneConverter.TZConvert.IanaToWindows(tz);
+ tzi = TimeZoneInfo.FindSystemTimeZoneById(id);
+ schedule = CrontabSchedule.Parse(expression, new CrontabSchedule.ParseOptions { IncludingSeconds = includingSeconds });
+ Next = TimeZoneInfo.ConvertTimeFromUtc(DateTime.UtcNow, tzi);
+ OnOccurence += OnOccurenceScheduleNext;
+ t = new Timer(s =>
+ {
+ var ea = new CronTimerEventArgs
+ {
+ At = Next
+ };
+ OnOccurence(this, ea);
+ }, null, InfiniteTimeSpan, InfiniteTimeSpan);
+ }
+
+ void OnOccurenceScheduleNext(object sender, EventArgs e)
+ {
+ var delay = CalculateDelay();
+ //Console.WriteLine($"Next for [{tz} {expression}] in {delay}.");
+ t.Change(delay, InfiniteTimeSpan);
+ }
+
+ public void Start()
+ {
+ var delay = CalculateDelay();
+ //Console.WriteLine($"Next for [{tz} {expression}] in {delay}.");
+ t.Change(delay, InfiniteTimeSpan);
+ }
+
+ TimeSpan CalculateDelay()
+ {
+ var nowUtc = DateTime.UtcNow;
+ Next = schedule.GetNextOccurrence(Next);
+ TimeSpan delay;
+ if (tz != UTC)
+ {
+ var nextUtc = TimeZoneInfo.ConvertTimeToUtc(Next, tzi);
+ delay = nextUtc - nowUtc;
+ }
+ else
+ {
+ delay = Next - nowUtc;
+ }
+ //Console.WriteLine($"Now: {nowUtc} [utc] {now} [{tz}], Next: {next} [{tz}] {nextUtc} [utc], Delay: {delay}");
+ if (delay < TimeSpan.Zero) delay = TimeSpan.Zero;
+ return delay;
+ }
+
+ public void Stop()
+ {
+ t.Change(InfiniteTimeSpan, InfiniteTimeSpan);
+ }
+}
diff --git a/CronTimer/CronTimer.csproj b/CronTimer/CronTimer.csproj
new file mode 100644
index 0000000..f488cf3
--- /dev/null
+++ b/CronTimer/CronTimer.csproj
@@ -0,0 +1,49 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+ <PropertyGroup>
+ <LangVersion>latest</LangVersion>
+ <TargetFrameworks>net461;netstandard2.1</TargetFrameworks>
+ <PlatformTarget>AnyCPU</PlatformTarget>
+ </PropertyGroup>
+
+ <PropertyGroup>
+ <!-- AssemblyFileVersionAttribute -->
+ <FileVersion>2.0.1</FileVersion>
+ <!-- AssemblyInformationalVersionAttribute -->
+ <Version>$(FileVersion)</Version>
+ <!-- AssemblyVersionAttribute -->
+ <AssemblyVersion>2.0.0.0</AssemblyVersion>
+ <!-- Nuget -->
+ <PackageVersion>$(Version)</PackageVersion>
+ <PackageId>CronTimer</PackageId>
+ <Company>https://github.com/ramonsmits</Company>
+ <Authors>ramonsmits</Authors>
+ <Description>Simple .net Timer that is based on cron expressions with second accuracy to fire timer events to a very specific schedule.</Description>
+ <PackageRequireLicenseAcceptance>false</PackageRequireLicenseAcceptance>
+ <PackageReleaseNotes></PackageReleaseNotes>
+ <PackageProjectUrl>https://github.com/ramonsmits/CronTimer/tree/$(PackageVersion)</PackageProjectUrl>
+ <PackageLicenseExpression>MIT</PackageLicenseExpression>
+ <IncludeSymbols>True</IncludeSymbols>
+ <SymbolPackageFormat>snupkg</SymbolPackageFormat>
+ <IncludeSource>True</IncludeSource>
+ <RepositoryUrl>https://github.com/ramonsmits/CronTimer</RepositoryUrl>
+ <Copyright>Copyright 2022 (c) Ramon Smits</Copyright>
+ <PackageTags>cron timer</PackageTags>
+ <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
+ <PublishRepositoryUrl>true</PublishRepositoryUrl>
+ <ContinuousIntegrationBuild>true</ContinuousIntegrationBuild>
+ <EmbedUntrackedSources>true</EmbedUntrackedSources>
+ </PropertyGroup>
+
+ <ItemGroup>
+ <PackageReference Include="ncrontab" Version="3.3.1" />
+ <PackageReference Include="TimeZoneConverter" Version="6.0.1" />
+ </ItemGroup>
+
+ <!--<ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.1'">
+ <PackageReference Include="Microsoft.Extensions.Logging.Abstractions">
+ <Version>3.1.4</Version>
+ </PackageReference>
+ </ItemGroup>-->
+
+</Project>
diff --git a/CronTimer/CronTimer.sln b/CronTimer/CronTimer.sln
new file mode 100644
index 0000000..adc7e3f
--- /dev/null
+++ b/CronTimer/CronTimer.sln
@@ -0,0 +1,36 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 16
+VisualStudioVersion = 16.0.30717.126
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "CronTimer", "CronTimer.csproj", "{FB64C227-8615-4AE1-94E3-F9F9DF192B72}"
+EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution Items", "{CCDD0B34-653C-430C-9B17-5129618F8D7D}"
+ ProjectSection(SolutionItems) = preProject
+ ..\README.md = ..\README.md
+ EndProjectSection
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Demo", "..\Demo\Demo.csproj", "{C2638357-1621-4422-8701-B55BFB37ACCF}"
+EndProject
+Global
+ GlobalSection(SolutionConfigurationPlatforms) = preSolution
+ Debug|Any CPU = Debug|Any CPU
+ Release|Any CPU = Release|Any CPU
+ EndGlobalSection
+ GlobalSection(ProjectConfigurationPlatforms) = postSolution
+ {FB64C227-8615-4AE1-94E3-F9F9DF192B72}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+ {FB64C227-8615-4AE1-94E3-F9F9DF192B72}.Debug|Any CPU.Build.0 = Debug|Any CPU
+ {FB64C227-8615-4AE1-94E3-F9F9DF192B72}.Release|Any CPU.ActiveCfg = Release|Any CPU
+ {FB64C227-8615-4AE1-94E3-F9F9DF192B72}.Release|Any CPU.Build.0 = Release|Any CPU
+ {C2638357-1621-4422-8701-B55BFB37ACCF}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+ {C2638357-1621-4422-8701-B55BFB37ACCF}.Debug|Any CPU.Build.0 = Debug|Any CPU
+ {C2638357-1621-4422-8701-B55BFB37ACCF}.Release|Any CPU.ActiveCfg = Release|Any CPU
+ {C2638357-1621-4422-8701-B55BFB37ACCF}.Release|Any CPU.Build.0 = Release|Any CPU
+ EndGlobalSection
+ GlobalSection(SolutionProperties) = preSolution
+ HideSolutionNode = FALSE
+ EndGlobalSection
+ GlobalSection(ExtensibilityGlobals) = postSolution
+ SolutionGuid = {A639B164-6581-40DF-ADC4-479DAB467CFE}
+ EndGlobalSection
+EndGlobal
diff --git a/song_of_the_day/song_of_the_day.csproj b/song_of_the_day/song_of_the_day.csproj
index 246c091..443368d 100644
--- a/song_of_the_day/song_of_the_day.csproj
+++ b/song_of_the_day/song_of_the_day.csproj
@@ -21,4 +21,7 @@
<ItemGroup>
<OpenApiReference Include="swagger.json" SourceUrl="https://bbernhard.github.io/signal-cli-rest-api/src/docs/swagger.json" />
</ItemGroup>
+ <ItemGroup>
+ <ProjectReference Include="..\CronTimer\CronTimer.csproj" />
+ </ItemGroup>
</Project>
\ No newline at end of file