From 814762816876cb50913742cb1a3bfdc2e40cf2a1 Mon Sep 17 00:00:00 2001
From: Steven <github@steven-h.net>
Date: Thu, 22 Aug 2024 17:51:12 -0400
Subject: [PATCH] Start working on a DataTableParser

---
 CSharp.Nixill/src/Grid/CSVParser.cs       |  2 +-
 CSharp.Nixill/src/Grid/DataTableParser.cs | 60 +++++++++++++++++++++++
 2 files changed, 61 insertions(+), 1 deletion(-)
 create mode 100644 CSharp.Nixill/src/Grid/DataTableParser.cs

diff --git a/CSharp.Nixill/src/Grid/CSVParser.cs b/CSharp.Nixill/src/Grid/CSVParser.cs
index d4eed19..4776abc 100644
--- a/CSharp.Nixill/src/Grid/CSVParser.cs
+++ b/CSharp.Nixill/src/Grid/CSVParser.cs
@@ -26,7 +26,7 @@ namespace Nixill.Collections.Grid.CSV
   /// </description></item>
   /// </list>
   /// </summary>
-  public class CSVParser
+  public static class CSVParser
   {
     /// <summary>
     /// Reads a CSV file into a Grid of strings.
diff --git a/CSharp.Nixill/src/Grid/DataTableParser.cs b/CSharp.Nixill/src/Grid/DataTableParser.cs
new file mode 100644
index 0000000..b1cf267
--- /dev/null
+++ b/CSharp.Nixill/src/Grid/DataTableParser.cs
@@ -0,0 +1,60 @@
+using System;
+using System.Collections.Generic;
+using System.Data;
+using System.IO;
+using Nixill.Utils;
+
+namespace Nixill.Collections.Grid.CSV;
+
+/// <summary>
+/// This class contains static methods to convert between DataTables and
+/// comma separated value format files and text.
+/// </summary>
+public static class DataTableCSVParser
+{
+  public static DataTable FileToDataTable(string path, IDictionary<string, DataColumn> columnDefs = null,
+    IDictionary<Type, Func<string, object>> deserializers = null, IEnumerable<string> primaryKey = null)
+    => EnumerableToDataTable(FileUtils.FileCharEnumerator(path), columnDefs, deserializers, primaryKey);
+
+  public static DataTable StreamToDataTable(StreamReader reader, IDictionary<string, DataColumn> columnDefs = null,
+    IDictionary<Type, Func<string, object>> deserializers = null, IEnumerable<string> primaryKey = null)
+    => EnumerableToDataTable(FileUtils.StreamCharEnumerator(reader), columnDefs, deserializers, primaryKey);
+
+  public static DataTable EnumerableToDataTable(IEnumerable<char> input,
+    IDictionary<string, DataColumn> columnDefs = null, IDictionary<Type, Func<string, object>> deserializers = null,
+    IEnumerable<string> primaryKey = null)
+  {
+    DataTable table = new();
+
+    columnDefs ??= new Dictionary<string, DataColumn>();
+    deserializers ??= new Dictionary<Type, Func<string, object>>();
+
+    var types = new List<Type>();
+
+    IEnumerable<IList<string>> rows = CSVParser.EnumerableToRows(input);
+    bool isHeaderRow = true;
+
+    foreach (var row in rows)
+    {
+      if (isHeaderRow)
+      {
+        foreach (string item in row)
+        {
+          if (columnDefs.TryGetValue(item, out DataColumn col))
+          {
+            table.Columns.Add(col);
+            types.Add(col.DataType);
+          }
+          else
+          {
+            table.Columns.Add(new DataColumn
+            {
+              ColumnName = item
+            });
+            types.Add(typeof(string));
+          }
+        }
+      }
+    }
+  }
+}
\ No newline at end of file