TextGenerator.cs

using BytecodeApi.Mathematics;
using System.Text;

namespace BytecodeApi.LanguageGenerator;

/// <summary>
/// Class that generates a random text sequence that match the pattern of real language.
/// A <see cref="LanguageGenerator.SentenceGenerator" /> is used to generate the sentences that generated text are composed of.
/// </summary>
public class TextGenerator : ILanguageStringGenerator
{
	/// <summary>
	/// Gets or sets the <see cref="LanguageGenerator.SentenceGenerator" /> that is used to generate sentences.
	/// </summary>
	public SentenceGenerator SentenceGenerator { get; set; }
	/// <summary>
	/// Gets or sets the minimum number of sentences used to build text.
	/// <para>The default value is 10</para>
	/// </summary>
	public int MinSentenceCount { get; set; }
	/// <summary>
	/// Gets or sets the maximum number of sentences used to build text.
	/// <para>The default value is 20</para>
	/// </summary>
	public int MaxSentenceCount { get; set; }
	/// <summary>
	/// Gets or sets a <see cref="double" /> value that specifies the chance of a linebreak being inserted after a sentence, where 0.0 means no linebreaks and 1.0 means a linebreak between every sentence.
	/// <para>The default value is 0.0</para>
	/// </summary>
	public double LineBreakChance { get; set; }
	/// <summary>
	/// Gets or sets a <see cref="double" /> value that specifies the chance of a paragraph being inserted after a sentence, where 0.0 means no paragraphs and 1.0 means a paragraph between every sentence. Randomly picked paragraphs have precedence over linebreaks and do not occur consecutively.
	/// <para>The default value is 0.1</para>
	/// </summary>
	public double ParagraphChance { get; set; }

	/// <summary>
	/// Initializes a new instance of the <see cref="TextGenerator" /> class with default values.
	/// </summary>
	public TextGenerator() : this(new())
	{
	}
	/// <summary>
	/// Initializes a new instance of the <see cref="TextGenerator" /> class with the specified <see cref="LanguageGenerator.SentenceGenerator" /> and with default values (<see cref="MinSentenceCount" /> = 10, <see cref="MaxSentenceCount" /> = 20, <see cref="LineBreakChance" /> = 0.0, <see cref="ParagraphChance" /> = 0.1).
	/// </summary>
	/// <param name="sentenceGenerator">The <see cref="LanguageGenerator.SentenceGenerator" /> to use for sentence generation.</param>
	public TextGenerator(SentenceGenerator sentenceGenerator)
	{
		Check.ArgumentNull(sentenceGenerator);

		SentenceGenerator = sentenceGenerator;
		MinSentenceCount = 10;
		MaxSentenceCount = 20;
		LineBreakChance = 0;
		ParagraphChance = .1;
	}

	/// <summary>
	/// Generates a random sequence of sentences using the specified parameters of this <see cref="TextGenerator" /> instance.
	/// </summary>
	/// <returns>
	/// A new <see cref="string" /> with dynamically generated text.
	/// </returns>
	public string Generate()
	{
		Check.ArgumentNull(SentenceGenerator);
		Check.ArgumentOutOfRangeEx.GreaterEqual0(MinSentenceCount);
		Check.ArgumentOutOfRangeEx.GreaterEqual0(MaxSentenceCount);
		Check.ArgumentOutOfRangeEx.GreaterEqualValue(MaxSentenceCount, MinSentenceCount);
		Check.ArgumentOutOfRangeEx.Between0And1(LineBreakChance);
		Check.ArgumentOutOfRangeEx.Between0And1(ParagraphChance);

		StringBuilder stringBuilder = new();
		int sentences = MathEx.Random.Next(MinSentenceCount, MaxSentenceCount + 1);

		for (int i = 0; i < sentences; i++)
		{
			stringBuilder.Append(SentenceGenerator.Generate());

			if (MathEx.Random.NextDouble() < ParagraphChance)
			{
				stringBuilder.AppendLine().AppendLine();
			}
			else if (MathEx.Random.NextDouble() < LineBreakChance)
			{
				stringBuilder.AppendLine();
			}
			else
			{
				stringBuilder.Append(' ');
			}
		}

		return stringBuilder.ToString().Trim();
	}
}