namespace HeuristicLab.Tests.Interpreter.Expressions {
  using HeuristicLab.Problems.ProgramSynthesis.Push.Expressions;
  using HeuristicLab.Problems.ProgramSynthesis.Push.Stack;

  using Microsoft.VisualStudio.TestTools.UnitTesting;

  public abstract class CommonTests<T> : ExpressionTest {
    protected const string FullInstructionNameFormat = "{0}.{1}";

    protected abstract string TypeName { get; }

    protected abstract IStack<T> Stack { get; }

    protected abstract T[] GetValues(int count);

    protected virtual T[] Get2Different() {
      return this.GetValues(2);
    }

    protected virtual void Test(Expression expression) {
      this.interpreter.Run(expression);
    }

    protected abstract void CheckOtherStacksAreEmpty();

    [TestMethod]
    [TestProperty("Time", "Short")]
    [TestCategory("ExpressionTest")]
    [TestCategory("CommonExpressionTest")]
    public virtual void TestEqualsTrue() {
      var values = this.GetValues(1);
      var merged = new[] { values[0], values[0] };

      this.Stack.Push(merged);

      var isBooleanStack = this.interpreter.BooleanStack.Count == 2;

      this.Test(ExpressionTable.GetStatelessExpression(this.TypeName + ".="));

      if (isBooleanStack) Assert.AreEqual(1, this.Stack.Count);
      else Assert.AreEqual(0, this.Stack.Count);

      Assert.IsTrue(this.interpreter.BooleanStack.Top);
    }

    [TestMethod]
    [TestProperty("Time", "Short")]
    [TestCategory("ExpressionTest")]
    [TestCategory("CommonExpressionTest")]
    public virtual void TestEqualsFalse() {
      var values = this.Get2Different();
      this.Stack.Push(values);
      var isBooleanStack = this.interpreter.BooleanStack.Count == 2;

      this.Test(ExpressionTable.GetStatelessExpression(this.TypeName + ".="));

      if (isBooleanStack) Assert.AreEqual(1, this.Stack.Count);
      else Assert.AreEqual(0, this.Stack.Count);

      Assert.IsFalse(this.interpreter.BooleanStack.Top);
    }

    [TestMethod]
    [TestProperty("Time", "Short")]
    [TestCategory("ExpressionTest")]
    [TestCategory("CommonExpressionTest")]
    public virtual void TestEqualsWithInsufficientArguments() {
      this.TestWithInsufficientArguments("=", 1);
    }

    [TestMethod]
    [TestProperty("Time", "Short")]
    [TestCategory("ExpressionTest")]
    [TestCategory("CommonExpressionTest")]
    public virtual void TestDuplicate() {
      var values = this.GetValues(1);
      this.Stack.Push(values);

      this.Test(ExpressionTable.GetStatelessExpression(this.TypeName + ".DUP"));

      Assert.AreEqual(this.Stack.Count, 2);
      Assert.AreEqual(this.Stack[0], values[0]);
      Assert.AreEqual(this.Stack[1], values[0]);
      this.CheckOtherStacksAreEmpty();
    }

    [TestMethod]
    [TestProperty("Time", "Short")]
    [TestCategory("ExpressionTest")]
    [TestCategory("CommonExpressionTest")]
    public virtual void TestPop() {
      var values = this.GetValues(2);
      this.Stack.Push(values);

      this.Test(ExpressionTable.GetStatelessExpression(this.TypeName + ".POP"));

      this.CheckOtherStacksAreEmpty();
    }

    [TestMethod]
    [TestProperty("Time", "Short")]
    [TestCategory("ExpressionTest")]
    [TestCategory("CommonExpressionTest")]
    public virtual void TestSwap() {
      var values = this.GetValues(3);
      this.Stack.Push(values);

      this.Test(ExpressionTable.GetStatelessExpression(this.TypeName + ".SWAP"));

      Assert.AreEqual(values[0], this.Stack[0]);
      Assert.AreEqual(values[2], this.Stack[1]);
      Assert.AreEqual(values[1], this.Stack[2]);

      this.CheckOtherStacksAreEmpty();
    }

    [TestMethod]
    [TestProperty("Time", "Short")]
    [TestCategory("ExpressionTest")]
    [TestCategory("CommonExpressionTest")]
    public virtual void TestSwapWithInsufficientArguments() {
      this.TestWithInsufficientArguments("SWAP", 1);
    }

    [TestMethod]
    [TestProperty("Time", "Short")]
    [TestCategory("ExpressionTest")]
    [TestCategory("CommonExpressionTest")]
    public virtual void TestRotate() {
      var values = this.GetValues(4);
      this.Stack.Push(values);

      this.Test(ExpressionTable.GetStatelessExpression(this.TypeName + ".ROT"));

      Assert.AreEqual(values[0], this.Stack[0]);
      Assert.AreEqual(values[3], this.Stack[1]);
      Assert.AreEqual(values[1], this.Stack[2]);
      Assert.AreEqual(values[2], this.Stack[3]);

      this.CheckOtherStacksAreEmpty();
    }

    [TestMethod]
    [TestProperty("Time", "Short")]
    [TestCategory("ExpressionTest")]
    [TestCategory("CommonExpressionTest")]
    public virtual void TestRotateWithInsufficientArguments() {
      this.TestWithInsufficientArguments("ROT", 2);
    }

    [TestMethod]
    [TestProperty("Time", "Short")]
    [TestCategory("ExpressionTest")]
    [TestCategory("CommonExpressionTest")]
    public virtual void TestShove() {
      var values = this.GetValues(3);
      this.Stack.Push(values);

      this.interpreter.IntegerStack.Push(1);
      this.Test(ExpressionTable.GetStatelessExpression(this.TypeName + ".SHOVE"));

      Assert.AreEqual(values[0], this.Stack[0]);
      Assert.AreEqual(values[2], this.Stack[1]);
      Assert.AreEqual(values[1], this.Stack[2]);

      this.CheckOtherStacksAreEmpty();
    }

    [TestMethod]
    [TestProperty("Time", "Short")]
    [TestCategory("ExpressionTest")]
    [TestCategory("CommonExpressionTest")]
    public virtual void TestShoveWithInsufficientArguments() {
      this.TestWithInsufficientArguments("SHOVE", 1);
    }

    [TestMethod]
    [TestProperty("Time", "Short")]
    [TestCategory("ExpressionTest")]
    [TestCategory("CommonExpressionTest")]
    public virtual void TestShoveWithNegativeIndex() {
      this.TestWithNegativeIndex("SHOVE");
    }

    [TestMethod]
    [TestProperty("Time", "Short")]
    [TestCategory("ExpressionTest")]
    [TestCategory("CommonExpressionTest")]
    public virtual void TestYank() {
      var values = this.GetValues(3);
      this.Stack.Push(values);

      this.interpreter.IntegerStack.Push(1);
      this.Test(ExpressionTable.GetStatelessExpression(this.TypeName + ".YANK"));

      Assert.AreEqual(values[0], this.Stack[0]);
      Assert.AreEqual(values[2], this.Stack[1]);
      Assert.AreEqual(values[1], this.Stack[2]);

      this.CheckOtherStacksAreEmpty();
    }

    [TestMethod]
    [TestProperty("Time", "Short")]
    [TestCategory("ExpressionTest")]
    [TestCategory("CommonExpressionTest")]
    public virtual void TestYankWithInsufficientArguments() {
      this.TestWithInsufficientArguments("YANK", 1);
    }

    [TestMethod]
    [TestProperty("Time", "Short")]
    [TestCategory("ExpressionTest")]
    [TestCategory("CommonExpressionTest")]
    public virtual void TestYankWithNegativeIndex() {
      this.TestWithNegativeIndex("YANK");
    }

    [TestMethod]
    [TestProperty("Time", "Short")]
    [TestCategory("ExpressionTest")]
    [TestCategory("CommonExpressionTest")]
    public virtual void TestYankDuplicate() {
      var values = this.GetValues(3);
      this.Stack.Push(values);

      this.interpreter.IntegerStack.Push(1);
      this.Test(ExpressionTable.GetStatelessExpression(this.TypeName + ".YANKDUP"));

      Assert.AreEqual(values[0], this.Stack[0]);
      Assert.AreEqual(values[1], this.Stack[1]);
      Assert.AreEqual(values[2], this.Stack[2]);
      Assert.AreEqual(values[1], this.Stack[3]);

      this.CheckOtherStacksAreEmpty();
    }

    [TestMethod]
    [TestProperty("Time", "Short")]
    [TestCategory("ExpressionTest")]
    [TestCategory("CommonExpressionTest")]
    public virtual void TestYankDuplicateWithInsufficientArguments() {
      this.TestWithInsufficientArguments("YANKDUP", 1);
    }

    [TestMethod]
    [TestProperty("Time", "Short")]
    [TestCategory("ExpressionTest")]
    [TestCategory("CommonExpressionTest")]
    public virtual void TestYankDuplicateWithNegativeIndex() {
      this.TestWithNegativeIndex("YANKDUP");
    }

    [TestMethod]
    [TestProperty("Time", "Short")]
    [TestCategory("ExpressionTest")]
    [TestCategory("CommonExpressionTest")]
    public virtual void TestStackdpeth() {
      var values = this.GetValues(3);
      this.Stack.Push(values);

      this.Test(ExpressionTable.GetStatelessExpression(this.TypeName + ".STACKDEPTH"));

      // if stack is integer stack
      if (this.Stack.Count != values.Length) {
        Assert.AreEqual(4, this.Stack.Count);
        this.CheckOtherStacksAreEmpty();
      } else {
        Assert.AreEqual(3, this.Stack.Count);
        Assert.AreEqual(values.Length, this.interpreter.IntegerStack.Top);
      }
    }

    protected void TestWithInsufficientArguments(string instructionName, int argCount = 0) {
      for (var i = 0; i < argCount + 1; i++) {
        var values = this.GetValues(i);
        this.Stack.Push(values);

        var fullInstructionname = string.Format(FullInstructionNameFormat, this.TypeName, instructionName);
        this.Test(ExpressionTable.GetStatelessExpression(fullInstructionname));

        for (var j = 0; j < i; j++) Assert.AreEqual(values[j], this.Stack[j]);

        this.CheckOtherStacksAreEmpty();
        this.interpreter.Clear();
      }
    }

    protected void TestWithNegativeIndex(string instructionName) {
      var values = this.GetValues(1);
      this.Stack.Push(values);

      this.interpreter.IntegerStack.Push(-1);

      var fullInstructionname = string.Format(FullInstructionNameFormat, this.TypeName, instructionName);
      this.Test(ExpressionTable.GetStatelessExpression(fullInstructionname));

      Assert.AreEqual(values[0], this.Stack[0]);
    }
  }
}