/******************************************************************************
 * Icinga 2                                                                   *
 * Copyright (C) 2012-2014 Icinga Development Team (http://www.icinga.org)    *
 *                                                                            *
 * This program is free software; you can redistribute it and/or              *
 * modify it under the terms of the GNU General Public License                *
 * as published by the Free Software Foundation; either version 2             *
 * of the License, or (at your option) any later version.                     *
 *                                                                            *
 * This program is distributed in the hope that it will be useful,            *
 * but WITHOUT ANY WARRANTY; without even the implied warranty of             *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the              *
 * GNU General Public License for more details.                               *
 *                                                                            *
 * You should have received a copy of the GNU General Public License          *
 * along with this program; if not, write to the Free Software Foundation     *
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.             *
 ******************************************************************************/

#include "config/aexpression.h"
#include "base/array.h"
#include "base/serializer.h"
#include "base/context.h"
#include "base/scriptfunction.h"
#include <boost/foreach.hpp>

using namespace icinga;

AExpression::AExpression(AOperator op, const AValue& operand1, const DebugInfo& di)
	: m_Operator(op), m_Operand1(operand1), m_DebugInfo(di)
{
	ASSERT(op == AEReturn);
}

AExpression::AExpression(AOperator op, const AValue& operand1, const AValue& operand2, const DebugInfo& di)
	: m_Operator(op), m_Operand1(operand1), m_Operand2(operand2), m_DebugInfo(di)
{
	ASSERT(op == AEAdd || op == AENegate || op == AESubtract || op == AEMultiply || op == AEDivide ||
		op == AEBinaryAnd || op == AEBinaryOr || op == AEShiftLeft || op == AEShiftRight ||
		op == AEEqual || op == AENotEqual || op == AEIn || op == AENotIn ||
		op == AELogicalAnd || op == AELogicalOr || op == AEFunctionCall);
}

Value AExpression::Evaluate(const Dictionary::Ptr& locals) const
{
	Value left, right;
	Array::Ptr arr, arr2;
	bool found;
	String funcName;
	ScriptFunction::Ptr func;
	std::vector<Value> arguments;

	left = m_Operand1.Evaluate(locals);
	right = m_Operand2.Evaluate(locals);

	std::ostringstream msgbuf;
	msgbuf << "Evaluating AExpression " << m_DebugInfo << "; left=" << JsonSerialize(left) << "; right=" << JsonSerialize(right);
	CONTEXT(msgbuf.str());

	switch (m_Operator) {
		case AEReturn:
			return left;
		case AENegate:
			return ~(long)left;
		case AEAdd:
			return left + right;
		case AESubtract:
			return left - right;
		case AEMultiply:
			return left * right;
		case AEDivide:
			return left / right;
		case AEBinaryAnd:
			return left & right;
		case AEBinaryOr:
			return left | right;
		case AEShiftLeft:
			return left << right;
		case AEShiftRight:
			return left >> right;
		case AEEqual:
			return left == right;
		case AENotEqual:
			return left != right;
		case AELessThan:
			return left < right;
		case AEGreaterThan:
			return left > right;
		case AELessThanOrEqual:
			return left <= right;
		case AEGreaterThanOrEqual:
			return left >= right;
		case AEIn:
			if (!right.IsObjectType<Array>())
				BOOST_THROW_EXCEPTION(std::invalid_argument("Invalid right side argument for 'in' operator: " + JsonSerialize(right)));

			arr = right;
			found = false;
			BOOST_FOREACH(const Value& value, arr) {
				if (value == left) {
					found = true;
					break;
				}
			}

			return found;
		case AENotIn:
			if (!right.IsObjectType<Array>())
				BOOST_THROW_EXCEPTION(std::invalid_argument("Invalid right side argument for 'in' operator: " + JsonSerialize(right)));

			arr = right;
			found = false;
			BOOST_FOREACH(const Value& value, arr) {
				if (value == left) {
					found = true;
					break;
				}
			}

			return !found;
		case AELogicalAnd:
			return left.ToBool() && right.ToBool();
		case AELogicalOr:
			return left.ToBool() || right.ToBool();
		case AEFunctionCall:
			funcName = left;
			func = ScriptFunctionRegistry::GetInstance()->GetItem(funcName);

			if (!func)
				BOOST_THROW_EXCEPTION(std::invalid_argument("Function '" + funcName + "' does not exist."));

			arr = right;
			BOOST_FOREACH(const AExpression::Ptr& aexpr, arr) {
				arguments.push_back(aexpr->Evaluate(locals));
			}

			return func->Invoke(arguments);
		case AEArray:
			arr = left;
			arr2 = make_shared<Array>();

			if (arr) {
				BOOST_FOREACH(const AExpression::Ptr& aexpr, arr) {
					arr2->Add(aexpr->Evaluate(locals));
				}
			}

			return arr2;
		default:
			ASSERT(!"Invalid operator.");
	}
}