/******************************************************************************
 * Icinga 2                                                                   *
 * Copyright (C) 2012-2016 Icinga Development Team (https://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 "icinga/macroprocessor.hpp"
#include "icinga/macroresolver.hpp"
#include "icinga/customvarobject.hpp"
#include "base/array.hpp"
#include "base/objectlock.hpp"
#include "base/logger.hpp"
#include "base/context.hpp"
#include "base/configobject.hpp"
#include "base/scriptframe.hpp"
#include "base/convert.hpp"
#include "base/exception.hpp"
#include <boost/assign.hpp>
#include <boost/foreach.hpp>
#include <boost/algorithm/string/split.hpp>
#include <boost/algorithm/string/join.hpp>
#include <boost/algorithm/string/classification.hpp>

using namespace icinga;

Value MacroProcessor::ResolveMacros(const Value& str, const ResolverList& resolvers,
    const CheckResult::Ptr& cr, String *missingMacro,
    const MacroProcessor::EscapeCallback& escapeFn, const Dictionary::Ptr& resolvedMacros,
    bool useResolvedMacros, int recursionLevel)
{
	Value result;

	if (str.IsEmpty())
		return Empty;

	if (str.IsScalar()) {
		result = InternalResolveMacros(str, resolvers, cr, missingMacro, escapeFn,
		    resolvedMacros, useResolvedMacros, recursionLevel + 1);
	} else if (str.IsObjectType<Array>()) {
		Array::Ptr resultArr = new Array();
		Array::Ptr arr = str;

		ObjectLock olock(arr);

		BOOST_FOREACH(const Value& arg, arr) {
			/* Note: don't escape macros here. */
			Value value = InternalResolveMacros(arg, resolvers, cr, missingMacro,
			    EscapeCallback(), resolvedMacros, useResolvedMacros, recursionLevel + 1);

			if (value.IsObjectType<Array>())
				resultArr->Add(Utility::Join(value, ';'));
			else
				resultArr->Add(value);
		}

		result = resultArr;
	} else if (str.IsObjectType<Dictionary>()) {
		Dictionary::Ptr resultDict = new Dictionary();
		Dictionary::Ptr dict = str;

		ObjectLock olock(dict);

		BOOST_FOREACH(const Dictionary::Pair& kv, dict) {
			/* Note: don't escape macros here. */
			resultDict->Set(kv.first, InternalResolveMacros(kv.second, resolvers, cr, missingMacro,
			    EscapeCallback(), resolvedMacros, useResolvedMacros, recursionLevel + 1));
		}

		result = resultDict;
	} else if (str.IsObjectType<Function>()) {
		result = EvaluateFunction(str, resolvers, cr, escapeFn, resolvedMacros, useResolvedMacros, 0);
	} else {
		BOOST_THROW_EXCEPTION(std::invalid_argument("Macro is not a string or array."));
	}

	return result;
}

bool MacroProcessor::ResolveMacro(const String& macro, const ResolverList& resolvers,
    const CheckResult::Ptr& cr, Value *result, bool *recursive_macro)
{
	CONTEXT("Resolving macro '" + macro + "'");

	*recursive_macro = false;

	std::vector<String> tokens;
	boost::algorithm::split(tokens, macro, boost::is_any_of("."));

	String objName;
	if (tokens.size() > 1) {
		objName = tokens[0];
		tokens.erase(tokens.begin());
	}

	BOOST_FOREACH(const ResolverSpec& resolver, resolvers) {
		if (!objName.IsEmpty() && objName != resolver.first)
			continue;

		if (objName.IsEmpty()) {
			CustomVarObject::Ptr dobj = dynamic_pointer_cast<CustomVarObject>(resolver.second);

			if (dobj) {
				Dictionary::Ptr vars = dobj->GetVars();

				if (vars && vars->Contains(macro)) {
					*result = vars->Get(macro);
					*recursive_macro = true;
					return true;
				}
			}
		}

		MacroResolver *mresolver = dynamic_cast<MacroResolver *>(resolver.second.get());

		if (mresolver && mresolver->ResolveMacro(boost::algorithm::join(tokens, "."), cr, result))
			return true;

		Value ref = resolver.second;
		bool valid = true;

		BOOST_FOREACH(const String& token, tokens) {
			if (ref.IsObjectType<Dictionary>()) {
				Dictionary::Ptr dict = ref;
				if (dict->Contains(token)) {
					ref = dict->Get(token);
					continue;
				} else {
					valid = false;
					break;
				}
			} else if (ref.IsObject()) {
				Object::Ptr object = ref;

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

				if (!type) {
					valid = false;
					break;
				}

				int field = type->GetFieldId(token);

				if (field == -1) {
					valid = false;
					break;
				}

				ref = object->GetField(field);
			}
		}

		if (valid) {
			if (tokens[0] == "vars" ||
			    tokens[0] == "action_url" ||
			    tokens[0] == "notes_url" ||
			    tokens[0] == "notes")
				*recursive_macro = true;

			*result = ref;
			return true;
		}
	}

	return false;
}

Value MacroProcessor::InternalResolveMacrosShim(const std::vector<Value>& args, const ResolverList& resolvers,
    const CheckResult::Ptr& cr, const MacroProcessor::EscapeCallback& escapeFn, const Dictionary::Ptr& resolvedMacros,
    bool useResolvedMacros, int recursionLevel)
{
	if (args.size() < 1)
		BOOST_THROW_EXCEPTION(std::invalid_argument("Too few arguments for function"));

	String missingMacro;

	return MacroProcessor::InternalResolveMacros(args[0], resolvers, cr, &missingMacro, escapeFn,
	    resolvedMacros, useResolvedMacros, recursionLevel);
}

Value MacroProcessor::InternalResolveArgumentsShim(const std::vector<Value>& args, const ResolverList& resolvers,
    const CheckResult::Ptr& cr, const Dictionary::Ptr& resolvedMacros,
    bool useResolvedMacros, int recursionLevel)
{
	if (args.size() < 2)
		BOOST_THROW_EXCEPTION(std::invalid_argument("Too few arguments for function"));

	return MacroProcessor::ResolveArguments(args[0], args[1], resolvers, cr,
	    resolvedMacros, useResolvedMacros, recursionLevel);
}

Value MacroProcessor::EvaluateFunction(const Function::Ptr& func, const ResolverList& resolvers,
    const CheckResult::Ptr& cr, const MacroProcessor::EscapeCallback& escapeFn,
    const Dictionary::Ptr& resolvedMacros, bool useResolvedMacros, int recursionLevel)
{
	Dictionary::Ptr resolvers_this = new Dictionary();

	BOOST_FOREACH(const ResolverSpec& resolver, resolvers) {
		resolvers_this->Set(resolver.first, resolver.second);
	}

	resolvers_this->Set("macro", new Function(boost::bind(&MacroProcessor::InternalResolveMacrosShim,
	    _1, boost::cref(resolvers), cr, MacroProcessor::EscapeCallback(), resolvedMacros, useResolvedMacros,
	    recursionLevel + 1)));
	resolvers_this->Set("resolve_arguments", new Function(boost::bind(&MacroProcessor::InternalResolveArgumentsShim,
	    _1, boost::cref(resolvers), cr, resolvedMacros, useResolvedMacros,
	    recursionLevel + 1)));

	ScriptFrame frame(resolvers_this);
	return func->Invoke();
}

Value MacroProcessor::InternalResolveMacros(const String& str, const ResolverList& resolvers,
    const CheckResult::Ptr& cr, String *missingMacro,
    const MacroProcessor::EscapeCallback& escapeFn, const Dictionary::Ptr& resolvedMacros,
    bool useResolvedMacros, int recursionLevel)
{
	CONTEXT("Resolving macros for string '" + str + "'");

	if (recursionLevel > 15)
		BOOST_THROW_EXCEPTION(std::runtime_error("Infinite recursion detected while resolving macros"));

	size_t offset, pos_first, pos_second;
	offset = 0;

	Dictionary::Ptr resolvers_this;

	String result = str;
	while ((pos_first = result.FindFirstOf("$", offset)) != String::NPos) {
		pos_second = result.FindFirstOf("$", pos_first + 1);

		if (pos_second == String::NPos)
			BOOST_THROW_EXCEPTION(std::runtime_error("Closing $ not found in macro format string."));

		String name = result.SubStr(pos_first + 1, pos_second - pos_first - 1);

		Value resolved_macro;
		bool recursive_macro;
		bool found;

		if (useResolvedMacros) {
			recursive_macro = false;
			found = resolvedMacros->Contains(name);

			if (found)
				resolved_macro = resolvedMacros->Get(name);
		} else
			found = ResolveMacro(name, resolvers, cr, &resolved_macro, &recursive_macro);

		/* $$ is an escape sequence for $. */
		if (name.IsEmpty()) {
			resolved_macro = "$";
			found = true;
		}

		if (resolved_macro.IsObjectType<Function>()) {
			resolved_macro = EvaluateFunction(resolved_macro, resolvers, cr, escapeFn,
			    resolvedMacros, useResolvedMacros, recursionLevel + 1);
		}

		if (!found) {
			if (!missingMacro)
				Log(LogWarning, "MacroProcessor")
				    << "Macro '" << name << "' is not defined.";
			else
				*missingMacro = name;
		}

		/* recursively resolve macros in the macro if it was a user macro */
		if (recursive_macro) {
			if (resolved_macro.IsObjectType<Array>()) {
				Array::Ptr arr = resolved_macro;
				Array::Ptr resolved_arr = new Array();

				ObjectLock olock(arr);
				BOOST_FOREACH(const Value& value, arr) {
					if (value.IsScalar()) {
						resolved_arr->Add(InternalResolveMacros(value,
							resolvers, cr, missingMacro, EscapeCallback(), Dictionary::Ptr(),
							false, recursionLevel + 1));
					} else
						resolved_arr->Add(value);
				}

				resolved_macro = resolved_arr;
			} else if (resolved_macro.IsString()) {
				resolved_macro = InternalResolveMacros(resolved_macro,
					resolvers, cr, missingMacro, EscapeCallback(), Dictionary::Ptr(),
					false, recursionLevel + 1);
			}
		}

		if (!useResolvedMacros && found && resolvedMacros)
			resolvedMacros->Set(name, resolved_macro);

		if (escapeFn)
			resolved_macro = escapeFn(resolved_macro);

		/* we're done if this is the only macro and there are no other non-macro parts in the string */
		if (pos_first == 0 && pos_second == str.GetLength() - 1)
			return resolved_macro;
		else if (resolved_macro.IsObjectType<Array>())
				BOOST_THROW_EXCEPTION(std::invalid_argument("Mixing both strings and non-strings in macros is not allowed."));

		if (resolved_macro.IsObjectType<Array>()) {
			/* don't allow mixing strings and arrays in macro strings */
			if (pos_first != 0 || pos_second != str.GetLength() - 1)
				BOOST_THROW_EXCEPTION(std::invalid_argument("Mixing both strings and non-strings in macros is not allowed."));

			return resolved_macro;
		}

		String resolved_macro_str = resolved_macro;

		result.Replace(pos_first, pos_second - pos_first + 1, resolved_macro_str);
		offset = pos_first + resolved_macro_str.GetLength();
	}

	return result;
}


bool MacroProcessor::ValidateMacroString(const String& macro)
{
	if (macro.IsEmpty())
		return true;

	size_t pos_first, pos_second, offset;
	offset = 0;

	while ((pos_first = macro.FindFirstOf("$", offset)) != String::NPos) {
		pos_second = macro.FindFirstOf("$", pos_first + 1);

		if (pos_second == String::NPos)
			return false;

		offset = pos_second + 1;
	}

	return true;
}

void MacroProcessor::ValidateCustomVars(const ConfigObject::Ptr& object, const Dictionary::Ptr& value)
{
	if (!value)
		return;

	/* string, array, dictionary */
	ObjectLock olock(value);
	BOOST_FOREACH(const Dictionary::Pair& kv, value) {
		const Value& varval = kv.second;

		if (varval.IsObjectType<Dictionary>()) {
			/* only one dictonary level */
			Dictionary::Ptr varval_dict = varval;

			ObjectLock xlock(varval_dict);
			BOOST_FOREACH(const Dictionary::Pair& kv_var, varval_dict) {
				if (!kv_var.second.IsString())
					continue;

				if (!ValidateMacroString(kv_var.second))
					BOOST_THROW_EXCEPTION(ValidationError(object.get(), boost::assign::list_of<String>("vars")(kv.first)(kv_var.first), "Closing $ not found in macro format string '" + kv_var.second + "'."));
			}
		} else if (varval.IsObjectType<Array>()) {
			/* check all array entries */
			Array::Ptr varval_arr = varval;

			ObjectLock ylock (varval_arr);
			BOOST_FOREACH(const Value& arrval, varval_arr) {
				if (!arrval.IsString())
					continue;

				if (!ValidateMacroString(arrval)) {
					BOOST_THROW_EXCEPTION(ValidationError(object.get(), boost::assign::list_of<String>("vars")(kv.first), "Closing $ not found in macro format string '" + arrval + "'."));
				}
			}
		} else {
			if (!varval.IsString())
				continue;

			if (!ValidateMacroString(varval))
				BOOST_THROW_EXCEPTION(ValidationError(object.get(), boost::assign::list_of<String>("vars")(kv.first), "Closing $ not found in macro format string '" + varval + "'."));
		}
	}
}

void MacroProcessor::AddArgumentHelper(const Array::Ptr& args, const String& key, const String& value,
    bool add_key, bool add_value)
{
	if (add_key)
		args->Add(key);

	if (add_value)
		args->Add(value);
}

Value MacroProcessor::EscapeMacroShellArg(const Value& value)
{
	String result;

	if (value.IsObjectType<Array>()) {
		Array::Ptr arr = value;

		ObjectLock olock(arr);
		BOOST_FOREACH(const Value& arg, arr) {
			if (result.GetLength() > 0)
				result += " ";

			result += Utility::EscapeShellArg(arg);
		}
	} else
		result = Utility::EscapeShellArg(value);

	return result;
}

struct CommandArgument
{
	int Order;
	bool SkipKey;
	bool RepeatKey;
	bool SkipValue;
	String Key;
	Value AValue;

	CommandArgument(void)
		: Order(0), SkipKey(false), RepeatKey(true), SkipValue(false)
	{ }

	bool operator<(const CommandArgument& rhs) const
	{
		return Order < rhs.Order;
	}
};

Value MacroProcessor::ResolveArguments(const Value& command, const Dictionary::Ptr& arguments,
    const MacroProcessor::ResolverList& resolvers, const CheckResult::Ptr& cr,
    const Dictionary::Ptr& resolvedMacros, bool useResolvedMacros, int recursionLevel)
{
	Value resolvedCommand;
	if (!arguments || command.IsObjectType<Array>() || command.IsObjectType<Function>())
		resolvedCommand = MacroProcessor::ResolveMacros(command, resolvers, cr, NULL,
		    EscapeMacroShellArg, resolvedMacros, useResolvedMacros, recursionLevel + 1);
	else {
		Array::Ptr arr = new Array();
		arr->Add(command);
		resolvedCommand = arr;
	}

	if (arguments) {
		std::vector<CommandArgument> args;

		ObjectLock olock(arguments);
		BOOST_FOREACH(const Dictionary::Pair& kv, arguments) {
			const Value& arginfo = kv.second;

			CommandArgument arg;
			arg.Key = kv.first;

			bool required = false;
			Value argval;

			if (arginfo.IsObjectType<Dictionary>()) {
				Dictionary::Ptr argdict = arginfo;
				if (argdict->Contains("key"))
					arg.Key = argdict->Get("key");
				argval = argdict->Get("value");
				if (argdict->Contains("required"))
					required = argdict->Get("required");
				arg.SkipKey = argdict->Get("skip_key");
				if (argdict->Contains("repeat_key"))
					arg.RepeatKey = argdict->Get("repeat_key");
				arg.Order = argdict->Get("order");

				Value set_if = argdict->Get("set_if");

				if (!set_if.IsEmpty()) {
					String missingMacro;
					Value set_if_resolved = MacroProcessor::ResolveMacros(set_if, resolvers,
					    cr, &missingMacro, MacroProcessor::EscapeCallback(), resolvedMacros,
					    useResolvedMacros, recursionLevel + 1);

					if (!missingMacro.IsEmpty())
						continue;

					int value;

					if (set_if_resolved == "true")
						value = 1;
					else if (set_if_resolved == "false")
						value = 0;
					else {
						try {
							value = Convert::ToLong(set_if_resolved);
						} catch (const std::exception& ex) {
							/* tried to convert a string */
							Log(LogWarning, "PluginUtility")
							    << "Error evaluating set_if value '" << set_if_resolved << "': " << ex.what();
							continue;
						}
					}

					if (!value)
						continue;
				}
			}
			else
				argval = arginfo;

			if (argval.IsEmpty())
				arg.SkipValue = true;

			String missingMacro;
			arg.AValue = MacroProcessor::ResolveMacros(argval, resolvers,
			    cr, &missingMacro, MacroProcessor::EscapeCallback(), resolvedMacros,
			    useResolvedMacros, recursionLevel + 1);

			if (!missingMacro.IsEmpty()) {
				if (required) {
					BOOST_THROW_EXCEPTION(ScriptError("Non-optional macro '" + missingMacro + "' used in argument '" +
					    arg.Key + "' is missing."));
				}

				continue;
			}

			args.push_back(arg);
		}

		std::sort(args.begin(), args.end());

		Array::Ptr command_arr = resolvedCommand;
		BOOST_FOREACH(const CommandArgument& arg, args) {

			if (arg.AValue.IsObjectType<Dictionary>()) {
				Log(LogWarning, "PluginUtility", "Tried to use dictionary in argument");
				continue;
			} else if (arg.AValue.IsObjectType<Array>()) {
				bool first = true;
				Array::Ptr arr = static_cast<Array::Ptr>(arg.AValue);

				ObjectLock olock(arr);
				BOOST_FOREACH(const Value& value, arr) {
					bool add_key;

					if (first) {
						first = false;
						add_key = !arg.SkipKey;
					} else
						add_key = !arg.SkipKey && arg.RepeatKey;

					AddArgumentHelper(command_arr, arg.Key, value, add_key, !arg.SkipValue);
				}
			} else
				AddArgumentHelper(command_arr, arg.Key, arg.AValue, !arg.SkipKey, !arg.SkipValue);
		}
	}

	return resolvedCommand;
}

