/******************************************************************************
 * Icinga 2                                                                   *
 * Copyright (C) 2012-2015 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.             *
 ******************************************************************************/

#ifndef VMOPS_H
#define VMOPS_H

#include "config/i2-config.hpp"
#include "config/expression.hpp"
#include "config/configitembuilder.hpp"
#include "config/applyrule.hpp"
#include "config/objectrule.hpp"
#include "base/debuginfo.hpp"
#include "base/array.hpp"
#include "base/dictionary.hpp"
#include "base/function.hpp"
#include "base/scriptglobal.hpp"
#include "base/exception.hpp"
#include "base/convert.hpp"
#include "base/objectlock.hpp"
#include <boost/foreach.hpp>
#include <boost/smart_ptr/make_shared.hpp>
#include <map>
#include <vector>

namespace icinga
{

class VMOps
{
public:
	static inline Value Variable(ScriptFrame& frame, const String& name, const DebugInfo& debugInfo = DebugInfo())
	{
		Value value;
		if (frame.Locals && frame.Locals->Get(name, &value))
			return value;
		else if (frame.Self.IsObject() && frame.Locals != static_cast<Object::Ptr>(frame.Self) && HasField(frame.Self, name))
			return GetField(frame.Self, name, debugInfo);
		else
			return ScriptGlobal::Get(name);
	}

	static inline Value CopyConstructorCall(const Type::Ptr& type, const Value& value, const DebugInfo& debugInfo = DebugInfo())
	{
		if (type->GetName() == "String")
			return Convert::ToString(value);
		else if (type->GetName() == "Number")
			return Convert::ToDouble(value);
		else if (type->GetName() == "Boolean")
			return Convert::ToBool(value);
		else if (!type->IsAssignableFrom(value.GetReflectionType()))
			BOOST_THROW_EXCEPTION(ScriptError("Invalid cast: Tried to cast object of type '" + value.GetReflectionType()->GetName() + "' to type '" + type->GetName() + "'", debugInfo));
		else
			return value;
	}

	static inline Value ConstructorCall(const Type::Ptr& type, const DebugInfo& debugInfo = DebugInfo())
	{
		if (type->GetName() == "String")
			return "";
		else if (type->GetName() == "Number")
			return 0;
		else if (type->GetName() == "Boolean")
			return false;
		else {
			Object::Ptr object = type->Instantiate();

			if (!object)
				BOOST_THROW_EXCEPTION(ScriptError("Failed to instantiate object of type '" + type->GetName() + "'", debugInfo));

			return object;
		}
	}

	static inline Value FunctionCall(ScriptFrame& frame, const Value& self, const Function::Ptr& func, const std::vector<Value>& arguments)
	{
		ScriptFrame vframe;
		
		if (!self.IsEmpty())
			vframe.Self = self;

		return func->Invoke(arguments);
	}

	static inline Value NewFunction(ScriptFrame& frame, const std::vector<String>& args,
	    std::map<String, Expression *> *closedVars, const boost::shared_ptr<Expression>& expression)
	{
		return new Function(boost::bind(&FunctionWrapper, _1, args,
		    EvaluateClosedVars(frame, closedVars), expression));
	}

	static inline Value NewApply(ScriptFrame& frame, const String& type, const String& target, const String& name, const boost::shared_ptr<Expression>& filter,
		const String& module, const String& fkvar, const String& fvvar, const boost::shared_ptr<Expression>& fterm, std::map<String, Expression *> *closedVars,
		const boost::shared_ptr<Expression>& expression, const DebugInfo& debugInfo = DebugInfo())
	{
		ApplyRule::AddRule(type, target, name, expression, filter, module, fkvar,
		    fvvar, fterm, debugInfo, EvaluateClosedVars(frame, closedVars));

		return Empty;
	}

	static inline Value NewObject(ScriptFrame& frame, bool abstract, const String& type, const String& name, const boost::shared_ptr<Expression>& filter,
		const String& zone, const String& module, std::map<String, Expression *> *closedVars, const boost::shared_ptr<Expression>& expression, const DebugInfo& debugInfo = DebugInfo())
	{
		ConfigItemBuilder::Ptr item = new ConfigItemBuilder(debugInfo);

		String checkName = name;

		if (!abstract) {
			Type::Ptr ptype = Type::GetByName(type);

			NameComposer *nc = dynamic_cast<NameComposer *>(ptype.get());

			if (nc)
				checkName = nc->MakeName(name, Dictionary::Ptr());
		}

		if (!checkName.IsEmpty()) {
			ConfigItem::Ptr oldItem = ConfigItem::GetObject(type, checkName);

			if (oldItem) {
				std::ostringstream msgbuf;
				msgbuf << "Object '" << name << "' of type '" << type << "' re-defined: " << debugInfo << "; previous definition: " << oldItem->GetDebugInfo();
				BOOST_THROW_EXCEPTION(ScriptError(msgbuf.str(), debugInfo));
			}
		}

		item->SetType(type);
		item->SetName(name);

		item->AddExpression(new OwnedExpression(expression));
		item->SetAbstract(abstract);
		item->SetScope(EvaluateClosedVars(frame, closedVars));
		item->SetZone(zone);
		item->SetModule(module);
		item->SetFilter(filter);
		item->Compile()->Register();

		return Empty;
	}

	static inline ExpressionResult For(ScriptFrame& frame, const String& fkvar, const String& fvvar, const Value& value, Expression *expression, const DebugInfo& debugInfo = DebugInfo())
	{
		if (value.IsObjectType<Array>()) {
			if (!fvvar.IsEmpty())
				BOOST_THROW_EXCEPTION(ScriptError("Cannot use dictionary iterator for array.", debugInfo));

			Array::Ptr arr = value;

			for (Array::SizeType i = 0; i < arr->GetLength(); i++) {
				frame.Locals->Set(fkvar, arr->Get(i));
				ExpressionResult res = expression->Evaluate(frame);
				CHECK_RESULT_LOOP(res);
			}
		} else if (value.IsObjectType<Dictionary>()) {
			if (fvvar.IsEmpty())
				BOOST_THROW_EXCEPTION(ScriptError("Cannot use array iterator for dictionary.", debugInfo));

			Dictionary::Ptr dict = value;
			std::vector<String> keys;

			{
				ObjectLock olock(dict);
				BOOST_FOREACH(const Dictionary::Pair& kv, dict) {
					keys.push_back(kv.first);
				}
			}

			BOOST_FOREACH(const String& key, keys) {
				frame.Locals->Set(fkvar, key);
				frame.Locals->Set(fvvar, dict->Get(key));
				ExpressionResult res = expression->Evaluate(frame);
				CHECK_RESULT_LOOP(res);
			}
		} else
			BOOST_THROW_EXCEPTION(ScriptError("Invalid type in for expression: " + value.GetTypeName(), debugInfo));

		return Empty;
	}

	static inline bool HasField(const Object::Ptr& context, const String& field)
	{
		Dictionary::Ptr dict = dynamic_pointer_cast<Dictionary>(context);

		if (dict)
			return dict->Contains(field);
		else {
			Type::Ptr type = context->GetReflectionType();

			if (!type)
				return false;

			return type->GetFieldId(field) != -1;
		}
	}

	static inline Value GetPrototypeField(const Value& context, const String& field, bool not_found_error = true, const DebugInfo& debugInfo = DebugInfo())
	{
		Type::Ptr ctype = context.GetReflectionType();
		Type::Ptr type = ctype;

		do {
			Object::Ptr object = type->GetPrototype();

			if (object && HasField(object, field))
				return GetField(object, field, debugInfo);

			type = type->GetBaseType();
		} while (type);

		if (not_found_error)
			BOOST_THROW_EXCEPTION(ScriptError("Invalid field access (for value of type '" + ctype->GetName() + "'): '" + field + "'", debugInfo));
		else
			return Empty;
	}

	static inline Value GetField(const Value& context, const String& field, const DebugInfo& debugInfo = DebugInfo())
	{
		if (context.IsEmpty())
			return Empty;

		if (!context.IsObject())
			return GetPrototypeField(context, field, true, debugInfo);

		Object::Ptr object = context;

		Dictionary::Ptr dict = dynamic_pointer_cast<Dictionary>(object);

		if (dict) {
			Value value;
			if (dict->Get(field, &value))
				return value;
			else
				return GetPrototypeField(context, field, false, debugInfo);
		}

		Array::Ptr arr = dynamic_pointer_cast<Array>(object);

		if (arr) {
			int index;

			try {
				index = Convert::ToLong(field);
			} catch (...) {
				return GetPrototypeField(context, field, true, debugInfo);
			}

			if (index < 0 || index >= arr->GetLength())
				BOOST_THROW_EXCEPTION(ScriptError("Array index '" + Convert::ToString(index) + "' is out of bounds.", debugInfo));

			return arr->Get(index);
		}

		Type::Ptr type = object->GetReflectionType();

		if (!type)
			return Empty;

		int fid = type->GetFieldId(field);

		if (fid == -1)
			return GetPrototypeField(context, field, true, debugInfo);

		return object->GetField(fid);
	}

	static inline void SetField(const Object::Ptr& context, const String& field, const Value& value, const DebugInfo& debugInfo = DebugInfo())
	{
		if (!context)
			BOOST_THROW_EXCEPTION(ScriptError("Cannot set field '" + field + "' on a value that is not an object.", debugInfo));

		Dictionary::Ptr dict = dynamic_pointer_cast<Dictionary>(context);

		if (dict) {
			dict->Set(field, value);
			return;
		}

		Array::Ptr arr = dynamic_pointer_cast<Array>(context);

		if (arr) {
			int index = Convert::ToLong(field);
			if (index >= arr->GetLength())
				arr->Resize(index + 1);
			arr->Set(index, value);
			return;
		}

		Type::Ptr type = context->GetReflectionType();

		if (!type)
			BOOST_THROW_EXCEPTION(ScriptError("Cannot set field on object.", debugInfo));

		int fid = type->GetFieldId(field);

		if (fid == -1)
			BOOST_THROW_EXCEPTION(ScriptError("Attribute '" + field + "' does not exist.", debugInfo));

		try {
			context->SetField(fid, value);
		} catch (const boost::bad_lexical_cast&) {
			Field fieldInfo = type->GetFieldInfo(fid);
			Type::Ptr ftype = Type::GetByName(fieldInfo.TypeName);
			BOOST_THROW_EXCEPTION(ScriptError("Attribute '" + field + "' cannot be set to value of type '" + value.GetTypeName() + "', expected '" + ftype->GetName() + "'", debugInfo));
		} catch (const std::bad_cast&) {
			Field fieldInfo = type->GetFieldInfo(fid);
			Type::Ptr ftype = Type::GetByName(fieldInfo.TypeName);
			BOOST_THROW_EXCEPTION(ScriptError("Attribute '" + field + "' cannot be set to value of type '" + value.GetTypeName() + "', expected '" + ftype->GetName() + "'", debugInfo));
		}
	}

private:
	static inline Value FunctionWrapper(const std::vector<Value>& arguments,
	    const std::vector<String>& funcargs, const Dictionary::Ptr& closedVars, const boost::shared_ptr<Expression>& expr)
	{
		if (arguments.size() < funcargs.size())
			BOOST_THROW_EXCEPTION(std::invalid_argument("Too few arguments for function"));

		ScriptFrame *frame = ScriptFrame::GetCurrentFrame();

		if (closedVars)
			closedVars->CopyTo(frame->Locals);

		for (std::vector<Value>::size_type i = 0; i < std::min(arguments.size(), funcargs.size()); i++)
			frame->Locals->Set(funcargs[i], arguments[i]);

		return expr->Evaluate(*frame);
	}

	static inline Dictionary::Ptr EvaluateClosedVars(ScriptFrame& frame, std::map<String, Expression *> *closedVars)
	{
		Dictionary::Ptr locals;

		if (closedVars) {
			locals = new Dictionary();

			typedef std::pair<String, Expression *> ClosedVar;
			BOOST_FOREACH(const ClosedVar& cvar, *closedVars) {
				locals->Set(cvar.first, cvar.second->Evaluate(frame));
			}
		}

		return locals;
	}
};

}

#endif /* VMOPS_H */