// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

package model

import (
	"sync"

	"github.com/casbin/casbin/v3/util"
	"github.com/casbin/govaluate"
)

// FunctionMap represents the collection of Function.
type FunctionMap struct {
	fns *sync.Map
}

// [string]govaluate.ExpressionFunction

// AddFunction adds an expression function.
func (fm *FunctionMap) AddFunction(name string, function govaluate.ExpressionFunction) {
	fm.fns.LoadOrStore(name, function)
}

// LoadFunctionMap loads an initial function map.
func LoadFunctionMap() FunctionMap {
	fm := &FunctionMap{}
	fm.fns = &sync.Map{}

	fm.AddFunction("keyMatch", util.KeyMatchFunc)
	fm.AddFunction("keyGet", util.KeyGetFunc)
	fm.AddFunction("keyMatch2", util.KeyMatch2Func)
	fm.AddFunction("keyGet2", util.KeyGet2Func)
	fm.AddFunction("keyMatch3", util.KeyMatch3Func)
	fm.AddFunction("keyGet3", util.KeyGet3Func)
	fm.AddFunction("keyMatch4", util.KeyMatch4Func)
	fm.AddFunction("keyMatch5", util.KeyMatch5Func)
	fm.AddFunction("regexMatch", util.RegexMatchFunc)
	fm.AddFunction("ipMatch", util.IPMatchFunc)
	fm.AddFunction("globMatch", util.GlobMatchFunc)

	return *fm
}

// GetFunctions return a map with all the functions.
func (fm *FunctionMap) GetFunctions() map[string]govaluate.ExpressionFunction {
	ret := make(map[string]govaluate.ExpressionFunction)

	fm.fns.Range(func(k interface{}, v interface{}) bool {
		ret[k.(string)] = v.(govaluate.ExpressionFunction)
		return true
	})

	return ret
}