using MathEngine.Parser.Tokeniser;
using MathEngine.Parser.Parser;
namespace EngineTests
{
    /// <summary>
    /// Class for testing the ExpressionTree Class
    /// </summary>
    [TestClass]
    public class ExpressionTreeTests
    {

        /// <summary>
        /// Test to see if a simple expression is constructed correctly
        /// </summary>
        [TestMethod]
        public void TestExpressionTreeSimpleExpression()
        {
            string testExp = "3+4";
            TreeNode exptectedTree = new(Token.Plus);
            Token tokfour = new("4", Token.Type.Numeric, Token.NumericType.Decimal, 0);
            Token tokthree = new("3", Token.Type.Numeric, Token.NumericType.Decimal, 0);
            TreeNode four = new(tokfour);
            TreeNode three = new(tokthree);
            exptectedTree.AddChildNode(four);
            exptectedTree.AddChildNode(three);
            ExpressionTree returnedTree = new ExpressionTree(testExp);
            Assert.IsTrue(returnedTree.Equals(exptectedTree));
        }

        /// <summary>
        /// Test to see if a simple expression is evaluated correctly
        /// </summary>
        [TestMethod]
        public void TestExpressionTreeSimpleExpressionEvaluation()
        {
            string testExp = "3+4*7";
            Token tok31 = new("31", Token.Type.Numeric, Token.NumericType.Decimal, 0);
            TreeNode exptectedTree = new(tok31);
            ExpressionTree returnedTree = new ExpressionTree(testExp);
            ExpressionTree evaluatedTree = returnedTree.Evaluate();
            Assert.IsTrue(evaluatedTree.Equals(exptectedTree));
        }

        /// <summary>
        /// Test to see if a simple expression using all base operators (+,-,*,/) is evaluated correctly
        /// </summary>
        [TestMethod]
        public void TestExpressionTreeSimpleExpressionAllBaseOperatorsEvaluation()
        {
            string testExp = "3+4*7-8/7";
            decimal testValue = decimal.Divide(209 , 7);
            Token tok31 = new(testValue.ToString(), Token.Type.Numeric, Token.NumericType.Decimal, 0);
            TreeNode exptectedTree = new(tok31);
            ExpressionTree returnedTree = new ExpressionTree(testExp);
            ExpressionTree evaluatedTree = returnedTree.Evaluate();
            Assert.IsTrue(evaluatedTree.Equals(exptectedTree));
        }
    }
}