using System;
using System.Collections.Generic;

namespace AspClassic.Parser;

/// <summary>
/// A parse tree for a case clause that compares values.
/// </summary>
public sealed class ComparisonCaseClause : CaseClause
{
	private readonly Location _IsLocation;

	private readonly OperatorType _ComparisonOperator;

	private readonly Location _OperatorLocation;

	private readonly Expression _Operand;

	/// <summary>
	/// The location of the 'Is', if any.
	/// </summary>
	public Location IsLocation => _IsLocation;

	/// <summary>
	/// The comparison operator used in the case clause.
	/// </summary>
	public OperatorType ComparisonOperator => _ComparisonOperator;

	/// <summary>
	/// The location of the comparison operator.
	/// </summary>
	public Location OperatorLocation => _OperatorLocation;

	/// <summary>
	/// The operand of the case clause.
	/// </summary>
	public Expression Operand => _Operand;

	/// <summary>
	/// Constructs a new parse tree for a comparison case clause.
	/// </summary>
	/// <param name="isLocation">The location of the 'Is', if any.</param>
	/// <param name="comparisonOperator">The comparison operator used.</param>
	/// <param name="operatorLocation">The location of the comparison operator.</param>
	/// <param name="operand">The operand of the comparison.</param>
	/// <param name="span">The location of the parse tree.</param>
	public ComparisonCaseClause(Location isLocation, OperatorType comparisonOperator, Location operatorLocation, Expression operand, Span span)
		: base(TreeType.ComparisonCaseClause, span)
	{
		if (operand == null)
		{
			throw new ArgumentNullException("operand");
		}
		if (comparisonOperator < OperatorType.Equals || comparisonOperator > OperatorType.GreaterThanEquals)
		{
			throw new ArgumentOutOfRangeException("comparisonOperator");
		}
		SetParent(operand);
		_IsLocation = isLocation;
		_ComparisonOperator = comparisonOperator;
		_OperatorLocation = operatorLocation;
		_Operand = operand;
	}

	protected override void GetChildTrees(IList<Tree> childList)
	{
		Tree.AddChild(childList, Operand);
	}
}