From 531c094e7c5ffc89b851d00d5bc644f8dd8dab12 Mon Sep 17 00:00:00 2001
From: EthanHair <ethan@astropanda.studio>
Date: Thu, 6 Nov 2025 13:43:23 -0600
Subject: [PATCH] Create CSVDownloadService

---
 .../AstroPanda.Blazor.Toolkit.csproj          |  3 ++-
 .../Services/CSVDownloadService.cs            | 20 +++++++++++++++++++
 .../Services/ICSVDownloadService.cs           |  6 ++++++
 3 files changed, 28 insertions(+), 1 deletion(-)
 create mode 100644 src/AstroPanda.Blazor.Toolkit/Services/CSVDownloadService.cs
 create mode 100644 src/AstroPanda.Blazor.Toolkit/Services/ICSVDownloadService.cs

diff --git a/src/AstroPanda.Blazor.Toolkit/AstroPanda.Blazor.Toolkit.csproj b/src/AstroPanda.Blazor.Toolkit/AstroPanda.Blazor.Toolkit.csproj
index bfc5b44..7f44907 100644
--- a/src/AstroPanda.Blazor.Toolkit/AstroPanda.Blazor.Toolkit.csproj
+++ b/src/AstroPanda.Blazor.Toolkit/AstroPanda.Blazor.Toolkit.csproj
@@ -8,7 +8,8 @@
 
   <ItemGroup>
     <PackageReference Include="BlazorComponentBus" Version="2.2.0" />
-    <PackageReference Include="Blazored.LocalStorage" Version="4.5.0" />    
+    <PackageReference Include="Blazored.LocalStorage" Version="4.5.0" />
+    <PackageReference Include="CsvHelper" Version="33.1.0" />    
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'net8.0'">
diff --git a/src/AstroPanda.Blazor.Toolkit/Services/CSVDownloadService.cs b/src/AstroPanda.Blazor.Toolkit/Services/CSVDownloadService.cs
new file mode 100644
index 0000000..ec3d242
--- /dev/null
+++ b/src/AstroPanda.Blazor.Toolkit/Services/CSVDownloadService.cs
@@ -0,0 +1,20 @@
+using System.Text;
+
+namespace AstroPanda.Blazor.Toolkit.Services;
+
+public class CSVDownloadService<T>(IDownloadService _downloads) : ICSVDownloadService<T>
+{
+    public async Task DownloadLocalAsync(string fileName, IEnumerable<T> collection)
+    {
+        using var stringWriter = new StringWriter();
+        using var csvWriter = new CsvHelper.CsvWriter(stringWriter, System.Globalization.CultureInfo.InvariantCulture, true);
+
+        csvWriter.WriteHeader<T>();
+        csvWriter.NextRecord();
+        csvWriter.WriteRecords(collection);
+
+        using var receivingStream = new MemoryStream(Encoding.UTF8.GetBytes(stringWriter.ToString()));
+
+        await _downloads.DownloadLocalAsync(fileName, receivingStream);
+    }
+}
diff --git a/src/AstroPanda.Blazor.Toolkit/Services/ICSVDownloadService.cs b/src/AstroPanda.Blazor.Toolkit/Services/ICSVDownloadService.cs
new file mode 100644
index 0000000..2bd1ec0
--- /dev/null
+++ b/src/AstroPanda.Blazor.Toolkit/Services/ICSVDownloadService.cs
@@ -0,0 +1,6 @@
+namespace AstroPanda.Blazor.Toolkit.Services;
+
+public interface ICSVDownloadService<T>
+{
+    public Task DownloadLocalAsync(string fileName, IEnumerable<T> collection);
+}