using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Tyro
{
	/// <summary>
	/// A Question whose answer must contain
	/// </summary>
	public class ContainsElementQuestion : Question
	{
		/// <summary>
		/// The elements to be searched for within the proposed answer.
		/// </summary>
		public string[] answerElements;

		/// <summary>
		/// Should character case be considered in the answer?
		/// </summary>
		public bool isCaseSensitive;

		/// <summary>
		/// How many of the elements must be present in the propoised answer for it to be correct? 0 for every element.
		/// </summary>
		public int elementsRequiredInAnswer;

		/// <summary>
		/// Creates a Questions whose answer must contain certain elements.
		/// </summary>
		/// <param name="question">The text to be displayed, the literal question being asked.</param>
		/// <param name="answerElements">The elements to be searched for within the proposed answer.</param>
		/// <param name="isCaseSensitive">Should character case be considered in the answer?</param>
		/// <param name="elementsRequiredInAnswer">How many of the elements must be present in the proposed answer for it to be correct? 0 for every element.</param>
		public ContainsElementQuestion(string question, string[] answerElements, bool isCaseSensitive, int elementsRequiredInAnswer) : base(question)
		{
			this.answerElements = answerElements;
			this.isCaseSensitive = isCaseSensitive;
			this.elementsRequiredInAnswer = elementsRequiredInAnswer;
		}

		/// <summary>
		/// Determines if the proposed answer contains enough answer elements to be correct.
		/// </summary>
		/// <param name="proposedAnswer"></param>
		/// <returns>Returns true if the proposed answer contains as many or more answer elements to be correct. Returns false otherwise.</returns>
		public override bool IsCorrect(string proposedAnswer)
		{
			// Remove case if case isn't being checked for
			if (!isCaseSensitive)
			{
				proposedAnswer = proposedAnswer.ToLower();

			}

			// Check how many answer element the proposed answer contains
			int correctCount = 0;
			foreach(string element in answerElements)
			{
				// Take case sensitivity into account
				string elementCased = element;
				if (!isCaseSensitive)
				{
					elementCased = element.ToLower();
				}

				if (proposedAnswer.Contains(elementCased))
				{
					correctCount++;
				}
			}

			// Check if we have enough elements in the proposed answer, or we have EVERY element should elementsRequiredInAnswer equal 0
			if (correctCount >= elementsRequiredInAnswer || (elementsRequiredInAnswer == 0 && correctCount == answerElements.Length))
			{
				return true;
			}
			else
			{
				return false;
			}
		}
	}
}