Create CSVObjectCollection

CSharp.Nixill/src/Grid/CSVObjectCollection.cs

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+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.IO;
+using System.Linq;
+using Nixill.Utils;
+
+namespace Nixill.Collections.Grid.CSV;
+
+public class CSVObjectCollection<T> : IList<T>
+{
+  readonly List<string> _Columns = [];
+  readonly List<T> _Contents = [];
+
+  public IEnumerable<string> Columns => _Columns.AsReadOnly();
+  public IEnumerable<T> Contents => _Contents.AsReadOnly();
+
+  public CSVObjectCollection() { }
+
+  public CSVObjectCollection(IEnumerable<T> contents)
+  {
+    _Contents = [.. contents];
+  }
+
+  public CSVObjectCollection(IEnumerable<string> columns, IEnumerable<T> contents)
+  {
+    _Columns = [.. columns];
+    _Contents = [.. contents];
+  }
+
+  public CSVObjectCollection(CSVObjectCollection<T> clones)
+  {
+    _Columns = [.. clones._Columns];
+    _Contents = [.. clones];
+  }
+
+  public static CSVObjectCollection<T> ParseObjectsFromFile(string path, Func<IDictionary<string, string>, T> deserializer)
+    => ParseObjects(FileUtils.FileCharEnumerator(path), deserializer);
+
+  public static CSVObjectCollection<T> ParseObjectsFromStream(StreamReader reader,
+    Func<IDictionary<string, string>, T> deserializer)
+    => ParseObjects(FileUtils.StreamCharEnumerator(reader), deserializer);
+
+  public static CSVObjectCollection<T> ParseObjects(IEnumerable<char> input,
+    Func<IDictionary<string, string>, T> deserializer)
+  {
+    IEnumerable<IList<string>> rows = CSVParser.EnumerableToRows(input);
+    bool isHeaderRow = true;
+    List<string> columns = [];
+    List<T> objects = [];
+
+    foreach (var row in rows)
+    {
+      if (isHeaderRow)
+      {
+        columns = [.. row];
+        isHeaderRow = false;
+      }
+      else
+      {
+        IDictionary<string, string> properties = columns.Zip(row).ToPropertyDictionary();
+        objects.Add(deserializer(properties));
+      }
+    }
+
+    return new CSVObjectCollection<T>(columns, objects);
+  }
+
+  public string NewRow(T item, Func<T, IDictionary<string, string>> serializer)
+  {
+    _Contents.Add(item);
+
+    var properties = serializer(item);
+    var columnValues = _Columns.Select(c =>
+    {
+      if (properties.TryGetValue(c, out string v)) return v;
+      return null;
+    });
+    return columnValues.Select(CSVParser.CSVEscape).SJoin(",");
+  }
+
+  public string ItemToRow(T item, Func<T, IDictionary<string, string>> serializer)
+  {
+    var properties = serializer(item);
+    var columnValues = _Columns.Select(c =>
+    {
+      if (properties.TryGetValue(c, out string v)) return v;
+      return null;
+    });
+    return columnValues.Select(CSVParser.CSVEscape).SJoin(",");
+  }
+
+  public IEnumerable<string> RowsAsCSV(Func<T, IDictionary<string, string>> serializer)
+  {
+    yield return _Columns.Select(CSVParser.CSVEscape).SJoin(",");
+    foreach (string str in _Contents.Select(i => ItemToRow(i, serializer)))
+      yield return str;
+  }
+
+  public string FormatCSV(Func<T, IDictionary<string, string>> serializer)
+    => RowsAsCSV(serializer).SJoin("\n");
+
+  public void FormatCSVToFile(string path, Func<T, IDictionary<string, string>> serializer)
+    => File.WriteAllText(path, FormatCSV(serializer));
+
+  #region IList: Contents
+  public int Count => _Contents.Count;
+
+  bool ICollection<T>.IsReadOnly => ((ICollection<T>)_Contents).IsReadOnly;
+
+  public T this[int index] { get => _Contents[index]; set => _Contents[index] = value; }
+
+  public int IndexOf(T item)
+  {
+    return ((IList<T>)_Contents).IndexOf(item);
+  }
+
+  public void Insert(int index, T item)
+  {
+    ((IList<T>)_Contents).Insert(index, item);
+  }
+
+  public void RemoveAt(int index)
+  {
+    ((IList<T>)_Contents).RemoveAt(index);
+  }
+
+  public void Add(T item)
+  {
+    ((ICollection<T>)_Contents).Add(item);
+  }
+
+  public void Clear()
+  {
+    ((ICollection<T>)_Contents).Clear();
+  }
+
+  public bool Contains(T item)
+  {
+    return ((ICollection<T>)_Contents).Contains(item);
+  }
+
+  public void CopyTo(T[] array, int arrayIndex)
+  {
+    ((ICollection<T>)_Contents).CopyTo(array, arrayIndex);
+  }
+
+  public bool Remove(T item)
+  {
+    return ((ICollection<T>)_Contents).Remove(item);
+  }
+
+  public IEnumerator<T> GetEnumerator()
+  {
+    return ((IEnumerable<T>)_Contents).GetEnumerator();
+  }
+
+  IEnumerator IEnumerable.GetEnumerator()
+  {
+    return ((IEnumerable)_Contents).GetEnumerator();
+  }
+  #endregion
+
+  #region IList: Columns
+  public int IndexOfColumn(string item)
+  {
+    return ((IList<string>)_Columns).IndexOf(item);
+  }
+
+  public void InsertColumn(int index, string item)
+  {
+    ((IList<string>)_Columns).Insert(index, item);
+  }
+
+  public void RemoveColumnAt(int index)
+  {
+    ((IList<string>)_Columns).RemoveAt(index);
+  }
+
+  public void AddColumn(string item)
+  {
+    ((ICollection<string>)_Columns).Add(item);
+  }
+
+  public void ClearColumns()
+  {
+    ((ICollection<string>)_Columns).Clear();
+  }
+
+  public bool ContainsColumn(string item)
+  {
+    return ((ICollection<string>)_Columns).Contains(item);
+  }
+
+  public void CopyColumnsTo(string[] array, int arrayIndex)
+  {
+    ((ICollection<string>)_Columns).CopyTo(array, arrayIndex);
+  }
+
+  public bool RemoveColumn(string item)
+  {
+    return ((ICollection<string>)_Columns).Remove(item);
+  }
+
+  public IEnumerator<string> GetColumnEnumerator()
+  {
+    return ((IEnumerable<string>)_Columns).GetEnumerator();
+  }
+  #endregion
+}
+
+public static class CSVObjectCollection
+{
+  public static CSVObjectCollection<T> ParseObjectsFromFile<T>(string path, Func<IDictionary<string, string>, T> deserializer)
+    => CSVObjectCollection<T>.ParseObjects(FileUtils.FileCharEnumerator(path), deserializer);
+
+  public static CSVObjectCollection<T> ParseObjectsFromStream<T>(StreamReader reader,
+    Func<IDictionary<string, string>, T> deserializer)
+    => CSVObjectCollection<T>.ParseObjects(FileUtils.StreamCharEnumerator(reader), deserializer);
+
+  public static CSVObjectCollection<T> ParseObjects<T>(IEnumerable<char> input,
+    Func<IDictionary<string, string>, T> deserializer)
+    => CSVObjectCollection<T>.ParseObjects(input, deserializer);
+}
+
+file class PropertyDictionary(Dictionary<string, string> backing) : IDictionary<string, string>
+{
+  readonly Dictionary<string, string> Backing = backing;
+
+  public string this[string key]
+  {
+    get => Backing.TryGetValue(key, out string value) ? value != "" ? value : null : null;
+    set => throw new InvalidOperationException("This dictionary is read-only.");
+  }
+
+  public ICollection<string> Keys => Backing.Keys;
+
+  public ICollection<string> Values => Backing.Values;
+
+  public int Count => Backing.Count;
+
+  public bool IsReadOnly => true;
+
+  public void Add(string key, string value)
+    => throw new InvalidOperationException("This dictionary is read-only.");
+
+  public void Add(KeyValuePair<string, string> item)
+    => throw new InvalidOperationException("This dictionary is read-only.");
+
+  public void Clear()
+    => throw new InvalidOperationException("This dictionary is read-only.");
+
+  public bool Contains(KeyValuePair<string, string> item)
+    => Backing.Contains(item);
+
+  public bool ContainsKey(string key)
+    => Backing.ContainsKey(key);
+
+  public void CopyTo(KeyValuePair<string, string>[] array, int arrayIndex)
+    => ((IDictionary<string, string>)Backing).CopyTo(array, arrayIndex);
+
+  public IEnumerator<KeyValuePair<string, string>> GetEnumerator()
+    => Backing.GetEnumerator();
+
+  public bool Remove(string key)
+    => throw new InvalidOperationException("This dictionary is read-only.");
+
+  public bool Remove(KeyValuePair<string, string> item)
+    => throw new InvalidOperationException("This dictionary is read-only.");
+
+  public bool TryGetValue(string key, [MaybeNullWhen(false)] out string value)
+  {
+    bool success = Backing.TryGetValue(key, out value);
+
+    if (value == "")
+    {
+      value = null;
+      return false;
+    }
+
+    return success;
+  }
+
+  IEnumerator IEnumerable.GetEnumerator() => Backing.GetEnumerator();
+}
+
+file static class PropertyDictionaryExtensions
+{
+  public static PropertyDictionary ToPropertyDictionary(this IEnumerable<(string, string)> dict)
+    => new PropertyDictionary(dict.ToDictionary());
+}