[Feature] Add useful utility methods to ModalBuilder (#2773)

* Add method to get a component of type

* Add methods to update a component

* Add methods to remove a component(s)

* Add missing `row` parameter to wrapper

* Update XML documentation

* Reorder properties to follow coding style

* Remove unnecessary usings to follow coding style

* Fix build usings

* Fix XML documentation

* Add `null` checks to remove methods

* Fix empty constructor

* Fix `CustomId` setter

* Update src/Discord.Net.Core/Entities/Interactions/Modals/ModalBuilder.cs

Co-authored-by: Misha133 <61027276+Misha-133@users.noreply.github.com>

* Fix `GetComponent` to return null

* Fix XML documentation

* Add `null` checks

* Update src/Discord.Net.Core/Entities/Interactions/Modals/ModalBuilder.cs

* Update src/Discord.Net.Core/Entities/Interactions/Modals/ModalBuilder.cs

* Update src/Discord.Net.Core/Entities/Interactions/Modals/ModalBuilder.cs

Co-authored-by: Misha133 <61027276+Misha-133@users.noreply.github.com>

---------

Co-authored-by: Misha133 <61027276+Misha-133@users.noreply.github.com>

src/Discord.Net.Core/Entities/Interactions/Modals/ModalBuilder.cs

@@ -1,43 +1,20 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 
 namespace Discord
 {
+    /// <summary>
+    ///     Represents a builder for creating a <see cref="Modal"/>.
+    /// </summary>
     public class ModalBuilder
     {
-        /// <summary>
-        ///     Gets or sets the components of the current modal.
-        /// </summary>
-        public ModalComponentBuilder Components { get; set; } = new();
-
-        /// <summary>
-        ///     Gets or sets the title of the current modal.
-        /// </summary>
-        public string Title { get; set; }
-
-        /// <summary>
-        ///     Gets or sets the custom id of the current modal.
-        /// </summary>
-        public string CustomId
-        {
-            get => _customId;
-            set => _customId = value?.Length switch
-            {
-                > ComponentBuilder.MaxCustomIdLength => throw new ArgumentOutOfRangeException(nameof(value), $"Custom Id length must be less or equal to {ComponentBuilder.MaxCustomIdLength}."),
-                0 => throw new ArgumentOutOfRangeException(nameof(value), "Custom Id length must be at least 1."),
-                _ => value
-            };
-        }
-
         private string _customId;
 
         public ModalBuilder() { }
 
         /// <summary>
-        ///     Creates a new instance of a <see cref="ModalBuilder"/>
+        ///     Creates a new instance of the <see cref="ModalBuilder"/>.
         /// </summary>
         /// <param name="title">The modal's title.</param>
         /// <param name="customId">The modal's customId.</param>
@@ -50,6 +27,30 @@ namespace Discord
             Components = components ?? new();
         }
 
+        /// <summary>
+        ///     Gets or sets the title of the current modal.
+        /// </summary>
+        public string Title { get; set; }
+
+        /// <summary>
+        ///     Gets or sets the custom ID of the current modal.
+        /// </summary>
+        public string CustomId
+        {
+            get => _customId;
+            set => _customId = value?.Length switch
+            {
+                > ComponentBuilder.MaxCustomIdLength => throw new ArgumentOutOfRangeException(nameof(value), $"Custom ID length must be less or equal to {ComponentBuilder.MaxCustomIdLength}."),
+                0 => throw new ArgumentOutOfRangeException(nameof(value), "Custom ID length must be at least 1."),
+                _ => value
+            };
+        }
+
+        /// <summary>
+        ///     Gets or sets the components of the current modal.
+        /// </summary>
+        public ModalComponentBuilder Components { get; set; } = new();
+
         /// <summary>
         ///     Sets the title of the current modal.
         /// </summary>
@@ -76,10 +77,11 @@ namespace Discord
         ///     Adds a component to the current builder.
         /// </summary>
         /// <param name="component">The component to add.</param>
+        /// <param name="row">The row to add the text input.</param>
         /// <returns>The current builder.</returns>
-        public ModalBuilder AddTextInput(TextInputBuilder component)
+        public ModalBuilder AddTextInput(TextInputBuilder component, int row = 0)
         {
-            Components.WithTextInput(component);
+            Components.WithTextInput(component, row);
             return this;
         }
 
@@ -108,21 +110,111 @@ namespace Discord
             return this;
         }
 
+        /// <summary>
+        ///     Gets a <typeparamref name="TMessageComponent"/> by the specified <paramref name="customId"/>.
+        /// </summary>
+        /// <typeparam name="TMessageComponent">The type of the component to get.</typeparam>
+        /// <param name="customId">The <see cref="IMessageComponent.CustomId"/> of the component to get.</param>
+        /// <returns>
+        ///     The component of type <typeparamref name="TMessageComponent"/> that was found, <see langword="null"/> otherwise.
+        /// </returns>
+        public TMessageComponent GetComponent<TMessageComponent>(string customId)
+            where TMessageComponent : class, IMessageComponent
+        {
+            Preconditions.NotNull(customId, nameof(customId));
+
+            return Components.ActionRows
+                ?.SelectMany(r => r.Components.OfType<TMessageComponent>())
+                .FirstOrDefault(c => c?.CustomId == customId);
+        }
+
+        /// <summary>
+        ///     Updates a <see cref="TextInputComponent"/> by the specified <paramref name="customId"/>.
+        /// </summary>
+        /// <param name="customId">The <see cref="TextInputComponent.CustomId"/> of the input to update.</param>
+        /// <param name="updateTextInput">An action that configures the updated text input.</param>
+        /// <returns>The current builder.</returns>
+        /// <exception cref="ArgumentException">
+        ///     Thrown when the <see cref="TextInputComponent"/> to be updated was not found.
+        /// </exception>
+        public ModalBuilder UpdateTextInput(string customId, Action<TextInputBuilder> updateTextInput)
+        {
+            Preconditions.NotNull(customId, nameof(customId));
+
+            var component = GetComponent<TextInputComponent>(customId) ?? throw new ArgumentException($"There is no component of type {nameof(TextInputComponent)} with the specified custom ID in this modal builder.", nameof(customId));
+            var row = Components.ActionRows.First(r => r.Components.Contains(component));
+
+            var builder = new TextInputBuilder
+            {
+                Label = component.Label,
+                CustomId = component.CustomId,
+                Style = component.Style,
+                Placeholder = component.Placeholder,
+                MinLength = component.MinLength,
+                MaxLength = component.MaxLength,
+                Required = component.Required,
+                Value = component.Value
+            };
+
+            updateTextInput(builder);
+
+            row.Components.Remove(component);
+            row.AddComponent(builder.Build());
+
+            return this;
+        }
+        
+        /// <summary>
+        ///     Updates the value of a <see cref="TextInputComponent"/> by the specified <paramref name="customId"/>.
+        /// </summary>
+        /// <param name="customId">The <see cref="TextInputComponent.CustomId"/> of the input to update.</param>
+        /// <param name="value">The new value to put.</param>
+        /// <returns>The current builder.</returns>
+        public ModalBuilder UpdateTextInput(string customId, object value)
+        {
+            UpdateTextInput(customId, x => x.Value = value?.ToString());
+            return this;
+        }
+
+        /// <summary>
+        ///     Removes a component from this builder by the specified <paramref name="customId"/>.
+        /// </summary>
+        /// <param name="customId">The <see cref="IMessageComponent.CustomId"/> of the component to remove.</param>
+        /// <returns>The current builder.</returns>
+        public ModalBuilder RemoveComponent(string customId)
+        {
+            Preconditions.NotNull(customId, nameof(customId));
+
+            Components.ActionRows?.ForEach(r => r.Components.RemoveAll(c => c.CustomId == customId));
+            return this;
+        }
+
+        /// <summary>
+        ///     Removes all components of the given <paramref name="type"/> from this builder.
+        /// </summary>
+        /// <param name="type">The <see cref="ComponentType"/> to remove.</param>
+        /// <returns>The current builder.</returns>
+        public ModalBuilder RemoveComponentsOfType(ComponentType type)
+        {
+            Components.ActionRows?.ForEach(r => r.Components.RemoveAll(c => c.Type == type));
+            return this;
+        }
+
         /// <summary>
         ///     Builds this builder into a <see cref="Modal"/>.
         /// </summary>
         /// <returns>A <see cref="Modal"/> with the same values as this builder.</returns>
-        /// <exception cref="ArgumentException">Only TextInputComponents are allowed.</exception>
+        /// <exception cref="ArgumentException">Modals must have a custom ID.</exception>
-        /// <exception cref="ArgumentException">Modals must have a custom id.</exception>
         /// <exception cref="ArgumentException">Modals must have a title.</exception>
+        /// <exception cref="ArgumentException">Only components of type <see cref="TextInputComponent"/> are allowed.</exception>
         public Modal Build()
         {
             if (string.IsNullOrEmpty(CustomId))
-                throw new ArgumentException("Modals must have a custom id.", nameof(CustomId));
+                throw new ArgumentException("Modals must have a custom ID.", nameof(CustomId));
             if (string.IsNullOrWhiteSpace(Title))
                 throw new ArgumentException("Modals must have a title.", nameof(Title));
-            if (Components.ActionRows?.SelectMany(x => x.Components).Any(x => x.Type != ComponentType.TextInput) ?? false)
+            if (Components.ActionRows?.SelectMany(r => r.Components).Any(c => c.Type != ComponentType.TextInput) ?? false)
-                throw new ArgumentException($"Only TextInputComponents are allowed.", nameof(Components));
+                throw new ArgumentException($"Only components of type {nameof(TextInputComponent)} are allowed.", nameof(Components));
 
             return new(Title, CustomId, Components.Build());
         }