using System;
using System.Text;
using TypeLibrary = Sandbox.Internal.TypeLibrary;

namespace BetterUI;

/// <summary>
/// A builder for styles.
/// </summary>
public sealed class StyleBuilder
{
	private readonly StringBuilder _builder = new();

	/// <summary>
	/// Adds a style to the builder.
	/// </summary>
	/// <param name="name">The name of the style.</param>
	/// <param name="value">The value of the style.</param>
	/// <returns>The builder.</returns>
	public StyleBuilder AddStyle( string name, object value )
	{
		Append( name, value );
		return this;
	}

	/// <summary>
	/// Adds a style to the builder if the condition is true.
	/// </summary>
	/// <param name="name">The name of the style.</param>
	/// <param name="value">The value of the style.</param>
	/// <param name="condition">The condition to check.</param>
	/// <returns>The builder.</returns>
	public StyleBuilder AddStyle( string name, object value, bool condition )
	{
		if ( condition )
			Append( name, value );

		return this;
	}

	/// <summary>
	/// Adds a style to the builder if the condition is true.
	/// </summary>
	/// <param name="name">The name of the style.</param>
	/// <param name="value">The value of the style.</param>
	/// <param name="condition">The condition to check.</param>
	/// <returns>The builder.</returns>
	public StyleBuilder AddStyle( string name, object value, Func<bool> condition )
	{
		if ( condition.Invoke() )
			Append( name, value );

		return this;
	}

	/// <summary>
	/// Appends a style to the builder.
	/// </summary>
	/// <param name="name">The name of the style.</param>
	/// <param name="value">The value of the style.</param>
	/// <remarks>
	/// If the builder is not empty, a space is prepended to the new style.
	/// </remarks>
	private void Append( string name, object value )
	{
		if ( _builder.Length is not 0 )
			_builder.Append( ' ' );

		_builder.Append( new CssPropertyBuilder().WithName( name ).WithValue( value ).Build() );
	}

	/// <summary>
	/// Builds the styles.
	/// </summary>
	/// <returns>The built styles.</returns>
	public string Build() => _builder.ToString();

	/// <inheritdoc />
	public override string ToString() => _builder.ToString();
}