using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;

namespace DominionBase.Players.AI.Bots
{
	public enum BotRuleConditionOperator
	{
		EqualsTo,
		NotEqualTo,
		LessThan,
		LessThanOrEqualTo,
		GreaterThan,
		GreaterThanOrEqualTo
	}

	public class BotRuleCondition
	{
		public BotRuleConditionOperand LeftOperand { get; set; }
		public BotRuleConditionOperator Operator { get; set; }
		public BotRuleConditionOperand RightOperand { get; set; }
		public object Value { get; private set; }

		public BotRuleCondition()
		{
			Value = null;
		}

	    public BotRuleCondition(XmlNode node)
	    {
	        if (node?.Attributes == null)
	            return;

            LeftOperand = new BotRuleConditionOperand(node.SelectSingleNode("left"));
            var operatorNode = node.SelectSingleNode("operator");
            RightOperand = new BotRuleConditionOperand(node.SelectSingleNode("right"), node.SelectSingleNode("extra_operation"));

            switch (operatorNode.Attributes["type"].Value)
            {
                case "equalTo":
                    Operator = BotRuleConditionOperator.EqualsTo;
                    break;
                case "smallerThan":
                    Operator = BotRuleConditionOperator.LessThan;
                    break;
                case "smallerOrEqualThan":
                    Operator = BotRuleConditionOperator.LessThanOrEqualTo;
                    break;
                case "greaterThan":
                    Operator = BotRuleConditionOperator.GreaterThan;
                    break;
                case "greaterOrEqualThan":
                    Operator = BotRuleConditionOperator.GreaterThanOrEqualTo;
                    break;
                default:
                    throw new Exception();
            }
        }

        public object Evaluate(IPlayer player)
        {
            LeftOperand.Evaluate(player);
            RightOperand.Evaluate(player);

            decimal lov = LeftOperand.Value;
            decimal rov = RightOperand.Value;
            switch (Operator)
            {
                case BotRuleConditionOperator.EqualsTo:
                    Value = LeftOperand.Value == RightOperand.Value;
                    break;

                case BotRuleConditionOperator.NotEqualTo:
                    Value = LeftOperand.Value != RightOperand.Value;
                    break;

                case BotRuleConditionOperator.LessThan:
                    Value = lov < rov;
                    break;

                case BotRuleConditionOperator.LessThanOrEqualTo:
                    Value = lov <= rov;
                    break;

                case BotRuleConditionOperator.GreaterThan:
                    Value = lov > rov;
                    break;

                case BotRuleConditionOperator.GreaterThanOrEqualTo:
                    Value = lov >= rov;
                    break;
            }
            return Value;
        }

		public bool IsTrue => Value as bool? == true;

	    public override string ToString()
	    {
	        string op;
	        switch (Operator)
	        {
	            case BotRuleConditionOperator.EqualsTo:
	                op = "=";
	                break;
                case BotRuleConditionOperator.NotEqualTo:
                    op = "<>";
                    break;
                case BotRuleConditionOperator.LessThan:
                    op = "<";
                    break;
                case BotRuleConditionOperator.LessThanOrEqualTo:
                    op = "<=";
                    break;
                case BotRuleConditionOperator.GreaterThan:
                    op = ">";
                    break;
                case BotRuleConditionOperator.GreaterThanOrEqualTo:
                    op = ">=";
                    break;
                default:
	                op = "";
	                break;
	        }
            return $"{LeftOperand} {op} {RightOperand}";
	    }
	}
}